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midlife
06-07-2009, 09:44 AM
Can a Phase Linear 700 power amp comfortably operate at a four ohm load? Haven't seen much mentioned about these amps, are they desireable and good performers? Are they compatible with different preamps? :bouncy:

SEAWOLF97
06-07-2009, 10:49 AM
Can a Phase Linear 700 power amp comfortably operate at a four ohm load? Haven't seen much mentioned about these amps, are they desireable and good performers? Are they compatible with different preamps? :bouncy:

Commonly referred as "Flame Linear" or "Fuse Linear" for their ability to catch fire while driving a low ohm load ..

My "other good vintage" speakers are 3 ohm OHMs. When I emailed tech support , the company president answered....He SPECIFICALLY told me NOT to use PL amps with his product as they have been the base for many failures in the past.

http://www.audiokarma.org/forums/showthread.php?t=123724

Phase Linear 700 series amps have some significant technicall differences depending on what exact model and when manufactured.

Last I knew there was a factory trained tech or engineer in the Washington State area that services and reconditions these.

These amps can sound very good and have a lot of current.

They CANNOT be abused or allowed to run hot.

The entire PL line from this era has earned a reputation for being tempramental and unreliable (with good reason).

The rudimentary protection circuits are faulty by design and they DO NOT WORK. In the event the amp fails and goes DC there is enough power and current to form a significant FIRE HAZARD.

Because of this, these amps earned nicknames such as 'Flame Linear' and 'Blaze Linear'

I understand that this amp was the brainchild of engineer Bob Carver and one of his first commercial successes.

I used to use 3 of these in commercial applications along with a couple of 400s all through the 80's and finally retired them in the 1998.

Careful as I am , I had a 400 go up in smoke on me just sitting there idling one day in a monitor application. These are delicate and fragfile amps despite their tough looks.

I think $500 is high unless it was recently reconditioned by a qualified tech experienced with the speicific issues these units had.

It is your choice - if you buy it you will probably become a fan.

whatever you decide, enjoy!

http://www.talkbass.com/forum/archive/index.php/t-515095.html

There are a multitude of amps that are smaller, lighter, better sounding and more reliable than the old Flame Linears. I had 3 400's years ago and all passed DC voltage at one time or another. I have a couple of Crest 7001s that are killer amps. YMMV, of course.

That made me lol!

Actually years ago I had a Phase Linear amp I was using with Roland pre and it DID flame out!

In the middle of a song all of a sudden there was no bass. When I turned around there were flames coming from in between the amp and pre. It went out when I yanked the plug from the wall though.!
62bass
02-09-2009, 02:38 AM

I too have had experience with a new Phase Linear amp going D.C. and destroying several JBL speakers.

hrgiger
02-09-2009, 07:49 AM

Okay this doesn't sound good, flaming linears and all, could you guys who had this problem mention whether you had your amps bridged at all or not? I read a reference to the amps being bridged but I'm not even sure if that's possible (w/ or w/out modification.) Also do you recall what ohm cabs you were running? I read about fuses blowing with 4 ohm loads with bench test signals...

xbassmanx
02-09-2009, 09:00 AM

Okay this doesn't sound good, flaming linears and all, could you guys who had this problem mention whether you had your amps bridged at all or not? I read a reference to the amps being bridged but I'm not even sure if that's possible (w/ or w/out modification.) Also do you recall what ohm cabs you were running? I read about fuses blowing with 4 ohm loads with bench test signals...

I was running one side @ 4 ohms when mine flamed out.

and from one of our members:
http://www.audioheritage.org/vbulletin/showpost.php?p=212198&postcount=7

Couldn't help it, sorry!:) All of the Fail Liners seemed to reach a point of un-stability sooner or later...700's and 700B's could take out twice as many speakers as a 400. Maybe the home stereo models like you are looking for had enough protection circuits added to make them safer. When we used to use them, they'd be an amplifier one day, smoke show the next. Those 700B's did sound really good, and made plenty of horsepower! Tim

midlife
06-07-2009, 11:08 AM
[quote=SEAWOLF97;254620]Commonly referred as "Flame Linear" or "Fuse Linear" for their ability to catch fire while driving a low ohm load ..

Yikes :(

robertbartsch
06-08-2009, 10:41 AM
Amp technology has come a long way so I make a habit of avoiding old electronics - it is just not worth it for me.

jcrobso
06-08-2009, 11:10 AM
That was about 15 years ago, 700B ran without problems into 4 ohms, both channels driven. I met Bob Carver shortly after that amp come out, very interesting guy.
Yes, when working good it is a great amp. However today I would use QSC or Crown.

jerry_rig
06-08-2009, 08:44 PM
I think we used to call them Fuzz Linear.

I bought the top line PL preamp in the mid '70s and returned it immediately. It was unlistenable. I settled for a Harmon Kardon Citation 11 instead.

Old curmudgeon
06-09-2009, 07:25 AM
I can easily recommend the use of a vintage Crown Power Amp. I have used DC300AIIs, Power Line Fours and PS-400s with nary a problem for many years.

They are very stable, rugged and sound very clean. DC300AIIs are available at reasonable prices and make a lot of clean power.

There are those that say the bad reputation for the PLs is not deserved and cite examples of how they've never had any trouble or that once certain items were fixed or modified, everything was OK. Check the "street reputation" for both PL and Crown and make your decision.

I have been running Crowns with JBLs for 25 years with no problems ever!

midlife
06-09-2009, 07:55 AM
I have been running Crowns with JBLs for 25 years with no problems ever![/quote]
My previous set up was a DC300 with L300s and I thought it worked very well. Had no experience with the Phases so was a bit curious about them.

scott fitlin
06-09-2009, 09:35 AM
I have been running Crowns with JBLs for 25 years with no problems ever!
My previous set up was a DC300 with L300s and I thought it worked very well. Had no experience with the Phases so was a bit curious about them.[/QUOTE]I have been using Crown DC-300A,s since 1977, and have had amps fail, on the job, but never took the load with them.

Today, I still use one DC-300A on my six JBL 2395/2441H, and came back to this amp last year, while overhauling my system, and I had a McIntosh 2125, a Bryston 3B SST, a BGWS 350A, and I even tried a high end McKormack amplifier. Endeavoring to upgrade to higher power levels, AND superior sonic results, I ran this gamut of amps, to replace my tried and true D-150A, and after tiring for one reason or another, I threw the DC-300A on the horns, and VOILA! THIS IS STILL THE SOUND FOR ME! The D-150A,s went up to the tweeters, replacing my Power Line 2,s, and I put my PSA-2,s on 15,s and all was well. NEW Crowns and one big QSC Powerlight 6.0 on subs.

About Phase linear? Well, all the years, everyone called them everything already mentioned here. I never really had much experience with them, except that I knew many guys who loved PL! In the early 1990,s I was working several clubs on Miami Beach as a DJ! One club, always had gear that looked like it came straight from an Audio Rummage sale. I went to work one thursday evening, i was one of three DJ,s for that night, and when I got to the club the tech was all excited, he had a Phase LINEAR 700B, and he was going to show me how this thing puts a Crown to bed! He was a PL freak. The 700B was driving a pair of JBL 2225H woofers in the booth monitor system, and it didn't sound bad, definitely had some oomph to it. I was the 3rd DJ in the nights lineup, and the 2nd DJ was playing, and pushing the booth monitors hard. We were in the booth around 1AM, and all of a sudden, one 2225 made a loud cracking noise, and I watched that woofers dust cap literally shoot off the cone, and a burst of flame and sparks fly out from the gap area. Like a muzzle flash from a rifle! The amp went to heaven, the 2225 burned to death, and I was going on at 1:30AM with NO monitors!

This is the stuff the sound pros used to tell us about in the 70,s but I had never seen it happen. As I said, I really had no experience with PL! Back at my main gig, The Warsaw Ballroom, our sound people were doing work one afternoon, and I got into a conversation with one tech, and I asked about the PL, and why it did that? As it was explained to me, the 700B had a massive transformer, and it did, but, it's protection circuitry was not the same way Crown did things. The 700B is DEFINITELY a BIGGER amp than a DC-300A, and it will keep putting out as hard as you drive it. OTOH, the DC-300A,s circuitry will not let you drive the amp to this point. Nonetheless, I saw it and heard it with my own eyes and ears.

Sonically, I did not think the 700B was as clean, detailed, or punchy as a DC-300A! The 700B did seem to be more powerful but was strictly brute force, not clean audio. As I said, back in the 70,s, many a story told about PL destroying Gauss woofers, and Gauss was considered pretty indestructible!

Whatever character the PL,s have, to me, is totally offset by the fact that under severe demanding use, they have a habit of self destruction, and taking the load with them. Of course, to be fair, this happens when severely overdriving this amp, BUT, it is this amps overdrive characteristic that everyone I knew that loves them, loves about the 700B!

IMHO, Crown is a superior sounding amplifier, and a MUCH safer amp to operate!

robertbartsch
06-09-2009, 11:59 AM
Wow - great story!

How do you think the 2225 dust cap shot off? Was the VC so hot that it melted the cap glue before it burst into flames? The driver is rear vented; right?

So the amp was dumping DC into the loads?

robertbartsch
06-09-2009, 12:06 PM
...I have an Adcom 200 x 2 amp that was dumping DC into a pair of 4312s. Fortunately, I caught it in time before the tweets got burned.

The amp is 25 years old but I have had trouble with Denons that are less than 10.

The Adcom repair was $250 and that is one reason why I don't plan on puting more dough into old electronics. ...basically, you have invested money in an old amp whose parts could go at any time.

MikeBrewster77
06-09-2009, 12:07 PM
I was working several clubs on Miami Beach as a DJ ... a burst of flame and sparks fly out from the gap area.


Hot club! ;)

SEAWOLF97
06-09-2009, 01:28 PM
I bought big late 80's BGW amps on the advise of some knowledgeable forumites , rock solid, run cool (375 wpc - 8 ohm..450 @ 4 ohms..very stable on low ohm loads) and not a nonosec of trouble ..and a bargain at going rates.

Allanvh5150
06-09-2009, 03:12 PM
Forget Phase Linear grenades and crusty old Crowns. If you want super quality and at very good prices keep an eye out for Perreuax on Ebay. Here is a 2150.

http://cgi.ebay.com/Perreaux-model-PMF-1250-B-power-amlifier-great-condtn_W0QQitemZ290322521130QQcmdZViewItemQQptZLH_ DefaultDomain_0?hash=item4398921c2a&_trksid=p3286.c0.m14&_trkparms=65%3A1%7C66%3A2%7C39%3A1%7C240%3A1318%7C 301%3A1%7C293%3A1%7C294%3A50

300WPC into 8 ohms, 500WPC into 4 ohms and it will pump out about 900W bridged into 8 ohms.

Allan.

Old curmudgeon
06-09-2009, 07:20 PM
Forget Phase Linear grenades and crusty old Crowns. If you want super quality and at very good prices keep an eye out for Perreuax on Ebay.


That's funny! :D

BMWCCA
06-09-2009, 07:22 PM
As long as everyone's just tossing about unsubstantiated opinions—and considering the original poster had been quite happy with his previous Crowns—let me add that I, too, am a happy Crown customer, have been for over 35 years, and still have the first one I ever bought in daily operation. Off the top of my head I believe I have nine Crown components. Any chance I get to buy quality made-in-USA items, I will do it! Believe me those opportunities don't come up very often these days: My last pair of Levi's® 501® jeans were made in Egypt!


Though I will admit, Kiwi makes some damn fine shoe polish! Oh wait. That's made-in-USA, too. ;)

Earl K
06-10-2009, 04:53 AM
- Every Phase Linear 700 I owned ( 3 in total ) dumped DC before they were rebuilt ( electrically & 2 mechanically ) .
- I was lucky because my " magic-smoke mishaps" never burned the traces on the amps puny circuit board ( as was fairly common with severe amp failures ) .
- Therefore, I never had to replace a charred pcb .

- Those amps cost me muchos monies in recones for my Gauss 4882 eighteens ( working in W460 / W151 horn bins ) .
- Muchos $$$ ( in Canada Dollars ) Muchos .

- I never held a grudge against Bob Carver ( for his shortcomings in design/protection chops ) Hell, I still own 8 of his Carver 1.5 amps .

- A Crown 300a was one of my first amps / it was quite underpowed for my usage .

- I still have a single PL700 here on my bench awaiting a chassis rebuild .
- I can't sell it since it's chassis is cracked & broken .
- Being a conservationist at heart / I just can't bring myself to throw away things that might be resurrected into something useful .

>< cheers :)

Allanvh5150
06-10-2009, 05:18 AM
As long as everyone's just tossing about unsubstantiated opinions—and considering the original poster had been quite happy with his previous Crowns—let me add that I, too, am a happy Crown customer, have been for over 35 years, and still have the first one I ever bought in daily operation. Off the top of my head I believe I have nine Crown components. Any chance I get to buy quality made-in-USA items, I will do it! Believe me those opportunities don't come up very often these days: My last pair of Levi's® 501® jeans were made in Egypt!


Though I will admit, Kiwi makes some damn fine shoe polish! Oh wait. That's made-in-USA, too. ;)

Kiwi shoe polish was originally made in Australia by a Scotsman who named the product after his Kiwi wife. But you probably knew that, right? My unsubstantiated opinions seem to concur with the many and I have seen many Phase Linears go up in flames. I have also seen many a Crown with smoke emanating from it. Although I consider the Crown to be head and shoulders above the PL they are not even in the same ballpark as the 80's series amps from Perreaux.

Allan.:)

BMWCCA
06-10-2009, 06:58 AM
My unsubstantiated opinions seem to concur with the many and I have seen many Phase Linears go up in flames. I have also seen many a Crown with smoke emanating from it. Although I consider the Crown to be head and shoulders above the PL they are not even in the same ballpark as the 80's series amps from Perreaux.My point was not to dismiss Perreaux but to simply add to the anecdotal information supplied here. Unsubstantiated is what these opinions are and that's why we call them opinions. Call them "empirical" if you want. For a picture-perfect dictionary definition of "unsubstantiated" look no further than this claim made on the Perreaux website itself:
In the entire history of Perreaux and after the sale of many thousands of units, warranty claims have been virtually nil.It's also easy to over-state power outputs. And that Perreaux model listed in your Ebay link as 700-watts is rated by the manufacturer at 200wpc @ 8-ohms. No one's denying that the 2105 is a good value at $500 and they've been trading at or around that number on Ebay for a while. I'd try one out if there was one near me. I love New Zealand, understand your patriotic support of its products, and hope to visit some day!

Anyone have a Perreaux they want to put in the next Mid-Atlantic JBL speaker shootout? ;) All I can tell you is I have two PS-400 Crowns I spent a total of $300 for that sound and work great with my L7s, L5s, L96, and L80Ts. Currently my 4345s are running bi-amped with a Crown D150A-II I bought when it was one-year-old, and a DC300A-II I bought out of a movie theater renovation on Ebay probably ten years ago. Sounds great to me, but then that, too, is simply empirical evidence. I know there are many here running Crowns and I don't recall any flame-out stories. We run MacroTechs all day and night long, outside in the heat of summer, pushing 1 and 2-ohm loads and in ten years nary a complaint. I feel comfortable relying on Crowns to pull easy duty in my home systems. My 030's have had nothing but Crown power put to them since 1973. I'm a satisfied customer. My neighbor, on the other hand, is the original owner of both a Phase Linear 400-II and a Phase Linear pre-amp, both sitting on his work bench, both in failure mode. :dont-know

SEAWOLF97
06-10-2009, 09:15 AM
My engineer friend in Sydney was telling me about a Perreaux / BGW connection ...I cant remember if it was a shared design or not , email is gone,,,mebbe I'll ask him again.
Have also heard that BGW made the big amps for Bose

I know they are highly sought after in Oz, and
there is a reason why they were all over Vegas , Hollywood and the White House :bouncy:

BGW Timeline

1971 - Started production in a garage.
First product the Model 1000 Laboratory Power Amplifier introduced the following new concepts to the industry:

Modular Construction
DC Speaker protection
Magnetic circuit breaker mains protection
Low impedance operation

1974 - Selected by Universal Studios to supply amplifiers for the Sensurround Systems for the movie Earthquake; Introduced Model 750A and 500D - Proves very successful with 500D replacing Crown DC300 as the new Industry Standard




http://www.bgw.com/about/bgw_timeline.asp

Mr. Widget
06-10-2009, 11:26 AM
1974 - Selected by Universal Studios to supply amplifiers for the Sensurround Systems for the movie Earthquake; Introduced Model 750A and 500D - Proves very successful with 500D replacing Crown DC300 as the new Industry Standard
I remember BGW as being a highly regarded line back then, but I wouldn't use the Sensurround System as a recommendation for anything other than loud distortion.

Don't know much about the Phase Linear 700, but I did briefly own a 400... was suckered by those big sexy meters... I was not impressed with the sound of the amp at all.


Widget

opimax
06-10-2009, 12:54 PM
Phil,

I have 3 Perreaux amps, want to have the shoot out at my place :)

From the 80's (2) 6000B and (1) 3000B

Mark

BMWCCA
06-10-2009, 03:08 PM
I have 3 Perreaux amps, want to have the shoot out at my place :)Yeah boy. This is sounding like more reasons to have too much fun! Are your L250/250Ti's back together? I know we talked about 10" and under for speakers, but if we're gonna compare amps, we really should do that with something big. And I can always find an excuse to drag a spare pair of L7s for comparison, again. I can cover 2x Crown 200-wpc amps and one Soundcraftsmen 200-wpc (both @ 8-ohms), and about as many 100-wpc as you can count on one hand. Guess we need to find someone with a BGW, too. No Phase Linears on my speakers, please!! ;)

We can always play the AFLAC commercial on Heather's new Daffy Lips. :D

opimax
06-10-2009, 05:55 PM
response in this thread on forum announcements

2nd east coast LHS social event

BTW , no one complained about off topic but I started a new thread

scott fitlin
06-10-2009, 07:08 PM
Wow - great story!

How do you think the 2225 dust cap shot off? Was the VC so hot that it melted the cap glue before it burst into flames? The driver is rear vented; right?

So the amp was dumping DC into the loads? The glue melted, the pressure was too much for the rear vent, and forced the dustcap forward.

PL 700,s were known for dumping DC, ESPECIALLY when overdriving them hard, which is what guys used to do! Like I said, PL protection circuitry will let you drive the amp as hard as you want to, putting out up to twice it's rated power, but this power is contaminated with severe distortion. And DC when the amp fails.

For one reason or another, I LOVE the sound of Crown! I have tried, and own MANY BRANDS OF DIFFERENT THINGS, I always come back to crown. Crown has been the most reliable amp for me over the years, and i have had amps fail in use, always uneventfully. Leaving my loads intact and unhurt. THIS is a GOOD thing.

:bouncy:

midlife
06-10-2009, 08:07 PM
I really like the Crown DC300 series, good! sound, very dependable, and reasonably priced. Of course there are sonically better audiophile power amps, but they will cost many many times what you can get a clean DC300 for.

Allanvh5150
06-10-2009, 08:09 PM
It's also easy to over-state power outputs. And that Perreaux model listed in your Ebay link as 700-watts is rated by the manufacturer at 200wpc @ 8-ohms.

Just FYI, The PMF series amps were seriously underated for some reason. Although I have never been offered an explanation from the factory I do know this to be true. As an example the PMF 1050 is rated at 100W into 8 ohms, the 3000B is rated at 180W into 8 ohms. The power supply and the circuit are identical. I have always been pleasently surprised when I put one of these amps on the scope. They are often looked over as dinosaurs but they reprodece audio very nicely. There is no protection circuitry whatsoever and the componant count is very small. Disregarding the output devices there are only 5 other transistors in the whole circuit. Very simplistic, the circuit was very similar to the guidelines setout bu Hitachi in the original mosfet data.

Allan.

BMWCCA
06-10-2009, 08:17 PM
I really like the Crown DC300 series, good! sound, very dependable, and reasonably priced. I know it's not a quantum leap in age or sophistication, but if I were you I'd be looking for a Series-II DC300A or (better yet) a PS-400. All the good stuff you loved but better protection and some more modern features, like (in the PS-series) turn-on delay. But that's just me! :)

midlife
06-10-2009, 08:27 PM
I know it's not a quantum leap in age or sophistication, but if I were you I'd be looking for a Series-II DC300A or (better yet) a PS-400. All the good stuff you loved but better protection and some more modern features, like (in the PS-series) turn-on delay. But that's just me! :)
I second the motion, ;)

Ian Mackenzie
06-11-2009, 04:17 AM
On the PL 700 thing I have some experience.

We ran a 700B (brand new not Ebay crap) for 15 years without any issues swinging -3 db into 2231As without any speaker damage. We then ran dual 2235Hs a side without any problems for extended periods in a pro rack with a large fan.

The only failure we experienced was user error when the pre /mixer power was accidentally turned off before the power amp.

Semiconductors do breakdown over time and the output stage (like any pro amp) must be replaced with the right devices by a qualified tech and this amp has had that service once in the past 30 years.

The chassis were originally sheet aluminum and unless they were properly braced that lead to relaibility issues. Same goes for heat. People would also run them without a solid mains supply and that is asking for trouble.

I then ran a Clair Bros 700B series 2 for 10 years (steel chassis) that was previously used exclusively by Jands for Clair Bros S4 boxes in dozens of racks for massive S4 arrays. They were the only amp ever specified for those systems at the time and I think Clair Bros know what they were doing.

If you buy off Ebay expect problems. We have seen this time and time again around here.

As to Perreaux they were legendary in the Pro Scene in the 80-90's and are used by Studios world wide.

Aust Monitor's K2 was another serious contendor but not by current day standards.

I am not sure why people want to have a yabba fest over such old amps when the the dollar per watt has come down so much over the past 10 years. It makes no sense to buy an amp on Ebay



As to the original question you can safely drive them into 4 ohms but refer to the manual regards the line fuses and run a fan on the heatsinks. They are optimised for 8 ohms however as that is where they are most efficient.

BMWCCA
06-11-2009, 07:44 AM
I am not sure why people want to have a yabba fest over such old amps when the the dollar per watt has come down so much over the past 10 years. It makes no sense to buy an amp on Ebay Perhaps suggest a current-model amp in the 200±wpc-@8ohms available for around the $200 it costs to get a gently used Crown PS-400, Adcom, JBL-Urei, or BGW and we'll try and toss one in our Mid-Atlantic JBL comparo in hopes of answering your question. I suppose we could just use Heather's H-K AV receiver but I don't think that's what you had in mind.

For me it's value for the dollar. I bought one PS-400 from an LH forum member for a reasonable price and the other from a DC-area recording studio off Ebay for $100. How could I pass up either of those offers? My DC300A-II came out of a Lowe's Theater regional refurb where they were selling them off in bulk on Ebay a few years back. I also have a two PS-200s, one of which came from Ebay from the original owner having just returned from Crown for a complete check-over—in the Crown packaging and with the receipt for work that totaled more than what I paid for the amp. So, if the question was more than just rhetorical: I use old amps because I like the sound, like the value they present, I can run three-or-four complete systems for less than one with new componentes, and I've never had a moment's trouble with what I have. I don't think I'm short-changing my system, I'm not into bling, blue lights, or big meters, but I am curious to hear your opinion on what it would cost and what you'd recommend to give my system what the Crown's offer but in a modern, new amp. :dont-know

robertbartsch
06-11-2009, 08:20 AM
This post has been amusing to me, I suppose.

In the 70s, I used to read articles in Stereo Review about the virtues of these amps. ....nothing but glowing praise and accolades. I always wanted one but they were out of reach, financially speaking.

Well, after reading this, you only have to realize the magizine's revenue source come from ads and the mag was filled with PL ads to know that the reviews may not have been truly independent.

BMWCCA
06-11-2009, 09:18 AM
Well, after reading this, you only have to realize the magizine's revenue source come from ads and the mag was filled with PL ads to know that the reviews may not have been truly independent.No different today. How do you think Motor Trend picks its Car Of The Year award? Just look for who made the biggest ad buy! You have to go back to 1972 to find a smaller manufacturer winning the overall award: http://en.wikipedia.org/wiki/Motor_Trend_Car_of_the_Year

Allanvh5150
06-11-2009, 01:39 PM
In the 70s, I used to read articles in Stereo Review about the virtues of these amps. ....nothing but glowing praise and accolades. I always wanted one but they were out of reach, financially speaking.

I also read the glowing reveiws and always wanted to get my hands on a Phase Linear. Unfortunately when I started to have dealing with them they never live up to my expectations. I am sure there are great examples of these amps out there but in my opinion, there was a very high propotion of failures. Maybe it had something to do with the freighting distance to down under......

Allan.

robertbartsch
06-11-2009, 01:57 PM
Allan:
What electrical current do they use in New Zealand - 120 volt AC? Perhaps your issues had something to do with the different NZ power supply?

Towards the end of the period that I was watching the Phase Linear product line (mid to late 70s) I beleive Bob Carver developed a powerful amp that used a small and inexpensive transformer. At the time it was hailed as a super tech breakthrough that was ready to transform (no pun) the industry.

...not sure what this was excactly - maybe the forerunner to the Class G amps of today.

Old curmudgeon
06-11-2009, 07:50 PM
I know it's not a quantum leap in age or sophistication, but if I were you I'd be looking for a Series-II DC300A or (better yet) a PS-400. All the good stuff you loved but better protection and some more modern features, like (in the PS-series) turn-on delay. But that's just me! :)


No, it's not just you (and you thought you were special :D ).

I have multiples of the PS-400 and I can third the recommendation!

BMWCCA
06-11-2009, 11:22 PM
I have multiples of the PS-400 and I can third the recommendation!Thanks. There's safety in numbers! I'm happy to have consensual validation. ;)

Allanvh5150
06-12-2009, 02:27 AM
Allan:
What electrical current do they use in New Zealand - 120 volt AC? Perhaps your issues had something to do with the different NZ power supply?

Towards the end of the period that I was watching the Phase Linear product line (mid to late 70s) I beleive Bob Carver developed a powerful amp that used a small and inexpensive transformer. At the time it was hailed as a super tech breakthrough that was ready to transform (no pun) the industry.

...not sure what this was excactly - maybe the forerunner to the Class G amps of today.

We use 240V ac. The assume the Phase Linear amps I saw here had the correct transformer in the power supply. I saw a few PL's that had been running fine go up in smoke for no apparent reason. The system that you are talking of had an odd name that escapes me at the moment. Esentially 3 or 4 rail voltages and the amp switched them as power demand grew. I guess it it class G. They were certainly the first amps that I saw that worked in this way. The amps were pretty good but if you loaded up both channels with bottom end the power supply would sag and so would the power output. When I ever ran Carver amps I would run one channel with bottom end and the other with highs maybe.

Allan.

P.S. "Magnetic field coil power amplifier"

Ian Mackenzie
06-13-2009, 07:48 AM
Perhaps suggest a current-model amp in the 200±wpc-@8ohms available for around the $200 it costs to get a gently used Crown PS-400, Adcom, JBL-Urei, or BGW and we'll try and toss one in our Mid-Atlantic JBL comparo in hopes of answering your question. I suppose we could just use Heather's H-K AV receiver but I don't think that's what you had in mind.

For me it's value for the dollar. I bought one PS-400 from an LH forum member for a reasonable price and the other from a DC-area recording studio off Ebay for $100. How could I pass up either of those offers? My DC300A-II came out of a Lowe's Theater regional refurb where they were selling them off in bulk on Ebay a few years back. I also have a two PS-200s, one of which came from Ebay from the original owner having just returned from Crown for a complete check-over—in the Crown packaging and with the receipt for work that totaled more than what I paid for the amp. So, if the question was more than just rhetorical: I use old amps because I like the sound, like the value they present, I can run three-or-four complete systems for less than one with new componentes, and I've never had a moment's trouble with what I have. I don't think I'm short-changing my system, I'm not into bling, blue lights, or big meters, but I am curious to hear your opinion on what it would cost and what you'd recommend to give my system what the Crown's offer but in a modern, new amp. :dont-know


There are always excpetions and obviously it was in your case as you know the seller(s). The reality is most people get screwed and then they pay what they bid to get it repaired.

I dont have a QSC, a Yamaha or a Crown $US dollar price list on hand but I know locally I can buy new 300+300 watts for less then AUD$700.

The concept of paying nothing for something reminds my of a recent newspaper article on American Securitisation of home loan lending.

midlife
06-13-2009, 08:18 AM
I have always bought used crown amps, sight unseen, and history unknown. They have never been a problem. Maybe I have been lucky that way, if so I hope my luck continues. I do attribute some of that luck to the reliability of the product. Should I get a "cooked" one I'll have to get it repaired and maybe a speaker or two.

BMWCCA
06-13-2009, 08:44 AM
I dont have a QSC, a Yamaha or a Crown $US dollar price list on hand but I know locally I can buy new 300+300 watts for less then AUD$700.

The concept of paying nothing for something reminds my of a recent newspaper article on American Securitisation of home loan lending.I was only providing my reason in response to your post:
I am not sure why people want to have a yabba fest over such old amps when the the dollar per watt has come down so much over the past 10 years. It makes no sense to buy an amp on Ebay
I doubt my experience is that far from normal, having purchased four Crown amps and one Soundcraftsmen off Ebay with no issues. Sure, the dollar value of buying used is compelling but then I sold new high-line cars for over twenty years and never bought one new for myself in forty years of owning them, either. If a used automobile provides such great value at half-new-price or less, then why not a used solid-state amp at one-tenth? I also think the older U.S.-made Crowns provide quality I'm not seeing in off-shore lower-line current models. I could be wrong, and I am a self-proclaimed Luddite. ;)

The fourteen-year old BMW I drive as my daily driver cost me $5,500 at 100k-miles versus $44,000 new. It has full leather, CD-changer, ABS, Traction Control, dual-zone A/C, 17" wheels, sunroof, etc. I've driven it almost 50k-miles in just under three years and replaced one light bulb, two rear shock mounts, and a set of brake pads just to kill the dust. Oh yeah, a set of tires. My 35-year-old Crown has had an easier life than my car and hasn't cost me a dime. Would I have made a similar purchase or relied similarly on a fourteen-year-old Chevy, Ford, SAAB, Chrysler? No. Would I have enjoyed any more reliability or driving enjoyment had I bought a 1995 Toyota Camry? Probably not on the reliability and definitely not on the enjoyment. Did I choose an old QSC or Phase Linear? No. I chose Crown. I think we've seen here on this forum what happens when you buy a new, DJ-intended, made-in-China, cheaper Crown version and apply it to home use. My first D-series amp was sold by a Crown/McIntosh/JBL dealer to me as a home-use hi-fi amp. I can't see that that has changed in thirty-five years or that anything near what I'm paying for my Crown's buys me anything that's new that would serve me better.

Taking advantage of a value on a used amp in an open market is a far cry from taking out a mortgage I don't qualify for on a home I can't afford that's inflated to start with, just to bolster a market economy controlled by banks whose losses are protected by the markets they control. But then you were just being provocative anyway, and we all knew that! ;)

robertbartsch
06-14-2009, 01:04 PM
I have a BMW that is 13 years old too. Beofor becomeing a CPA, I was a mechanic 30 years ago and this pile of bolts blows.

I've done a fair amount of mechancial work on it since I bought it 6 years ago. Yesterday, I tried to replace the front blinker bulb and after being completely stumped after looking under the hood, I consulted the BMW Internet forum. Apparently, you need to remove the bumper and front headlights to replace the blinker bulb - UHG!

I just bought a new Honda Accord and will not look back.

BMWCCA
06-14-2009, 01:22 PM
Since we are now hopelessly off-topic anyway and have beaten the PL horse to death:
Apparently, you need to remove the bumper and front headlights to replace the blinker bulb - UHG!I find that impossible to believe but you got my curiosity up. What model? E39 5-series? Or just PM me if you prefer. ;)

I've sold and worked on Porsches where the bumper/front valance had to be removed to replace the air-cleaner element. Stories are legendary of GM cars that had to have a hole drilled in the wheel housing to change a spark plug, too. Don't by a Citroen if you don't like jigsaw puzzles!

Othello
06-16-2009, 08:57 PM
Interesting thread, with all the bad news about Phase Linears....

I have a Phase Linear 400 which is about to go DC on me, right now it passes intermittent DC into my speakers, and I wonder if someone here knows what most likely goes on these amps, it would make the repair easier.

Also, what is a good quality low power modern amp, preferably a kit??

Uwe

midlife
06-16-2009, 09:32 PM
Interesting thread, with all the bad news about Phase Linears....

I have a Phase Linear 400 which is about to go DC on me, right now it passes intermittent DC into my speakers, and I wonder if someone here knows what most likely goes on these amps, it would make the repair easier.

Also, what is a good quality low power modern amp, preferably a kit??

Uwe
I am a Crown fan, they offer D40, D60, D75, in what I consider a low power output. Wish I could offer advise on your Phase but I don't have the experience. This a good forum, so you probably will get solid advise. :)

MikeBrewster77
06-16-2009, 09:37 PM
I have a Phase Linear 400 which is about to go DC on me, right now it passes intermittent DC into my speakers

With all due respect, unless you want to trash your speakers, might I respectfully suggest that you immediately disconnect the amp and take it to a qualified tech for diagnostics?!?!?!?! :blink:

Othello
06-16-2009, 10:00 PM
With all due respect, unless you want to trash your speakers, might I respectfully suggest that you immediately disconnect the amp and take it to a qualified tech for diagnostics?!?!?!?! :blink:


Well sure, I disconnected the speaker.
But sending it out for diagnostics?!? that is not going to happen, I will have to figure that out myself.
But I had hoped for help, often these failure modes are similar from one amp to the next and it would help to hear about the most likely failure-easier to troubleshoot that way...
I looked at the diagram, I don't think it's a faulty power supply, it only happens in one channel. The meter jerks violently in that channel, but intermittently. Hopefully some members here have hands-on experience with these amps.
Uwe

ratitifb
06-17-2009, 12:33 AM
But I had hoped for help, often these failure modes are similar from one amp to the next and it would help to hear about the most likely failure-easier to troubleshoot that way...
I looked at the diagram, I don't think it's a faulty power supply, it only happens in one channel. The meter jerks violently in that channel, but intermittently. Hopefully some members here have hands-on experience with these amps.Uwe What are the power transistors type (MJ15003 is a bad choice due to the low Vceo value compared to the +/- DC voltage supply and some instability) ?
In that case you have to change all power trans (don't mix power trans types) of the faulty channel plus probably drivers. Bias and output offset and no instability behavior have to be doublechecked after servicing process ...

Please take a look at
http://synthetizer-sche.chez-alice.fr/power%20ampli/phase%20linear/repair.htm

;)

jcrobso
06-17-2009, 11:21 AM
If you read to the bottom where it talks about how much more power the PL amps can put out compared to their rated power.
Bob Carver called this dynamic head room, because of this the amps became very popular for live sound. The downside is that they were designed for the consumer market, I feel the this is why they ended up getting a bad name.

BMWCCA
06-17-2009, 12:33 PM
Bob Carver called this dynamic head room, because of this the amps became very popular for live sound. The downside is that they were designed for the consumer market, I feel the this is why they ended up getting a bad name.I've seen plenty of blowed-up 400s. Never saw any used in "pro" applications. Doesn't deny that people used them for pro use, just that they blew regardless. There's plenty of discussion of why this is and what it takes to fix them and make them safe elsewhere on the Internet, including Bob Carver, himself. Fun diversion but nothing new here.

I had a friend who blew-up a 400 at a yard party driving one pair of ARs. No such problem with my baby Crown D150 even driving my 030s loud enough outside to be heard clear to the Blue Ridge from the Doyles River. To show how hard I was driving it, the Crown had one thermal-shutdown incident because it was the early model version with no faceplate and I played it on it's side on a shelf with the logo pointing out when the feet were intended for the logo to be up. I lifted the amp by shoving a pencil underneath it and it played without further incident for at least eight more hours. That was over thirty-years ago and it's still working fine today.:applaud:

robertbartsch
06-17-2009, 02:59 PM
My +20 year old Adcom was dumping DC into both channels. The repair was $240 which is slightly less than the FV of an equivalent working unit. Repair shops know this value, so be advised.

I no longer buy older electronics for this reason.

JeffW
06-18-2009, 09:55 AM
I'd have to dig for a link, but Carver recently (within the last year or so) has come out with a flat fee to refurbish any Carver amp. I'm not sure if PL would be covered or not. Seems like it was $170 + shipping.

BMWCCA
06-18-2009, 10:05 AM
I'd have to dig for a link, but Carver recently (within the last year or so) has come out with a flat fee to refurbish any Carver amp. I'm not sure if PL would be covered or not. Seems like it was $170 + shipping.

You can try this link (http://ritasvintageaudio.net/) but I may have posted this information previously:

Rita Helm and I (Bob Carver) have opened a new shop for fixing and restoring all vintage Carver Corp, Phase Linear and Sunfire audio equipment.
We also restore ALL vintage tube amps as well. Rita's Vintage Audio Repair.

Each unit will be repaired, updated and gone through from top to bottom, restored to the same performance and condition as it was the day it was built.

A flat fee of $175 dollars + shipping covers it all. Our minimum inspection fee is $35 dollars.

The address is:
Rita Helm, Old Sunfire building
1920 Bickford Ave
Snohomish WA 98290

Phone 425-530-9557. Ask for Harry Abbott.


XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XX

Updated post from another thread. This is from Lisa at Bob's repair shop..............and I quote.......

Hi Everyone,
I am Lisa from Rita's Vintage Audio Repair. Here is some helpful info:

Here is our info:

Rita's Vintage Audio Repair
1920 Bickford Ave.
Snohomish, WA 98290
360-568-4700
ritasvintageaudio@gmail.com

Our Charges:

$175.00 Flat Fee
$175.00 for active drivers ONLY if it needs it
$75.00 for passive drivers ONLY if it needs it
$75.00 for tech labor time on unit over 3hrs.
$ 20.00 ONLY IF box & packing material are needed or wanted.
Customer pays Shipping & Handling both ways.
We ship UPS Ground for return UNLESS customer chooses otherwise, also we insure for $999.00 for return.
Please include all contact info when shipping to us. We will not ship your unit back until we receive payment.
Billing will occur at the time of return shipment. Please include the best time to contact you for payment.
We warranty any work We performed for one year.

Any questions please feel free to call.
P.S. Occasionally Mr. Carver finds time to drop by & we can get him to sign units!:-"

Thank You,
Lisa Selph

JeffW
06-18-2009, 12:37 PM
Yep, that's what I remembered seeing.

jcrobso
06-19-2009, 10:24 AM
http://www.audioheritage.org/vbulletin/showthread.php?t=21365

Othello
06-20-2009, 02:28 PM
What are the power transistors type (MJ15003 is a bad choice due to the low Vceo value compared to the +/- DC voltage supply and some instability) ?
In that case you have to change all power trans (don't mix power trans types) of the faulty channel plus probably drivers. Bias and output offset and no instability behavior have to be doublechecked after servicing process ...

Please take a look at
http://synthetizer-sche.chez-alice.fr/power%20ampli/phase%20linear/repair.htm

;)


Well, thank you for your help and for the link to the article.
I opened the amp and found an original set of transistors.
The amplifier works and the DC appears intermittently on one channel.
Since I don't believe that semiconductors can have intermittent behavior I am looking at the amplifier trying to identify passive components which could be responsible for a on/off appearance of DC at the output.

I will report back.

Uwe

PS. I have to say I was a bit disappointed regarding the workmanship of this amplifier, the innards seem not to deliver what the nice front panel promises...

ratitifb
06-20-2009, 04:41 PM
i just downloaded free of charge this doc after having paid 22$ for a paper copy on the bay :applaud::p :o: :( :D

Front panel led indicator has to be adjusted according to the measured RMS output power ;)

Woofer
06-24-2009, 03:50 AM
i just downloaded free of charge this doc after having paid 22$ for a paper copy on the bay :applaud::p :o: :( :D


Is there a trick to seeing the contents of your attached .pdf?
When I try to open it, it opens up as a series of blank pages. :(

hjames
06-24-2009, 04:13 AM
Is there a trick to seeing the contents of your attached .pdf?
When I try to open it, it opens up as a series of blank pages. :(

I opened it just fine on my Mac - cover page says HiFi Engine, last page looks great, rest seem ok too ...
HiFi Engine folks are great,
got a Yamaha and a Denon manual from them last year myself

Woofer
06-24-2009, 04:19 AM
I opened it just fine on my Mac - cover page says HiFi Engine, last page looks great, rest seem ok too ...
HiFi Engine folks are great,
got a Yamaha and a Denon manual from them myself

Most unusual....
Did it open by default in Preview or did you use Acrobat, Heather?

UPDATE: Doesn't matter H, opens up on my other Mac OK.
(Most strange. Other .pdf's open fine!!)

bigstereo
06-26-2009, 03:30 AM
You can try this link (http://ritasvintageaudio.net/) but I may have posted this information previously:

Damn, wish I'd of seen that before I had mine restored and upgraded. It would be cool to have a PL amp that has been touched by the man himself.
Loved that amp. Sold her recently to afford a bigger (128 lb) beast.

http://i175.photobucket.com/albums/w160/bigstereo/DSCN1462.jpg

http://i175.photobucket.com/albums/w160/bigstereo/DSCN1465.jpg

Woofer
06-26-2009, 05:39 AM
What can I say?
OK, so I'm not that close to God! :o:

http://i35.photobucket.com/albums/d193/bobbysdad/MyPLstuffleft.jpg

That's a Clair Bros. 700 on the bottom missing it's Face Plate.
(... hey, if anyone has a spare 700 Series 2 face, let me know, PLEASE)
There's one behind it too, but at least it's complete and almost mint. (best place for it)
Both 700's operate into 4 ohm loads and always have with no ill effect.
That's a 400 in the middle and then a 200, and then a 5100 Tuner.
The 4000 pre-amp is on the other side of the unit, along with an Amcron EQ2.

Speakers are 4x 2215's in 4530's and a pair of 10 cubic foot ported boxes, and 2421's (yes, I know, should be 2440's but at AU$800pr that ain't gonna happen too soon), plus adaptors on 2309's with 2310 lenses plus 077's all crossed with Crown VFX2A's and a FFX2.
I'm also using 4x 10" speakers from my L40's and L36's for the lo-mids.
For what it is, it's incredibly quiet, and I don't realise it's on most of the time, until the power bill comes around.
As far as popping any of my PL's are concerned, haven't had any problems with daily use for the last 10 years. (... touch wood!)

The Luxman LV103 on the top is on my 4301's. Very nice combo.

It's really just repaired stuff from a pile of rubbish, but it's all I got. :blink:

Cheers all. :)

mikethebike
09-11-2009, 06:56 PM
I've seen plenty of blowed-up 400s. Never saw any used in "pro" applications. Doesn't deny that people used them for pro use, just that they blew regardless. There's plenty of discussion of why this is and what it takes to fix them and make them safe elsewhere on the Internet, including Bob Carver, himself. Fun diversion but nothing new here.

I had a friend who blew-up a 400 at a yard party driving one pair of ARs. No such problem with my baby Crown D150 even driving my 030s loud enough outside to be heard clear to the Blue Ridge from the Doyles River. To show how hard I was driving it, the Crown had one thermal-shutdown incident because it was the early model version with no faceplate and I played it on it's side on a shelf with the logo pointing out when the feet were intended for the logo to be up. I lifted the amp by shoving a pencil underneath it and it played without further incident for at least eight more hours. That was over thirty-years ago and it's still working fine today.:applaud:

I have experience with PL 4000, PL 400, Sonic Hologram and the Cube amps. Killed tweeters in L-100 AND L-150. Buy what you want but I prefer CROWN amps to all others.
We called the PL 400 the "FLAME-LINEAR" back in the 70's.

spkrman57
09-22-2009, 11:20 AM
A friend of mine still has his

Regards, Ron

Ian Mackenzie
09-22-2009, 10:46 PM
Can a Phase Linear 700 power amp comfortably operate at a four ohm load? Haven't seen much mentioned about these amps, are they desireable and good performers? Are they compatible with different preamps? :bouncy:


With a fan Yes: per the original owners manual (install 8 amp fuses)

The thing about this amp was its threshold of clipping into 8 ohms was around 450 watts into 8 ohms and 700 into 4 ohms. That was the whole point of the design and high damping factor like 1000 : 1 to drive the ART LST and other relatively low sensitivity loudspeakes. The advent of high voltage transisters used in TV HT power supplies made the 700B a reality.
http://images.google.com.au/images?hl=en&source=hp&q=AR+LST&um=1&ie=UTF-8&ei=Jqa5SpH8CNGTkAXJs5XlBQ&sa=X&oi=image_result_group&ct=title&resnum=4


Obviously efficiency goes to hell into 4 ohms in a linear amplifier (with such high supply rails) . The problem with 4 ohms is the losses with such high currents and high power levels and the heat. Most of the class leading super amps can now approach 6 fold those numbers into 8 ohms and down to 2 ohms with switchmode PS. The point is a dyanmic range from an amp that can put out such large voltage swings.

http://www.labgruppen.com/downloads/product/PLM_Series_Technical_Data_Sheet_TDS_PLM14000_V3.pd f

The Crown amps of that era could not do that and only then in bridge mode.

Woofer
09-22-2009, 11:56 PM
It must be remembered that we're talking about amps that are 40+ years old don't forget.
These were the first of the 'Super-Amps' and were at the forefront of technology for the times.
It was a HUGE transition going from reasonably low powered Valve/Tube amps to these Solid State high powered devices.
I think the Crown DC300 came just before the Phase Linear 700, (correct me if I'm wrong), and there wasn't much more about except for maybe the BGW's which came a little later.
(... feel free to add to that list, IF you're old enough!)
Some have said that they don't remember seeing these in 'action' but there were companies about during the 70's and 80's, eg Clair Bros, USA, that must have had a thousand PL's for their huge Concert Touring Rigs.
You may not have seen them, but you certainly heard them.
.... but then again, this only applies to those from THAT era that were out and about at the time.
Some companies used PL's, and some used Crowns.
Same as recording studios.
It was always one or the other, but the one thing most had in common were JBL monitors. A match made in heaven regardless of which amp you used.
We have so much to be grateful for to these two Audio Co's as we wouldn't have some of the most exotic stuff today without their, (PL & C's), pioneering R&D and productivity.
I mentioned before I have a heap of PL's. I'm now starting up a similar Crown set-up. Again from 'found' broken bits.
I don't necessarily prefer one over the other. I love both.
They both have their problems, but there's so many solutions available on the 'net these days, that not having a perfectly working unit is no excuse really.
Anyway, whichever you have, enjoy it/them.

Cheers all. :)

Ian Mackenzie
09-23-2009, 12:13 AM
Agreed,


Has anyone heard of SAE.

I repaired a 50/50 watt SAE power amp about 18 months ago and it was really nice. I replaced most of the transisters including the drivers with original types (darlington outputs) and used more modern low noise true equivalents for the Dual input Diff pairs and matched the HFE. Some capacitors were also past their used by date.

That made a hugh difference from being just another amp to the dizzy heights of a Levinson. Its surprising how different a transister can sound with the same spec. When match with the optimum HFE it can be night and day in terms of resolution and tonal balance. In this amp the previous repairer put in odd types (probably from another repair) so it was a sick puppy for a long time. Now I get a free beer whenever I see the owner!

I think SAE man has a big stash of those.

The point of this post is that if you buy an old Phase Linear it probably wont sound as good as new and even less likely to be working properly if it had been blown up.

Woofer
09-23-2009, 12:37 AM
Agreed,


Has anyone heard of SAE.

I repaired a 50/50 watt SAE power amp about 18 months ago and it was really nice. I replaced most of the transisters including the drivers with original types (darlington outputs) and used more modern low noise true equivalents for the Dual input Diff pairs and matched the HFE. Some capacitors were also past their used by date.

That made a hugh difference from being just another amp to the dizzy heights of a Levinson. Its surprising how different a transister can sound with the same spec. When match with the optimum HFE it can be night and day in terms of resolution and tonal balance. In this amp the previous repairer put in odd types (probably from another repair) so it was a sick puppy for a long time. Now I get a free beer whenever I see the owner!

I think SAE man has a big stash of those.

The point of this post is that if you buy an old Phase Linear it probably wont sound as good as new and even less likely to be working properly if it had been blown up.

Absolutely spot on Ian....
I think anyone reading this can apply what you said to just about any of the BIG amps of the time.

So the best advice for possible future purchasers of any VINTAGE amp, go over it first before you power it up.
... and as Ian already mentioned, replace a few of the essential bits, eg, make sure all the transistors are matching and working, and chuck out any capacitors in the signal path and replace with the better stuff available today, and be prepared to have the biggest grin on your dial for a good length of time.

SAE stuff was good too I thought. On par with the big ALTEC amps.

I think I'll go and have a nap now.... ;)

Dual-500
11-04-2009, 08:11 PM
Can a Phase Linear 700 power amp comfortably operate at a four ohm load? Haven't seen much mentioned about these amps, are they desireable and good performers? Are they compatible with different preamps? :bouncy:

This question always draws out the naysayers. Gotta laugh. Yes it's true, if you load up a Phase Linear model 700 with a stout 4 ohm load and pour the coals to it - it will indeed go China Syndrome and in relatively short order. I guarantee it.

Now, is it the amp or the user? Not to bash here. It's already been posted the owners manual mentions cooling fans being necessary for high power applications. They are.

Lots of air and air exchange - cool air. I always use 200+ CFM of fans (2 x 100 cfm) on the 700's in commercial use. And ensure the air in the rack circulates properly.

Companies like Audio Analysts, Heil Sound, and Clair Brothers Audio used Phase Linear amps back in the day for many years. That fact speaks volumes about the amps and how robust they are/were.

I used 400's, 700's and 300's in pro sound, disco's and my home system for many years. 3 clubs running 700's through the 80's open 7 nights a week and I had 2 amp failures from the 700's and 1 failure with a 300. Also had 2 portable systems running - one for DJ and one for club bands.

Tore up a few JBL E-120 12" 16 ohm low mids and a few E-155 8 ohm 18's with the 700's until I learned to correctly calobrate the gain structure in the systems with the old Ashly limiters and crossovers.

What I'm saying is they are flamethrower amps and about as reliable as any if properly setup.

For home use, 12v 120mm whisper fans work pretty well - depending upon how hard the amp is pushed at 4 ohms and for how long.

About the only thing one can grip about for these amps is the fan noise needed to push enough air across them to prevent amp failure.

mikeharris
01-05-2010, 10:23 AM
Sorry for the late reply...but one of our clients used 700's exclusively many (30+)years ago. They had BiPolar 140v power supplies and could swing some current...but no protection.
Not to say DC300's didnt have issues..but most were due to crappy equalisers or poor stage habits. A Soundcraftsman EQ would put out DC on turn on...or when the cord was plugged back into the wall (after being kicked out). Not the Crowns fault but it would smoke the drivers every time.

Progneta
03-16-2010, 08:49 PM
I once came across some McIntosh amplifiers because the guy liked the phase linears better. I was happy, got some Mc's :D

He fired the PL on some altec A7's and it did sound good man...

tinevalen
04-04-2010, 02:07 PM
the first amplifier i recall as being 100wpc and over, or (then) "super-amp" material was the Mattes SSP200, a 100 wpc pwer amplifier. i believe within a year of it's release Mattes produced the SSA 200 which was an integrated amplifier. I owned an SSA200 and ran a pair of Altec-Lansing Flamenco's (see Bogator's avatar). It was a very good-looking piece of equipment, with a very coplex control panel. :blink::blink:I haven't been able to find a picture of any Mattes components online, and even mention of it is hard to come by. there is some discussion at this link.
http://www.audiokarma.org/forums/archive/index.php/t-25298.html

and roger russel of mcintosh fame also has a review of one for sale at
http://www.roger-russell.com/magrevhf.htm

jcrobso
04-05-2010, 08:52 AM
the first amplifier i recall as being 100wpc and over, or (then) "super-amp" material was the Mattes SSP200, a 100 wpc pwer amplifier. i believe within a year of it's release Mattes produced the SSA 200 which was an integrated amplifier. I owned an SSA200 and ran a pair of Altec-Lansing Flamenco's (see Bogator's avatar). It was a very good-looking piece of equipment, with a very coplex control panel. :blink::blink:I haven't been able to find a picture of any Mattes components online, and even mention of it is hard to come by. there is some discussion at this link.
http://www.audiokarma.org/forums/archive/index.php/t-25298.html

and roger russel of mcintosh fame also has a review of one for sale at
http://www.roger-russell.com/magrevhf.htm

The factory was not to far from school. One I stopped over and talked to the owner and designer of the Mattes amp. I was a very interesting, the amp operated class A up to 15 w then switched over to class AB. HK used this concept in HK Ciation 16.

craig strong
10-28-2010, 04:27 PM
Hi guys, seeing this thread brought back some memories, some good, some bad about my much loved (back then at least ) PL 700.

A friend at the time was importing some nice American kit to the UK, and having compared his then set up, of a Crown IC 150, driving a PL 700 into Bose 901's , to my Quad set up (brand, not the 4 channel audio of the era) I fell in love with it!

A short time later, I had my own PL 700 and original Bose 901's, and thought there was nothing to compare with it.

Except one day, returning from holiday, I switched it on, and was aware that only one channel was working, long story short, it had gone dc, and take with it one of my 901's ( 9 drivers!)

The then UK distributor very kindly swapped the amp for a brand new unit, and I bought replacement drivers for the Bose.

This combination lasted for a while, but then, just like history repeating itself, one channel went awol, and I decided my love affair with the PL had come to an end.

When they worked they were amazing, when they didn't, they cost you money!

Woofer
10-29-2010, 02:59 AM
...... When they worked they were amazing, when they didn't, they cost you money!

Ain't that the truth?
I've still got 2x 700 II's, a 400 II, and a 200 II on my 'stereo' which hasn't been turned on for almost a year after being used daily for ten years, and now I'm just too scared to turn the sucker on! :(
I could pull 'em all out and go over them, but I just can't be bothered anymore. Maybe one day....
So, I use my Crown stereo instead for now, which has been in constant reliable use for ages. :)
.... but I do miss the PL's. Nothin' like a bit of headroom to spare! :p

Cheers. ;)

martin2395
06-20-2016, 11:08 AM
I know this thread is 6 years old but for everyone who is running the 700/700B - get it restored and add speaker protection, for the love of God.
I just bought one in almost immaculate, not misused condition and it worked fine until one channel blew (sparks,smoke, big DC on speaker outputs) for no reason at all, without playing anything, if I wasn't at home it would've probably started a fire.

Ian Mackenzie
06-20-2016, 04:27 PM
Yes apparently

The parts fail.

My brother one from new (30 years ) and the power transistors die , the carbon power resisters fail.

martin2395
06-21-2016, 03:57 AM
I was shocked because I just bought it, the first day it worked fine and on the next day it went bananas directly after turning it on. I had a 400 and 2000 in the past that worked great but I surely won't be buying any PL gear anytime soon, lol.

Repairing them without a full refurb is a bit pointless, it will probably die again soon or the other channel will go.:(
If someone wonders how does it sound when it blows up - at first a loud boom and then like a very dirty volume knob on maximum volume. Unplug the speaker cable ASAP as the amp will still discharge through the main PSU caps.

Odd
06-21-2016, 05:10 AM
I had the same problem a few years ago.
Bought speaker protection cards that was designed for FL.
Do not know if the seller is still in business.

You can try here;

Don Imlay <watts.abundant@yahoo.com>

BMWCCA
06-21-2016, 05:19 AM
Isn't Bob Carver running a business that also re-furbs Flame Linears?
Or perhaps his daughter or other family members, if I'm remembering correctly?
http://www.carveraudiorepair.com/index.html

Ian Mackenzie
06-23-2016, 01:32 AM
I do recall ours blowing and my bowel movement as a result was particularly violent.

To be honest there are better options around new like class D plate amps if you are biamping.

martin2395
06-23-2016, 05:05 AM
I'm sure you can buy better sounding amps for the same money today but they all miss the 'wipers' :bouncy: There is just that something in that old heavy metal stuff from the 70's.
Even better option would be to buy a totaled PL 400 or 700, sell whats salvageable inside and stick some Class D Hypex 700 (would match the original power nicely) or even the newest nCore modules in the old case.

Odd
06-23-2016, 06:17 AM
Yes and with Hypex it is still a 700 :)

iamhifi
08-04-2016, 08:33 PM
I used to have the 700B back 1986 and I can say it sounds nice, however you have to be careful not to short the outputs or overdrive because it will burn your speaker and there goes the name Flame Linear. Now you want a beast find a D500, I used to drive 4 double scoops loaded with 2225H and it would not even feel it.

hsosdrum
08-12-2016, 02:16 PM
When I was a touring rock musician more than 40 years ago, on an off night I was watching a friend's band play in a club when their Flame Linear 700 lived up to its nickname by melting-down in the middle of a their performance and setting fire to the 4 JBL drivers it was running (in A7-clone enclosures) in spectacular fashion. Thankfully the bartender was quick on-the-draw with a fire extinguisher, otherwise the cabs would have ignited. BTW, much of the audience thought it was part of the act. (In those days every band, including ours, used pyro in their shows, and club owners and bartenders always had fire extinguishers handy, just in case.) After seeing that, my personal rule-of-thumb has always been to never ever use a Phase Linear to power anything that I cared about in the least. Ever. (ever).

Our band used Crown DC 300As and old [Cerwin] Vega amps and never had a problem, except for the time the roadies forgot to roll-down the door at the rear of the truck and one of the road cases with a pair of Vega amps rolled out on the way to the next gig. Fortunately we got them back (we had ID cards on the inside top lids of all the cases and the farmer who found the amps got hold of us). The roadies paid for the gas to drive the 200 miles and pick up the amps. They worked fine, even after falling out of the truck at what must have been at least 50 MPH.

Odd
08-12-2016, 02:54 PM
All the older power amp will sooner or later be able to have this problem.
Not only Flame Linear. And they will make great damage to the speakers.
This summer I have mounted speaker protection on all my older power amps. Phase Linears, Crowns, Marantz and diy Pass Labs.
I've used Velleman K4700 kit. They come with built in power supply.
Delivered for 115volt and 230volt.
They are quick and also takes away turn on and turn off click.
Velleman (http://www.velleman.eu/products/view/?country=be&lang=en&id=9233)

martin2395
08-14-2016, 02:30 PM
I've had a Crown DC300A-II with completely toasted middle part of the PCB, believe it or not it still worked :D:D The sine was of course distorted, around 200mV DC offset but hey - it still amplified and didn't blow the outputs! :p
Just look at that op-amp socket (the opamp itself is already removed but it was still in place by then).
It looked like this: http://i68.tinypic.com/et5vty.jpg


(http://i68.tinypic.com/et5vty.jpg)