Underpowering JBL 250TIs....?? [Archive]

opimax

07-26-2007, 03:01 PM

I think his amp would do fine, you are probably making him worry. I would bet his set up could damage your ears before truly running out of ompf(hitting audible distortion). the speakers certainly can do more but 100+ watts of quality amp will do fine but for the most critical situation. I have read a couple places that in general these are a relatively easy load on the amp too, helps

as far as damage goes I don't think he will have any issues unless a drunk at his party grabs the volume contrtol and challanges his system.

I am not as educated as many here in the physics of all this but I do have the speakers and have had a few amps on them. my experience is what i am going by.

But lastly I must again say I have a quality 300 per side amp on mine :D

Mark
PS the 120TIs would just shine on that Nak (shameless plug) :bouncy:

edgewound

07-26-2007, 03:23 PM

It only takes once...to indulge a 100 watts with your favorite heavy hitting track to completion to fry the tweeters.

Especially with a very dynamic movie soundtrack, you need all the headroom and dynamic range you can get.

I have many customers that did just that.

"It's only 100 watts":blink:;:p;)

Storm

07-26-2007, 03:28 PM

So, I should get the PA-7 that has 200 watts per channel in order not to damage the 044TI tweeters?

Thanks for all the advice.

-Storm.

;)

kingjames

07-26-2007, 03:41 PM

I am running my 250's with my Pioneer SX 1250 and have no problem with them. This receiver is 160 watts per side and the 250's love it.Half way up on the volume and I can rattle the windows.I don't believe my speakers lack anything and I'm not afraid to blow anything with my receiver. 100 watts of music is awful loud and not too many people can stay in the room when you're that loud.I just don't see running only 100 watts will damage my speakers.

Robh3606

07-26-2007, 04:02 PM

So, I should get the PA-7 that has 200 watts per channel in order not to damage the 044TI tweeters?

No not really. That is 3db increase in maximum SPL. 3db is barely noticeable. You would want at least 6db or 400 watts to make any kind of substantial difference. The whole point is not to push your amp into clipping. An extra 3db or 6db of headroom is no guarantee you won't. Just use some common sense. No speaker is safe from a careless owner.

Rob:)

johnaec

07-26-2007, 04:08 PM

The whole point is not to push your amp into clipping.And to clarify that statement, what clipping does is chop off the top of the waveform, resulting in a "wave" that is "squarer". What that means is the top, (flat), portion of this squarewave is a steady voltage signal, instead of varying, and this is what quickly overheats and melts voice coils, since as it switches polarity, it's basically going from one extreme to the other, instead of a normal "smooth" transition. More power means it's less likely to go into clipping towards a squarewave.

John

edgewound

07-26-2007, 04:24 PM

Storm,

Here's a link to JBL Pro Website on amp power and what happens.

Maybe this will clarify things....no-pun intended.

http://www.jblpro.com/pub/technote/lowpower.pdf

Storm

07-26-2007, 04:31 PM

edgewound

07-26-2007, 04:38 PM

Musical watts is not a constant.

The key is not to run your amp into clipping or distortion...distortion kills voice coils because of the DC voltage offset nature of clipping that overheats the coil by pushing it partially out of the gap with no movement, thus eliminating the heatsinking ability of the motor structure.

There is a balance between over and underpowering....sure speakers can be overpowered too...but boy would that be loud.

At any given reasonable listening level with a good quality amp, the 400 watt amp will have way less of a chance to clip than a 100 watt amp.

And it will sound better too.

Moderation is the key..and common sense. if it sounds distorted or scratchy...turn it down.

Storm

07-26-2007, 04:47 PM

Understood.

My Nak has never clipped and living in an apartment, I never crank it up at all. Normal to above normal listening levels.

So, what is the verdict?

Do I need a better amp or am I fine?

I am not being rude, I just dont want to ruin the speakers.

Thank you.

-Storm.

Musical watts is not a constant.

The key is not too run your amp into clipping or distortion...distortion kills voice coils because of the DC voltage offset nature of clipping that overheats the coil by pushing it partially out of the gap with no movement, thus eliminating the heatsinking ability of the motor structure.

There is a balance between over and underpowering....sure speakers can be overpowered too...but boy would that be loud.

At any given reasonable listening level with a good quality amp, the 400 watt amp will have way less of a chance to clip than a 100 watt amp.

And it will sound better too.

Moderation is the key..and common sense. if it sounds distorted or scratchy...turn it down.

JSF13

07-26-2007, 05:00 PM

Nakamichi PA5 Stasis amplifier. 100wpc into 8ohms,160wpc into 4ohms....Dynamic power 150wpc into 8ohms,270wpc into 4ohms....Dynamic Headroom 1.7db into 8ohms, 2.2db into 4ohms....Output current capability 12 amps continuous, 35 amps peak per channel...Power supply; 450watt toroidial transformer.

My opinion is you should be just fine given your living conditions and the fact it's a Nak. Some 100 wpc amps are better than others.:D

Andyoz

07-26-2007, 05:08 PM

Stay with the Nak.

kingjames

07-26-2007, 05:15 PM

I am still confused..

If JBL recommends one to power speakers with more than needed watts, then why do they only state the "MAXIMUM WATTS PER CHANNEL" in their catalogs?

You would think they would have a minimum watts per channel.

So, am I really underpowering them or am I fine?

Thanks.

;)

-Storm.

Storm, amps are rated at minimum wattage whereas speakers are rated at maximum wattage.An example is that my SX1250 is rated at 160 Watts rms per channel but I have read numerous post and articles that it is closer to 200 watts per channel.An amplifier or receiver must meet minimum stated wattage but can be in excess of stated wattage.

Storm

07-26-2007, 05:19 PM

Storm, amps are rated at minimum wattage whereas speakers are rated at maximum wattage.

If we are talking about damaging speakers, wouldn't the makers of both want to be on the same page so one knows which one to get in order not to damage anything?

Just my $0.02 worth.

;)

-Storm.

JSF13

07-26-2007, 05:58 PM

If we are talking about damaging speakers, wouldn't the makers of both want to be on the same page so one knows which one to get in order not to damage anything?

Just my $0.02 worth.

;)

-Storm.

Unfortunately it's just not that simple. But I do agree that consumers should be made more aware of the fact that underpowering speakers is more likely to damage them than overpowering for the reasons stated earlier.

edgewound

07-26-2007, 05:58 PM

If we are talking about damaging speakers, wouldn't the makers of both want to be on the same page so one knows which one to get in order not to damage anything?

Just my $0.02 worth.

;)

-Storm.

In a perfect world...yes. But you know how perfect this world is;).

Along with that...not all manufacturers answer to the same ethical standards.

Some quality amps are deliberately rated on the conservative side, while others are rated...well...let's just say on the optimistic side.

Storm, it sounds like given your cirumstances, you're fine.

Just use it wisely, that's all.

clmrt

07-26-2007, 06:52 PM

You're fine, Storm.

As you may have read, I've had as much as 225w available per channel and currently run 15w.

Granted the 225 watter worked better than the 15, but when I had an HK PA2200, rated @ 100 per with no headroom (guessing on my part, since the specs look weak) it would play very loud with authority for long periods and I could detect no stress. Iron Maiden, 98db peaks in the room, for an entire album...which is plenty damn loud. I wasn't even in there for most of it - I just wanted to see if the rig could do it, and it did.

Your Nak is a class or two above that, and your domestic situation won't allow it to approach the danger zone. You're just experiencing normal paranoia audiophilia. Don't start chasing power amps. Let them come to you through happenstance.

Storm

07-26-2007, 08:22 PM

Yes, it does.

When it clips, two red LEDS flicker.

With the valencias, I cranked it up so high I clipped it a couple times. Learned my lesson quickly.

-Storm.

dont know the piece..does it have clipping LEDS ?

Titanium Dome

07-28-2007, 12:56 PM

Yes, it does.

When it clips, two red LEDS flicker.

With the valencias, I cranked it up so high I clipped it a couple times. Learned my lesson quickly.

-Storm.

There you have your own answer. If it clips, turn it down.

If this happens a lot and the result is that you're unhappy with the volume level you can safely get, then look for another amp.

grumpy

07-28-2007, 05:23 PM

If this happens a lot and the result is that you're unhappy with the volume level you can safely get, then look for another amp.

...and make friends with a budding otologist.

My thinking is that you might try out different amplifier types as you have
the funds and desire, rather than concentrate on watts and clipping... or
just enjoy the fine sounds that you have and pursue more important things
:duck:

-grumpy

garyl

07-28-2007, 09:19 PM

Since the tweets are no longer repairable and this is what is most likely to be damaged if you do go into clipping, I wonder if you can fuse the tweets as an additional protection.

Don't know if it is possible or worth trying but might be food for thought and I bet Zilch would have the answer.

Gary

Ian Mackenzie

07-29-2007, 06:16 AM

I think that is the bottom end of the power range for a loudspeaker that has the potential for dynamic range like the 250.

If you have it in a bedroom okay but 100 watts is not going to give you any headroom on that one ocassion when you need it.

Try a more powerful amp (300-400 watts, don't bother with 150 or 200 watts) if you have the opportunity but getting the same quality as the Naka at a good price is going to be stuff.

A big Bryston would be nice or this that is too $$ look at the Crown or QSC stuff. (even hire one and try it out)

Titanium Dome

07-29-2007, 02:26 PM

I run my L250s (not 250Tis) with a Hafler SR2600 (600W/ch) and they can produce an immense amount of sound with no disortion. I usualy stop at around 1/3 rotation of the volume knob on the pre/pro, with the amp gains set at 0.

Ian Mackenzie

07-29-2007, 02:50 PM

Ti Dome,

Those are nice amps!

Ian

subwoof

07-29-2007, 08:07 PM

Power in reserve is everything...think of this example.

You are driving on a small highway at normal speeds and you need to pass 3 slow cars at once due to circumstances and the lack of balls of the drivers in front of you.

With a 100hp generic sedan you need to wait until (A) road is level or downhill, (B) there is a lot of room on the other side, and (C) Some wonderful alignment of road conditions makes it possible. The you hit the gas and do it...maybe..

Now with a 400hp muscle car, you simply stomp on it and make the pass and return to normal speed without even THINKING about all the previous conditions / circumstances needed.

Now in both scenarios you are driving the same speed, the same road, the same idiots in front of you and such. With the power in reserve ( headroom / horsepower ) it is made much easier and actually SAFER.

Now with your system you are playing a quiet passage and suddenly there is a fast snare drum attack or saxophone "bleat" that taxes your electronics. With a 100 watt amplifier it probably will go into distortion for that super-quick moment and probably not hurt anything BUT your ears have registered it as an annoyance and unless you know exactly where the limits are, you might chalk it up to karma...or blame your CD player..the wires..the cat...whatever.

Now do the EXACT same passage with a 400 watt amp ( that's ONLY a 6db increase ) and the passage goes thru with NO clipping or distortion and you suddenly don't notice that "limitation" anymore.

The "transient" was so quick it didn't heat up the coil, didn't over excursion the cone / diaphragm and since you DIDN'T clip the amp, you also did NOT create unbelievable weird waveforms from sending a square wave thru a PILE of passive components ( ever look at all the stuff on your crossover?? )...No coils saturated...no caps turned into clamping circuits...no smoke..

Get the picture??

Power is cheap. Repairing components is NOT.

And suffering thru limited headroom on 3 thousand dollar speakers since you only have a little amp makes no sense.

The nak is ok for bookshelve speakers, I would spend some $$ and get a 400 watt/ch+ amplifier.

This is basic physics - not marketing hype.

sub

Storm

07-29-2007, 10:49 PM

Subwoof --

You have got me scared, now.

So, what amp should I get that is 200 to 400 watts per channel that is reasonably priced?

Would an ADCOM be suitable?

Thanks.

:blink:

-Storm.

majick47

07-29-2007, 10:52 PM

I had an opportunity to hear a pair of 250tis and they were impressive. They were powered by a 420 watt amp and the owner held nothing back and the volume was right up there even for me. Not a bit of distortion/clipping was I able to detect. If you decide to go for a larger power amp try to audition it first if possible. I just switched amps, it was an even swap as the rateings go (250 watts X 2) but one listen told me I had made the right move. I now have my L300 powered by a Threshold S500 Series II. Clipping, distortion, not a chance, everything was cleaner and with a lot more impact at my normal listening level which is quite moderate for a large room.

JSF13

07-30-2007, 05:47 AM

Subwoof --

You have got me scared, now.

So, what amp should I get that is 200 to 400 watts per channel that is reasonably priced?

Would an ADCOM be suitable?

Thanks.

:blink:

-Storm.

Typically,for me at least,once you get up into the 400 wpc plus range the only affordable option, unless you get extremely lucky, is to go the pro amp route,ie QSC,Crown,or get a couple of smaller bridgeable amps.

I used to have a pair of 4430 clones that I ran off of a QSC mx1500 @ 375 WPC that would just never run out of gas. I now have a pair of genuine 4430's that I run off a 250 wpc Yamaha M80 that I can push to its limits quite easily. Overall however I'd have to say the Yammy sounds better within it's limits,(based on my 10 year old memories, lol). JMO.

BMWCCA

07-30-2007, 08:36 AM

Power in reserve is everything...think of this example.

You are driving on a small highway at normal speeds and you need to pass 3 slow cars at once due to circumstances and the lack of balls of the drivers in front of you.

With a 100hp generic sedan you need to wait until (A) road is level or downhill, (B) there is a lot of room on the other side, and (C) Some wonderful alignment of road conditions makes it possible. The you hit the gas and do it...maybe..

Now with a 400hp muscle car, you simply stomp on it and make the pass and return to normal speed without even THINKING about all the previous conditions / circumstances needed.

Now in both scenarios you are driving the same speed, the same road, the same idiots in front of you and such. With the power in reserve ( headroom / horsepower ) it is made much easier and actually SAFER.Is there an audio equivalent to torque? Because that's what you're talking about in your example. Horsepower will get you to the ultimate top speed but torque is what gets you moving. More torque, faster acceleration. Of course they usually go hand-in-hand until you put a modern European turbo-diesel in the mix and then all conventional wisdom goes out the window. And how 'bout weight? 100-hp is much more effective on a 400-pound motorcycle than it is in a 3700-pound "muscle car". There's got to be a similar resistance to movement in speaker mass or motor response in audio, or is that simply called "efficiency"?

(I figured this thread had gotten so off the mark already, another detour wouldn't hurt it.)

edgewound

07-30-2007, 11:48 AM

Is there an audio equivalent to torque?

Maybe....Something called damping factor.

The higher the damping factor, the quicker the amp can stop and start the voice coil...Very effective for tight, deep bass response.

It's really noticeable when damping factor is greater than 500. That's what made the Crown K2 so attractive....a damping factor of greater than 3000:blink:.

1 horsepower = 745 watts.
400 horsepower = 298,000 watts:applaud:

subwoof

07-30-2007, 11:55 AM

Well I guess the equivalent of torque would be a combination of the slew rate ( change of voltage on the output with respect to input ) and the internal resistance.

Here is another analogy ( sorry )...

You are in the desert southwest in a small town hauling ore samples to the assayer along a dirt road. You have ONE horse and a small cart.

Your speed is fairly slow but it gets the job done. Now you want to haul 5 times as much ore at the same time. You get a bigger cart, fill it up and your horse tells you to eat dung and die.

Now you get 4 more horses and they now can pull the larger cart together.

BUT it will NOT be any faster even though you have 5X the horsepower...minor variations in speed and elevation are also smoothened due to the larger mass / inertia. You just hope that they are friends and your emission controls can keep up ( whew ).

Now in an amplifier, a small amp will have a small power transformer and as few as 2 output transistors ( horses ) per channel. When you look at the big amps you will see LARGE transformers and a LOT of output transistors.

The crown single channel 10K amp has EIGHTY of them...A D150 channel has only 2.....

And if you remember your math, putting resistors in parallel reduces the overall resistance so the more outputs, the lower the internal resistance ( and this relates to the damping factor in a big way..

Amplifier suggestions??? I only do crowns and urei's and do not know much about the semi-pro / home tweako market but they do have pretty feet and heatsinks but like cars they are subject to marketing whims and outright "creative" science.

Physics is still the same no matter what picard or cochrane say.

Probably the cheapest option is a JBL/UREI 6290 at 300 w/ch. I have seen them on epay for 200-300 but shipping is up there for any large amp.

Crown's macro reference models are also a good choice but start at 1500.

Of course a 400 watt rarium model transmorgifier with unobtanium beveled heatsinks that you can audition at the big city "emporium" will also do an outstanding job and you don't even need the hot water bottle acessories or compass ( you do orient your wires to the van allen belt right ? ) to use it but it will cost you as much as your hybrid in the driveway

oooooo i like doing that...:)

:cheers:

sub

edgewound

07-30-2007, 12:09 PM

Nuthin' like good 'ol horse sense subwoof.

High Fives to ya.:applaud:

Van Allen Belt......lmao

Rolf

07-30-2007, 01:01 PM

So many advices in this thread.

The bottom line Storm is what Ian says. You need a bigger, and not to forget a better amp.

Many years ago I tried both the PA-5 and the PA-7 on my JBL's. In my opinion none of them can be recommended on a large JBL. They are to weak, not enough headroom or Amper. In specs, yes, in practice, NO.

Why not get yourself a newer amp? There has been a lot going on in "the amps world" since those Naka amps.

Much more than in "the speaker world".

DavidF

07-30-2007, 03:32 PM

Yes, it does.

When it clips, two red LEDS flicker.

With the valencias, I cranked it up so high I clipped it a couple times. Learned my lesson quickly.

-Storm.

A 100w rated amp pushed to clipping through the high-sensitivity Altecs seems very, very loud. Or the amp may be overrated at 100w. You ran it this loud in an apartment? Was there equalization in the circuit, a la a bass boost? If you have the need and ability to drive Altecs that high- with no EQ- and try to match that volume with the JBls, you will need lots of power. And be concerned about your hearing as much as your tweeters!

David F

BMWCCA

07-30-2007, 04:32 PM

Now you get 4 more horses and they now can pull the larger cart together.

BUT it will NOT be any faster even though you have 5X the horsepower...minor variations in speed and elevation are also smoothened due to the larger mass / inertia. You just hope that they are friends and your emission controls can keep up ( whew ).Horsepower in the classic sense! :applaud:
Not the same as a unit of power in a car we call "horsepower". Torque is what's pulling that ore, even if the unit is "horse". And all horses are not created equal! The Crown Macros are Clydesdales! And, sadly, discontinued.

Zilch

07-30-2007, 05:49 PM

Issue: Input sensitivities of consumer vs. pro amps; constant gain vs. constant sensitivity.... :hmm:

subwoof

07-30-2007, 06:02 PM

I have 4 of the 10K and 12 ( I think ) of the 2K monoblocks in the shop storage area...need power???

The big amp is 3 phase BUT if you are very very good with electrical distribution, you can run these off single phase by rectifying the 120V AC line...a few more main caps are needed ( about 30,000 uF at 200v will do )

The 2K monoblock is standard 120 and since it has 32 output devices for a modest 1400 into 4, and dual power supplies, it packs one helluva punch for the low end and they are DC coupled so no meddlesome coupling caps to get in your way of in-phase reproduction all the way to DC.

You can start your car, weld an eye bold and shock a few thousand worms with these guys...

Sadly the world is sliding towards the self-regulating, self-correcting DSP based switching power supply type amplifiers which work well but it's like a new gee-whiz hybrid car.

Me, I like the big-block V8 approach. it may not be the most current technology but when the low end is going good, breathing is difficult and the cat is throwing up in the next room.

sub ( and I don't mean boat )

:cheers:

louped garouv

07-30-2007, 06:17 PM

I have 4 of the 10K and 12 ( I think ) of the 2K monoblocks in the shop storage area...need power???

...

sub ( and I don't mean boat )

:cheers:

building home theater subs, for the neighborhood?

;)

i agree with the notion of having lots and lots of headroom....

when i had the Altec M19s, they sounded absolutely grand on a 350 WPC amp..... they did well with 14 WPC EL84 push pull job, but hook up some real power and they really, really blew me away....

but don't kill your ears by turning it up too high....

kingjames

07-30-2007, 06:56 PM

I prefer to rattle windows and not break them. My old ass Pioneer SX1250 pushes these speakers just fine. I only go up to 12 O'Clock on the dial and it's so loud my office windows rattle. What more is needed here? I don't turn it all the way up because this power is not necessary.Where does this clipping come in? When you're amp is maxed!

Everone assumes that they are gonna max the volume on their amp my question would be why would you want to do that because true 50 watts of power is quite loud. I don't mind the neighbor's across the street listening to my system but people down the block got nothing coming.

If you're intent is to max the volume on you're amp all the time then it is wise to get a more powerful amp but if you are gonna run it say around 12 o'clock like I do then what you have is quite sufficent.

After all who listen's to their stuff at full throttle?

louped garouv

07-30-2007, 07:16 PM

I have my amps set to wide open, but the preamp normally only gets up to 3 or 4....

every once in awhile, i'll push it up to 6/7...

nice to be able to do so if the need arises....

louped garouv

07-30-2007, 09:59 PM

Marty DiBergi (http://www.imdb.com/name/nm0001661/): Why don't you just make ten louder and make ten be the top number and make that a little louder?
Nigel Tufnel (http://www.imdb.com/name/nm0001302/): [pause] These go to eleven.

http://www.philasound.com/Steve_Dash.htm

http://www.philasound.com/images/SDX%203700%20front.jpg

:D

Andyoz

07-31-2007, 02:11 AM

Storm,

One of your "concerns" was blowing the precious 044Ti tweeters.

Just remember that as the 250's are a four way, they have a relatively high crossover point to the tweeter (5.2kHz). That helps to limit the amount of power fed into the unit at the lower frequencies and that really helps with the power handling of the driver. I understand that the crossiver does use a 6dB slope though which reduces some of the advantages of the high x-over point but you can see what I mean.

Having said that, an amp clipping heavily would still kill them fast enough. :(

hjames

07-31-2007, 04:24 AM

You don't get it - the amp goes into clipping when it is called to reproduce a signal outside its limits. For the obvious example - lets say you play the 1812 overture. Sound is nice, not too loud but full and robust - suddenly - BOOM BOOM BOOM - the Cannons fire. Those cannons are a huge leap of volume above what your normal listening levels are. You may have been running your 50 watt amp at 1/2 level, but that cannon wants 10 times the power to play those sudden sharp reports accurately. Your amp doesn't HAVE 500 watts, so the waveform flattens out - it no longer is the same as the input signal, it has distorted, or clipped the signal. That my friend, is the distortion and clipping they speak about.
Its not average levels that this happens, its the sudden peaks.

Now, if all you listen to is the smooth "jazz" stylings of say, Kenny G, there may be no dramatic peaks in your music, this may never happen. But most folks into classic rock or the classics do get sudden peaks.

Zat help?

I prefer to rattle windows and not break them. My old ass Pioneer SX1250 pushes these speakers just fine. I only go up to 12 O'Clock on the dial and it's so loud my office windows rattle. What more is needed here? I don't turn it all the way up because this power is not necessary.Where does this clipping come in? When you're amp is maxed!

Everone assumes that they are gonna max the volume on their amp my question would be why would you want to do that because true 50 watts of power is quite loud. I don't mind the neighbor's across the street listening to my system but people down the block got nothing coming.

If you're intent is to max the volume on you're amp all the time then it is wise to get a more powerful amp but if you are gonna run it say around 12 o'clock like I do then what you have is quite sufficent.

After all who listen's to their stuff at full throttle?

Ian Mackenzie

07-31-2007, 05:53 AM

That is an extreme and obvious example in which they warn on the label.

For a thorough and correct explanation refer to John Eargle's publication.

http://www.amazon.co.uk/Handbook-Recording-Engineering-John-Eargle/dp/0387284702/ref=sr_1_3/026-6845423-6260462?ie=UTF8&s=books&qid=1185883986&sr=1-3

It has more to do with the relative sensitivity of the loudspeaker, the listening distance and the maximum undistorted SPL required at that distance. In the above manual 6 db is suggested as the minimum headroom and while peak to average power can vary considerably depending on the recording the case of a 50 watt amp with would mean a 200 watt amp.

As a practical matter a significantly more powerful amplifier as in a 400 watt / channel model does have audibly more dynamic range. This is noticably typically on a piano or trumpet sole and not Telarc demonstration disks.. The transients which the JBL is noted for are otherwise flattened and the scale of dynamic contrast will be diminished.

Although a now out dated design I previously used a Phase Linear 700 Series 11 Clair Bros model. Subjectively that amplifier was vastly superior to a 100 watt amp in terms of dynamic capability at any volume level. The threshold of clipping was 450 watts a side. I only ever used it once in a pro application and that driving a pair of 2 way J bins for a band where the 2226 drivers were pushed to extraordinary levels (over 1 inch p-peak) but with incredible control and they survived to play anoher day.

Of course this is only useful if the loudspeaker can handle the transients which is the case with the L250.

clmrt

07-31-2007, 06:08 AM

Another stick on the fire...

http://www.crownaudio.com/amp_htm/amp_info/how_much_power.htm

BMWCCA

07-31-2007, 06:48 AM

I have my amps set to wide open, but the preamp normally only gets up to 3 or 4....

every once in awhile, i'll push it up to 6/7...

nice to be able to do so if the need arises....Not really the best way to run the amp with respect to pre-amp output and its effect on S/N ratio and pre-amp output voltage. I've probably posted this before, since it was in response to my question on power-amp input-attenuator controls (which is what some incorrectly call "volume controls"), but here again is the reply---snipped for brevity---from Crown on their forum:
When setting the Gain Structure of a system up properly you should set the mixer and preceding gear to be hitting 0VU at the maximum you would be running the system. Then turn the amp up for as loud as you need it. This way you know that when the mixer levels are hitting 0VU the system will be driving the amp with enough to go full volume (if the input attenuators were turned all the way up). If you don’t need the system this loud turn down the amps and you will still have the best System Signal to Noise.

If you turn the amp up all the way or always to a higher setting than most of the time you will be running the mixer in the area were the mixers output is very low with very little meters. When running a mixer at these lower levels the audio signal is closer to the mixers noise floor and all the system gain will be at the amp. However, with the system gain at the amp the audio signal and the mixers noise floor are so close that now the noise floor (of the mixer) gets amplified as well causing a hissy output at the speakers.

This is why amplifiers have volume controls and why it is best to set the mixer and preceding gear to be hitting 0VU at the maximum you would be running the system. Then turn the amp up for as loud as you need it for the room.

When working with a non-metered Preamp 3/4 of the way up, on the preamp output, is a good place to start as this is usually about the nominal output.If you're interested in reading the entire reply and give-and-take around it, here's the thread link (http://www.crownaudio.com/forums/index.php?showtopic=1282).

sourceoneaudio

07-31-2007, 06:57 AM

You don't get it - the amp goes into clipping when it is called to reproduce a signal outside its limits.

Heather,
He never gets it.........:blink:

Storm,

One of your "concerns" was blowing the precious 044Ti tweeters.

Just remember that as the 250's are a four way, they have a relatively high crossover point to the tweeter (5.2kHz). That helps to limit the amount of power fed into the unit at the lower frequencies and that really helps with the power handling of the driver. I understand that the crossover does use a 6dB slope though which reduces some of the advantages of the high x-over point but you can see what I mean.

Hey Andy,
The tweet uses a 12db slope from what I'm looking at.

Andyoz

07-31-2007, 07:10 AM

The tweet uses a 12db slope from what I'm looking at.

Cool, even better. That's nearly an octave higher than used on the 18Ti (for example)

louped garouv

07-31-2007, 07:26 AM

Not really the best way to run the amp with respect to pre-amp output and its effect on S/N ratio and pre-amp output voltage. I've probably posted this before, since it was in response to my question on power-amp input-attenuator controls (which is what some incorrectly call "volume controls"), but here again is the reply---snipped for brevity---from Crown on their forum:If you're interested in reading the entire reply and give-and-take around it, here's the thread link (http://www.crownaudio.com/forums/index.php?showtopic=1282).

thanks for the tip, I read that before somewhere, but it must have slipped my mind....

i'll try it the other way too....

:)

when i bring the system outside, i am much more likely to run the preamp closer to unity....

it's just to damn loud and unsafe to do so in a home....

Storm

07-31-2007, 11:04 AM

Source,

I do get it, but when another 250TI owner PM's me and tells me that he runs just fine with under 200 watts, then I am feeling more comfortable with my NAK. But thank you for the bashing, anyway's.

I don't have extra money laying around to buy another amp.

I have played the 1812 overture and at loud volumes, and no clipping occurred.

-Storm

;)

Heather,
He never gets it.........:blink:

Hey Andy,
The tweet uses a 12db slope from what I'm looking at.

kingjames

07-31-2007, 12:18 PM

You don't get it - the amp goes into clipping when it is called to reproduce a signal outside its limits. For the obvious example - lets say you play the 1812 overture. Sound is nice, not too loud but full and robust - suddenly - BOOM BOOM BOOM - the Cannons fire. Those cannons are a huge leap of volume above what your normal listening levels are. You may have been running your 50 watt amp at 1/2 level, but that cannon wants 10 times the power to play those sudden sharp reports accurately. Your amp doesn't HAVE 500 watts, so the waveform flattens out - it no longer is the same as the input signal, it has distorted, or clipped the signal. That my friend, is the distortion and clipping they speak about.
Its not average levels that this happens, its the sudden peaks.

Now, if all you listen to is the smooth "jazz" stylings of say, Kenny G, there may be no dramatic peaks in your music, this may never happen. But most folks into classic rock or the classics do get sudden peaks.

Zat help?

What causes an amp to reproduce a signal outside it's limit? Is the volume control the culprit or the signal.I can run my 250ti's at say 50 watts and they sound beautiful and my receiver can handle the extra load.I am in my 50's as you all know and I am trying to understand the logic here.

I bought a 160 watt per channel receiver because I figured the extra power though not needed for my listening pleasures was better to have it as the receiver wouldn't strain under high volume.

I am not sure of all the electronics being spoken here but I get great enjoyment out of my setup and at times on a particular song I will crank it up a little and my speakers love it however even I can only take so much volume.

In the end I run my receiver at 12 o'clock on the dial at most times and is quite loud in fact loud enough where I can hear it all the way out of my front door. I figure this is the loudest that I can handle before the music is annoying to me.Understand though that half way up on this receiver is very loud and will reproduce any sound from any source the way it should be heard.I guess I just don't get it. I just don't get why I should buy a 400 watt amp when my 70's receiver that I only paid $500.00 for can do the job and then some.

Storm

07-31-2007, 12:44 PM

Did someone suggest you should? Sounds like you're fine to me.

-grumpy

I think he is stating that because the overall concensous is for me to get a better amp. However, some agree that my amp is good enough.

My pre-amp volume level is at about 10 O Clock -- and that is plenty loud for me.

;)

-Storm.

kingjames

07-31-2007, 01:06 PM

when the input signal, multiplied by the amplifier gain exceeds the power supply limit
(or triggers protection circuits).

Your volume knob is there to attenuate the input signal
before it gets to the amplifier (which has fixed gain ... probably in the neighborhood of
20dB... unless there's some pre-amp gain too...maybe 6-10dB)

WIth your equipment (CD, tuner, whatever) the 12 o'clock position just happens to be
where you've found a reasonable limit. Home audio equipment tends to have a maximum
output of 1-2volts. Turning your amp all the way up would probably result in clipping.
If you had a component that had a weaker (comparatively) output, you could turn up the
volume more than 12 o'clock to get the same apparent loudness. In other words, the
volume knob does not -set- how many watts come out of the amplifier... it just reduces
the input signal before it gets the the power amplifer section.

Did someone suggest you should? Sounds like you're fine to me.

-grumpy

I noticed on my receiver that most of the volume comes in after 12 0'clock.I don't believe I am getting half the volume at 12 0'clock as after 12 0'clock the volume shoots up dramatically.However you're explanation makes sense.I am fine with my setup and I was trying to find out why my system would blow my 044ti's when I find that everything I have is matched for my listening pleasure.

I guess I can be thankful that I am in my 50's because there was a day I would have blown any speaker and have blown quite a few of them because it seemed I was never satisfied with the volume.Alway's had to max them out.Was costly in the end.Now I enjoy music at a moderate level.

edgewound

07-31-2007, 01:40 PM

I noticed on my receiver that most of the volume comes in after 12 0'clock.I don't believe I am getting half the volume at 12 0'clock as after 12 0'clock the volume shoots up dramatically.

That reason behind that perception is that distortion is perceived as being "louder", when in fact it's filled with all sorts of nasty harmonic artifacts that hopefully tells your ears to "turn it down"...because in reality....it's just plain unpleasant to listen to.

Ironically....it's also very unpleasant for the speakers to reproduce.

Again...to reiterate....

It's not the lack of power that burns up speakers. It's the distortion level.

Again...to reiterate. If you need...or like to listen at loud volume levels....you need the power to get there cleanly.

So...if you listen loud....get more power.

Practice "Safe Sound":p:D...or you'll eventually kill your speakers...tweeters and mids go first.

kingjames

07-31-2007, 01:53 PM

That reason behind that perception is that distortion is perceived as being "louder", when in fact it's filled with all sorts of nasty harmonic artifacts that hopefully tells your ears to "turn it down"...because in reality....it's just plain unpleasant to listen to.

Ironically....it's also very unpleasant for the speakers to reproduce.

Again...to reiterate....

It's not the lack of power that burns up speakers. It's the distortion level.

Again...to reiterate. If you need...or like to listen at loud volume levels....you need the power to get there cleanly.

So...if you listen loud....get more power.

Practice "Safe Sound":p:D...or you'll eventually kill your speakers...tweeters and mids go first.

I have always heard that more wattage meant cleaner sound and not so much more volume. I would have to say based on all I read here that is a true statement.

edgewound

07-31-2007, 01:56 PM

I have always heard that more wattage meant cleaner sound and not so much more volume. I would have to say based on all I read here that is a true statement.

Actually....both are true.

Because in the end result with a given system, you can't get more sound without more power.

johnaec

07-31-2007, 02:57 PM

I have always heard that more wattage meant cleaner sound and not so much more volume. I would have to say based on all I read here that is a true statement.I think what you're referring to is the fact that doubling the input power only results in a 3dB increase in sound output.

It's long been determined that it takes about a 10dB increase in sound output for most people to perceive a sound as twice as loud. Since it takes 10 times the power input for a 10dB increase in sound output, an amp that's only twice the power will only result in a small (3dB) increase in volume.

John

subwoof

07-31-2007, 07:52 PM

For a treatise on this in a consumer lingo refer to the JBL note titled: Danger: low power.

One thing that has not been mentioned at all is what happens when you clip a waveform. This is 1st year stuff in an EE program or engineering school.

Now here is yet another analogy for the "library"

You take your sweetheart on a hiking trip to a waterfall. You climb down the steep gorge and marvel at the thunderous noise when the water hits the rocks. You can't even hear your self think let alone have a conversation.

You walk back to the car and talk about the experience during the drive home.

NOW the next day you are getting a wiener from a street vendor during your lunch break and the local DPW is chopping up the sidewalk with a jack hammer the whole time you are waiting. You go back to the office and your ears ring all afternoon and you have a headache that evening.

Now BOTH of these sources were loud. BOTH were very wide range. BOTH were of the same duration but the after effects were different because the JACKAHMMER pounding the concrete was producing odd AND even harmonics while the waterfall produced only even.

....The math....

A pure sinewave of 1000hz will have just a single component when viewed on a spectrum analyzer or listened to.

When you add harmonics ( overtones for the musicians amongst us ) the "timbre" is changed and it will begin to sound like a specific instrument depending on:

(A) The level of the original note
(B) The number of Harmonics ( odd and even )
(C) The level of EACH of those harmonics.

This is why middle C sounds one way on a piano, another on a flute and yet another on a violin. Same note, DIFFERENT harmonic composition.

Now when an amplifier is fed a nice, pure signal and you run out of headroom, the output clips and for you guys ( and gals ) who got a little into advanced math, the result is a whole spectrum of odd order harmonics.

This is basic transform analysis....and when you sum a series of odd order harmonics you get a square wave. If you add up a series of even harmonics you get a triangle wave. Cause and effect - if the squared portion of a wave form is there, there HAS to be odd order harmonics.

So the bottom line is that even though you have a tweeter in a cabinet that is crossed over at 5000 hz, ANY clipping at ANY frequency below that will produce artifacts that the tweeter WILL be forced to reproduce and this is why so many tweeters die an early death while the woofers are unscathed.

Look at it this way: Clipping a floor tom drum (100hz) will create odd harmonics of 300,500,700,900,etc all the way up into your beloved tweeter. So that means ( in the example of a 250Ti ) it will impact the low mid, high mid AND tweeter....for a nice listening experience.

:cheers:

sub ( and I don't mean sandwich )

JSF13

07-31-2007, 08:08 PM

Cool! :cool:

Robh3606

07-31-2007, 08:51 PM

Some good info on this

http://sound.westhost.com/tweeters.htm

Rob:)

JBLRaiser

07-31-2007, 09:05 PM

http://cgi.ebay.com/Mint-DYNACO-400-Stereo-Power-Amplifier_W0QQitemZ200129828548QQihZ010QQcategoryZ 50593QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

They come up often for around $300. I love mine.

sourceoneaudio

07-31-2007, 10:24 PM

Source,

I do get it, but when another 250TI owner PM's me and tells me that he runs just fine with under 200 watts, then I am feeling more comfortable with my NAK. But thank you for the bashing, anyway's.

I don't have extra money laying around to buy another amp.

-Storm

;)

No bashing here going on, just speaking the truth. We have all discussed this same issue with you b4. It just gets a little old repeating the same sheeet all the time. Remember the massive discussion on the 14 watt amp verses something else to run you Val's. Pretty much the same subject. Also the constant repeating on how to fix your noise issues.

I also remember discussing this same power issue with you in person. :banghead:

sourceoneaudio

07-31-2007, 10:28 PM

PA-5 SPECS:

Specs are as follows: Nakamichi PA-5 Stasis amplifier.

Continuous Average Power Output: 100wpc into 8ohms

Continuous Average Power Output: 160wpc into 4 ohms

Dynamic Power: 150wpc into 8ohms

Dynamic Power: 270wpc into 4 ohms

Dynamic Headroom: 1.7db into 8ohms

Signal to noise ratio: Better than 120db

Output current capability 12 amps continuous, 35 amps peak per channel...

Output Compliment: 10 transistors per channel.....

Power Consumption: 500 watts max

Approximate weight: 35lbs

Power Supply: 450 VA toroidial transformer

PA-5AII SPECS:

Specs are as follows: Nakamichi PA-5 Stasis amplifier.

Continuous Average Power Output: 150wpc into 8ohms both channels driven 20-20,000 HZ, 0.05% THD

Dynamic Power: 225wpc into 8ohms

Dynamic Headroom: 1.7db into 8ohms

Signal to noise ratio: Better than 120db

THD @ rated power 20-20,000 hz less than 0.05%

Output current capability 18 amps continuous, 70 amps peak per channel...

Output Compliment: 14 transistors per channel.....

Power Consumption: 650 watts max

Approximate weight: 47lbs

Power Supply: 470 VA toroidial transformer, 94,000 uf total filter capacitance

PA-7 Specs

Dimensions: 17-1/8 (W) X 7-7/8 (H) X 16-9/96 (D) inches Approximate weight: 59 lbs., 8 oz
Continuous Average Power Output (NEW IHF): 200wpc (8 ohms, both channels driven, 20-20,000 Hz, 0.1% THD)
Continuous Average Power Output 330wpc (4 ohms, both channels driven, 20-20,000 Hz, at no greater than 0.1% THD)
Dynamic Power per Channel: 300wpc (8 ohms)
Dynamic Power Per Channel: 550wpc (4 ohms)
Dynamic Head Room (NEW IHF): 1.7 dB (8 ohms)
Power Bandwidth (Half Rated Power, 0.1%
Damping Factor: (NEW IHF) 20 Hz/1 kHz/20 kHz: Greater than 60/60/60
Input Sensitivity/Impedance (NEW IHF): 2.0 V/ 75k ohms (rated power) 140 mV (1W output)
Frequency Response: (1 W, NEW IHF): 20-20,000 Hz + 0, -0.5 dB, 7-150,000 Hz +0, -3 dB
Signal to Noise Ratio (Input Shorted, Rated Power, IHF A-WTD) : Better than 120 dB Residual Noise Level (IHF A-WTD): Less than 25 u V/
Total Harmonic Distortion: Less than 0.1%
Intermodulation Distortion: Less than 0.1%
Stereo Separation (Input Shorted): 110/100/80 dB
Output Complement: 16 Transistors Per Channel
Output Current Capability: 18 A continuous, 50 A peak (per channel)
Power Supply: 700 W toroidal transformer, 132, 000 u F total filter capacitance
Power Source: 120, 220, 240 or 110-120/220-240 V AC; 50/60 Hz,
Power Consumption: 700 W max.

PA-7AII Specs

Dimensions: 17-1/8 (W) X 7-7/8 (H) X 16-9/96 (D) inches Approximate weight: 62 lbs. 13oz

Continuous Average Power Output (NEW IHF): 225W x 2 (8 ohms, both channels driven, 20-20,000 Hz, 0.05% THD)

Dynamic Power per Channel: 340 W (8 ohms) Dynamic Head Room (NEW IHF): 1.7 dB (8 ohms) Power Bandwidth (Half Rated Power, 0.05% THD Damping Factor: (NEW IHF) 20 Hz/1 kHz/20 kHz: Greater than 60/60/60

Input Sensitivity/Impedance (NEW IHF): 2.0 V/ 50 k ohms (rated power) 140 mV (1W output)

Frequency Response: (1 W, NEW IHF): 20-20,000 Hz + 0, -0.2 dB, 7-150,000 Hz +0, -3 dB

Signal to Noise Ratio (Input Shorted, Rated Power, IHF A-WTD) : Better than 120 dB Residual Noise Level (IHF A-WTD): Less than 25 u V/

Total Harmonic Distortion: Less than 0.05% Rated Power 20-20,000 Hz

Intermodulation Distortion: Less than 0.1%

Stereo Separation (100 Hz/1kHz/1okHz) (Input Shorted): 120/105/90 dB

Output Complement: 18 Transistors Per Channel

Output Current Capability: 20 A continuous, 90 A peak (per channel)

Power Supply: 700 W toroidal transformer, 132, 000 u F total filter capacitance

Power Source: 120, 220, 240 or 110-120/220-240 V AC; 50/60 Hz,

Power Consumption: 900 W max

opimax

08-01-2007, 07:28 AM

Storm,

I wrote you a pm om my opinion which was the same as i said here publically and you responded.

2 things from your response struck me as ...different

the last you thing you wrote was "So I am I perfectly fine w/my Nak ? Do I need more power"

I then said to myself why did I write this ? a waste of time...

And lastly you also said something "I don't like startring a feud."

maybe not but I begining to think you really enjoy all this attention...

I'm done

Mark
And yes I could have pm'ed this but I think it should be here

majick47

08-01-2007, 09:03 AM

Getting back to the 250ti that I had an opportunity to listen to, I forgot to mention that they were biamped, 420 watts for the low end and 250 watts for the top end for a total of 670 watts, both were Yamaha Pro amps. After 5 pages on this issue from what I'v read the majority opinion stated that you will benefit in many ways with a much larger amp. Even the few that were on the fence and didn't originally see the need for a larger amp have seen the light and now agree in principal if not practice.

clmrt

08-01-2007, 10:11 AM

Maybe he needs less speaker.

JSF13

08-01-2007, 10:28 AM

Even the few that were on the fence and didn't originally see the need for a larger amp have seen the light and now agree in principal if not practice.

I've always been a true believer of that principal.:D Unfortunately not always as easy as one would like,to put into practice.$$$

jblnut

08-01-2007, 11:05 AM

That would be me :). Sorry I'm late to this party but I don't seem to have a lot of free time these days. I no longer have the dual Yamahas powering my 250Ti's. I am now using some real sweet Dynaco Mark III's on top with the smaller Yamaha (260w) powering just the LE14H-1s. The move from transistor to tube was just what the doctor ordered. The max SPL might be down a few DB but the overall sound is smoother and more listenable, especially at higher volumes (which rock seems to demand).

I have tried smaller amps on the 250's and have always come away wanting more. I tried the Mark III's by themselves (full range) and the bass just withered and died. I have tried other transistor amps in the 65-120w range and also didn't feel they controlled the lows anywhere as well as the big Yamahas do.

I've still got the huge PC4002M gathering dust in my living room if someone wants to come over here, give me $400 for it and cart (wouldn't recommend carrying) it away. It'll rock your 250Ti's and your world like few other amps ever will.

jblnut

Getting back to the 250ti that I had an opportunity to listen to, I forgot to mention that they were biamped, 420 watts for the low end and 250 watts for the top end for a total of 670 watts, both were Yamaha Pro amps. After 5 pages on this issue from what I'v read the majority opinion stated that you will benefit in many ways with a much larger amp. Even the few that were on the fence and didn't originally see the need for a larger amp have seen the light and now agree in principal if not practice.

Ian Mackenzie

08-01-2007, 02:14 PM

JBLnut,

Nice to see you around!!

I think this thread has been quite useful..what happnes if you underpower a loudspeaker and overdrive an amp and the outright benefits of more power.

Storm

08-01-2007, 02:16 PM

I have a line out on a Bryston 3B amplifier.

Any thoughts??

Thanks.

;)

-Storm

clmrt

08-01-2007, 02:44 PM

Don't you have bills to pay?

Sell the Nak for $500, buy that Yamaha for $400, spend the $100 on gas money for the road trip.

louped garouv

08-01-2007, 02:58 PM

I have a line out on a Bryston 3B amplifier.

Any thoughts??

Thanks.

;)

-Storm

you'll have to listen for yourself there Storm,

they are considered very high quality amps, but can be unforgiving from what i understand....

jackgiff

08-01-2007, 02:59 PM

Andyoz

08-01-2007, 03:09 PM

I have a line out on a Bryston 3B amplifier.

Any thoughts??

Thanks.

;)

-Storm

I probably wouldn't bother unless you could stretch to a Bryston 4B

grumpy

08-01-2007, 03:34 PM

I probably wouldn't bother unless you could stretch to a Bryston 4B

...that was my first thought as well. There have been a number of iterations.
Do some serious checking before you drop that kind of wad. -grumpy

sourceoneaudio

08-01-2007, 10:05 PM

[quote=sourceoneaudio;179498]PA-5 SPECS:

Specs are as follows: Nakamichi PA-5 Stasis amplifier.

PA-5AII SPECS:

Specs are as follows: Nakamichi PA-5 Stasis amplifier.

PA-7 Specs

PA-7AII Specs

Jeff, what is the purpose of all the Nakamichi amplifier specs on the Lansing Product Technical Help Forums? Are you hoping to sell Storm another Nak amp? Shouldn't that sort of thing be on the marketing forum?

I don't see any benefit to this thread to have all those Nelson Pass specs here. Just my 2 cents worth.

Jack,
I placed them there so for comparison sake, for his power wanted and or needs, and any questions people might have about the amps.

Seems lots of questions and or doubts about what they can do, so specs in black and white should help.

Second I'm not trying to sell him another amp. What ever gave you that idea????? No selling going on here Jack.

Third, we are all talking power amps here........... Last time I reviewed the thread.

edgewound

08-01-2007, 10:20 PM

I sense a devolution to this thread.

grumpy

08-02-2007, 07:10 AM

"Are we not men?!"

Krunchy

08-02-2007, 10:47 AM

"Are we not men?!"

Thank you!, for putting everything into perspective:rotfl: :shock: :homer: !

johnaec

08-02-2007, 11:01 AM

"Are we not men?!""We are Devo!" :p

John

Ian Mackenzie

08-02-2007, 11:53 AM

Storm,

Seeing as you have the Nak if you wanted to follow a logical progression for more powerful and seriously better amps look at these. The older Threshold amps are not bad either but I think spending good money on a new technology is a wiser decision. These are a two man job to move by the way!

No affiliation with Mark (his father is the company president). Both amps are highly recommended.

http://www.marksammut.com/List.html

X-350 $3295
http://www.passlabs.com/amplifiers/x350_reviews.htm

X-250 $2495
http://www.passlabs.com/amplifiers/x250_reviews.htm

grumpy

08-02-2007, 12:41 PM

I'd agree, especially as the nice Threshold gear, that would have been a good intermediary step a few years ago, has found favor with the flipper crowd (bumped up prices). -grumpy

majick47

08-03-2007, 06:18 AM

Did I go wrong purchaseing a "vintage" mid/late 1980s Threshold S500 Series II amp (250X2) a few months back? After installing it I couldn't help but hear a noticable improvement in the sound of my L300. To me it sounds like an excellent match up to the L300. I'm sure their are newer amps that are better but at what price?

Ian Mackenzie

08-03-2007, 06:43 AM

Depends what you paid for it and how you value spending money on audio equipment. I am sure your Threshold will serve you well.

In Storm's case he has the Nak....that used Pass topologies. In this instance going to a Threshold would be a sideways/ backward step and not one I would recommmend. The Passlabs amps advertised by Reno hifi are factory re-conditioned, tested and work like new.

Personally I don't think US $2500 -3300 is a lot of money on an amp of this calibre these days when we read about people paying the bid up prices we see on Ebay for vintage "flipperised" JBL's like the JBL L300.

Of course it becoming common knowledge that almost any JBL will sound its best on a superior amplifier. Its unfortunate that many are unaware of this and trade in their JBLs on Tad and other exotic brands without hearing what they can really do. I am sure that will raise eyebrows but thats how it is because many people under value the importance of the power amplifier and pre-amplifier.

Its no surprise that current model K2 /E2 JBLs are often demonstrated on Pass Labs & Mark Levinson amplification.

Andyoz

08-03-2007, 07:05 AM

Of course it becoming common knowledge that almost any JBL will sound its best on a superior amplifier. Its unfortunate that many are unaware of this and trade in their JBLs on Tad and other exotic brands without hearing what they can really do. I am sure that will raise eyebrows but thats how it is because many people under value the importance of the power amplifier and pre-amplifier.

Couldn't agree more. I personally think amplifier design has progessed much further in the last 25 years than speaker design. This is particularly apparent when it comes to low-frequency reproduction. It costs a small fortune to get new speakers that do good bass at realistic levels.

grumpy

08-03-2007, 11:03 AM

Did I go wrong purchaseing a "vintage" mid/late 1980s Threshold S500 Series II amp (250X2) a few months back?

I would be quite proud to have that pairing. I'm just constantly amazed at
how prices on some items continue to spiral up. -grumpy

edgewound

08-03-2007, 11:25 AM

Its no surprise that current model K2 /E2 JBLs are often demonstrated on Pass Labs & Mark Levinson amplification.

It's a no brainer for JBL to demo on Mark Levinson amps...it's a Harman acquired brand.

Ian Mackenzie

08-03-2007, 01:10 PM

They were acquired for a reason I guess.

But the point being Edgewound out in the channel markets particularly in Japan JBL dont have contol over what amps dealers sell or demonstrate with. I don't think there is any doubt that the Japanese are the most critical market when it comes to Hifi and high end audio.

From the pictures posted by Don and others in the showrooms over in Japan (where the gear actually moves off the floor) we see one brand and model on that stands out on floor most of the time. Pass Labs X350 and X600. This is also noticable from dealers web pages.

JSF13

08-03-2007, 01:19 PM

X350 = 350 watts maximum @ 1% THD, 1 kHz, 8 ohms.

Don't know much about this but what would it be at say .05 % THD, 20-20khz. Would it be near the same? Or somewhat less to meet this criteria?

Ian Mackenzie

08-03-2007, 01:47 PM

Probably the onset of clipping. (see earlier post). In certain respects the traditional specs rule book got thrown out the window with these design. They use almost zero NF (in the conventional sense) and use other very clever approaches to obtaining the desired technical and subjective performance with very high power output.

Back on topic Halcro and Mac make some big but also rather expensive amps. I always liked the big meters on the Mac's! I actually heard some big Mac's on JBL's at John Nebel's some time back. As I recall John had 4 250watt stereo Mac's biamping his 4343 and 4435. No shortage of power here!

Titanium Dome

08-03-2007, 02:03 PM

Just for comparison, my Hafler GX2600 specs out like this:

600W/ch @ 0.2% THD 10Hz-20kHz +/-0.1dB
or
600W/ch @ 0.2% THD 0.2Hz-100kHz +/-3dB

My Hafler SR2600 is identical.

These are wonderful, wonderful amps and they spec out quite well. However, you'd virtually never see them in a high end shop driving anything. After all, specs tell us nothing about how they sound.

I think they sound great, just the way I like, but the topology is quite different from a Pass or a Levinson, and the Haflers are meant to go on the road or in the studio (or the fanatic's home), but Pass and Levinson are definitely targeting the upscale audio market with highest quality products.

If I could get a Pass or Levinson, of course I would. In fact if I could trade a Hafler for one of them, I'd do that, too, though probably one or two of the SR2300s. Those 2600s are just too hard to let go. ;)

Rolf

08-03-2007, 02:08 PM

What is wrong with some of you here? The ampflifiers has come a loooonnnng way since the 70's and up to now. Regarding the Pass power, that Ian talks about I do not agree. They are good ... yes, but compared to other brands they are not any better.

Use whatever the brand you choose, but the one thing to do is "overpower" your JBL's. They sound much better that way.

majick47

08-03-2007, 02:34 PM

Grumpy thanks for the encouraging remark re my vintage Threshold amp. I'd love to have a new high power Pass, Levinson or other TOTL amp but boy does this hobby drain your wallet in a hurry. I consider myself very fortunate to have been able to afford the "vintage" stuff let alone the latest. I'm an amature compared to many LH members having a lot less background/experience/equipment but I'm grateful to have what I have and I enjoy it and I'm always open to suggestions from my esteemed fellow LH members. Probably the reason for the esculateing prices of vintage equipment, speakers/amps/etc, is the astronomical prices of new/current equipment. Re pro amps/equipment if it works as well and sounds as good as "consumer" and is reasonably priced I wouldn't hesitate to use it. I remember talking with the tech at my local JBL pro shop and he said the rule of thumb for JBL speakers was to have amp/amps that had three times the power rateing of the speakers to be on the safe side.

Charlie4350

08-03-2007, 02:40 PM

runs 4350's with the Levinson's. He walks to work to pay for it, but said he had to do one thing the best he could. Funny guy.

Rolf

08-03-2007, 02:43 PM

runs 4350's with the Levinson's. He walks to work to pay for it, but said he had to do one thing the best he could. Funny guy.

Lowley setup. 200 Ampere? More?

Ian Mackenzie

08-03-2007, 02:58 PM

majick47,

I agree 100% with everthing you said, my other posts are just in context of the original discussion. I just think its unfortunate that Ebay preys on music lovers.

Rolf,

What wrong with you??

Rolf, we are all entitled our opinion.

I never actually said they are better. What I was talking about was what people see as a standard and what they obviously prefer. I mean they can have anything in their shops that they like. But we see the same boxes on the floors Pass, Levinson, Macs.

You are entitled to agree to disagree if you like. Some people do that for a living.

Just don't insult those of us who own and can obviously lay claim to what we are talking about when you dont own the same equipment or appear to be able to support your own remarks with some factual supporting information.

Of course anyone can come on the forums and argue to support their own cause to just cause an argument. I am not in that business.

Ian

Storm

08-04-2007, 10:17 AM

Would a Crown K2 series amp be better than the Nak?

How hot does it run?

Specs read 500 watts into 8 ohms.

;)

-Storm.

Ian Mackenzie

08-04-2007, 01:08 PM

http://www.stereotimes.com/amp031302.shtml

Storm,

Read this review for what its worth.

I have looked at a few other references including some posts on the forums and I think the bottom end would be impressive but for full range it might be a different cup of tea to the Nak.

I am inclined to think if your ear is trained on the Nak you are looking at real money to follow the same path at that power level. Hence the links to Reno hifi. I know if Iived in CA I'd be all over the X350 like a hot rash!

Although not the norm the 250ti could be biamped (different from bi wired) and that will certainly cure the dyamic range but that invites critical review of the active crossover and a bunch of extra boxes and cables but it can be done.

Ian