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View Full Version : Tube bi-amp or not to bi-amp



John Y.
07-27-2003, 04:57 AM
I was told by my esteemed aerospace electronics brother (real bro, not social bro) that my idea of bi-amping using tubed electronics on the high frequencies (2440) and solid state on the lows (2226) would result in phase differences that might be audible due to the differences in circuits. Anyone concur with this assessment? I would think this would be in the noise, compared to the phase differences from crossover configuration and from driver location. Am I right?

John Y.

PSS AUDIO
07-27-2003, 06:17 AM
Originally posted by John Y.
I was told ... that my idea of bi-amping using tubed electronics and solid state on the lows would result in phase differences that might be audible due to the differences in circuits.John Y.
Hello John,

Take two amplifiers, wire them, call your brother, let him know that you followed his idea and just ask to listen to the system.

After that, let him know, if it is the case, that he could not hear any phase differences.

I do love people with a lot of theatrical, rhetorical and theory knowledge (in this case itís quite the same) put I by far more prefer someone with practical experience!

Earl K
07-28-2003, 06:54 PM
Hi JohnY

Always dangerous to bring a family member to the bear pit.

- I biamp or triamp everything I use .

In a biamp scenario , one enclosure type that I use is a JBL 15" with JBL 1" exit driver. This speakers can be driven by 1 of any 3 of the following amplifier combinations.

#1 - All QSC PL 1.8
#2 - Bryston 2B-LP for the highs & Carver PM 1.5 on the woofer
#3 - All Carver PM 1.5 ( combo since retired )

My personal rating or "likeabilty index" for the above combos for home use goes like this ;

Best - by a long shot is the #2 combo
Typical of "todays'" sound - goes to #1 combo
& "I Won't ever do that again" :no: - goes to #3 combo - and I like those Carver amps / I really do.

( I keep Crests around for their stiff power supplies for subwoofing )

- My point - It's just all so subjective. I'll eventually try tubes for home use ( just to give it a go ) .

- Engineering theory still hasn't quantified "likeability". :hmm:

- Expose a music-loving electrical enigeer to some of these apparent paraodoxes and that person is likely to have a stroke trying to determine the reasons. :spin: Show him the typical offset in voice coil locations - another stroke. :shock:
Ask him to accept the ubiquitous mix of horn loaded compression drivers & reflex tuned woofers - it's now too late for the ambulance. :bomb:

just my opinion <> Earl K :cheers: ( try the tubes )

scott fitlin
07-28-2003, 09:06 PM
You most certainly can bi amp and go solid state on the lows and tube on your highs! I have a freind who runs his JBL woofers on a BGW 750 amp and his horns on a McIntosh 2105 and his tweeters are driven by the Classic McIntosh MC-240!

I love the way that tube Mc sounds on his tweeters and if their are phase problems I cant hear it!

Earl, I do like that Bryston 2B! Thats what Im going to run my six 2405 slots on!

MikeM
07-29-2003, 08:48 PM
Crossover design has come a long way in newer speakers ware biamping actually is not reccomended. Ive found there are advantages and dis. Maybe a great single amp will do as good or better. There will be less in line to degrade the original signal. Ive found on my 4435 single amped has better imaging and less midrange problems. On my 4350 I used monblock lows and high resolution tube highs with astounding results. Ive had some pretty good stuff too.:banghead:

PSS AUDIO
07-30-2003, 12:10 AM
Originally posted by MikeM
Maybe a great single amp will do as good or better. ... On my 4350 I used monblock lows and high resolution tube highs with astounding results. Ive had some pretty good stuff too.:banghead:

I do use a great single amp with my 4350, I just added a 250 Hz 12/dB xover made by a "huge" coil made of 1,4mm of copper and excellent polypropylene capacitos, and I must sayt that it sounds GREAT.

http://www.pssaudio.com/images/filtre/fpb250.jpb

I haven't tried bi-amping as:

I like the global sound of the amplifier as it is VERY smooth in the mids and sweet in the high,

There is no significant loss of power where bi-amping is sucesfull and usefull in PA systems

PSS AUDIO
07-30-2003, 12:13 AM
Originally posted by PSS AUDIO
I just added a 250 Hz 12/dB xover made by a "huge" coil made of 1,4mm of copper and excellent polypropylene capacitos

Here is the pic (I hope so)!

Ian Mackenzie
07-30-2003, 04:25 AM
I recall in some JBL literature that both amps should be the same, but this could be for a variety of reasons apart from sonics, matching sensitivity, power output, etc.

The origin of bi amping is Pro sound where power and power losses are a concern. These days they have taken the idea to state of art levels with digital system controllers make even the space shuttle look ordinary. But I have not heard great reports about the sonics for hifi applications.

For the home brewer bi/tri amper, it opens up Pandoras Box for a whole mix of options to blend the sound to your own taste..just like Wine..

Unless done with great care though, all you end up with is a head ache trying to get the phasing right on all the drivers, particularly with different amps as some amps invert the absolute signal phase from input to output. Then there are the earth loops.

I image the tube amp will be sweet on the top end.

Also, a lot of times the active Xover does not replicate the passive version so well at the crossover point and you get odd image problems particuarly around the infamous 1.00 - 2 khertz area as some have hinted at.

However, at 250-300 hertz, an active crossover can be quite effective and even less costly than a A1 passive xover with 5.LB coils for low dcr.

With the high sensitivity of the 2440 you may need to pad it back a little to improve the signal to noise ratio via the active crossover and tube amp!

A great big Class A Solid state amp seems the best bet for me but is beyond the reach of most unless you can make it your self.

macka

Ian Mackenzie
07-30-2003, 04:29 AM
Eyes of the chick lads (Elle McPherson),

The interior of my diy class A amp.

If anyone is interested in this area of diy send me an email.

I also have a discrete Class A crossover in the wind.

macka

all4medeq
02-17-2008, 11:12 AM
Dear all, dear JBL guru,

I have 4350A system and a Mark Levinson 336 as power amp. Unfortunately I cannot afford the cost to upgrade the system to bi-amp so I am looking for a professional passive network to replace the recommended electronic xover @ 250Hz. Any of you has a schematics or a link where I can found it. I could DIY but I am SURE the result will not be comparable with the quality of the existing system and i do not want jeopardize the sound quality because my poor experience. Building from a schematics is fine for me. Thank you in advance.

Tweak48
04-11-2008, 10:22 AM
I was told by my esteemed aerospace electronics brother (real bro, not social bro) that my idea of bi-amping using tubed electronics on the high frequencies (2440) and solid state on the lows (2226) would result in phase differences that might be audible due to the differences in circuits. Anyone concur with this assessment? I would think this would be in the noise, compared to the phase differences from crossover configuration and from driver location. Am I right?

John Y.

I'm doing exactly that with my L-300s, and I think it sounds pretty good. Talk about tight bass! That direct coupled Rotel s/s amp wired straight into those woofs rules with with an iron fist!

http://audioheritage.org/vbulletin/attachment.php?attachmentid=8649&stc=1&d=1119662088

spkrman57
04-11-2008, 11:24 AM
I have used in the past a electronic crossover (SS) with SS amp on the bottom, and a tube amp for the compression drivers on horns.

The result was very good.

However, my favorite is all tube system with sub plate amp for bottom octave response. This keeps the SS amp only on the bottom with no SS in the signal chain to the main speakers.

Just my opinion though!

Regards, Ron

PSS AUDIO
05-07-2008, 03:54 PM
Dear all, dear JBL guru,

I have 4350A system and a Mark Levinson 336 as power amp. Unfortunately I cannot afford the cost to upgrade the system to bi-amp so I am looking for a professional passive network to replace the recommended electronic xover @ 250Hz. Any of you has a schematics or a link where I can found it. I could DIY but I am SURE the result will not be comparable with the quality of the existing system and i do not want jeopardize the sound quality because my poor experience. Building from a schematics is fine for me. Thank you in advance.


Hi,

As said earlier, you can use this xover (browse the site for the schematics): http://www.pssaudio.com/indexuk.php?rubrique=filtrespassifs

ALTEC9846-8A
05-10-2008, 01:51 AM
I biamped my system. Tested it out with 2 tube amps and couldn't hear a difference so I went back to the origional crossover and one amp.:(

arawak1969
05-23-2008, 07:53 PM
Have you tried the 771 bi-amp or the 1224 yet?

These were the original units for the 9846.
I have both units and they are AWSOME on these speakers.

I tried other setups including Crown VFX-2A with Crown amps and Altec amps. They could not beat the Hi-Fi accuracy of those little biamps.

I have a pair of the 9846B's and a pair of the Santiago's.

They are a much better sounding speaker with the biamping than just going thru the N501-8A.

Look for a pair, preferably the 1224's.
You will not be disappointed.

Peter

Nothing good can come out of Trenchtown..............Bob Marley
Bob playing in the basement................... My Sunday afternoon heaven. http://www.audioheritage.org/vbulletin/images/icons/icon12.gif

scott fitlin
10-12-2008, 08:48 AM
Have you tried the 771 bi-amp or the 1224 yet?

These were the original units for the 9846.
I have both units and they are AWSOME on these speakers.

I tried other setups including Crown VFX-2A with Crown amps and Altec amps. They could not beat the Hi-Fi accuracy of those little biamps.

I have a pair of the 9846B's and a pair of the Santiago's.

They are a much better sounding speaker with the biamping than just going thru the N501-8A.

Look for a pair, preferably the 1224's.
You will not be disappointed.

Peter

Nothing good can come out of Trenchtown..............Bob Marley
Bob playing in the basement................... My Sunday afternoon heaven. http://www.audioheritage.org/vbulletin/images/icons/icon12.gif
Marchands XM-136 tube active crossover would float your boat.

Custom tailorted for your needs/application;i,e. slopes, filter types and points, gain and voltage drive, they use 12AX7A tjbes, and then, you source genuine NOS early to mid 60,s Amperex 12AX7A tubes.

EARGASMS!