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Futterman versus whatever

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Posted on December 17, 2010 at 16:39:57
decca4
Audiophile

Posts: 16
Joined: October 7, 2010
 It is a bit tiring to read about comparisons between the original Futterman and other OTL amplifiers. The Atmasphere for example is built with modern components that were not available to Julius Futterman. The electrolytics in the Futtermans are at best 30 years old. How can you expect such an old amplifier to show what the circuitry is capable of?

Today a friend and I ran a comparison between my original old Futterman H3AA and my friends H3AA where all the critical component had been replaced (all electrolytics, coupling capacitors and so on had been replaced as well as meny of the resistors) some of the capacitors had been increased. The difference was really remarkable. Although mine sounded very pleasing it could not compete in terms of low end power performance and clarity. The sonic signature was the same. However the resolution an attack in his amplifiers went all the way down into the low register. The dynamics was certainly also superior. The top end was similar although his amplifiers had slightly better control.

So please take these facts into consideration when commenting on the performance fo the original Futterman amplifiers.

Stefan

 

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RE: Futterman versus whatever, posted on December 18, 2010 at 21:39:20
garymuffley@fuse.net
Dealer

Posts: 445
Location: Maryland
Joined: March 29, 2006
 He speaks the truth.

 

RE: Futterman versus whatever, posted on December 19, 2010 at 08:59:14
Tre'
Industry Professional

Posts: 17294
Location: So. Cal.
Joined: February 9, 2002
 The big difference between the Futterman and the Atma-Sphere is not the parts used but the circuit.

In the Futterman one bank of tubes are cathode followers and the other is not. So there has to be compensation for this in the driver stage.

In the Atma-Sphere (Circlotron) both banks are the same with no need to compensate.

So the Circlotron is inherently a better circuit than the Futterman.

Now what that means in terms of sound and how the two compare to your ears is entirely up to you. But technically speaking, the Atma-Sphere should sound better.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

all things being equal..., posted on December 19, 2010 at 11:28:34
Jim Dowdy
Manufacturer

Posts: 1518
Location: Atlanta, GA
Joined: July 22, 2000
 I'm of the opinion that a SEPP stage sounds better than a cathode-follower stage.

 

RE: all things being equal..., posted on December 19, 2010 at 12:41:41
Tre'
Industry Professional

Posts: 17294
Location: So. Cal.
Joined: February 9, 2002
 Interesting.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Futterman versus whatever, posted on December 19, 2010 at 17:24:16
decca4
Audiophile

Posts: 16
Joined: October 7, 2010
 Tre

I think that how the respective amplifiers sound should be the criteria by which you judge rather than what one thinks about a particular circuitry. My point was that if you want to make a comparison between the Futterman and other OTL amps you should at least restore the Futterman and not evaluate it based on long since worn out electrolytics and other capacitors (polyester) that are not used in any design today. Have you or anyone else done that?

I have nothing whatsoever against the Ciclotron by the way, just looking for a fair test.

 

RE: all things being equal..., posted on December 19, 2010 at 23:27:10
airheadair
Audiophile

Posts: 393
Location: California
Joined: October 18, 2010
 how do the output impedances of these amplifiers compare? I suppose it depends on the tubes used. The 6LF6's, which are very hard to find now, might be one advantage for the Futerrman design.

 

RE: FWIW, posted on December 20, 2010 at 08:24:33
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 There have been plenty of Futterman-style OTLs in the last 30 years. One of the best was the Prodigy, made in Texas. They went under in the early 1990s. We did get to compare the amplifiers at that time, and also last year when one came through the shop to be refurbished.

We've also done comparisons with the Sans Pariel and Triumphe (Fourier Components), the latter being a 6AS7-based version of the Futterman circuit. These comparisons were done in the late 1990s when the company was still around or just barely had gone out of business.

So the issue of newer parts, while important, may well be moot, if any of these amplifiers are considered valid Futterman candidates.

 

RE: Futterman versus whatever, posted on December 20, 2010 at 14:16:32
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 Excuse me, but I have responded to most of the inquiries about Futterman amplifiers. First, I have never put down the sonics of the Futterman amplifier except to say that in my extensive experience of using both breeds (Futterman and now one Atma-sphere amp), I prefer the latter. It is very conceivable to me that someone else could have a different opinion. Moreover, I don't recall that anyone who regularly posts here has made a categorical disparaging remark about Futterman amps, including Ralph. Second, the first thing I have advised every single nouveau owner of a Futterman to do is to change out those old electrolytics, bypass them with film caps, etc, etc. In fact, you virtually quoted me in saying that Julius did not have access to the high quality electrolytics we can buy today.

So, now that that is settled, I myself would love to hear a rejuvenated H3aa, of which I owned two pairs in my earlier audio life. But my preference for the one Atma-sphere amp that I do own and have owned for about 12 years is not based on comparing it to an ancient unrestored H3aa. My previous amp was a Prodigy OTL, sort of a super-Futterman once made in Texas. It used six or eight 6LF6s per side and was very modern in all ways, circa 1996 or so.

 

But your premise re this website is unfounded, posted on December 20, 2010 at 18:55:18
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 see above, please

 

What truth?, posted on December 20, 2010 at 18:57:38
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 That Futterman amps are superior to other OTL topologies or that the OTL Asylum has dissed Futterman amps? The former statement is a matter of opinion to which anyone is entitled, and the latter statement is just plain false.

 

RE: Futterman versus whatever, posted on December 21, 2010 at 07:33:47
decca4
Audiophile

Posts: 16
Joined: October 7, 2010
 Lew and Ralph
Please read my original post. I am reffering to the original Julius Futterman amplifier and not copies, interpretations or "improvements" of this amplifier. Also I am not addressing any particular person on this forum. However it is my impression that to often you find comments regarding the Futterman amplifier when it is really something else than the original that is meant.

Its mentioned in some posts that Futterman blows up or can hurt your speakers. But it has also been pointed out by some of you that this is not true of the amplifiers built by Julius Futterman.

I once visited Harvey Rosenberg in his home and he said: "We will gladly publish the circuitry. Anyone that tries to build one will find out that it is a self-destructing booby-trap. It took us more that a year to make it work without blowing up." Maybe Julius Futterman knew something that others did/do not.

If you want to pass judgement on how the Futterman sound or behaves compared to other designs I think that you should use one built by Julius Futterman properly refurbished and not an amplifier built by someone else.

I have had the opportunity to compare the OTL-3 and the Futterman H3AA. Although the circuitry is probably 90-95% the same they do not sound the same. The original was clearly better.

I suggest than when people wright about amplifiers using the Futterman topology that they would not call it a Futterman because it is not.

 

RE: Futterman versus whatever, posted on December 21, 2010 at 08:17:44
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 I assume that English is your native language. Please then read again what I wrote above, and then I invite you to do an archival search of this website using the key "Futterman". I hope after you do that you will see that you are trying to create a straw man; Futterman amps have not been dissed on this site, except for an occasional remark about reliability. On that score, I too defended the original Futterman design. I NEVER had an operational problem with a real Futterman amp or with the Prodigy, which by the way was a REAL orthodox Futterman amp built to a higher level of quality than the H3aa, albeit the printed circuit boards they used might have been inferior to the point to point wiring used in the H3aa. By the way, although the NYAL, Fourier, KSS, and Counterpoint OTLs (all basically Futterman types) did have reliability issues, the problems were usually due to the way in which the topology of the respective amplifiers departed from the original Futterman circuit, most often in an attempt to do away with the output coupling caps. I have repeated this sentiment many times here.

When I bought H3aa's, they were fresh, new amplifiers. In fact, I have vivid memories of picking up my second pair of H3aa's in 1979, direct from Julius at his small factory on 72nd St off Broadway in NYC. The varnish on the transformers had hardly dried. Julius was a charming and classy gentleman of the old school. But as you say, and as I have said, the true potential of those amps was probably never realized due to the limitations of the parts available to Julius and to the fact that he probably would have been amused by the current obsession with types of wire, capacitors, resistors, tube sockets, RCA connectors, speaker outputs, etc, etc. That stuff just was not a part of home audio back then, and for a brand new pair of H3aa monoblocks, I probably paid about the same in 1979 as what you might pay now for a pair of Vcaps. The 18ga AC cords on my Futtermans were no different from that used on my table lamp. The Prodigy effort was closer to incorporating the modern ideas about parts quality, for better or worse. I'd love to hear an SEPP OTL built by Jim Dowdy using modern parts from the get-go.

 

RE: Futterman versus whatever, posted on December 21, 2010 at 15:54:13
decca4
Audiophile

Posts: 16
Joined: October 7, 2010
 Hi Lew

Let me reiterate: I have never addressed anyone particular at this forum with my original post. My concern has been that in some of the postings there has been a lack of stringency regarding what people are comparing and what a particular circuitry will bring about. You cannot say that if you want to compare A to B that you use C instead of A to make the comparison. IMO there has been some carelessness in the use of the Futterman name in some of the comments on this forum. I think that we should all show the proper respect to the legacy of the man who pioneered the stand alone OTL amplifiers. You will most certainly not have any problems agreeing to this.

Rereading your comments regarding the issue I raised I believe that we have a common view of things in general. I have stated my view and stand firmly by it. Shall we give this topic a rest now?

As you may have noted I have not uttered a word about my listening experience with the Atmasphere. The reason for this is that I have never heard one. From first hearing about it I have longed to here one. I am a Swede and live in the south of Sweden. Tomorrow I am going to Stockholm and had hoped to have the opportunity to listen to a pair at an audio shop in Stockholm. I was informed that they had just sold the pair they had in their store. What a disappointment! I will sign off now for a couple of days and end by wising you all a Merry Christmas!

Stefan

 

RE: Futterman versus whatever, posted on December 21, 2010 at 17:20:16
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 I agree that we agree in principle. That's part of what I have been saying. Happy holidays to you as well.

 

Are you also on the Hammond group? NT, posted on December 22, 2010 at 09:56:59
tesla
Audiophile

Posts: 3180
Location: San Diego County, California
Joined: October 25, 2000
 NT
Proudly serving content-free posts since 1984.

 

RE: Futterman versus whatever, posted on May 6, 2014 at 11:02:15
lucisfero1
Audiophile

Posts: 20
Location: NYC
Joined: August 17, 2000



I just wanted to add having come across this thread today, I am currently listening to a KLH-Model Nine system powered by a Futterman H3a. Julius tweeked it for me in 1984, almost 12 years after i had bought it. So I got it in 1972 this being 2014 the amp is 42 years old and still working fine.(I have changed the 8-6KG6a output tubes)

 

RE: Futterman versus whatever, posted on July 20, 2019 at 13:43:58
lucisfero1
Audiophile

Posts: 20
Location: NYC
Joined: August 17, 2000
 And that very same Futterman H3a which is now 47 yrs old (from the time I bought it) is still working today.

 

RE: OTL amps in contrast, posted on March 31, 2021 at 11:29:23
Mike Mount
Audiophile

Posts: 573
Location: midwest
Joined: September 25, 2004
 ~ virtues of point to point wiring ~
has to factor into the equation.

I own a NYAL OTL4 (bought last year)
I have yet to 'compare' it to either of
my M60s or MA1s.

Not really an imperative to me,
OTL4 was an 'investment'.

*I realize the original post mention
was specific to 'original' design
and builds...

**Not being snarky** or remotely
meant as criticism... I was stunned
by the *kind of messy* wiring, I am
surprised H3(xxx) do not oscillate
like mad.

 

RE: OTL amps in contrast, posted on May 5, 2021 at 11:18:52
Volker
Audiophile

Posts: 22
Joined: May 23, 2001
 "I once visited Harvey Rosenberg in his home and he said: "We will gladly publish the circuitry. Anyone that tries to build one will find out that it is a self-destructing booby-trap. It took us more that a year to make it work without blowing up."
This is myth from Mr. Rosenberg.
Years ago i scratch-built a pair of H3AAa using the original schematics found on the net, only difference was PL519s output tubes instead of 6LF6.
The amps worked stable from start on without any tendency of oscillation, instability or "blow up". Stability tests were done with R/C combinations connected as load and square wave test signals.
The only critical things to keep in mind are:
-You have to put ferrite beads on the anode and G2 connections of each output tube to prevent local HF oscillation (typical for this tubes and not related to the Futterman circuit). I used small toroid cores with 2 cable windings.
-you have to use true star grounding. I used the short connection between input rca and speaker cold connector as central ground point.
-the connection between the input tube anode and phase splitter tube grid has to as short as possible (due to high output impedance of the "starvation" input circuit.
Summary: The original Futterman circuit is stable and there is no "secret" or "magical" component. The only secret is that Mr. Futterman coming from tube test equipment design did know how to build things right.


 

RE: OTL amps in contrast, posted on May 6, 2021 at 07:00:21
rogerh113
Audiophile

Posts: 507
Location: San Francisco South Bay
Joined: October 20, 2014
 Always interested in hearing one of these. I imagine with a couple of updated components it might be quite stunning. Went through the schematic, and it looks well considered. Tried to get a H3 to rebuild, but never did find one.

 

there are other designs than futterman, posted on December 5, 2021 at 16:24:47
LtMandella
 For example, I own Transcendent Sound T8-LN.

Perhaps a more efficient and reliable design. So I have heard anyway, but I have never listend to a futterman...

My T8 has been running for about 20 years now and I only had to replace some tubes and a few small caps that may have been damaged after a move and the power tubes became loose in their sockets.

 

what if?, posted on January 21, 2023 at 19:48:08
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009



?

 

RE: what if?, posted on January 21, 2023 at 19:49:12
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009



?

 

RE: what if?, posted on January 21, 2023 at 19:50:06
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009



?

 

RE: what if?, posted on January 21, 2023 at 19:51:25
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009



?

 

RE: what if?, posted on January 21, 2023 at 19:52:39
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009



think anyone would ?

 

RE: what if?, posted on January 21, 2023 at 19:56:38
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009



just wondered, I hope everyone is doing well,

BC

 

RE: what if?, posted on January 21, 2023 at 20:47:31
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009



in my system

 

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