OTL Asylum

OTL, Output Transformerless Amplifier User Group.

Return to OTL Asylum

Message Sort: Post Order or Asylum Reverse Threaded

Fourier Panthers Inquiring About Reliability And History

73.42.229.40
Posted on August 29, 2021 at 20:51:55
Mister Pig
Audiophile

Posts: 535
Joined: September 21, 1999
Posts: 449
Joined: September 21, 1999
Happen to be considering a pair of Fourier Panthere amplifiers and am wondering what the history is on them. Supposedly these are some of the last production models and are more reliable than previous versions.

I have never been an OTL owner and would use them with a pair of JBL 4365 speakers. I know the earlier version of OTL amps such as the Futterman were not the most reliable of designs, and they tended to fail catastrophically. Or at least that is what I had heard of.

How reliable are the Fourier? I understand the company is out of production, how would one get them serviced?

I see they use a closed case and forced air fan, what are ventilation requirements?

Are they worth spending money on? Or is it more akin to own a vintage English roadster or Italian sportscar?

 

Hide full thread outline!
    ...
RE: Fourier Panthers Inquiring About Reliability And History, posted on August 30, 2021 at 06:25:07
Mister Pig
Audiophile

Posts: 535
Joined: September 21, 1999
 Never mind. Did some searching of old threads and found out they are bad news. Will stay away.

 

RE: Yay! good work on your part nt, posted on August 30, 2021 at 10:48:29
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 -

 

RE: Yay! good work on your part nt, posted on August 30, 2021 at 12:49:06
airheadair
Audiophile

Posts: 393
Location: California
Joined: October 18, 2010
 BTW, there is some disagreement about the reputation of Futtermans, and the NYAL incarnation thereof, as to being unreliable.

My own experience has not been perfect, but I remain satisfied. I have owned my NYAL for 30 years.
One of them caught fire once, but was repairable. They have been retubed twice in the time.
My understanding is that dialing them in after a retube is tricky. However, this only needed to be done twice, and the amps drive a very very difficult load and sound fantastic, after all this time.

Well, we've been through this before.

 

This really isn't isn't about Futterman amps, posted on August 30, 2021 at 13:35:24
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 It really wouldn't have mattered what kind of circuit was in use with the Fourier amps. When you run filter caps of questionable quality a good 40 volts above their rating you can expect fireworks.

 

RE: This really isn't isn't about Futterman amps, posted on August 30, 2021 at 14:01:08
airheadair
Audiophile

Posts: 393
Location: California
Joined: October 18, 2010
 Was that the problem with the Fourier's? If so, could one swap out that part and expect reliability?

Using under-spec'ed parts seems to be more common than one would like....

 

RE: This really isn't isn't about Futterman amps, posted on August 30, 2021 at 14:55:57
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 This question was asked on audiogon this morning. Here is my response:

Do yourself a favor and stay away from them. We serviced (or tried to) some of the fourier products and ran into serious engineering issues. One example: the rather questionable filter caps used in the power supply were run about 40 volts **above** their marked rating! This results in their exploding. Before I figured this out we had one of these amps on the bench. At one point when I looked away from it one of the caps on the power supply board exploded and embedded itself in a dropped ceiling panel. I'm glad it didn't hit me in the face but my ears were ringing for ten minutes. It made a mess.

I regard it as unethical to service these amps unless problems like that are sorted out. This is simply because they can't otherwise be made reliable, and the cost of fixing the engineering bugs is more than the purchase price. If a person had one of these and didn't experience this or other problems he is a very lucky person and should have invested in the lottery instead.

Now it is true that I am associated with Atma-Sphere which is the largest and oldest OTL manufacturer worldwide. But Fourier was already out of business when this anecdote occurred and that was a good 20 years ago. It was their reliability issues that drove them out IMO. I don't care what amp you get, just don't get a Fourier. If you google my posts on this and other websites, you'll see that I'm not in the habit of badmouthing other's products. I make the exception for this one because so many things were problematic with them. In a nutshell the purchase price is only the tip of the iceberg.

 

RE: This really isn't isn't about Futterman amps, posted on August 30, 2021 at 16:40:53
garymuffley
Dealer

Posts: 445
Location: Maryland
Joined: March 29, 2006
 Ralph is right; the quality of the parts left much to be desired. I owned the Fourier Triomphe and the Bindu caps from India were an accident waiting to happen. I also own a Futterman H 3A and it has been very reliable. I used it for 15 years without a single failure, but it has long been retired when I changed speakers.

 

RE: Fourier Panthers Inquiring About Reliability And History, posted on August 31, 2021 at 08:58:46
rhinohifi714
Audiophile

Posts: 174
Location: oklahoma
Joined: June 13, 2009
 If the fourier panthere's are in working condition and a manual is included.
I think if you have the chance to acquire them at a reasonable price I would say go for it.

Ralph is always going to give a less than favorable reply about the reliability of Futterman designed amplifiers.

Air Head can attest to the reliability of their design.


 

RE: This really isn't isn't about Futterman amps, posted on August 31, 2021 at 09:24:17
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 the Bindu caps from India were an accident waiting to happen.

Back 25 years ago when they were made, India simply was not the place you went to find good quality electrolytics. That they were run well above their stated ratings was adding insult to injury.

 

RE: Fourier Panthers Inquiring About Reliability And History, posted on September 1, 2021 at 14:20:33
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 Ralph is always going to give a less than favorable reply about the reliability of Futterman designed amplifiers.

Referring to an earlier post of mine: 'This really isn't about Futterman amplifiers.'

Again, I had a Fourier amp blow up, almost in my face. I moved enough out of the way that the exploding cap missed me. Stuff like that tends to stay with you. It would not matter what kind of amp this was, if **any** amplifier is built with parts operated substantially past their ratings it will fail, and it won't be repairable until the circuit has all the parts operating well within their ratings.

Its that simple.

 

There seems to be some confusion regarding the difference between circuit design and parts selection. Nt, posted on September 1, 2021 at 14:39:55
viridian
 Nt

 

Exactly nt, posted on September 1, 2021 at 14:41:48
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 -

 

Fourier and Futterman, posted on November 19, 2021 at 08:50:24
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 After reading your opening post and associated question, my first thought was that you have the history backwards. It is not that Futterman amplifiers, designed and built by Julius Futterman, are or ever were unreliable. It is that subsequent copycat products, many of which purportedly "improved" upon Futterman's circuit, like the Fourier, the KSS, and the Counterpoint SA4, WERE unreliable, and the unhappy experiences of the owners of those amplifiers fed back on the reputation of Futterman. I have used only OTL tube amplifiers since the early 1970s. In those days, I used Futterman amplifiers, which were by then sort of a boutique item. You had to order from Julius, and he built them to order. I don't know if he even shipped them by that time; I picked up two pairs at his "factory" on 72nd St and Broadway in NYC. He was a very nice man. I ran the same tubes in a pair of H3aa Futtermans for 10 years before replacing them. I never had a single problem, ever. Later on, I owned a pair of Fourier amplifiers and after that a pair of Prodigy amplifiers, which were built like tanks, pretty nearly exactly the Futterman circuit, and pretty reliable. The Fouriers were cheaply built with very poor quality PCBs and connectors, and that may have been their Achilles heel. The KSS and Counterpoint SA4 departed from the Futterman standard in their circuit design, and that may have been the cause of their unreliability. Then of course, there was NYAL. I never owned one of those, but the guys at NYAL were disciples of Julius. They modified his circuit for better bass response. Ralph can say more about that. Suffice to say, when I finally heard an Atma-sphere amplifier in the 90s, I was hooked on the circlotron. However, a real Futterman amplifier properly refurbished or freshly built would still be very nice.

 

RE: Fourier Panthers Inquiring About Reliability And History, posted on November 19, 2021 at 09:01:47
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 As I wrote below, some of the later iterations of the Futterman design were faulty in their conception, where it deviated from the classic Futterman, and/or in their construction, and their resulting high failure rates contributed to the notion that "Futterman" amplifiers are unreliable. Amplifiers built by Futterman and maybe a few other sources like NYAL, are not unreliable, at least based on my 20 years of owning real Futterman amplifiers. In my one experience with a Fourier, my judgement was that the parts content and build quality were at fault.

 

RE: Fourier and Futterman, posted on October 8, 2022 at 14:26:58
lucisfero1
Audiophile

Posts: 20
Location: NYC
Joined: August 17, 2000
 How right you are Lew regarding original Futtermans being reliable. Ive owned a Futterman since 1970 and aside from the caps being replaced, its never had a problem. Ive been driving I've been driving KLH Model Nines since 1971 with the same amp.

 

Page processed in 0.029 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]