OTL Asylum

OTL, Output Transformerless Amplifier User Group.

Return to OTL Asylum


Message Sort: Post Order or Asylum Reverse Threaded

Fourier Components "Sans Pareil"??

63.228.196.122

Posted on October 21, 2004 at 14:16:16
Ivan303
Audiophile

Posts: 41953
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
A person claims these were designed by Atmosphere and/or Ralph Karsten.

Is that so? Are they "Knock-offs?"

What's the story on these rather large amps?

TIA

 

Hide full thread outline!
    ...
Re: Fourier Components "Sans Pareil"??, posted on October 21, 2004 at 15:01:34
Dr Legendre


 
I can tell you beyond the shadow of a doubt, that none of the Fourier components were in any way designed by Ralph Karsten. However, when Fourier went out of business in the mid-90's, Atma-Sphere attempted to do service and support for their existing customers. One set was repaired.. but upon power-up a large, hi-voltage cap exploded and violently ejected itself from the chassis, leaving a dent in the Atma-ceiling. It was found that the cap, which was rated for some 340V, was being run significantly higher than that - either due to faulty design, or improperly selected components.

After these events, it was decided that the Fourier amps were far too problematic to deal with. If we could not offer a repair solution in good concience, then we just simply could not offer a repair. From that point, we declined to service any more Fourier equipment. To this day, all that remains is the dent.

DrL

 

Fourier OTLs, posted on October 21, 2004 at 15:12:54
Jim Dowdy
Manufacturer

Posts: 1504
Location: Atlanta, GA
Joined: July 22, 2000
I know very little about the Fourier OTLs beyond looking at their schematic (courtesy of good-guy John Atwood).
This is essentially a Futterman design - and totally different from the Circlotron approach of Atmasphere/Karsten.

 

Hmmmmmmmm!, posted on October 21, 2004 at 15:20:53
Ivan303
Audiophile

Posts: 41953
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
Someone been telling me a STORY!

That explains a lot ;-)

 

Re: Its late . . . should not post . . ., posted on October 21, 2004 at 23:56:21
Mike Mount
Audiophile

Posts: 560
Location: midwest
Joined: September 25, 2004
Fourier, indeed appeared (on paper at least) to be a more robust circuit (than my OTL3 anyway), I am certain a totem pole or stacked series parallel configuration, tube bank ala' JF.

Absolutely a variation of, (90% like) my OTL3s, I studied them both a while back. Most certainly NOT (as good as) Ralph Karsten concepts . . . I own both.

Calling...Brian Walsh - Where are you?

 

I owned..., posted on October 23, 2004 at 10:36:27
Brian Walsh
Distributor or Rep

Posts: 10766
Location: IL
Joined: December 6, 1999
a Fourier Triode, the ~90 w/ch stereo version of the Panthere monoblocks. It sounded great, when it worked, which was far too infrequent. Like the Panthere, it used the 6C33 dual triode output tubes, four per channel. All of the Fourier amps were modified Futterman designs, although Tom Gambill didn't design all of them.

Fourier Components was purchased by Bryan Carey sometime in the mid 90s as I recall, and prices were raised substantially - Tom Gambill, the original designer/builder/owner of Fourier who remained there, supposedly had priced the Sans Pareils initially below his cost of materials - not a very good business model :-)

Owning the Triode was a love-hate relationship because of the unreliability. One of the Binda coupling caps (1300 uF @ ~330 V) spilled its guts and was very tough to replace due to the ultra-tight spacing on the board. A piggyback solution might be necessary unless one is lucky as I was to find near replacements that would fit. It's believed the Binda high voltage electrolytic caps were salvaged from somewhere in India. Tom Gambill may the only one who knows. When Fourier closed down in early '97 soon after showing at CES a few weeks before (getting great sound with Sound Lab A-1s in a very small room), they refused to sell me any parts, saying all of their spares had gone to their dealers. There's a lot more to the story, but let's just say I gave my amp to a friend who had been, and has been, very helpful with it and other things.

There are a few people out there who have worked on Fourier amps, but they're not for the faint of heart. Schematics help. I was able to get hand drawn schematics of the Panthere/Triode from Tom while picking up my unrepaired amp at their place in the St. Louis area as they were about to close down.

Tom seemed to be a pretty nice guy with a good ear, a technician but not a business person. Parts quality was very good, while layout and build quality left something to be desired. I hope he is doing well in whatever he's doing now.

click here for info

 

Re: Its late . . . should not post . . ., posted on October 27, 2004 at 06:59:14
Brian Walsh
Distributor or Rep

Posts: 10766
Location: IL
Joined: December 6, 1999
Mike,
The Fourier amps sounded excellent...a completely different approach from Atma-Sphere, which also are excellent but a different flavor... You might want to change your registration here to (D) to reflect the fact that you are a dealer of the latter...

click here for info

 

Page processed in 0.021 seconds.