OTL Asylum

Mystery OTL maybe??? (pic attached)

108.26.50.22

Rich Brkich

Customer sent me this pic of old used OTL amp he picked up. He says it looks like it is built in a computer type rack mount chassis....

Ralph (& fellow OTL fans), is this a Atma-Sphere unit???? Except for using a circuit board, it looks like a Atma-Sphere OT given the layout, use a 6AS7's...but I have not seen one before that looks like this.

Happy Listening,
Rich Brkich
Retailer & Audio Asylum Industry Liaison

Follow Ups:

RE: Mystery OTL maybe??? (pic attached) - used-hifi 21:55:50 08/20/16 (0)
Ralph, wonder if these were built by Fred Deviur that was close friends to Mr Robert Fulton
Fred had a recording studio in his house...but worked an engineering job at Honeywell

Lawrence
Its amazing where these things turn up. - Ralph 09:18:00 02/17/16 (5)
This is an amplifier that was built by a friend of mine, based on the early MA-1 circuit, but using 8 power tubes per channel. I'm pretty sure it runs series filaments.

If I remember right this amp was built as a one-off about 1985 or so.
- RE: Its amazing where these things turn up. - AJ 10:54:04 02/17/16 (4)
  Quite a bit of skill there on the part of the builder for a "one-off"
  
  Looks like nice work and a lot of resources and time put into the effort.
  - He hand-taped the circuit board but had it made at a local shop. - Ralph 11:21:02 02/17/16 (3)
    He got some of the parts from us. The chassis was re-purposed.
    - RE: He hand-taped the circuit board but had it made at a local shop. - Lew 12:02:04 02/18/16 (2)
      Looks like REL TFTF coupling caps in there, although from this view I am not sure. Were those available back then? Toroids are advanced as well.
      - Yes, they are REL caps - ruffian 19:55:45 02/18/16 (0)
        
        In Reply to: RE: He hand-taped the circuit board but had it made at a local shop. posted by Lew on February 18, 2016 at 12:02:04
        
        The chassis is undoubtedly from a 6U rack mount computer. It does have REL-CAPs in it. And it does say ATMA-SPHERE inside.
        
        Edits: 02/18/16 02/18/16
      - I'm pretty sure it was not built with the Teflons; they were added about 15 years ago. - Ralph 12:38:34 02/18/16 (0)
        
        In Reply to: RE: He hand-taped the circuit board but had it made at a local shop. posted by Lew on February 18, 2016 at 12:02:04
        
        But we've had the toroids going 'way back.

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