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Futterman. Jump in? Or, not so fast...

Today I heard a Futterman OTL powering a pair of Quad ESL57s. The Futterman has been recently serviced and is in nice shape. It sounded wonderful. I understand this is a rare beast.

I've been advised a set of tubes can last 10,000 hours. But these are not common tubes and they need to be closely matched, an their are 12 of them. If I were to buy this amp I'd immediately start worrying about putting together a backup set of spares, which could run into quite a bit of money.

So - Futterman owners - what say ye?  Jump on the chance to own a legend? Or stick with my "set and forget" Quad 909 powering my ESL 2805s...
markusthenaimnut
ndevamp
55 posts
 
Roger and I had some great discussions way back when about Futterman circuits. The genius was getting a pentode to operate at low plate voltage with high screen voltage, operated by a bootstrapped driver pentode. The oscillations partly came from paralleling the output tubes to get enough drive current. I’ve built a few over the years with PL519s and 6HB5 compaction tubes and can vouch for their transparency. The frequency compensation on the H3 I serviced was a bit of a compromise so I tweaked it to get better stability and make it more linear in the extreme top end. The gas filled regulator tubes sounded far better than zener diodes and solid state regulation in the screen driver circuit and so I decided the circuit did need to be as complex as the original. They look extremely cool too.
Clio09, build it! If you need a hand to interpret Roger’s take on it let me know!
bigkidz
3,427 posts
 
I have not looked at one in over 10 years.  The one we looked at had PS cap issues and if I remember correctly, they were not easy to find or have built.  But that was a long time ago.
kacomess
203 posts
 
I have a New York Audio Labs Moscode 300 (which I may wrongly think is connected to the originator of the Futterman amps) and it was super nice. For some reason, it stopped working and it's been sitting at my brother's house for about a decade. Maybe it's time to look into reviving it!
bdp24's avatar
bdp24
10,182 posts
 

@kacomess, New York Audio Labs was started by hi-fi provocateur Harvey Rosenberg. Harvey hired engineer George Kaye, and the two of them developed the company’s line of tube (input stage) / ss (output stage) hybrid Moscode power amps.

Harvey worked with Mr. Futterman before the latters passing, and bought the rights to the Futterman name and OTL design shortly before that came to pass. Harvey himself died at a fairly young age, but George Kaye continued to support the Moscode amps with service.

kacomess
203 posts
 
Eric,
Thanks for the esoteric and informative news on NYAL. How do you know all this stuff? I’m wondering if Doug at Audio Specialties can fix it (provided I can get my brother to ship it to me from Chicago). Is it worth the cost?

Keith
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