What is the best OTL out there?

I hope someone worked on the Futterman circuit to cure it’s well-known problems. Harvey Rosenberg and George Kaye tried for years without being entirely successful. Both Ralph Karsten (Atma-Sphere) and Roger Modjeski (Music Reference) have designed and offer better OTL amps than any Futterman.

There's some out there who designed and build their own  OTL that uses better tubes like KT88/120/150,,300b,,VV52b,,even 211 / VT 4C can  be used and  they are more efficient than the ones  on the market today.

This statement is false- there are no OTLs based on any of the tubes listed above.

How can you be sure,I build and designed these types of OTL and they sound excellent.using KT120,KT88,VVT52b,300bMaybe you are just concentrated on your OTL.

I build and designed these types of OTL and they sound excellent.using KT120,KT88,VVT52b,300b Maybe you are just concentrated on your OTL.

Can you indicate the impedance of the speakers you use with these OTLs? These tubes were designed to work into impedances that are vastly higher than the 4 to 16 ohm impedances of most modern speakers.

For example, without an output transformer it seems impossible that a 300B, which in most and perhaps all versions can handle a plate current of at most about 0.1 amperes, could supply anything close to a reasonable amount of current (and hence a reasonable amount of power) into an 8 ohm speaker. Even if several such tubes were used in parallel.

On the other hand, if you were using something like the horn-type antique radio speakers that were made in the early 1920s, many of which had impedances of 1000 or 2000 ohms or thereabouts, I can see that such a design might work.

Regards,
-- Al

Al,
Intelligent and logical inquiry as usual. Xonex77 could you share more detail about your very unique OTL amplifiers using these unusual (for this application )tubes. This is quite interesting. David Berning makes a 300b SET /OTL amplifier  (Siegfried) to my understanding.
Charles,