Thought on OTL tube amps

"...what we want to do is engage the human limbic system rather than the cerebral cortex "

That should be motto of every audio designer and it is ours, see - http://www.enjoythemusic.com/magazine/manufacture/0708/index.html

Yet, I cannot agree with Athmasphere that negative feedback is bad.

Our entire method of amplifier design is based on the approach which considers an amplifier as a control system. Because of this, our amplifiers are designed with an emphasis on very, very, very high speed control loops. The ultra-short transit time allows the amplifier to correct for many small errors; and the control loop can follow the input much more accurately. It does not (or very minimally) create odd order harmonics, it does not create pahse discrepencies and other garbage conventional NF does. These electrical characteristics result in a more detailed, transparent sound with less noise and louder yet cleaner musical reproduction.

Its very difficult to compete with OTL in harmonic richness for any solid state amplifier. I admit it. We are doing our best but its difficult. However, if don;t like heat, weight, tuning up, warming time and may be have difficult to drive speakers then - you are welcome to try our (and others) ss amps.....otherwise, everybody would own OTL amp...

Oh, almost forgot - there were a few well deserved praises to Jud Barber (of Joule-Electra) OTL designs but Jud does use very judiciously negative feedback....to control speakers even better.

I hope that after RMAF 2010, we will be able to add to this discussion of fidelity to true acoustic music we all strive to achieve and have in our systems.

Good Luck to Everybody.

Hi Athmaspere.

"Negative feedback cannot be used to control speakers. It can only be used to control amplifiers. The idea that it helps with speaker control is part of the myth of damping factor, a subject that has its own thread on this forum right now. "

Dumping factor is a "myth", I agree with you 100%.

I also agree with you that more accurate describtion of Jud Barber use of negative feedback in his OTL amps leads to control amplifier for....for......for...better sound coming from ... from...speakers. So lets not play with words ( it is not presentation of peer-review technical paper here)

If you do not use negative feedback then its great for you, however, in my eyes its not the virtue either. I will propose that for every technology used in amplifier design there is its own advantages and its own disadvantages. Otherwise we all would use one "perfect" design. Solid state amps have class A, AB,C, D etc. Tube amplifiers have traditional push-pull, OTL, SET etc.

I firmly believe that its not "what" technology you use is important but "how" you use it and sonic results are that count at the end. Obviously, each technology has some advantages specific to it e.g. low weight per watt of power in class D - but by itself its totally useless

Finally, regarding gorgeous OTL amplifiers (and I am lover of them!!!!) I can only repeat you conclusion:

" In the end, this means that there are dozens of speakers that work with our (OTL) amps rather than hundreds." - Sure and when it works its spectacular !!!

In our approach (i.e. control theory, which I believe unique in this industry), we are trying to match not only hundreds but every speakers available to produce musically involving sound comparable to the sound of acustic music.