That's the answer from Paltauf to Spritzers Nd Gillmore critics:
This is for readers interested in a little broader view:
-3db at 5Hz and -1,5db at 100KHz, 0,04%thd at 100Vrms are the datas of our KHV-ES, without negative feedback! The KHV-ESD has about 8db feedback and the technical datas are even more impressive!
A tube amplifier that is constructed propperly does not need any feedback to work with very low distortion, wide bandwith and low noise - in contrast to amps with semiconductors. They depend on a very high amount of negative feedback with all the problems that come with it. Nelson Pass has written some very interesting articles about it.
Transformers or anode chokes do not ask what they are made for, speakers or headphones! We choose the parts that meet our requirements or have them modified to make them fit into our amps. In our first hv amplifiers we used CCS (cascoded mosfet -tube) in the output stage but we could not see any advantage over a very high quality anode choke, on the contrary, we lost the k2 cancellation of the pp triode class a output stage with a transformer.
Our amplifiers have an output voltage of a little more than 1000Vpp (up to 1100Vpp, with the 7189 tubes) so our transformer based amp will not destroys headphones! Step up transformers without amplitude limiting can do that very easily, I did some measurements recently, the voltage swing was a little less than 2,5 KV!!
There are many ways to design a good amplifier, some do it with ss, others with tubes, we use the best of the two worlds and go our own way. And what is very important for me after 3 and a half decades in this business: I respect others, see the beauty and the drawbacks of other designs and what I really know is: there is no "best amplifier", it can only be my! favorite amp, nothing else!
Readers who are interested in more detailed information can contact us directly, we will be happy to answer your questions!
kind regards to all forum members - Wolfgang Paltauf