http://audiophilediyer.com/diy-discrete-r2r-dac-part-1/
Pathos's Inpol / Mofo SE class A amplifier V2
Since in 1999 I saw the first review of the T.T. of Pathos this intrigued me, I had already made my Power Follower 99 and the sound performances were surprising but with the Inpol it was possible to double the efficiency.
After 20 year I have created a new verson of the my amplifier the Power Follower 2019 because this has incredible sonic performance but has a big efficiency problem even if this is normal in a true class A single ended amplifier.
However, the idea of using an inductance to double the efficiency was exciting, even if it meant losing the isolation from the power that my Power Follower has.
From the simulations I had verified that an inductance of about 100mH must be used with an air gap capable of manage at least 4A.
In the following years I started a lot of projects with the output transformers for valves and anode load inductors so I got the idea that the Inpol inductance had to be sectioned / stratified to reduce the parasitic capacities so the project has been forgotten.
I recently read Mike Rothacher's article about the Mofo project which got an excellent frequency response using a normal Hammond 193T, cost only 39$.
The Mofo project is very popular on the DIY audio forum (more than 500000 views) [Build This MoFo!].
The Mofo and Inpol are basically the same thing, a mosfet in the common source configuration with an inductance connected between the source and the ground. I don't think you can patent such a circuit because it is equivalent to any tube circuit.
For me it was necessary to check if these performances were confirmed even by using larger inductances with at least 100mH and capable of handling 5A like the Hammond 195T5.
Performance triodes, made in Russia
This page is dedicated to my favorite tubes, my declared favorites, they all come from Russia.
They are all power triodes, triodes which are mostly manufactured as linear regulating tubes for power supplies, but are now very popular high-end output stage tubes for many.
The following photo is one of a whole series that I created, and of which I would like to show each of them in the first place - which of course forbids itself due to loading times. Instead, the first, the following image, is also the link to a page that shows all of these photos. (And I am free from the decision to choose just one - and not be able to show all of the others ..)
https://tubes-store.com/index.php?cPath=103_104_110
http://www.jogis-roehrenbude.de/Roehren-Geschichtliches/Trioden/Russische_Leistungstrioden/Russische_Leistungstrioden.htm
http://wzone.vegalab.ru/faq/cd_transport_list/k
https://item.taobao.com/item.htm?spm=a230r.1.14.195.416814ea489rzK&id=38907622302&ns=1&abbucket=17#detail
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