Looks like it's all been done. Wish you said how so, so we could all understand.
KMG shows full winding data in the page linked above. Turns, wire (mostly 0.6mm enamelled wire), core.
If you can't get the one he used, which is somewhat special , use regular EI Silicon steel, what everybody uses. Just pick a lamination size with same core area or the next higher up, check that wire fits in available window size.
Russians use Metric cores (same as Germans and all of Europe) but you can find a "same or next larger* US core.
Project is very doable.
KMG is a talented EE working for Russian Subway and Electric Train on those huge control panels as a "day job" and doing this as a side Hobby, with impressive results.
His 12AX7 emulation is the best so far, anywhere.
His design is fine.
If adapting it for US laminations pick same core area or "next larger".
Listen at his demos, including side by side comparison with "real" tube powered JCM800
Thank you. His stuff does sound incredible. I will have to make an amp based on one of his projects. I am in Eurpoe (Ireland) so metric measurements are good for me. What does he mean by 20x60 core? Is that not missing a dimension for core area? Sorry if that is a silly question, I'm not familiar with winding my own transformers.
Should look again at some closeup for scale comparing it to some nearby component but (without looking) he might be meaning
In any case very different looking to each other so not difficult to decide.
Too late now, will check tomorrow.
What city are you from?
I visited Ireland in the late 80s, including the customary "visit Grandpa's town" near Galway 😄
- "E" center leg width of 20mm so full lamination width 3x that so 60mm , by 60 mm height, or:
- 20 mm center leg width, stacking 60 mm
In any case very different looking to each other so not difficult to decide.
Too late now, will check tomorrow.
What city are you from?
I visited Ireland in the late 80s, including the customary "visit Grandpa's town" near Galway 😄
Yep, was planing on using those with the KMG power amp design. They're a bit pricey, but hey, so are power tubes! Ten ECW20N20 cost about as much like, 3/4rs of a pair of mathed power tubes. One thing I'm unsure on is if the "s" designation, meaning selected, is necessary for the ECW20N20 Mosfets.
If you bias them with an independent adjustment / servo, as is ideal for tubes, I wouldnt think so.
Because of the push pull output transformer, you can expect drain voltages twice B+ when the amp gets overdriven. That would mean you can run the exicons at 100v or so maximum, and so I don't think you can use a standard tube output transformer.
Look at the KMG amps, he uses 200v mosfets and 80v B+.
The 70V distribution transformers are usually autotransformers - no isolation from "primary" to "secondary" - all one coil with taps.
However, there might be an interesting approach to using them similar to the approach taken by McIntosh amplifiers in some of their amps. In this case, the output stage would still be a typical complementary-symmetry approach, with the output feeding the "hot" end of the autoformer.
I am considering building such a beast (mostly for fun) and using an approach that employs the LT1166 Class AB driver chip designed especially for vertical MOSFETs. This chip takes care of all of the biasing, overload protection, and thermal runaway issues sometimes found in vertical mosfet designs. The application support documents appear to be nicely written.
These chips appear to be in plentiful supply through the usual distribution channels,
Why is there no quote function for LVQ's post but previous posts have it?
The 70V distribution transformers are usually autotransformers - no isolation from "primary" to "secondary" - all one coil with taps.
However, there might be an interesting approach to using them similar to the approach taken by McIntosh amplifiers in some of their amps. In this case, the output stage would still be a typical complementary-symmetry approach, with the output feeding the "hot" end of the autoformer.
I am considering building such a beast (mostly for fun) and using an approach that employs the LT1166 Class AB driver chip designed especially for vertical MOSFETs. This chip takes care of all of the biasing, overload protection, and thermal runaway issues sometimes found in vertical mosfet designs. The application support documents appear to be nicely written.
These chips appear to be in plentiful supply through the usual distribution channels,
I have not come across an autotransformer 70V transformer and I have six different types. I have used them in P-P tube circuits,
The 70V distribution transformers are usually autotransformers - no isolation from "primary" to "secondary" - all one coil with taps.
However, there might be an interesting approach to using them similar to the approach taken by McIntosh amplifiers in some of their amps. In this case, the output stage would still be a typical complementary-symmetry approach, with the output feeding the "hot" end of the autoformer.
I am considering building such a beast (mostly for fun) and using an approach that employs the LT1166 Class AB driver chip designed especially for vertical MOSFETs. This chip takes care of all of the biasing, overload protection, and thermal runaway issues sometimes found in vertical mosfet designs. The application support documents appear to be nicely written.
These chips appear to be in plentiful supply through the usual distribution channels,
I have not come across an autotransformer 70V transformer and I have six different types. I have used them in P-P tube circuits,
Just an opinion here, but I don't see why a standard tube output transformer would have a problem with running at lower B+. Of course the max output power is reduced, less efficient etc, but a B+ at 100 Volts in push pull, the Mosfets could drive 200 mA or so and could still make decent power, well within their limits.