bypass them if you wish (I bypassed them in Papa's Koan with 10nF MKC)
in this case they aren't so critical as signal caps , they're more level shifters
in this case they aren't so critical as signal caps , they're more level shifters
Thank you, I am not completely sure what to do yet.
Having an idea to build in a BA-3 with a pot at the input, so it will turn into an integrated amp with just one input and a volume control.
Alternatively to build the BA-3 as a separate preamp with a DDDAC1794 NOS DAC inside, with either transformer coupling or a modified D1 IV stage.
Could also be nice - USB in, loudspeaker out.
Having an idea to build in a BA-3 with a pot at the input, so it will turn into an integrated amp with just one input and a volume control.
Alternatively to build the BA-3 as a separate preamp with a DDDAC1794 NOS DAC inside, with either transformer coupling or a modified D1 IV stage.
Could also be nice - USB in, loudspeaker out.
Just want to say I have some serious compliments from some members of a local audio group regarding my F4 power amp. This F4 is driven by an Aikido tube voltage gain stage. Several members agree that this combination competes with and has better sound than commercial units costing much more.
Many thanks to papa and others on this site for sharing their knowledge and helping with my projects.
Happy holidays.
Many thanks to papa and others on this site for sharing their knowledge and helping with my projects.
Happy holidays.
Hi William,
did you use a nacked/liberated F4, and which tubes did you choose for the Aikido ?
I am very satiesfied with my F5, but thought I needed to try an F4 also, waiting for the matched Toshibas, which I also used in the F5.
Also just finished a BA-3 as a preamp - thanks for sharing your designs Nelson.
I have the best sound ever right now - took a little tweak on my speakers to get there. I am using 6 dB cutoff, and the tweeters needed a selfresonance dampening L-C-R filter to be up to the new equipment.
Best regards
Arthur.
did you use a nacked/liberated F4, and which tubes did you choose for the Aikido ?
I am very satiesfied with my F5, but thought I needed to try an F4 also, waiting for the matched Toshibas, which I also used in the F5.
Also just finished a BA-3 as a preamp - thanks for sharing your designs Nelson.
I have the best sound ever right now - took a little tweak on my speakers to get there. I am using 6 dB cutoff, and the tweeters needed a selfresonance dampening L-C-R filter to be up to the new equipment.
Best regards
Arthur.
My F4 is straight from the original schematic with matched fets and I use 12ax7 followed by 6dj8 in the Aikido. The tubes are NOS telefunkin and I added global nfb to bring gain down to around 20db. I had 6cg7 without feedback in the gain stage originally but find the 12ax7 has better detail and high end even with it. On the F4 I have dual power supplies with 200va transformers and 8x10000uf filtering on each. Don't know if any of this is a magic recipe but I can say it sounds pretty good.
And yes, I too started with an F5 first and in my system the F4/Aikido sounds much better to me.
Cheers
Just realized I interrupted your conversations here about the crippled and other variations on on the F4, Sorry about that. I hadn't been following this thread lately.
So to catch up on this, it looks like with the crippled version we would be trading the jfet front end for electrolytic coupling caps. It's not obvious to me that this would be a win, sonically. Am I missing something? Other than an easy way to allow increasing the PS rails.
thanks
So to catch up on this, it looks like with the crippled version we would be trading the jfet front end for electrolytic coupling caps. It's not obvious to me that this would be a win, sonically. Am I missing something? Other than an easy way to allow increasing the PS rails.
thanks
Yes, The Circlotron. There was a P device where ther should have been an N 😀
We overlooked that because we thought we knew what you meant 😉
There are not enough circlotrons in the world, believe it or not
We overlooked that because we thought we knew what you meant 😉
There are not enough circlotrons in the world, believe it or not
Looks like a good idea, but how do you drive the gates? Most of the complications will be to obtain the necessary gate voltage swings and bias currents for the output FETs.
There are many ways - here are the two complete circlotron projects:
http://www.diyaudio.com/forums/pass-labs/130810-amazing-fet-circlotron-mike-rothacher.html
http://www.diyaudio.com/forums/pass-labs/157915-simple-cirklotron-lateral-mosfets.html
I'm sure you'll find more if you use the search button...
Probably yes. But ...
Advantages:
- The drive circuits have 1/2 the capacitance to drive vs. the push-pull F4.
- Excellent H2 cancellation
- Power supply complications.
- Twice the gate drive circuitry, unless someone comes up with a very clever design.
replace voltage with CCS-es , drive them as M2 is driven , use matched mosfets , use servo for one CCS if you're hysteric 
anyhow - are sources on proper side ?
polarity (N) is OK < if that's what's meant , but symbols are flipped
anyhow - are sources on proper side ?
polarity (N) is OK < if that's what's meant , but symbols are flipped