Tube 6DJ8/ECC88 Half-Diamond/ Anode-Follower Hybrid preamp or buffer

[jcalvarez]

I make a tube line/HP/preamp board (two versions, one is SE and actively loaded, the other is a WCF).
I also have 3 versions of the SE version shown in this schematic. The other two use 6N1P or 12AU7 instead of 6N3P respectively.
All have been built, used, and enjoyed for many years now.

15$ for a blank board, more for a kit or complete.
The schematic below is set up for driving headphones - For line/preamp use, you'd change resistors 1 and 100 to 240, and leave out the 470u cap.

View attachment 1139628

Just in case somebody is interested, a simulation of that schematic. Nice harmonic profile I have to say, it would be interesting to measure in a real circuit.

 

[kodabmx]

I am 🙂 Thank you for this!

If it's not too much trouble, what difference does it make if R4 is 0R, and R3 is bypassed with 1mF?
I'm also running this at 330V in my preamp (because I think it scales with voltage, and it's easier than a dropping resistor)...
The boards I have on hand don't have a spot for the caps per se, but it's very easy to solder them across the R3 on the board.
I've already designed the updated board with a place for the cap, but I didn't order them yet.
I should also add the 470uF cap is NOT off board anymore - the schematic I posted was for version 1.0.

 

[jcalvarez]

Great, I'll continue via PM in order not to divert the thread.