tube guitar preamp mounted instead TL071!!!

[padamiecki]

Hi!
For all of you that are dreaming for tube amp...
I have bought cheap Ukrainian solid state guitar amp.
In the preamp section originally worked TL071. Really **** sound.
But this is what I have done; I have placed this circuit into the place of TL071:
Now I have really tube distortion, very smooth! Maybe not metal type but if I use for example Marshall blues breaker at hi input I get thrash metal type distortion.
In reality R3 and R6 were potentiometers that were regulated to obtain halve of the power supply at anodes of ECC83.
ECC83 is working with positive voltage at the grids. It is due to voltage loss on R3 and R6. After regulation of 0.5 power supply voltage I changed potentiometers into fixed, regular resistors.
+23.4V is from a strict type voltage regulator: 24V Zener diode and emitter follower (in amp section was +/-35V).
-15V was taken from the socket of TL071.
As for a heater supply I used 3W 5.9V~ transformer, one wire connected to the ground, second for the heater. This was enough to heat ECC83, the hum is really absent!
I guess that you know how to connect hi and lo sockets using the switch which makes the connection from “to_lo_socket” to “lo”.