A simple shunt regulator

[aria]

That's the original one...

 

[aria]

Perhaps VR tube would have higher noise than a regulator.

fyi - Shindo used a simple FET based cap multiplier on screens. If you’re not adverse to using a FET, this would be simplest and possibly the best approach.

I am not familiar with semiconductors. Since I have an extra 8 pin socket, I could use a 6V6, changing the two cathode resistors with one 560R resistor.

 

[TonyTecson]

I was also wondering if it makes sense... does a VR tube make something similar?

i have an ARRL handbook 1960 edition, and yes, vr tubes like the 0a2 are used to regulate G2 voltages even then...

 

[aria]

So should it be possible to use a shunt in its place too?

 

[TonyTecson]

So should it be possible to use a shunt in its place too?

of course.....in my 12gt5/6bn11 all pentode builds, i used a 150vdc series CCS zener shunt regs to supply the G2's.....

 

[aria]

5 watts could be enough for a pair of 94dB loudspeakers. So i could use a pair of vintage OTs made to order for 15 ohm loudspeakers. it could be more or less like this. What's wrong?

 

[aria]

So it is perhaps better ... a single transformer and the cathode of the 6AF4 at 7 volts, with less gain, but with an even more linear sine curve... All this if the curves of Ayumi and PSU designer are reliable, aren't they?

 

[aria]

In the end I did it like this ... at 30 volts DC at point A (using a Variac) and at minimum volume the amplifier already sounds very loud and already a bit distorted .... I tested the voltages at different points strategic and are accurate .... what did I do wrong?

 

[aria]

[first 100k resistors mean the 100k Pot]

 

[aria]

I decreased the cathode resistance values ​​of the preamp tubes (from 400 ohms to 220 ohms) to make them work at a more ideal point, but the result remained the same. Can anyone give me some advice? I can't get out of it in any way.

 

[aria]

Tested in this way, a single channel on a platform, using the same components, works perfectly ... reported with two channels, on the other hand, it always has the same defect ... volume too high at the minimum of the potentiometer and "wah-wah effect" when with the variac I exceed 50 volts ... the voltages in percentages are accurate in all points.. I also tried replacing the shunt circuit with a usual RC filter, but nothing changes if you have any suggestions because I no longer know what to think ...