B+ Regulator for Audio Tube Amplifier

[abbey road d enfer]

Question> how would the acoustic performance be affected in this case?

I don't think it would matter much, since the amp is under control of a healthy dose of negative feedback. You would get some more headroom with the slightly higher plate voltage.

 

[Breezio]

I don't think it would matter much, since the amp is under control of a healthy dose of negative feedback. You would get some more headroom with the slightly higher plate voltage.

Thanks, I'll see if I can fix the existing circuit first and, if not, will definitely follow your suggestion (will need additional rewiring in the amp)

 

[Breezio]

Dear all,

Thanks to your precious help I believe the regulator now works pretty fine!
In the schematic attached you can see that I substituted one 100V zener with an 82V zener and used an 18k resistor to obtain the right regulating current. Also, I bypassed R2.

Now the ripple is gone for good!

The only little concern I have is the power dissipated by the mosfet which is around 6.3W  (I~260mA)
The heat exchanger gets quite hot  - around 70C - so I might consider to add R3 again to dissipate some of that power.

Other than that, do you have any other suggestions to improve performance and/or reduce part count/footprint?

Thanks again!

Fabrizio

 

[Breezio]

Vin

 

[Breezio]

Vout