The latest update to the 100 Watt 6P45S tube amplifier is about a lot of testing and fault finding that have gone into the tube amplifier. This is to correct noise and hum issues. It is now in a state where the audio amplifier itself is as stable as it will get.
Further improvements lie solely on the power supply, regarding more filtering capacitance. Limiting the inrush current and micro controller supervision and shutdown logic to protect valves and speakers.
2 thoughts on “100 Watt 6P45S amplifier update #2”
Perhaps consider building a couple of regulators for the LTP and the driver tube voltages. I’ve just built a new power supply unit for my amp with the 6P36S, and have got adjustable, but regulated mini-supplies for the small tubes.
Also – contrary to some beliefs, I’ve put in another regulator for the bias voltage, and another one (adjustable) for the G2. The amp performs much better, and now it’s immune to any mains fluctuations. Only the B+ of the power tubes remained unregulated, however, from the simulations it seems that the variation of the mains voltage will not have such a great effect with G2&bias regulated, than before.
I can send the schematics of the PSU, if interested!
BTW, for B+ filtering, I found a guy on ebay, who sells 730uF/400V RIFA capacitors at good price. Putting two in series seems to be more than enough.
For the sake of simplicity I have chosen to use classic power supplies while learning about the amplifier itself.
We can quickly agree that any good engineering is a waste with a bad power supply 🙂
You can upload the schematics here in the comments or send it to email@example.com
I have plenty of components and are in no need of more 🙂