Tube Amp Archive

You might be getting your oscillation from your lead dress. Chop stick the wires while the amp oscillates and listen for changes. It's a great idea you had here ! I did it and oscillation frequency change and tend to disappear in a certain position for V1 wiring. Not sure, but V1 anodes wires seems...

1. Schematic: What are those zeners doing in front of the cathode follower? 2. CH1 issue: sounds like a bad (solder) connection or a bad tube. 3. CH1 Osc issue: 6 kHz parasitic oscillation. I think you got positive feedback somewhere in the circuit, the proximity between components/wires/pcb traces...

Is this 'microprocessor' just to control the relay switching by midi? There is a good chance this causes some of your problems due to emi and interference (wiring/ground) injecting high frequency switching noise of the processor in your audio circuit (harsh sound) and detection of the clock frequen...

Thanks erwin_ve,

The full schematic of the current build would be complicated to understand because of the microprocessor, i had design it for me and there is probably a lot of missing things about the switching matrix. I will make something more understable and post it here with pics an audio.

Hi everybody, I currently doing preamplifier tests before building the power amp and I meet some issues with the dumble channel. The pre-amplifier have severals channels with different mod on them, each of them turn on/off some relays and everything is controlled by an μC. So, each mods of the chann...