• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Poll..anyone interested in an Aikido linestage PCB group buy?

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#166
this looks pretty basic or am I missing something? I don't know a filament from a heater, but have made a GC, BOSOZ and krell clone. Do you think I could make this?
Click to expand...
It is not difficult. BUT..it has HIGH voltages that could KILL.
And no tube project is cheap..because you need filament transformers and high voltage transformers.
Plus there is something that is not solved in the PCB and that is to "elevate" the filament/heater to say 60V (because of heater cathode insulation specs)

The heater/cathode insulation of most small signal tubes is around 100V (up and down)...the cathode of the second triode inside the "bottle" is at around half the b+, in this case around 100VDC.. if you bias the heater up to the example of 80v the top one will see a 40v potential difference and the bottom one 60v difference..for example.

This elevation is done by referencing the center tap of the heater transformer to a particular voltage by making a voltage divider on the b+ supply. (Schematic hopefully tonight)

Or by referencing the negative wire from a dc supply to that particular voltage.
 
#173
Sample psu with the promised heater bias..feel free to comment. I left out a choke because of the costs.
 

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