got a custom 829b amp that i got laying around, need to know what driver to use

[ryuji]

my buddy sent this to me as a ride-on in a package of tubes he sent me a few months ago. I worked out with him/my own analysis that the power tube must be a 829b as it has screen connections, but what do people typically drive these with? ill be buying the 829 tubes so i wouldn't mind buying the intended/required driver tubes to have a listen to this amp

walking through the circuit, it seems like a double triode input, with anode of triode '1' being coupled to triode 2, and equal cathode+anode resistance on triode '2' and capacitors on both anode and cathode acting as phase inverter for the dual beam tetrodes?

if i remember right, the resistor leading to the double triode is 275k, and the grid 2 resistor for the power tube screen was about 5k, so im guessing about 300v b+?

got some 15w rated PP transformers laying around, i think it should be good enough long as i keep volume level down?

heres a picture if it means anything at all

An externally hosted image should be here but it was not working when we last tested it.

 

[aardvarkash10]

sounds conventional triode voltage gain, triode cathodyne splitter, pp output. 15 w should be plenty in iron, around a 10k load. From memory the 829b needs around 18v pp of drive a g1 in pentode on a 10k load, so that starts to identify your other tubes...

I've got some 829b's sitting around and they are on the list for a build... maybe for my 60th birthday...

 

[mastodon]

As aardvaskash points out, it's a pretty common design. High impedance voltage amplification stage followed by a cathodyne splitter that's DC coupled to the input stage. Pinout is standard ECC/12AX type; I bet an ECC81 would work just fine there.