tape recorder to amp conversion

[Justin Thomas]

A la Ritchie Blackmore? That'd work for me!

Justin

[olddawg]

Just for the hell of it... Before you do anything ... Try using it as an overdrive preamp into another amp. It might surprise you.

[Jazz P Bass]

I'm looking over this amp before I take it apart and I notice that all the heaters are wired in parallel but the 12ax7 has resistors between the heater supply and the tube. What would be the purpose of this? They all run on 6.3v, right?

If the resistors are 100 ohms (or there abouts) I would say that they are being used as 'hum balance' resistors ala Fender.

[dmartn149]

Looks like grey, red, gold, silver to me. 8.2ohms

[Justin Thomas]

What's the values? Maybe they lowered them a tiny bit to extend tube life?

Justin

[dmartn149]

I'm looking over this amp before I take it apart and I notice that all the heaters are wired in parallel but the 12ax7 has resistors between the heater supply and the tube. What would be the purpose of this? They all run on 6.3v, right?

[dmartn149]

oh yeah, I didn't realize it was a preamp tube. That's what I'll do. Thanks.

[Justin Thomas]

I'd try it as a preamp tube channel... sounds like it could be an "American" AC4. High gain, low hum, what's not to love? The 5C1 had a pentode preamp... at least worth trying before scrapping it entirely.

Justin

[dmartn149]

I bought an old RCA tape recorder at auction last night. I thought I would rebuild it into a 5f1 champ style circuit. There is a lot of extra circuitry in the chassis so I figured I would take it all out and start from scratch.
I'm not sure what to do with the extra tube. It's a 5879. The other tubes (the ones I'm planning to use) are 6x4, 12ax7, 6aq5. Can I just leave that one socket (for the 5879) disconnected? What effect will that have on the B+ and heaters for the rest of the tubes?
Any advice? warnings?
Thanks