Baldwin PC 40 amplifier

[robbrochu]

I have a Baldwin PC40 amplifier that I am working on converting to a bass amp. The tube compliment is 2- 5U4GB rectifier tubes, 4-6L6GC Power Tubes and a 6SL7 "preamp"/phase splitter. The amp is PPP configured. I've got an external 6SC7 preamp I am attempting to connect and got some excellent advice for specific questions regarding the preamp. I was told to connect B+ to 250V. My question is can I scavenge this voltage from the 6SL7 tube? I know this is probably a hugely basic question, but this is my first foray into tube anything and I got the amplifier for like $10 and the preamp for a dollar. So $11 for a tube amplifier is something the tinkerer in me couldn't pass up and I've always been curious about them.


I know the amplifier works because I can hook my sansamp to it and get good sound. I also have an ART mic preamp that drives the amp extremely well. It's just the amp itself needs an additional gain stage or 2 and this other preamp should provide the additional voltage gain I need.

 

[thoglette]

Short answer: yes.

Longer answer: read the schematic and check what the voltage is. And you need some heater current. The Baldwin is pretty overbuilt, according to urban legend (TDRI), so you should be in luck.

 

[robbrochu]

Yeah heater wires aren’t a problem. I know where they are and where they go. I also know where the ground wire goes and the output signal wire. That’s really the only connection I was unsure of. I thought as much but wasn’t sure. Thank you. I’ll get it soldered up this weekend, Fire it up and see if it works. If it doesn’t, I’m going to buy a chassis sockets and start from scratch

 

[PRR]

Not sure this is the same amp, it has an extra tube.

But the end of the main B+ string is where you would tap preamp power. The preamp should have its own B+ filtering.

 

[robbrochu]

I think I'm going to build a new chassis, order some sockets and start over so I can add volume, bass and treble controls. I think that would be the most expedient thing to do instead of continually modifying and adding stages. Thank you for your responses.