Not really a guitar amp... but let's see what we can do:

[IDSkoT]

I'm a newbie to amp building. I have a lot of experience / knowledge in speaker enclosures / passive crossover networks, and a lot of car audio knowledge. But that doesn't prove much in the world of home audio amps. I wanted to get a kit amp, but upon reading further people say you should just buy an old amp and mod it. Well, about a year ago I got an old Vinyl player, circa 1940's. It has a basic tube amp with a rectifier and a power tube. I was wondering... anything I can do for this thing?

A picture of the outside:


Here's a schematic I drew up... don't have much schematic knowledge. But here's the basic. Hopefully you'll get the point. SW is switch, and TU is Tube. The thing to the middle left that looks like an H is a jumper of some sort. Also, the circle thing that goes to the motor is just labeled R6. So, I'm guessing it's a huge resistor. Things giant.



Excuse the gibberish in the center of 50C5 tube. It was just me trying to make sense of tubes.


Here's a gut shot:



I'm going to replace the tubes to see if I can get a better sound. Any mods anyone have in mind?
Maybe try to build a preamp so I can plug my guitar into this thing...? I'm open to suggestions of any sort. Even if that suggestion is to not touch it and get a guitar amp to tweek.

[IDSkoT]

And... I'm kind of new to tubes, and I love this:

[olddawg]

This is a series filament amp. There is no power transformer. It's dangerous. IMHO if it was a complete guitar amp you might justify using it with an isolation transformer, but since it is a project I would look for something else to play with. Seriously.

[Robert M. Martinelli]

Hi,
+1 on what olddawg said!

As a foot-note to his post, the first number (50, 35....) denotes the heater's operating voltage, and they were connected in series to spare the heater winding on the power transformer. The ( serious ) problem is, there's no insulation from mains, so the whole thing is very unsafe to operate as a guitar amp. In today's world a similar arrangement is ( quite rightfully ) forbidden.

I therefore join olddawg in advising you to find something else to play with.

Hope this helps

Best regards

Bob

[IDSkoT]

Haha, noted. It will stay untouched.