Voice of Music Amp - VM 160

[tigerzilly]

Ok. I know I have a problem. The first step to recovery is to admit the problem. I'm a vintage tube amp addict! Here is my latest acquisition. Appears to be about 1952 Voice of Music Model 160 amp. Its not a guitar amp, but it looks like a good candidate. Here are the pics as it arrived.

[tigerzilly]

More pics.

[nickb]

Could make a guitar amp with some mods.

Schematic:

[tigerzilly]

Could make a guitar amp with some mods.

Schematic:

[ATTACH=CONFIG]56739[/ATTACH]

Thanks for the schematic! Besides replacing the input jacks with 1/4", what mods would you suggest?

[nickb]

I'd cascade the mic input through a tone stack and then to the phono input. Maybe add a cathode bypass cap to to mic input for less hum and more gain. Also add a further RC filter stage in the power supply to feed the mic input.

[Chuck H]

FWIW I built a little 2x6v6 amp from the guts of a VOM phonograph. It sounded remarkably better than you might expect from the 300Vp and that tiny OT. It actually had a great low end and literally perfect , classic, definition of the model BF Fender clean tone. And because of the low-ish plate voltage it would move very gracefully into thick, cello like clipping. The cabinet I made for it was pretty crappy and I'd built the rest of the circuit from scrap components PTP and all squeezed into the tiny chassis. So I decided to tear it down for a proper build of the same circuit some time. So I still have the transformers. My PT is a stand up whereas yours is a lay down (Z mount?). But the OT looks like the same one I have. I don't think you'll be disappointed

[tigerzilly]

I don't think you'll be disappointed

That's what I'm thinking. The cabinet on this one looks pretty decent. Its cleaning up real nice. I really like the way the amp chassis slide out and can sit on the side. Very cool.

[tigerzilly]

Heres the underside of the chassis. Comes with a schematic too!

[Enzo]

The schematic looks good but hard to see. Do you have a scanner? My printers are also scanners, for example. A pdf scan might be easier to work with. Unless it is the same as the one posted up in post #3?

It looks like someone already replaced a filter cap, but that orange one has a date code of 1973, so evven it is getting old. meanwhile I would be surprised if all those paper caps didn't need replacement. Probably leaky by now. Note the resistors are all 20%, and even then likely drifted, but frankly that probably doesn't matter much. Just don't expect a "100k" resistor to measure 100k.

But looks good and clean.

[Rhodesplyr]

What looks like a Sprague black tubular capacitor would not be original either if the amp is from the early 1950s.

At this point in history, it's not unusual to be doing a 2nd refurbishment of amps from this era.

[tigerzilly]

The schematic looks good but hard to see. Do you have a scanner? My printers are also scanners, for example. A pdf scan might be easier to work with. Unless it is the same as the one posted up in post #3?

Here is a scan of the schematic. Not much better though.

VM160.pdf

[tigerzilly]

What looks like a Sprague black tubular capacitor would not be original either if the amp is from the early 1950s.

At this point in history, it's not unusual to be doing a 2nd refurbishment of amps from this era.

The can cap and the sprague look like replacements. The values are also double of the schematic values. 40mf instead of 20.

[Enzo]

Here is a scan of the schematic. Not much better though

You're right, not much better. But a have to say thanks for doing it.

[tigerzilly]

You're right, not much better. But a have to say thanks for doing it.

Ok. One more time. This time I took a pic of the schematic with a better camera.

[DrGonz78]

Ok. One more time. This time I took a pic of the schematic with a better camera.

[ATTACH=CONFIG]56768[/ATTACH]

Picture seems a bit dark so lighted it up a tad.