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Voice of Music Amp - VM 160

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  • Voice of Music Amp - VM 160

    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.

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    Last edited by tigerzilly; 01-23-2020, 07:37 PM.

  • #2
    More pics.

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    • #3
      Could make a guitar amp with some mods.

      Schematic:

      Click image for larger version

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      Experience is something you get, just after you really needed it.

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      • #4
        Originally posted by nickb View Post
        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?

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        • #5
          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.
          Experience is something you get, just after you really needed it.

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          • #6
            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
            "Take two placebos, works twice as well." Enzo

            "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

            "Being born on third base and thinking that you must have hit a triple is pure delusion!" Steve A

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            • #7
              Originally posted by Chuck H View Post
              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.

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              • #8
                Heres the underside of the chassis. Comes with a schematic too!

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                • #9
                  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.
                  Education is what you're left with after you have forgotten what you have learned.

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                  • #10
                    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.

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                    • #11
                      Originally posted by Enzo View Post
                      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

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                      • #12
                        Originally posted by Rhodesplyr View Post
                        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.

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                        • #13
                          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.
                          Education is what you're left with after you have forgotten what you have learned.

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                          • #14
                            Originally posted by Enzo View Post
                            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.

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                            • #15
                              Originally posted by tigerzilly View Post
                              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.
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                              When the going gets weird... The weird turn pro!

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