Electrolytic capacitor values for portable phono?

5/3/2009 7:29:05 PMDaveF

hello everyone. I am restoring a 1960's portable 45 rpm record player made in Italy, called the Masterwork rover. It has 2 electrolytic caps in it, with no markings anywere, the player takes 8 D batteries for power, can someone suggest capacitor values that would work as replacements? There are no schematics around for this. Thanks for reading.

5/3/2009 7:47:12 PMLewis L

:hello everyone. I am restoring a 1960's portable 45 rpm record player made in Italy, called the Masterwork rover. It has 2 electrolytic caps in it, with no markings anywere, the player takes 8 D batteries for power, can someone suggest capacitor values that would work as replacements? There are no schematics around for this. Thanks for reading.

kSomething form the sixties could either be transistor or tube. Can you give a lineup of whichever it uses? We really need more information.
Lewis

5/3/2009 8:59:04 PMDave F

::hello everyone. I am restoring a 1960's portable 45 rpm record player made in Italy, called the Masterwork rover. It has 2 electrolytic caps in it, with no markings anywere, the player takes 8 D batteries for power, can someone suggest capacitor values that would work as replacements? There are no schematics around for this. Thanks for reading.
:It is definitely a transistor. It only has a small circuit board about 4 inches square. There are two aluminum cans, with a definitel + and - side. (also some transisitors). This is a slot load 45 rpm player made in Italy for Columbia.
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:kSomething form the sixties could either be transistor or tube. Can you give a lineup of whichever it uses? We really need more information.
:Lewis
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5/6/2009 11:38:02 PMThomas Dermody

Since you are dealing with low voltage, you are probably also dealing with low resistances (loads, etc.). This all equates to faster draining of capacitors. You will need larger caps than you would in a high voltage tube circuit, since in a tube circuit there is more voltage to begin with, and the impedances are higher, and thus draw off the voltage more slowly.

If the caps are filter caps (and aren't part of something delicate, like transistor bias), you can probably get away with capacities as high as 1000 MFD, or maybe even higher. You can start at 100 or 200 MFD and work up from there until you get what you like, or if you know that you won't destroy something (you're working with a pi filter), start with 500 or 1000. You'll be able to find all that you want at Radio Shack.

Actually the batteries should provide quite a bit of regulation on their own, but there is a need for audio bypassing, as well as sudden or spike loads, such as would be the case from a DC motor. In this case you can probably get away with 100 or 200 MFD caps. 1000 would be more ideal for AC rectification. If the phonograph produces a lot of powerful bass, you might still want the 1000 MFD caps.

5/6/2009 1:06:47 PMZ-

Which capacitors? If the phono works using 8 "D" batteries (12V) I would suspect the max voltage for any capacitor would be 16V. The value of the cap would be related to it's function in the phono.

If you can identify the function of the capacitor (filtering, audio bypass etc), then value would be easy to figure.

Syl