On 11/6/2019 2:34 PM, 6295LARGE . wrote:
> Hello everyone.
> I don't understand why I can get *great sound* from one Edison Diamond Disc
> and practically *NO SOUND* from another, and they're both in good condition.
> I've got the cartridge wired correctly with a 3.5FCR stylus and the cables
> from the Shure M44-cartridge is "monofied" before going into the stereo
How, exactly, have you "monofied" the cartridge connections? The usual
technique of strapping a stereo cartridge for plsying mono records is to
connect the coils of the two channels in parallel. Specifically:
L hot connected to R hot and thence to preamp input hot
L ground connected to R ground. and thence to preamp input ground.
This combines the two channels of a lateral-groove disc (which mnost 78s
are) properly. A lot of folks do this by using a Y-connector;
Two RCA female jacks > 1 RCA male plug, which goes into the preamp input.
If you play a disc with vertically-cut grooves (like most Diamond
Discs), the signal from the L channel will come out in reverse polarity
to the signal from the R channel -- when the voltage from the L channel
goes positive, the voltage from the R channel goes negative by an
approximately equal amount -- and when you combine these two signals by
strapping the cartridge for mono as described above, the positive
excursions of the L channel are cancelled by the negative excursions of
the R channel, and you're left with little or no signal. That's the
*normal* condition when playing Diamond Discs with a strapped-for-mono
cartridge; the thing that's hard to understand is why you had some discs
that played properly (plenty of signal), As others have mentioned, a
very few Diamond Discs were produced with lateral-cut groove -- maybe
you lucked into some of those.
Please verify that the above description corresponds to the way you
"monofied" the wiring, and we'll go from there.
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