[Jukebox-list] A Wurly 2510 amp question

[Jjmscf at aol.com]

I'll check the manual again. I know the original Sonotone had only 3 wires as 
mine did. I had a bad channel in mine but I got a n.o.s Pfanstiehl exact 
replacement. The original as well as the  exact replacement are nla now. The exact 
replacement and original are red in color.Sonotone 8TA.So I don't know what 
cartridge you have in there now. The one that is most commonly provided as a 
replacement is the newer black 4 pin type by Pfanstiehl.I think it's a P132.The 
commons have to be wired together for the stereo version. The output is lower 
and and the weight of it is different so some weight has to be removed from 
the lower end or added on top for proper balancing but you should get sound out 
of it if at least one hot lead and ground are connected.
I'll drag out the manual and check on the mono cartridge wiring and make sure 
it is the same cartridge .I'm pretty sure it is though.No Cobra circuits on 
the mono amp.I know that for sure.Have you checked for hum from the amp input 
when you touch it with the volume up high and a record clamped on the turntable 
so it's unmuted as Ron suggested?
 
J.C.
 
In a message dated 9/20/2007 2:58:05 PM Eastern Daylight Time, 
steve at pro-ns.net writes:

>So do I hear you right, there's a stereo cartridge feeding a mono amp?

>How did Wurlitzer originally wire it, with the channels in parallel,
>or in series?  (Or did they just use one channel of the cartridge?  I
>doubt that.)  Are there four pins or three on the cartridge?  (I
>believe some ceramic carts, not necessarily ones used in jukeboxes,
>had a single common ground; I can't remember what it looks like on my 2410s.)

>Thinking along the lines that the person who replaced the cartridge is
>of unknown technical ability: If there are four pins, I can think of a
>couple ways to screw up the wiring so it looks OK but yields no
>sound.

>If wired in series, there would need to be a jumper between the - of
>one channel and the + of the other channel, with the lead to the amp
>connecting to the remaining pins.  If you mistakenly connect the
>jumper to both + pins, and the outputs to both - pins (or vice-versa),
>you'd get a phase cancelation, which would greatly reduce the output
>of a mono record, or make a stereo record sound "hollow", but I
>wouldn't expect silence.  BUT, if you leave the jumper off because you
>didn't know you had to transfer it from one cartridge to the other,
>you would get silence.

>If wired in parallel, each lead to the amp would connect to two pins;
>one to both + pins on the cartridge, the other to both - pins.  If you
>swap two of the pins by accident, you can connect one lead to the +
>and - outputs of one channel, and the other lead to the + and -
>outputs of the other channel, shorting both out and sending nothing to
>the amp.  (A different set of swapped pins could end up with the phase
>cancelation problem, like above.)

>So, I'm thinking it might be worth inspecting the cartridge
>connections even closer than just looking for a broken wire.
>Esp. if the finger-to-the-amp input method gives a hum.





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