[ Jim Heyworth wrote in 041230 MMDigest:


>> First off, I'm sorry to say that I can offer no help regarding the
>> connector ribbon.  There is one thing of which I'm fairly sure,
>> however.  If you truly have a crystal pickup at the end of the reverb
>> line there is a very good chance it is dead.  Salt crystals do not age
>> well and it is very common for them to fail after a number of years.
>> The delay in my much later A-100 uses a magnetic pickup and if what
>> you believe to be a crystal pickup is actually magnetic then, of
>> course, the question doesn't arise.


My experience is confined to other sorts of reverb units, but I found
that one common problem was broken wire leads at the pickup.


>> If the crystal has indeed failed then you will probably need to work
>> out another method of sound pickup at the end of the delay line.  This
>> could alter the qualities of the connector ribbon needed and perhaps
>> the level of amplification needed in the reverberation amplifier.
>> I have a feeling that there's nothing particularly special about that
>> connector ribbon other than to transmit sound to the pickup but
>> I could be wrong here.


If the pickup is indeed a crystal type and is dead, you might consider
adapting a phonograph cartridge or a microphone.  This would require
a degree of craftsmanship of which I am personally incapable, but the
electronics would work out: most crystal pickups of any sort generate
a couple of volts.  "Ceramic" pickups generate less than one volt, but
there's not a vast difference between the two except that the ceramic
type required a bit less mechanical drive and was thus easier on your
old records; they're pretty interchangeable for most purposes.  If you
can't salvage a cartridge from a junked phonograph, it turns out that
you can buy them from several purveyors: I checked Google and found
several.  But watch the prices: one fellow charges US$75 for a
not-particularly-distinguished cartridge.

A more likely possibility would be to find a magnetic phonograph
cartridge and adapt it.  The output voltage is only a few thousandths
of a volt, but you can compensate with a phonograph preamplifier; these
are still available.

Warning and disclaimer: I haven't tried any of this, but it seems to
make sense.

Mark Kinsler

PS: And there's someone who is selling Grado phonograph cartridges.
They are now hand-made, out of wood.  I am not making this up.