Circuit diagram for Ortofon MCA-10?

Can anyone point me at a copy of the Ortofon MCA-10 mc 'head amp' circuit
diagram?

I'm asking because I'm currently dissecting a magazine review of the
Armstrong 700 amps. The review contains a depressing number of confusions,
misleading comments, and slips. But I'd forgotten until today that the
'postscript' included a comment to the effect that the reviewer compared
the 700 mc preamp with the MCA-10 - which he found to be much better.

So far as he was concerned the 700 mc stage had poorer overload and
distortion performance. It also committed the sin of including electrolytic
caps which (allegedly) probably degraded the sound.

The irony is that IIRC I based the 700 amp on improving what I'd seen in
the Ortofon amp. Where I think the MCA-10 used a very similar circuit with
electrolytics. I'd changed the details to give *more* headroom and *lower*
distortion than the Ortofon, but used the same topology.

I had a diagram at the time but lost track of it years ago. It would be
nice to be able to report now on the reviewer's inability to show he was
"golden eared" by hearing the (alleged) effect of electrolytics when he
hadn't seen them in the box or checked the circuit diagram. ignorance is
bliss, eh?... 8-]

If no-one can find one, I'll go to the source and ask Ortofon. They might
also find this amusing. Although sadly, 30+ years too late to matter.

Jim

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