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Columbia BM

Posted: Tue Jul 24, 2012 11:44 pm
by MTPhono
Can a Columbia expert tell me what the purpose of the brass part (indicated below in photo) is used for? I must be missing something.

Were there any horns made to fit directly onto the Bm reproducer? Or is rubber tubing the only answer?

Thanks for looking!
Scott

Image

Re: Columbia BM

Posted: Wed Jul 25, 2012 7:21 am
by phonogfp
I don't think you're missing anything. The brass sleeve is part of the telescoping assembly that drives the Higham.

George P.

Re: Columbia BM

Posted: Wed Jul 25, 2012 11:53 am
by MTPhono
Thanks George. But I don't see it "driving" anything and seems to be more or a floating bearing than anything else.

Have you heard any BMs that play loudly? I've heard several BCs that were quite loud, while the two BMs I've heard were on par with a standard two minute machine.

Re: Columbia BM

Posted: Wed Jul 25, 2012 1:47 pm
by VintageTechnologies
What is the difference between a BM and a BC? I have seen a number of BC's over the years and heard a few, but none of them sounded any louder than a regular machine. I read somewhere that the friction materials used in the Higham reproducer deteriorated rapidly. You can hear a restored BC on YouTube that uses modern materials for the friction parts. Does anyone know what those materials could be? A friend of mine just bought a BC and will eventually want to restore his.

Re: Columbia BM

Posted: Wed Jul 25, 2012 2:28 pm
by barnettrp21122
In Eric Reiss's book "The Compleat Talking Machine," on page 75 he describes how an owner molded a new friction shoe strap using a semi-elastic plastic car putty known as "Bondo." Quoting: "After carefully turning down the amber wheel on a lathe in order to remove chips and scars, the putty was formed around the wheel and left to dry. Afterwards, the new strap was filed and fitted to the rest of the mechanism."
There are further details regarding adjustment and audio performance in the book.
Bob

Re: Columbia BM

Posted: Wed Jul 25, 2012 3:27 pm
by JohnM
Harold Braker of British Columbia, Canada is producing quality rebuild parts for Type BC-sized Higham amplifiers. Contact me by pm if you want his contact info.

Re: Columbia BM

Posted: Wed Jul 25, 2012 4:03 pm
by phonogfp
MTPhono wrote:Thanks George. But I don't see it "driving" anything and seems to be more or a floating bearing than anything else.

Have you heard any BMs that play loudly? I've heard several BCs that were quite loud, while the two BMs I've heard were on par with a standard two minute machine.
If that sleeve is revolving as the machine runs, it's doing its job. The slots on the sides allow it to travel with the reproducer.

I've only heard one or two BMs, and neither were any louder than a regular machine. I'm pretty sure they had their original parts, so that would explain it.

George P.