Turntable Modification

[KA4HJH]

>    I have an old Philips 312 turntable.  I need to run at 78 rpm (this
>thing is 33/45 stock).  Since it has a servo control for the platter
>speed, I was thinking I could pervert this thing to run at 78.  Has any
>body ever attempted this, and if so, were you succesful.  I would not
>want to ruin a perfectly good turntable on a fools errand.

Aside from the speed difference, which may be as easy as fooling with an
oscillator, 78's use a different, larger stylus. I don't know what might
happen if you try to use an LP stylus to play one. Maybe nothing, maybe it
would damage something, maybe it would sound like crap.


>    (This is so I can record some old shelac records.  I have found a
>source for the stylus and cartridge, I just need a turntable.  Cheapest
>new one I have found is $300).

A lot of old turntables had a dual stylus--you flipped it over to play
78's. You should be able to snag one of those old BSR turntables somewhere
for nothing. They were used in practically every cheap (and some not quite
so cheap) stereo made in the 70's. I see this junk in flea markets all the
time. That would be the simplest approach. And then like Paul says filter
it in the digital domain...


-- 
Terry Bowman, KA4HJH
"The Mac Doctor"