On Sun, 12 Aug 2012 22:37:59 -0700, isw wrote:

In article ,
Jeff Liebermann wrote:

On Sun, 12 Aug 2012 11:23:23 -0700 (PDT), klem kedidelhopper
wrote:

I got an old, (what looks like a BSR) three speed automatic turntable
in for repair. It doesn't work on auto because the plastic trip pawl
is worn. I can't get to the trip pawl without doing a semi major strip
down. And this guy isn't going to go for that.

It's also likely that the rubber parts are going bad on anything that
old.

I would like to replace
the turntable with an equivalent inexpensive BSR type for him. I used
to be able to buy these from my parts suppliers for about 20 bucks
about 100 or so years ago but I haven't looked into this for a long
time. Is it still possible to find something like this, a basic
general replacement type idler driven mechanical turntable with a
cheapo ceramic cartridge? Thanks, Lenny

https://www.google.com/#q=usb+turntable&hl=en&tbm=shop
http://www.shopping.com/usb-turntable/products?CLT=SCH&KW=usb+turntable
I have one I picked up at Costco for about $75. The big problem is
finding replacement needles. Check for availability before buying.
Also, make sure that it will play 33.3, 45, and 78 rpm disks. The one
I bought only does 33.3 and 45.

However, such turntables are boring. Sell the customer one of these:
https://www.google.com/search?q=ultimate+turntable&hl=en&tbm=isch
Only $150,000.
http://www.onedof.com
or maybe this 400 lb monster:
http://goodwinshighend.com/manufacturers/basis/work_of_art.htm
But those use a stylus. Modern turntables use a laser:
http://www.elpj.com
Only $9,000 to $12,000.

The laser ones actually don't do that good a job. There are a *lot* of
mechanical "errors" in a needle-in-groove system that are
"automatically" taken care of by stylus reproducers, in a system that
has been refined by "cut and try" over a period of years and has no real
spec. Basically, the cutter "pre-distorts" the groove so that when the
reproducer adds its own distortion, things sort of come out even -- sort
of. If you use a laser to read the groove, then you have to do all those
things some other way, and the list of them is long and isn't well
defined.

Isaac

One plays a vendor supplied calibration record on the turntable to
calibrate it for those distortions and anomalies. For example, they
record a clean low distortion sine wave at various frequencies using
the standard record cutting lathe. When played back on a laser
turntable, the processor look for distortion products (harmonics) and
tweak a DSP to compensate. Resonances can be taken out via a freqency
sweep.
http://www.elpj.com/about/howitworks.php

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558