Sounds like a turntable speed control device, when you said did for, did you
mean that literally, ie killed?


Brian

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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Phil Allison" wrote in message
...
Eiron wrote:


I became quite adept at fixing Z30s in my youth.
http://rk.nvg.ntnu.no/sinclair/audio/z30.htm
Maybe a much bigger heat sink would have helped
but they hardly ever survived a party.


** Someone gave me one Z30 module and a "Project 60" manual in the early
70s - it all sat in a drawer for several years until I figured out a use. In
the manual was a schem for making the Z30 into a power sine wave oscillator
using a Wein bridge circuit. See figure 4.16.1.a

http://www.epanorama.net/sff/Audio/C...oject%2060.pdf

I quickly lashed up one built to oscillate at 67Hz, with a few Hz range of
adjustment. Used with an unregulated 30V supply, it ran nicely with the
output feeding the 8ohm winding of a 15W UL output tranny from an old valve
amplifier.

The primary was used to drive a small synchronous motor with a 240V pure
sine wave. The finished version had a toggle switch to bring the frequency
down to a nominal 50Hz.

This is a pretty tough job for a puny Sinclair Z30 module, but it never
failed in over 20 years of use.

Who can guess what it did ?


..... Phil

Brian Gaff wrote:


Sounds like a turntable speed control device,



** Correct.

Was used it to drive the 16 pole, synchronous motor of a JH Turntable.

Made in Melbourne by "JH Reproducers" the TT used a soft belt wrapped around a lightweight, 30cm dia aluminium platter driven by a almost vibrationless motor with a two step pulley. The steps enabled 45rpm and 33.3rpm discs to be played.

It was far more convenient to have electronic control and the ability to trim the speed as JHs usually ran a few percent fast - allegedly to compensate for the drag effect of a "dust bug".

I know such a combination sounds unpromising, but when mounted on an inch thick acrylic base and supported on three beehive springs - it became a genuine Linn Sondek killer.

I used mine with a uni-pivot tone arm and Shure V15 mkIII up to and well beyond the arrival of CDs.


when you said did for, did you
mean that literally, ie killed?



** No, I gave the set up away to a friend, along with all my LPs, when they had been long out of use.



.... Phil

I still have an old Technics SL5 with an Ortofon cart which still goes, but
is begining to make noises in the parrarell arm mechanics due to the grease
drying out.

I use it cos it needs no sight.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Phil Allison" wrote in message
...
Brian Gaff wrote:


Sounds like a turntable speed control device,



** Correct.

Was used it to drive the 16 pole, synchronous motor of a JH Turntable.

Made in Melbourne by "JH Reproducers" the TT used a soft belt wrapped
around a lightweight, 30cm dia aluminium platter driven by a almost
vibrationless motor with a two step pulley. The steps enabled 45rpm and
33.3rpm discs to be played.

It was far more convenient to have electronic control and the ability to
trim the speed as JHs usually ran a few percent fast - allegedly to
compensate for the drag effect of a "dust bug".

I know such a combination sounds unpromising, but when mounted on an inch
thick acrylic base and supported on three beehive springs - it became a
genuine Linn Sondek killer.

I used mine with a uni-pivot tone arm and Shure V15 mkIII up to and well
beyond the arrival of CDs.


when you said did for, did you
mean that literally, ie killed?



** No, I gave the set up away to a friend, along with all my LPs, when
they had been long out of use.



... Phil