can anyone add any thoughts on adding a pitch control to an older
turntable which doesnt have it?

i was thinking about adding a wider pitch control to a turntable which
has a pitch control wheel that allows a few rpms higher than 33.3, say
up to 37, and when switched to 45, the wheel can then cause the pitch
to go as low as maybe 41... with quite a gap inbetween (its listed as
10% pitch control in the manual, but that might be 5% in either
direction)... not necessarily making mixing 2 turntables impossible,
but far more challenging...

i was thinking there could be 2 ways to do it... replace that wheel
with something else, that allowed a higher boost, if the wheel was
going to a zero setting at its lowest point...

or somehow limiting voltage to the unit, with a seperate control,
which allowed to at least set the turntable at its highest possible
speed setting, and then limiting down to zero...

i figured the latter would be easier and far less damaging to the
unit... but then wonder if it would even still function when less
than appropriate voltage was applied to it, or if the led for the
stroboscope would still function...

i was thinking with power transformers for model trains, there could
be a transformer or something that could affect voltage in a smooth
manner, and use one to control the pitch, once setting the turntable
to its highest possible speed, and allow it to go as low as possible
before the motor ceased to function entirely...

i dont know enough about motors and wonder if "quartz" turntables are
different, required a specific voltage (mine is not a "quartz") the
motor type is listed in the manual as direct drive, brushless DC
motor.

thx in advance for any info

In , on 09/24/03
at 10:19 PM, (golgo) said:

can anyone add any thoughts on adding a pitch control to an older
turntable which doesnt have it?

i was thinking about adding a wider pitch control to a turntable which
has a pitch control wheel that allows a few rpms higher than 33.3, say
up to 37, and when switched to 45, the wheel can then cause the pitch
to go as low as maybe 41...

[ ... ]

In some cases it can be done, it depends on the underlying design of
the turntable. We have a turntable that can be set to any speed from
about 27 to 107 rpm.

I don't think this is a project that you should undertake. Perhaps you
have an expert friend who could help. Obviously, you could damage the
turntable in your attempt, but modifying some models will involve
significant personal safety issues.

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Why don't you tell us what turntable it is, how it works (belt, idler,
direct-drive) and which type of motor it uses? Then, we might be able
to help.

Kal


On 24 Sep 2003 22:19:47 -0700, (golgo) wrote:

can anyone add any thoughts on adding a pitch control to an older
turntable which doesnt have it?

i was thinking about adding a wider pitch control to a turntable which
has a pitch control wheel that allows a few rpms higher than 33.3, say
up to 37, and when switched to 45, the wheel can then cause the pitch
to go as low as maybe 41... with quite a gap inbetween (its listed as
10% pitch control in the manual, but that might be 5% in either
direction)... not necessarily making mixing 2 turntables impossible,
but far more challenging...

i was thinking there could be 2 ways to do it... replace that wheel
with something else, that allowed a higher boost, if the wheel was
going to a zero setting at its lowest point...

or somehow limiting voltage to the unit, with a seperate control,
which allowed to at least set the turntable at its highest possible
speed setting, and then limiting down to zero...

i figured the latter would be easier and far less damaging to the
unit... but then wonder if it would even still function when less
than appropriate voltage was applied to it, or if the led for the
stroboscope would still function...

i was thinking with power transformers for model trains, there could
be a transformer or something that could affect voltage in a smooth
manner, and use one to control the pitch, once setting the turntable
to its highest possible speed, and allow it to go as low as possible
before the motor ceased to function entirely...

i dont know enough about motors and wonder if "quartz" turntables are
different, required a specific voltage (mine is not a "quartz") the
motor type is listed in the manual as direct drive, brushless DC
motor.

thx in advance for any info

Kalman Rubinson wrote in message . ..
Why don't you tell us what turntable it is, how it works (belt, idler,
direct-drive) and which type of motor it uses? Then, we might be able
to help.

Kal

i appreciate any help... maybe most of my first message got missed...

its a technics sl-d3, "brushless DC motor", direct drive. a "real"
technics, with the "s-shaped" tone arm, not like other "technics
sl-d3" or sl-series ive seen made by other companies like pioneer or
sony.

im thinking about applying this to a couple others, both the same
motor, one an sl-d2, and another sl-d3.

i thought just a voltage limiter dial or something to plug the units
into... figuring that LESS voltage, controlled carefully, would be as
safe as full voltage.

In , on 09/25/03
at 08:00 PM, (golgo) said:

Kalman Rubinson wrote in message
... Why don't you
tell us what turntable it is, how it works (belt, idler,
direct-drive) and which type of motor it uses? Then, we might be able
to help.

Kal

i appreciate any help... maybe most of my first message got missed...

its a technics sl-d3, "brushless DC motor", direct drive. a "real"
technics, with the "s-shaped" tone arm, not like other "technics
sl-d3" or sl-series ive seen made by other companies like pioneer or
sony.

You are right, I didn't see that message. Unfortunately, I'm not
familiar with the internal design of this model.

im thinking about applying this to a couple others, both the same
motor, one an sl-d2, and another sl-d3.

i thought just a voltage limiter dial or something to plug the units
into... figuring that LESS voltage, controlled carefully, would be as
safe as full voltage.

Modifying the power line voltage will not be productive because this
type of unit is designed to maintain a constant speed when the power
line fluctuates. The unit will keep the speed nearly constant over a
wide voltage range. Below a certain voltage the unit will simply stop
working. Above the maximum safe voltage the unit will be destroyed. In
between these points the speed won't vary much.

-----------------------------------------------------------
SPAM:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, SPAMers are ruining my mailbox]
-----------------------------------------------------------

"golgo" wrote ...
its a technics sl-d3, "brushless DC motor", direct drive. a "real"
technics, with the "s-shaped" tone arm, not like other "technics
sl-d3" or sl-series ive seen made by other companies like pioneer or
sony.

Likely controlled by a solid-state circuit of moderate complexity.
Start by purchasing a service manual for the unit(s) and hope that
the circuitry is documented (not potted in an annonymous block of
plastic or embedded into the motor).

Strongly discourage trying to control speed by varying the power
line voltage! The circuit is designed to RESIST this kind of
sensitivity to external conditions.

thx to all who responded... i think i can see why their motor allows
5% sway in either direction with this generation, and only 8% in far
newer models.

if there is circuitry, id assume it would take more circuitry, or a
very intelligent tweak to manage it...

thanks for the insight... i love them too much to turn them into
frankenstein experiments anyway

On 25 Sep 2003 20:00:08 -0700, golgo wrote:
Kalman Rubinson wrote in message . ..
Why don't you tell us what turntable it is, how it works (belt, idler,
direct-drive) and which type of motor it uses? Then, we might be able
to help.

Kal

i appreciate any help... maybe most of my first message got missed...

its a technics sl-d3, "brushless DC motor", direct drive. a "real"
technics, with the "s-shaped" tone arm, not like other "technics
sl-d3" or sl-series ive seen made by other companies like pioneer or
sony.

im thinking about applying this to a couple others, both the same
motor, one an sl-d2, and another sl-d3.

i thought just a voltage limiter dial or something to plug the units
into... figuring that LESS voltage, controlled carefully, would be as
safe as full voltage.

The motor isn't voltage controled, it's frequency controled. Most likely
the source of it's timing is a quartz crystal and they can't be easily
varied. You'll need to come up with a new variable frequency timing
source and switch it in when desired.