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Turntable A/C Question

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Anonymous
April 20, 2005 8:00:58 AM

Archived from groups: rec.audio.pro (More info?)

Hi folks! Long time no post!

i have a lovely Thorens TD 160 turntable with a fancy Shure cartridge
that plays those old fashioned plastic records with the hole in the
middle. Trouble is, it spins 'em too slow! A held solo note on a record
will read out about 50 cents flat on my trusty Korg DTR-1000 Tuner, and
the vocals sound a little groggy.

As far as i can understand i'll have to pump a bit more A/C voltage
into it to speed it up, and i'd like to do it on the cheap. i have a 110
to 220 volt transformer that i use to run my old european Korg MS20
synth - could i simply add some kind of household dimmer switch/knob to
it and get the 130 or so that i'd need without burning the house down?
Would i need a *220* dimmer?

--t
[london, canada & echo cañon, nyc]

More about : turntable question

Anonymous
April 20, 2005 9:15:21 AM

Archived from groups: rec.audio.pro (More info?)

"tim glasgow" <rorytate@sympatico.ca> wrote in message
news:rorytate-AC96E4.04005720042005@news.bellglobal.com...
> Hi folks! Long time no post!
>
> i have a lovely Thorens TD 160 turntable with a fancy Shure cartridge
> that plays those old fashioned plastic records with the hole in the
> middle. Trouble is, it spins 'em too slow! A held solo note on a record
> will read out about 50 cents flat on my trusty Korg DTR-1000 Tuner, and
> the vocals sound a little groggy.
>
> As far as i can understand i'll have to pump a bit more A/C voltage
> into it to speed it up, and i'd like to do it on the cheap. i have a 110
> to 220 volt transformer that i use to run my old european Korg MS20
> synth - could i simply add some kind of household dimmer switch/knob to
> it and get the 130 or so that i'd need without burning the house down?
> Would i need a *220* dimmer?
>
> --t
> [london, canada & echo cañon, nyc]

Hit the belt with some Pledge furniture cleaner. It leaves a wax behind
that gives the belt more grip. Fixed many a flat-belted turntable.
Anonymous
April 20, 2005 12:55:43 PM

Archived from groups: rec.audio.pro (More info?)

In article <rorytate-AC96E4.04005720042005@news.bellglobal.com>,
tim glasgow <rorytate@sympatico.ca> wrote:
>Hi folks! Long time no post!
>
> i have a lovely Thorens TD 160 turntable with a fancy Shure cartridge
>that plays those old fashioned plastic records with the hole in the
>middle. Trouble is, it spins 'em too slow! A held solo note on a record
>will read out about 50 cents flat on my trusty Korg DTR-1000 Tuner, and
>the vocals sound a little groggy.
>
> As far as i can understand i'll have to pump a bit more A/C voltage
>into it to speed it up, and i'd like to do it on the cheap. i have a 110
>to 220 volt transformer that i use to run my old european Korg MS20
>synth - could i simply add some kind of household dimmer switch/knob to
>it and get the 130 or so that i'd need without burning the house down?
>Would i need a *220* dimmer?

I am sorry, I refuse to respond to such an obvious troll. This is not
even funny.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Related resources
Can't find your answer ? Ask !
Anonymous
April 20, 2005 12:56:19 PM

Archived from groups: rec.audio.pro (More info?)

"tim glasgow" <rorytate@sympatico.ca> wrote in message
news:rorytate-AC96E4.04005720042005@news.bellglobal.com...
> Hi folks! Long time no post!
>
> i have a lovely Thorens TD 160 turntable with a fancy Shure cartridge
> that plays those old fashioned plastic records with the hole in the
> middle. Trouble is, it spins 'em too slow! A held solo note on a record
> will read out about 50 cents flat on my trusty Korg DTR-1000 Tuner, and
> the vocals sound a little groggy.
>
> As far as i can understand i'll have to pump a bit more A/C voltage
> into it to speed it up, and i'd like to do it on the cheap. i have a 110
> to 220 volt transformer that i use to run my old european Korg MS20
> synth - could i simply add some kind of household dimmer switch/knob to
> it and get the 130 or so that i'd need without burning the house down?
> Would i need a *220* dimmer?

My suspicion is that you need to get your motor and bearing cleaned and
lubed, and your belt replaced. Thorens is still in business, and they can
recommend a good service place.

Peace,
Paul
Anonymous
April 20, 2005 4:38:48 PM

Archived from groups: rec.audio.pro (More info?)

tim glasgow wrote:
> Hi folks! Long time no post!
>
> i have a lovely Thorens TD 160 turntable with a fancy Shure cartridge
> that plays those old fashioned plastic records with the hole in the
> middle. Trouble is, it spins 'em too slow! A held solo note on a record
> will read out about 50 cents flat on my trusty Korg DTR-1000 Tuner, and
> the vocals sound a little groggy.
>
> As far as i can understand i'll have to pump a bit more A/C voltage
> into it to speed it up, and i'd like to do it on the cheap. i have a 110
> to 220 volt transformer that i use to run my old european Korg MS20
> synth - could i simply add some kind of household dimmer switch/knob to
> it and get the 130 or so that i'd need without burning the house down?
> Would i need a *220* dimmer?
>
> --t
> [london, canada & echo cañon, nyc]

http://www.theanalogdept.com/thorens_dept_.htm

Everything (or more than) you ever wanted to know about Thorens..

Hans

--




This is a non-profit organization;
we didn't plan it that way, but it is

=====================================


(remove uppercase trap, and double the number to reply)
Anonymous
April 21, 2005 11:07:25 AM

Archived from groups: rec.audio.pro (More info?)

And while you are at it, use the Pledge on the dust cover...fills in all the
scratches.

Pledge, duct tape, and my trusty Leatherman. My life is complete.


"Zigakly" <zigakly@nospam.cx> wrote in message
news:o 4p9e.13423$If1.3581093@read2.cgocable.net...
>
> "tim glasgow" <rorytate@sympatico.ca> wrote in message
> news:rorytate-AC96E4.04005720042005@news.bellglobal.com...
>> Hi folks! Long time no post!
>>
>> i have a lovely Thorens TD 160 turntable with a fancy Shure cartridge
>> that plays those old fashioned plastic records with the hole in the
>> middle. Trouble is, it spins 'em too slow! A held solo note on a record
>> will read out about 50 cents flat on my trusty Korg DTR-1000 Tuner, and
>> the vocals sound a little groggy.
>>
>> As far as i can understand i'll have to pump a bit more A/C voltage
>> into it to speed it up, and i'd like to do it on the cheap. i have a 110
>> to 220 volt transformer that i use to run my old european Korg MS20
>> synth - could i simply add some kind of household dimmer switch/knob to
>> it and get the 130 or so that i'd need without burning the house down?
>> Would i need a *220* dimmer?
>>
>> --t
>> [london, canada & echo cañon, nyc]
>
> Hit the belt with some Pledge furniture cleaner. It leaves a wax behind
> that gives the belt more grip. Fixed many a flat-belted turntable.
>
>
April 21, 2005 1:20:47 PM

Archived from groups: rec.audio.pro (More info?)

you guys aren't BS-ing with your Pledge thing, are you? Before I ruin my
Thorens with the same problems (slippery, slightly too slow)

cheers,
Bob
Anonymous
April 21, 2005 1:20:48 PM

Archived from groups: rec.audio.pro (More info?)

"Bob" <b.dewever@amc.uva.nl> wrote in message
news:1114068049.176787@aquila.amc.uva.nl...
>
> you guys aren't BS-ing with your Pledge thing, are you? Before I ruin my
> Thorens with the same problems (slippery, slightly too slow)

I don't know if they're BS-ing, but I wouldn't mess with trying to treat the
belt with anything. New belts are cheap. At least for this turntable they
are.

Peace,
Paul
April 21, 2005 2:05:12 PM

Archived from groups: rec.audio.pro (More info?)

Curiously enough a couple of weeks ago I got my old Thorens TD 160 out
of long term storage and it also played slow. I cleaned the platter,
pulley and belt using a dry cloth and oiled the bearing. It now plays
very slightly too fast according to a strobe disc but this is not
audible to my ears and is apparently normal.

The belt is 30 years old and probably knackered - it will not climb
onto the 45 rpm part of the drive without a nudge from a finger - but
this is not affecting the speed.
Anonymous
April 21, 2005 2:33:24 PM

Archived from groups: rec.audio.pro (More info?)

Bob <b.dewever@amc.uva.nl> wrote:
>
>you guys aren't BS-ing with your Pledge thing, are you? Before I ruin my
>Thorens with the same problems (slippery, slightly too slow)

Just change the damn belt. It's five dollars. Put a drop of turbine
oil on the center bearing, on the top and bottom bearings of the motor,
and on the tonearm pivots. Then if it's one of the servo models, set
the speed with a strobe disc.

If you don't lubricate it every couple years, the bearings will go bad.
If you don't replace the belt every couple years, it will get loose.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 21, 2005 2:40:32 PM

Archived from groups: rec.audio.pro (More info?)

Paul Stamler <pstamlerhell@pobox.com> wrote:
>"Bob" <b.dewever@amc.uva.nl> wrote in message
>>
>> you guys aren't BS-ing with your Pledge thing, are you? Before I ruin my
>> Thorens with the same problems (slippery, slightly too slow)
>
>I don't know if they're BS-ing, but I wouldn't mess with trying to treat the
>belt with anything. New belts are cheap. At least for this turntable they
>are.

Pledge, or any other wax, is a temporary fix that works until you can
get the new belt in the mail. In the US, Radio Shack sells a gum
solution specifically designed for the job.

Occasional treatment with methyl acetate or Fedron will keep rubber from
hardening and stretching, but once it's hardened and stretched there
really isn't anything to do about it.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 21, 2005 4:01:13 PM

Archived from groups: rec.audio.pro (More info?)

tim glasgow wrote:
> Hi folks! Long time no post!

I believe that turntable motors are AC synchronous and not
DC. I don't know how the motor could rotate at any rate
other than that determined by line frequency. Unless the
motor is really wimpy, as load is applied and phase angle
increases, so does torque so as to prevent slippage.

If it's slow, it almost has to be that something in the
mechanical chain has changed.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
April 21, 2005 10:18:30 PM

Archived from groups: rec.audio.pro (More info?)

Bob Cain <arcane@arcanemethods.com> wrote:
>I believe that turntable motors are AC synchronous and not
>DC. I don't know how the motor could rotate at any rate
>other than that determined by line frequency. Unless the
>motor is really wimpy, as load is applied and phase angle
>increases, so does torque so as to prevent slippage.

Depends on the turntable. The Thorens TD-124 has a synchronous motor.
The TD-126 has a DC tachometer motor with a PLL to control the speed.

Either way, if the motor is running at speed and the belt slips, the
table will not run on-speed. If the main bearing is badly grinding,
the belt will slip and the flutter will be much worse than it should
be. Clean and lube every 12 months.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 21, 2005 11:12:33 PM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:
> Bob Cain <arcane@arcanemethods.com> wrote:
>
>>I believe that turntable motors are AC synchronous and not
>>DC. I don't know how the motor could rotate at any rate
>>other than that determined by line frequency. Unless the
>>motor is really wimpy, as load is applied and phase angle
>>increases, so does torque so as to prevent slippage.
>
>
> Depends on the turntable. The Thorens TD-124 has a synchronous motor.
> The TD-126 has a DC tachometer motor with a PLL to control the speed.

Why on earth would they do that? Line is a _very_ precise
oscilator and a synchronous motor is actually an analog
phase locked loop. The larger the phase angle, the greater
the torque applied to lower it.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
April 21, 2005 11:47:11 PM

Archived from groups: rec.audio.pro (More info?)

"Bob Cain" <arcane@arcanemethods.com> wrote in message
news:D 48tac01b9j@enews1.newsguy.com...
>
> I believe that turntable motors are AC synchronous and not
> DC. I don't know how the motor could rotate at any rate
> other than that determined by line frequency. Unless the
> motor is really wimpy, as load is applied and phase angle
> increases, so does torque so as to prevent slippage.
>
> If it's slow, it almost has to be that something in the
> mechanical chain has changed.

Depends on the motor -- various turntables have AC synchronous motors (as
you describe), DC motors, AC motors that run off an internal oscillator
(with servo, usually), or DC with servo. In the case of the Thorens
described by the OP, I'd agree that the problem is almost certainly
mechanical.

Peace,
Paul
Anonymous
April 22, 2005 7:51:41 AM

Archived from groups: rec.audio.pro (More info?)

On Thu, 21 Apr 2005 19:12:33 -0700, Bob Cain
<arcane@arcanemethods.com> wrote:

>> Depends on the turntable. The Thorens TD-124 has a synchronous motor.
>> The TD-126 has a DC tachometer motor with a PLL to control the speed.
>
>Why on earth would they do that? Line is a _very_ precise
>oscilator and a synchronous motor is actually an analog
>phase locked loop. The larger the phase angle, the greater
>the torque applied to lower it.

Two big reasons are that A: they can; and don't have to depend
on precise mechanical dimensions, including the effective
thickness of the belt, which is PFM-ish.

And 2: they can; and don't have to mechanically change motor
pulley diameters for different speeds.

Neither is a terribly compelling reason thirty years later,
of course. (And the TD 160 is a simple synchronous AC motor,
I'm pretty sure. Wash the motor bearings, relube, report back.)

Chris Hornbeck
Anonymous
April 22, 2005 9:40:19 AM

Archived from groups: rec.audio.pro (More info?)

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in message
news:kksg61t9nk23apjkkd85b33fh2fh8tm1qt@4ax.com...
> On Thu, 21 Apr 2005 19:12:33 -0700, Bob Cain
> <arcane@arcanemethods.com> wrote:
>
> >> Depends on the turntable. The Thorens TD-124 has a synchronous motor.
> >> The TD-126 has a DC tachometer motor with a PLL to control the speed.
> >
> >Why on earth would they do that? Line is a _very_ precise
> >oscilator and a synchronous motor is actually an analog
> >phase locked loop. The larger the phase angle, the greater
> >the torque applied to lower it.
>
> Two big reasons are that A: they can; and don't have to depend
> on precise mechanical dimensions, including the effective
> thickness of the belt, which is PFM-ish.
>
> And 2: they can; and don't have to mechanically change motor
> pulley diameters for different speeds.

Third big reason: DC motors are often less likely to radiate hum into the
cartridge, which is an issue on certain cartridges, most of them named
Grado.

Peace,
Paul
Anonymous
April 22, 2005 10:22:24 AM

Archived from groups: rec.audio.pro (More info?)

Bob Cain wrote:
> Scott Dorsey wrote:
>> Bob Cain <arcane@arcanemethods.com> wrote:
>>
>>> I believe that turntable motors are AC synchronous and not
>>> DC. I don't know how the motor could rotate at any rate
>>> other than that determined by line frequency. Unless the
>>> motor is really wimpy, as load is applied and phase angle
>>> increases, so does torque so as to prevent slippage.
>>
>>
>> Depends on the turntable. The Thorens TD-124 has a synchronous
>> motor. The TD-126 has a DC tachometer motor with a PLL to control
>> the speed.

> Why on earth would they do that?

(1) Works on either 50 Hz or 60 Hz without adjustments.

(2) Works well in situations where the power line does not have a
steady frequency. These include LDCs, and people who are running off
local power supplies.

> Line is a _very_ precise oscilator

In most US communities, but not all over the world.

> and a synchronous motor is actually an analog phase locked loop.

I guess you could say that.

>The larger the phase angle, the greater the torque applied to lower
it.

However, the servo gain is not as high as what you can do with active
electronics.
April 22, 2005 12:47:01 PM

Archived from groups: rec.audio.pro (More info?)

I *have* put in a new belt, damned ;-)
Still slippery on start u and won't 'slide' to the 45 rpm part... BTW it
cost me $25 over here.....
Its a TD160-s mkV.
Regards,
Bob


"Scott Dorsey" <kludge@panix.com> schreef in bericht
news:D 48djk$k6g$1@panix2.panix.com...
> Bob <b.dewever@amc.uva.nl> wrote:
> >
> >you guys aren't BS-ing with your Pledge thing, are you? Before I ruin my
> >Thorens with the same problems (slippery, slightly too slow)
>
> Just change the damn belt. It's five dollars. Put a drop of turbine
> oil on the center bearing, on the top and bottom bearings of the motor,
> and on the tonearm pivots. Then if it's one of the servo models, set
> the speed with a strobe disc.
>
> If you don't lubricate it every couple years, the bearings will go bad.
> If you don't replace the belt every couple years, it will get loose.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 22, 2005 3:09:38 PM

Archived from groups: rec.audio.pro (More info?)

Bob Cain <arcane@arcanemethods.com> wrote:
>Scott Dorsey wrote:
>> Bob Cain <arcane@arcanemethods.com> wrote:
>>
>>>I believe that turntable motors are AC synchronous and not
>>>DC. I don't know how the motor could rotate at any rate
>>>other than that determined by line frequency. Unless the
>>>motor is really wimpy, as load is applied and phase angle
>>>increases, so does torque so as to prevent slippage.
>>
>> Depends on the turntable. The Thorens TD-124 has a synchronous motor.
>> The TD-126 has a DC tachometer motor with a PLL to control the speed.
>
>Why on earth would they do that? Line is a _very_ precise
>oscilator and a synchronous motor is actually an analog
>phase locked loop. The larger the phase angle, the greater
>the torque applied to lower it.

To deal with records that were not recorded so precisely.

Guys that listen to acoustical 78s get discs that are recorded anywhere
from 60 to 110 rpm. But I regularly get LPs that are a couple semitones
off.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 22, 2005 3:15:01 PM

Archived from groups: rec.audio.pro (More info?)

Bob <b.dewever@amc.uva.nl> wrote:
>I *have* put in a new belt, damned ;-)
>Still slippery on start u and won't 'slide' to the 45 rpm part... BTW it
>cost me $25 over here.....
>Its a TD160-s mkV.

Sounds like a lubrication issue. I _think_ you can shift the motor on
that to adjust the belt tension, but you shouldn't have to if you have
the right belt. But if the platter bearing is not turning properly, the
belt will slip on startup.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 23, 2005 2:05:12 AM

Archived from groups: rec.audio.pro (More info?)

On Fri, 22 Apr 2005 06:22:24 -0400, "Arny Krueger" <arnyk@hotpop.com>
wrote:

>Bob Cain wrote:
>> Scott Dorsey wrote:
>>> Bob Cain <arcane@arcanemethods.com> wrote:
>>>
>>>> I believe that turntable motors are AC synchronous and not
>>>> DC. I don't know how the motor could rotate at any rate
>>>> other than that determined by line frequency. Unless the
>>>> motor is really wimpy, as load is applied and phase angle
>>>> increases, so does torque so as to prevent slippage.
>>>
>>>
>>> Depends on the turntable. The Thorens TD-124 has a synchronous
>>> motor. The TD-126 has a DC tachometer motor with a PLL to control
>>> the speed.
>
>> Why on earth would they do that?
>
>(1) Works on either 50 Hz or 60 Hz without adjustments.

Furthermore, most such turntables have a speed adjustment control
so you can adjust the speed above or below the 'correct' speed, so you
can 'tune' the pitch of the music on the LP to a musical instrument
when you want to play along but it's a lot of trouble to tune the
instrument (such as a piano).
There are mechanical systems to make small speed changes, notably
on Dual turntables, but the more recent the model, the more likely it
uses a DC servomotor that (has the potential to) keep the speed more
steady than a line-powered synchronous motor. Cheap electronics is (in
some cases) a Good Thing.

>(2) Works well in situations where the power line does not have a
>steady frequency. These include LDCs, and people who are running off
>local power supplies.
>
>> Line is a _very_ precise oscilator
>
>In most US communities, but not all over the world.

Even in the USA it's "good enough" for most music and recording
applications, but it's not VERY precise. The grid loses several cycles
during the day, and is then sped up during the night to catch up on
cycles so that powerline-based syncronous clocks (almost any electric
clock ever made) will keep the correct time. I recall a thread on
sci.electronics.design on how accurate the power line frequency is in
the short-term - it's good, but not nearly as good as the long-term
average would indicate.
I'd think with current technology they could keep modern electric
power generators all in precise sync at the same frequency using WWVH
or GPS receivers, but I obviously don't know much about power
generation.

There's a similar distinction with tape recorders. Older/cheaper
models use a powerline synchronous motor for capstain drive (and often
other duties as well), and newer/higher-end models use DC servo
motors.

>> and a synchronous motor is actually an analog phase locked loop.
>
>I guess you could say that.
>
>>The larger the phase angle, the greater the torque applied to lower
>it.
>
>However, the servo gain is not as high as what you can do with active
>electronics.

For really accurate speed, the servo shouldn't be based on the
detected MOTOR speed but rather on the PLATTER speed. Direct-drive
turntables do this, though usually not as well as they could.

-----
http://mindspring.com/~benbradley
Anonymous
April 23, 2005 4:42:44 AM

Archived from groups: rec.audio.pro (More info?)

Bob Cain wrote:

>
> Why on earth would they do that? Line is a _very_ precise oscilator and
> a synchronous motor is actually an analog phase locked loop. The larger
> the phase angle, the greater the torque applied to lower it.

Thanks for all the answers. Sometimes you gotta ask a
stupid question to learn anything. :-)


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
!