Author Topic: Turntable power supply - Thorens TD150 MkII  (Read 1912 times)

alternativeroute

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Turntable power supply - Thorens TD150 MkII
« on: September 04, 2010, 03:12:36 pm »
following on from this thread: http://www.avforums.co.za/index.php/topic,6011.0.html

I have two Thorens TD150's that I want to do something with...

The one I wanna just do a basic type thing...

  • New plinth - vanilla - following the same dimensions & basic look as the original
  • service (usual suspects like new belts and cleaning and oiling) & spring adjustment
  • New power cable
  • New cable/Rca plugs...
  • A new dustcover or restoration of the current dustcover

Now the other I wanna do a whole hog type thing...

  • CLD hybrid type plinth...
  • service (usual suspects like new belts and cleaning and oiling) & spring adjustment/modification
  • New power cable
  • New cable/Rca plugs...
  • New dustcover
  • extenal power supply
  • modern tonearm

This brings me to the question I pose in this thread.

I seem to be reading conflicting reports on external power supplies... Particularly the hercules/mose one...

This site: http://www.stamfordaudio.co.uk/pages/1102.htm seems to say that you can use the Hercules II Power Supply with the Thorens TD150...

yet when I visit this guys page http://cgi.ebay.com/MOSE-Hercules-acclaimed-External-PSU-Linn-LP12-/320583714789?pt=LH_DefaultDomain_0&hash=item4aa44747e5

He says the following:
Quote
If someone tell you the same PSU can be apply to LP12 and Thorens turntable, it is lie or has no knowledge in AC motors. They are different in poles.

From what I can gleam, the Thorens has a 16 pole motor and the Linn has a 24 pole motor... Subsequently a Linn power supply with a Thorens motor will result in the Thorens motor not having enough torque to start up....

I am pretty clueless regarding these things...

Another potential problem that I am trying to wrap my head around is where the diameter of your pulley of the pulley comes into this... My (perhaps flawed) logic says to me that it will only work if the the motor pulley and the inner platter of the Thorens td150 and the Linn LP12 were exactly the same??? Does that sound right...

Does anyone have some useful insights for me?  :)

Hi-Phibian

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #1 on: September 04, 2010, 08:49:49 pm »
Will reply properly tomorrow. less poles, motor turns faster, smaller pulley. ac freq and qty of poles governs motor speed. Hercules has no reason not to work, one might change the pase cap on the hercules depending on what thorens uses.

alternativeroute

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #2 on: September 04, 2010, 09:09:29 pm »
Thank Mr Hi-Phibian, I was hopping you were gonna chime in. It was one of your older posts ( http://www.avforums.co.za/index.php?topic=4543.0 ) that got me onto the Mose/Hercules train of thought...

Just to clarify. I like the Mose/Hercules solution as I do not want to design a power supply. I have perused this thread: http://www.avforums.co.za/index.php/topic,1632.0.html

It's greek to me and scraps aside. I wanna go the 'buy the product' route instead of the design/DIY route...

Hi-Phibian

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #3 on: September 04, 2010, 10:10:47 pm »
I distribute the hercules in sa.

alternativeroute

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #4 on: September 04, 2010, 10:13:06 pm »
whoohoo  ;D

I didn't do a South Africa only search... Will call

Ampdog

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #5 on: September 04, 2010, 10:42:17 pm »
Ah gee .....

Alternativeroute,

One does not need to be 'stupid' to get confused by some of the gobbledigook written with great conviction, not only by advertisers (they are at least earning their money that way), but even more so by some self-appointed 'gurus'.

I also tried to make head or tail .... oh well, let me just try emphasising some basics. But first a proviso: I do not know what internal 'power supplies' either the Lin or the Thorens have. I conclude from limited descriptions that they are fed plain mains 50 Hz (for RSA) current for their motors - I stand to be corrected on that; obviously then the scene changes. Whatever the case, I take it these run at their rotational speeds as governed by the mains frequency. That would mean that the number of poles the motor has is immaterial to the final record speed, say 33,3 rpm. Naturally the 24 pole motor would run slower, but that would be accounted for by the mechanical conversion [spindle - platter], as you intuitively felt. That renders the remark you hilighted in your first post worthless (so much for knowledge of turntables). That would also make the starting torque of secondary importance: the (possible) advantage of a higher pole number motor is offset by the lower mechanical speed ratio as a first approximation (the real figure would also depend on the motor design).

As far as the lauded audible advantages of so-called boutique power supply designs go .... let me just be kind and say that it has as little to do with motor power supply as does your car seat covers have with your car's performance. The audible interference of so-called 'dirty' mains supplies can be sorted out by much simpler means than an expensive separate supply except in absolutely disasterous situations, and the 'sonic advantages' of a crystal-controlled frequency will only be evident if the original supply was manually generated by a slave with a crank. [Subjective experiences to the contrary are, respectfully, just that. As to improved sound stage, better imaging, clearer treble (especially in Diana Krall or Mario Lanza's voice), more transparency etc. - no comment.]      
Judging a person does not define who he is; it only defines who you are. (Anon)

Ampdog

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #6 on: September 04, 2010, 10:50:16 pm »
PS: While I was typing Hi-Phibian's response #3 came through. So kindly note that I am not saying that the unit is not worth its price for what is in it. Hi-Phibian is often in a difficult situation as a commentator as well as a dealer, and I respect that and his agency. He has always given us substantial advantage from his knowledge of commercial equipment. My comments above was purely technical. I would buy from him should the need arise.
Judging a person does not define who he is; it only defines who you are. (Anon)

alternativeroute

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #7 on: September 04, 2010, 11:10:57 pm »
As far as the lauded audible advantages of so-called boutique power supply designs go .... let me just be kind and say that it has as little to do with motor power supply as does your car seat covers have with your car's performance. The audible interference of so-called 'dirty' mains supplies can be sorted out by much simpler means than an expensive separate supply except in absolutely disasterous situations, and the 'sonic advantages' of a crystal-controlled frequency will only be evident if the original supply was manually generated by a slave with a crank. [Subjective experiences to the contrary are, respectfully, just that. As to improved sound stage, better imaging, clearer treble (especially in Diana Krall or Mario Lanza's voice), more transparency etc. - no comment.]      

Lets just say I am game for anything really... Like I said, I have two (Thorens TD150's). The one I want to fix up sensibly the other I want to go the whole hog....

To give you a car analogy... Say I buy an oldish Honda Ballade. The sensible thing to do to extract a little more performance without laying out too much cash would be to give it a good service and replace any worn parts... Or I can do all that, add some low profiles, a pipe and a nice big shopping trolley handle spoiler/wing to the boot...

Now. Anyone versed in aerodynamics will tell you that you are wasting your cash adding the spoiler to the boot. It will only be affective above 200km/h... Any speed below that all its doing is adding drag (and weight)...

So ye, going the crystal-meth-power-supply route is in that in-between cryogenic zone of audio... Highly debatable...

BTW. I got at least an extra 5kw flywheel power adding those racing stripes to my car...  ::) ::)  ::)  :)  :D  ;D  ;D  ;D

Quote
I conclude from limited descriptions that they are fed plain mains 50 Hz (for RSA) current for their motors
True

pss. I was under the impression that an external power supply would 'lock' the speed of the turntable regardless of voltage fluctuations... Am I labouring under a false impressions?

PS: While I was typing Hi-Phibian's response #3 came through. So kindly note that I am not saying that the unit is not worth its price for what is in it. Hi-Phibian is often in a difficult situation as a commentator as well as a dealer, and I respect that and his agency. He has always given us substantial advantage from his knowledge of commercial equipment. My comments above was purely technical. I would buy from him should the need arise.

Cool...  :)

Hi-Phibian

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #8 on: September 04, 2010, 11:19:04 pm »
@ ampdog. Have a listen to the different powersources driving the exact same motor, same turbtable, same arm, same cartridge, same phono, same cables in the previously mentioned thread. If you can not hear any difference then good audio is wasted on your ears.
If you are on dial up and need higher res files to play on your cd player, gimme a postal addie and I will post you a disc.
Sorry, music genre is light, not your usual strykgoed.
Oh, and as far as the Linn goes, there are 3 supply versions from linn, only one direct from mains, two crystal generated. Then there are half a dozen options made by others for the Linn. They all sound different.

Hi-Phibian

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #9 on: September 04, 2010, 11:28:23 pm »
AC motor speed is governed by the ac frequency driving the motor. voltage drop affects torque but will need to be dramatically reduced before the motor struggles and slows even a little. reducing voltage does reduce motor vibration and this in most instances, despite decoupling and some isolation, is typically beneficial.

alternativeroute

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #10 on: September 04, 2010, 11:35:27 pm »
AC motor speed is governed by the ac frequency driving the motor. voltage drop affects torque but will need to be dramatically reduced before the motor struggles and slows even a little. reducing voltage does reduce motor vibration and this in most instances, despite decoupling and some isolation, is typically beneficial.

Ahhh OK - (penny drops). That makes sense now... 220v/50hz

What about this question:
Quote
Another potential problem that I am trying to wrap my head around is where the diameter of the pulley comes into this... My (perhaps flawed) logic says to me that it (the Linn power supply) will only work if the the motor pulley and the inner platter of the Thorens td150 and the Linn LP12 were exactly the same??? Does that sound right...
?

Or. Does it not make a difference as both motors turn at the same speed? So how the platter is 'geared' does'nt make a difference...

Hi-Phibian

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #11 on: September 05, 2010, 12:10:31 am »
"Or. Does it not make a difference as both motors turn at the same speed? So how the platter is 'geared' does'nt make a difference..."

You almost got it, both pulleys are geared to turn their platters corectly when fed a 50hz ac voltage.
The thorens driven platter size is close to that of the linn but that is not the point.
The thorens motor has fewer poles and turns faster and as a result is made with a smaller pulley, the ratio between the Linn pulley size and the Thorens pulley size is again in ratio to the number of poles on the motors. The math is actually quite complex on pulley size as you need to factor in a wee slip.

Hi-Phibian

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #12 on: September 05, 2010, 12:21:57 am »
simply put, when fed 50hz, a linn motor spins at 250 rpm, thorens at 375. Thus the thorens pulley is smaller.

Hi-Phibian

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #13 on: September 05, 2010, 12:25:01 am »
and as long as you don't mix up platters, motors and pulleys between the decks, as long as the ac it is fed is the frequency it was designed for, the paltter spins at the right speed.
Both Linn and Thorens want the same 50hz... (or 67.5Hz for electronic 45 rpm selection).

alternativeroute

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Re: Turntable power supply - Thorens TD150 MkII
« Reply #14 on: September 05, 2010, 12:33:00 am »
Quote
or 67.5Hz for electronic 45 rpm selection

Glad you mentioned that. Another reason I was keen to try the external power supply with my no holds barred TD150 project...

I read this bit with interest:

Quote
Bushman's comments on knob and selector removal: "I am still a bit amused by the change I experienced since removing the selectors completely.  The reason is I can not believe this mod should result in such a change.  The bass is much better defined and also deeper."
source = http://www.theanalogdept.com/bushman.htm

ps. again cryogenic treated warning... I am game for anything with this project... Even if the proof is subjective and the evidence at best analogous...
pss... Maybe after completion (hopefully before the end of the Mayan calender) I can treat everyone to two sample recordings and see who can guess which is which (of the 2 projects - vanilla Thorens vs over-the-top tinted windows low riding boof-boof Thorens)...
« Last Edit: September 05, 2010, 12:38:44 am by alternativeroute »