Lenco's R Us

classic analog rigs Thorens, Garrard, Lenco, EMT, etc..

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Re: Lenco's R Us

Postby setup1 » Thu Dec 11, 2008 9:10 am

Mamimili wrote:I had a better idea, take a look at the Lenco Lovers website as someone must have answered the frequency question.


Yup!

Mamimili wrote:For frequency, they suggest a simple mechanical answer - turn down the tapered spindle by 20%.


There was a guy in Arizona who tried this with initial success but the temper of the metal was lost (if I understood correctly) in long term use.

Mamimili wrote:However, i still think my first idea is worth a try, look at his spindle measurements for 33 and 45 rpm on both shafts, it must be possible to adjust (sounds better than bend?) the idler wheel arm to run on the correct diameter for the required speed.


As pictured in LL the 50hz shaft is larger than the 60hz. If there is a point where the 50hz and 60hz shafts share the same diameter for 33.3rpm, then there's a chance for a 50hz motor to work in a 60hz environment.....although the 16 rpm indentation towards the end of the shaft bothers me plus the versatility of continously variable speed of a Lenco is lost.

Mamimili wrote:My only worry now is if it's as simple as i think, why hasn't anyone done it this way


Ditto

A frequency converter is basically a clean sine wave generator driving a low distortion power amp. Years ago I did an experiment on a Hurst motor in my Merrill modified AR turntable. I hooked a sine wave generator (set @ 60HZ) to a bridged Hafler DH120 and and drove the motor from the speaker output, it worked!!! But as you can see, it is an expensive proposition. The only reason I ditched the project was because my TD124II still had significantly better pitch stability. ;)

It is very possible to do this on an idler drive motor. For ex: 50hz Lenco set the motor to 110/120V and the generator to 50hz, increase the output of the generator until the motor starts running from a 100W amp's output terminal. Those of you adept with solid state (I'm not) can experiment. Build a 100-200W IC amp with a built-in 50hz/60hz oscillator, or make it variable from 30hz to 100hz so that speed is electronically controlled.

je
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Re: Lenco's R Us

Postby pigdog » Thu Dec 11, 2008 11:44 am

Clearaudio made a devise for such purpose called the Synchro I just sold one to Hypertriode you might want to check it and see if it works for you. my initial purpose is to use it with my westrex but never really got around to trying it. also Ihatejazz carries these items
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Re: Lenco's R Us

Postby Mamimili » Thu Dec 11, 2008 11:48 am

Hello Joel

I hope most motors have the Thoren's like selector screw :)
I saw the terminal strip motor on Lenco Lovers, but also saw a sentence in another LL thread that stated following the connection diagram would not give the desired results :(

So much information on LL, too much for one evening session. I will browse slowly and try to take it all in!

I did see a plinth design i liked, sort of Art Deco / Avantgarde in black and chrome..........

Cheers, Paul
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Re: Lenco's R Us

Postby Mamimili » Thu Dec 11, 2008 11:57 am

pigdog wrote:Clearaudio made a devise for such purpose called the Synchro I just sold one to Hypertriode you might want to check it and see if it works for you. my initial purpose is to use it with my westrex but never really got around to trying it. also Ihatejazz carries these items


Hey Chester

I will.

I have been toying with the idea of using a "proper" industrial DC, AC or frequency drive for TT speed control.
Speed resolution to 0.0001% is possible, 0.001 as standard !!!WoW (i assume no WoW :rofl: )

Problem is they are rather expensive, triple $$$ digits :(
I am waiting for our supplier to sell me at cost, i keep dropping hints.....a DC system could be very affordable soon as AC is winning the "format war".

Cheers, Paul
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Re: Lenco's R Us

Postby setup2 » Thu Dec 11, 2008 12:23 pm

pigdog wrote:Clearaudio made a devise for such purpose called the Synchro I just sold one to Hypertriode you might want to check it and see if it works for you. my initial purpose is to use it with my westrex but never really got around to trying it. also Ihatejazz carries these items



Be careful, if I remember right, the synchro does not have enough juice, the motors of the Clearaudios have lower ratings. I remember seeing the motor of that Westrex, I think it is even bigger than the motor of the EMTs... Chester, did you try it with your Westrex?

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Re: Lenco's R Us

Postby setup1 » Thu Dec 11, 2008 12:32 pm

pigdog wrote:Clearaudio made a devise for such purpose called the Synchro I just sold one to Hypertriode you might want to check it and see if it works for you. my initial purpose is to use it with my westrex but never really got around to trying it. also Ihatejazz carries these items


If the Clearaudio unit has a wall-wart transformer, it might burn! Like what Joel said, we are talking
current draw/watts from a HUGE idler motor .

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Re: Lenco's R Us

Postby Jon Agner » Mon Dec 15, 2008 1:09 pm

setup2 wrote:Nice one, Paul! Hope to see the final outcome of your project soon...

Going to the other topic regarding the 50hz - 60hz thing... Jon, nice to hear that something came out from our talk at home when I asked you about this when I was working on the EMTs with the same problem some months ago... I think the power supply of the VPIs and Clearaudios are frequency converters but for low wattage motors... Won't work with the huge motors of the EMTs, or even the Lencos, I think the Rek-o-Kut have huge motors,too... The Lenco motor looks small but in reality, it is bigger than the motor of a TD124... Ask Mr. Sevilla about this... I think this is the stumbling block for frequency converters, unless you want to buy the industrial types available, the smallest, 1KVA :D

Regards,
Joel


Joel,

Those 1 KVA single phase frequency converters are locally available (adjustable to 400 hz) :D We were able to find one in Binondo last week :)

For those that use a smaller motors (300 watts or less), the combination of AC-DC converters and DC-AC inverters can do the trick ;) I'll try to work on a prototype one of these days and see if it works :)

For smaller AC motors (normally used in current production turntables - Pro-Ject, Rega, Music Hall, or Gold-Ring), I found a site that used a KT-88 pushpull amp as the power supply and motor controller. All it needs is a voltage transformer on the output, and an ipod that will serve as frequency controller :)
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Re: Lenco's R Us

Postby setup2 » Mon Dec 15, 2008 1:41 pm

Nice find, Jon... Just wondering about power consumption of those 1KVA frequency converters...

Here is an after-market frequency converter for the EMT, I think it will work for most idler turntables, too... I think,it is expensive... You can add to your data, the specs... Hope you can design something that is affordable...
http://www.emt-profi.de/multiconverter_du_9373.htm
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Re: Lenco's R Us

Postby Jon Agner » Mon Dec 15, 2008 4:47 pm

setup2 wrote:Nice find, Jon... Just wondering about power consumption of those 1KVA frequency converters...

Here is an after-market frequency converter for the EMT, I think it will work for most idler turntables, too... I think,it is expensive... You can add to your data, the specs... Hope you can design something that is affordable...
http://www.emt-profi.de/multiconverter_du_9373.htm


Joel,

The multiconverter for the EMT is similar to the frequency coverters we saw at Binondo :) At less 20%, the price of this would fall to an amount under 10K lang :)
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Re: Lenco's R Us

Postby setup1 » Mon Dec 15, 2008 5:21 pm

Jon Agner wrote:I found a site that used a KT-88 pushpull amp as the power supply and motor controller. All it needs is a voltage transformer on the output, and an ipod that will serve as frequency controller :)


That PP KT88 amp was probably derived from a Fairchild schematic for a controller for their 412 studio belt drive TT which if memory serves me right used the Papst Aussenlaufer (sp?) motor which was also utilized in later model idler ROKs - B12GH and L34H as well as their belt drive units, e.g R34.

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Re: Lenco's R Us

Postby Jon Agner » Mon Dec 15, 2008 7:12 pm

setup1 wrote:
Jon Agner wrote:I found a site that used a KT-88 pushpull amp as the power supply and motor controller. All it needs is a voltage transformer on the output, and an ipod that will serve as frequency controller :)


That PP KT88 amp was probably derived from a Fairchild schematic for a controller for their 412 studio belt drive TT which if memory serves me right used the Papst Aussenlaufer (sp?) motor which was also utilized in later model idler ROKs - B12GH and L34H as well as their belt drive units, e.g R34.

je


je,

It may well be, as the website mentioned that this was taken from an old design. What they did was to replace the output tranny with a voltage rating suited for the motor it will be controlling. Similarly, A 555 timer circuit can also be used in place of the Ipod :)
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Re: Lenco's R Us

Postby setup1 » Mon Dec 15, 2008 8:04 pm

Jon Agner wrote:]
je,
It may well be, as the website mentioned that this was taken from an old design. What they did was to replace the output tranny with a voltage rating suited for the motor it will be controlling. Similarly, A 555 timer circuit can also be used in place of the Ipod :)


As I understood it, in the case of the Fairchild the output transformer secondary supplied a clean ~ 90-120VAC @ 60HZ to the turntable motor. The AC voltage is not as critical as the frequency since AC synchronous or hysteresis motors lock into the frequency for speed stability.

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Re: Lenco's R Us

Postby Mamimili » Mon Dec 15, 2008 11:40 pm

There is a DIY signal generator for S$220 listed here, just scroll down a bit....
http://www.zenn.com.sg/electronics.htm

The box could be cleaned up easily, if anyone is interested i can probably collect it from Singapore and deliver in Manila before Christmas
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Re: Lenco's R Us

Postby Jon Agner » Tue Dec 16, 2008 10:21 am

Mamimili wrote:There is a DIY signal generator for S$220 listed here, just scroll down a bit....
http://www.zenn.com.sg/electronics.htm

The box could be cleaned up easily, if anyone is interested i can probably collect it from Singapore and deliver in Manila before Christmas


Paul,

I think you still need to hook this up to an amp. Reading the description, it seems quite similar to signal generators sold in electronic shops here in Manila. :)
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Re: Lenco's R Us

Postby 6a3fan » Tue Dec 16, 2008 10:37 am

The free Audacity audio editing software has a built in sine wave generator. Just hook up to a tranny amp and a step down transformer used in reverse, meaning the amp's output is connected to the low voltage side of the amp. Use the amp's volume control to get the proper voltage at the high voltage side and then plug in the turntable.
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Re: Lenco's R Us

Postby setup1 » Wed Dec 17, 2008 10:04 am

6a3fan wrote:The free Audacity audio editing software has a built in sine wave generator. Just hook up to a tranny amp and a step down transformer used in reverse, meaning the amp's output is connected to the low voltage side of the amp.


You probably meant, ".....the amp's output is connected to the low voltage side of the step-down transformer ..... "

I never tried an amp driven reverse step-down transformer (good idea!) but you are on the right track. :clap:

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Re: Lenco's R Us

Postby kabubi » Wed Dec 17, 2008 10:27 am

6a3fan wrote:The free Audacity audio editing software has a built in sine wave generator. Just hook up to a tranny amp and a step down transformer used in reverse, meaning the amp's output is connected to the low voltage side of the amp. Use the amp's volume control to get the proper voltage at the high voltage side and then plug in the turntable.


Boss Felix,

for tech idiots like me, hope you can tell us more --- with pictures!
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Re: Lenco's R Us

Postby setup1 » Wed Dec 17, 2008 11:03 am

kabubi wrote:for tech idiots like me, hope you can tell us more --- with pictures!


Hook up of the audio generator to the power amp is very similar to testing the power output of an amp, ttommy has already posted a tutorial in this link - viewtopic.php?f=74&t=19413 - instead of an 8 ohm resistor/scope/DVM terminating the amp the turntable motor becomes the load (ex:TD124 motor primary DCR = 200ohms). The 60hz (or 50hz) sine wave input to the amp is increased until the motor spins the platter to the desired speed. Thus adequate "undistorted" power is needed or 6a3fan's idea of a step up transformer at the amp's output may help lower powered amps assuming the step up transformer is capable of producing a clean 50hz or 60hz sine wave.

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Re: Lenco's R Us

Postby 6a3fan » Wed Dec 17, 2008 11:13 am

Thanks JE for correcting my post. Step up transformers are meant to operate on 50 or 60 hetz and should give clean enough power. But remember GIGO. This means that the signal generator should be generating a clean signal and the amp should also be clean. The amp should also be capable of handling the inductive loads.

How about using a tube amp, with the OPT wound to output 110 volt? I can imagine that such a TT motor driver will sell very well to the tubeheads like me. An appropriate name would be VACuum Cleaner, because it will clean Voltage AC using vacuum tubes.
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Re: Lenco's R Us

Postby kabubi » Wed Dec 17, 2008 11:25 am

6a3fan wrote:How about using a tube amp, with the OPT wound to output 110 volt? I can imagine that such a TT motor driver will sell very well to the tubeheads like me. An appropriate name would be VACuum Cleaner, because it will clean Voltage AC using vacuum tubes.


Andreeeeeeeeeeewwwwwwwwww! :D

as in Andrew Sevilla
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