Sander's Speed Controller

[ian]

As there seems to be quite a bit of interest in the speed controller buit by Sander' for me and talk of having some more built I thought it only fair to contact Sander and let him know the situation.  Sander gave me permission to pass on the circuit design to Jean but not for us to go into small scale production!  My feeling is that Sander has intellectual property rights on his design and do not want to betray the trust he gave me by supplying me with the circuit diagram in case I needed to get it repaired.  I will let you know how things develop when I have his reply.

Cheers, Ian

[gninnam]

Thanks Ian for sharing this info and we all hope that it comes out in our favour (as in either a production run of the units or access to the schematic).

[mred]

Ian,
 I would certainly be happy if Sander would be willing to allow LH members to purchase the schematic at a reasonable fee.
He certainly should protect himself from being exploited 

Great job with the meeting 

Ed

[jloveys]

Ian: I also think that Sander should be contacted. I have no intention to produce the controller for others than myself. If Sander is O.K. we could produce more of them for our interested members, but on a non-commercial basis. BTW,  the circuit schema is already online here : http://lenco.reference.xooit.fr/t182-Variateur-de-frequence-secteur.htm

 

[nigel]

the circuit schema is already online here : http://lenco.reference.xooit.fr/t182-Variateur-de-frequence-secteur.htm

Interesting to note that the circuit is designed to output 115V, not 230! Ian, is your version modified for 230V output, or is it also 115? I'm just wondering, thinking about the good results various people have had running 230V motors on 110V ... ?

[ian]

Hi Jean, even if it is already published I would still prefer Sander's express permission otherwise it feels like a betrayal of trust.

Hi Nigel, mine is built for 230v.

Cheers, Ian

[hatehifi]

Hi Ian, I'll wait for feedback from Sander. The schematic is appealing as it is about a third the 'size' of Schulz', designed for syncronus motors. Obviously I'd like to link Christian to the schematic but will wait for a green light.

Cheers!

[GP49]

Interesting to note that the circuit is designed to output 115V, not 230! Ian, is your version modified for 230V output, or is it also 115? I'm just wondering, thinking about the good results various people have had running 230V motors on 110V ... ?

All that need be changed to output 230V is the output transformer.  It's a conventional power transformer for 115V with a center-tapped 15-0-15 volt secondary...hooked up backwards. A 230V power transformer with a center-tapped 15-0-15 volt secondary, hooked up backwards, is all that's needed.

[nigel]

All that need be changed to output 230V is the output transformer.  It's a conventional power transformer for 115V with a center-tapped 15-0-15 volt secondary...hooked up backwards. A 230V power transformer with a center-tapped 15-0-15 volt secondary, hooked up backwards, is all that's needed.

Hi Gene,

yes I realised that - I was just interested in looking for reasons why the controller might give better results, than running straight from the supply. Less motor vibration, due to lower voltage, might be one reason - but I guess not, if Ian's is running at 230V.
Other possibilities? Well, it will be cleaner power - the transformer in the power supply will filter out some HF noise, by virtue of its limited bandwidth. Likewise the output transformer. Will this make any difference to the motor? Unlikely, I would have thought, but it might make a difference to what might be radiated by the motor and associated wiring (which could then be picked up by the cartridge and its associated wiring, or not, maybe?)
I don't know - pure conjecture - but it's an interesting question 

[GP49]

Absolute accuracy of the supply frequency seen by the motor, and an absolutely accurate, unvarying waveform to that AC power, perhaps?  And, the elimination of any DC offset that may be in the mains supply?

The parameter of the mains supply with the most direct influence on the non-synchronous, induction-type motor used in the Lenco would probably be line frequency.  Although the frequency is very strictly specified at 50/60 Hz, that's a long-term average and there can be short-term fluctuations. Voltages fluctuate more commonly, and in the non-synchronous, induction-type motor this can affect speed, though there would have to be quite a large and longer-term variation to really make a difference, given the rotating mass of the platter.

Some brief research turned up nothing about mains supply waveforms and DC offset.

There are some results that have been reported on the extent of variances in line voltage and frequency; a UK example being at

http://www.picotech.com/experiments/mains_voltage/results.html

Note that as a result of harmonization of mains power regulations under the European Union, line voltage in Britain is now LESS strictly specified than it was before 2003, a step backward for the sake of "joining Europe."

[ian]

Hi Folks,
Sander has replied to my email and here are the relevant parts extracted from it.

Hi Ian,
........................


I'm surprised the speed controller makes any audible difference.
I mean.. all the thing does is make line power at 50 hz, albeit clean.
It's hard to image that the motor would notice a difference.
Unless of course the wall power is really, really shitty.
It goes perhaps to something  Jean was mentioning.. that "US" lenco motors sound better than "euro"
lenco motors. He explains it by a difference in torque, which is indeed there. The US motors draw slightly more current, and hence have slightly more power.


As for building some of these..  I haven't come across anybody who is willing to make it worth my while to do that.
You have a bit of a prototype unit at cost, not counting my time.
So..  I'd far prefer that people use the schematics to build their own.
I am of course willing to offer email assistance.
If Jean or anybody else wants to produce a batch of these, I'd like to design a proper amp to drive the transformer. These one-chip audio amps are a quick solution, but their internal protection circuitry gets in the way if one wants to put out 220 or 240 volts. They are at their limit under those conditions, but they are comfy at 120 volt.
So.. I'll volunteer to be involved in such an effort as a consultant, basically to make sure that we're outsourcing something that is actually going to work well and reliably.
If they want to have a go at it on their own.. that's fine too, as long as they keep my name out of it.
In terms of "intellectual property" .. well.. the idea isn't new, nor is any of the circuitry.
If I can design it, so can any other competent electronics guy.


Cheers,
Sander

So if Jean or John or anyone else wants to have a go using the schematic Sander gave me there is no problem in doing so.

Oh, it's worth pointing out that the schematic published on Lenco Reference linked above has some differences with mine although I'm not competent to recognise the significance of these.

[daiwok]

great guy ! we should post about his V-blocks as well 

[jloveys]

Very interesting, thank you Ian . 
Very kind also is Sander consultancy proposal, as very few ( if any ) persons have experience with building a proper Lenco motor controller ( LMC ).
He points out that there should be no reason for LMC sounding better than without. Well, the experience that Ian has done @ the meet was clearly in favor of the LMC. I also tried the LMC
with Yoda and the speed was more steady ( KAB strobe 33 letters not moving at all ) and the sound had more definition. Switching from 33 to 45 is spot on with no schifting or readjustments needed.
This is not the case with the 110 V SDS , even if I noticed a better sound than without it. Is the current @ Scalford so dirty ? who knows...

Ian, I believe that if you ordered the Sander LMC it was for your previous slate 3 TT because no switches on it . But you use the LMC also with your last creation, a L70 in wood plinth with all the original
speed switches, so I believe that you hear a difference ?

The future LMC I will use for Yoda is to avoid the switches because not accessible in the new design, but if it also make is sound better, that is a real upgrade ...

 

[colin]

Hi Folks,
Sander has replied to my email and here are the relevant parts extracted from it./
.............................................
/So if Jean or John or anyone else wants to have a go using the schematic Sander gave me there is no problem in doing so.

Oh, it's worth pointing out that the schematic published on Lenco Reference linked above has some differences with mine although I'm not competent to recognise the significance of these.

Well done Ian, definitely the right procedure and a positive result.  Good guy Sander is 

[ian]

Hi Jean,
I originally got the speed controller for Stanley as I wanted to remove as many of the sub-plate levers as possible.  Using this box of tricks means you can have a fixed idler position but still adjust speed, either fine tuning or for playing the occasional 45's with a flick of a switch.  That, I think, is its real benefit and I had never really heard such an obvious change in sound quality before as we observed at the meet.  I can only assume this is because the hotel's mains supply is not as clean as my domestic mains.  Improved power supplies are a common enough upgrade with turntable manufacturers so presumably there is something in it at least for the puny belt drive motors and maybe for our mighty Lenco too!