TD125 frequencies?
Ouch .. just realized one thing .. probably been to fast on the trigger getting parts for this controller
Intended use was/is a TD125 mkII, which has it's own analog/Wien-bridge motor controller with quad outputs -- think it is a 16 pole AC sync. motor - and controller outputs frequencies directly proportional to platter rpm (am in my cottage so cannot get to my gear now)-> hmm in this case this 4 phase DIY, is of no use here - and have to ship it off, or use for another turntable
what I can find online right now https://www.vinylengine.com/library/thorens/td125.shtml
motor 250rpm for 33 1/3 platter rpm. With 16 poles ->f=(rpm/60)*#poles=66 2/3 Hz controller frequency needed .. is that right?.. and proportionally 90Hz for 45rpm. This brings it right on the edge of the tuning range of this controller . Don't know if this is for Mk1 or if MKII has same motor
However, found an earlier measurement I did of the analog controller-> indicating as I remember: frequencies 'like' platter rpm (approx ½ of above calculation), but will have to cross check the time base again. The 78rpm was a test to get 16rpm setting to some use .. but did not work so nice
Have another digital controller for the TD125, I halfly finished assembling .. BUT it is not adjustable on the fly, apart from 33/45 switch.. (has to be set via a controlling PC each time.. and has other limitations too)
well had already ordered the rotary PCB as well .. but will for moment hold back on other stuff
@Pyramid, tuning range I guess is logically hard coded right? or is it already enough for the TD125 .. else a custom uP w frequencies suited for TD125 33/45rpm .. any option you would consider?
Ouch .. just realized one thing .. probably been to fast on the trigger getting parts for this controller
Intended use was/is a TD125 mkII, which has it's own analog/Wien-bridge motor controller with quad outputs -- think it is a 16 pole AC sync. motor - and controller outputs frequencies directly proportional to platter rpm (am in my cottage so cannot get to my gear now)-> hmm in this case this 4 phase DIY, is of no use here - and have to ship it off, or use for another turntable
what I can find online right now https://www.vinylengine.com/library/thorens/td125.shtml
motor 250rpm for 33 1/3 platter rpm. With 16 poles ->f=(rpm/60)*#poles=66 2/3 Hz controller frequency needed .. is that right?.. and proportionally 90Hz for 45rpm. This brings it right on the edge of the tuning range of this controller . Don't know if this is for Mk1 or if MKII has same motor
However, found an earlier measurement I did of the analog controller-> indicating as I remember: frequencies 'like' platter rpm (approx ½ of above calculation), but will have to cross check the time base again. The 78rpm was a test to get 16rpm setting to some use .. but did not work so nice
Have another digital controller for the TD125, I halfly finished assembling .. BUT it is not adjustable on the fly, apart from 33/45 switch.. (has to be set via a controlling PC each time.. and has other limitations too)
well had already ordered the rotary PCB as well .. but will for moment hold back on other stuff
@Pyramid, tuning range I guess is logically hard coded right? or is it already enough for the TD125 .. else a custom uP w frequencies suited for TD125 33/45rpm .. any option you would consider?
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The formula is: freq=(motor RPM * pole PAIRS)/60
If you have a 16 pole 250 RPM motor, the drive frequency is (250*8)/60 or 33.333 Hz for 33.333 RPM. That doesn't seem right.
From your graph, the period of the blue waveform (33 RPM) looks to be ~27mS. That would put the frequency at 37.037 Hz. That happens to be the frequency you would need for 33.333 RPM if you put the belt on the 45 RPM spindle of a 50 Hz motor. 45 RPM would be 50Hz (matches the 20mS period on your graph) and 78 RPM would be 86.666Hz (matches the 11.5mS period on your graph). I did this on one of the Phoenix controllers to get all 3 speeds from one spindle using a two speed 50Hz pulley with the belt on the 45 RPM spindle.
I would guess you have a 250 RPM motor with 24 poles and a 2 speed pulley designed for 50Hz.
Is your TT belt drive? If so, does it have a 2 spindle pulley? What are the diameters of the pulley and platter (subplatter).
If you have a 16 pole 250 RPM motor, the drive frequency is (250*8)/60 or 33.333 Hz for 33.333 RPM. That doesn't seem right.
From your graph, the period of the blue waveform (33 RPM) looks to be ~27mS. That would put the frequency at 37.037 Hz. That happens to be the frequency you would need for 33.333 RPM if you put the belt on the 45 RPM spindle of a 50 Hz motor. 45 RPM would be 50Hz (matches the 20mS period on your graph) and 78 RPM would be 86.666Hz (matches the 11.5mS period on your graph). I did this on one of the Phoenix controllers to get all 3 speeds from one spindle using a two speed 50Hz pulley with the belt on the 45 RPM spindle.
I would guess you have a 250 RPM motor with 24 poles and a 2 speed pulley designed for 50Hz.
Is your TT belt drive? If so, does it have a 2 spindle pulley? What are the diameters of the pulley and platter (subplatter).
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@ wolf_skate-
Just re-read your last post and found a service manual on line. The TD-125 MKII was designed for 16/33/45 RPM and did use a 16 pole low voltage AC motor. The frequencies were 16/33/45 Hz.
The SG4 would be capable of 33 Hz and 45Hz, but would take custom software. Why do you want to replace the internal controller?
Just re-read your last post and found a service manual on line. The TD-125 MKII was designed for 16/33/45 RPM and did use a 16 pole low voltage AC motor. The frequencies were 16/33/45 Hz.
The SG4 would be capable of 33 Hz and 45Hz, but would take custom software. Why do you want to replace the internal controller?
ahh ok I see pole-pairs. Then there is 'ok' agreement with the statement of a 16 pole motor and my measurements .. freq. [Hz] approx '=' platter speed [rpm].. Found the old data the plot was made from and the time base is right.
Yes it is a belt drive with a single 50Hz pulley (and I even invested in a special composite pulley w inner part close to axle made of some plastic then alu around it). But no option to 'flip' to a 60Hz or 45 rpm .. it is just one pulley .. the rest 'electronics'
It is Thorens first pure belt drive I am aware of. They made their own built in analog controller - and thus did not rely on supply frequency at all ( apart from a glim-bulb to illuminate a strobe disc). SO yes believe the numbers are in right neighborhood (whether pulley is for 33.33 or 37 Hz I can't tell.. the 250rpm info is from the net .. the 37Hz is what I measured having tuned my TD125 in).
The original wien bridge made clean quad-sines, but was made w some old opamps, carbon trimmers etc and the adjustments not that stable. Aging cause the thing to drift a bit as well. SO like the idea of a dependable digital control where fine tuning of frequency, phase and amplitude is easier than on the analog board
thanks for your fast replies
Yes it is a belt drive with a single 50Hz pulley (and I even invested in a special composite pulley w inner part close to axle made of some plastic then alu around it). But no option to 'flip' to a 60Hz or 45 rpm .. it is just one pulley .. the rest 'electronics'
It is Thorens first pure belt drive I am aware of. They made their own built in analog controller - and thus did not rely on supply frequency at all ( apart from a glim-bulb to illuminate a strobe disc). SO yes believe the numbers are in right neighborhood (whether pulley is for 33.33 or 37 Hz I can't tell.. the 250rpm info is from the net .. the 37Hz is what I measured having tuned my TD125 in).
The original wien bridge made clean quad-sines, but was made w some old opamps, carbon trimmers etc and the adjustments not that stable. Aging cause the thing to drift a bit as well. SO like the idea of a dependable digital control where fine tuning of frequency, phase and amplitude is easier than on the analog board
thanks for your fast replies
should be, that is what I intend to do with one unit, drive a Studer C37 capstan motor. No reason to drive the reel motors with it unless you want to do a TOTALLY different control circuit. Waiting for the cpu chip and time to do it.
Oh, one of the other ones will be used on a turntable, lathe that is.
Cheers,
Alan
Oh, one of the other ones will be used on a turntable, lathe that is.
Cheers,
Alan
It may be that yours is completely different, but this is something to look out for
I have the capstan motor from a Revox PR99, I can drive it from my Papst setup, but the motor is quite a bit bigger than any of my other motors.
There is however a much more significant difference:- The capstan motor is not synchronous! On mine at least there is a set of grooves machined in the edge and a magnetic pickup to provide speed feedback.
I have the capstan motor from a Revox PR99, I can drive it from my Papst setup, but the motor is quite a bit bigger than any of my other motors.
There is however a much more significant difference:- The capstan motor is not synchronous! On mine at least there is a set of grooves machined in the edge and a magnetic pickup to provide speed feedback.
My second TFK M15A is far to be perfect and the original spare parts are difficult to find and ( very often ) expensive if in NOS condition. In your opinion a BLDC 24v 40 years old has a better speed control than the best available sync motor with SG4 board? I'm not a technician and I'm only asking
we like our candy in this part of Oregon! Also received the programmed chips yesterday from Roe. Not working on anything today as there is a foot of snow between home and the shop. We only have something like 4 snowplows in the whole city of Portland!
Repairing the servo would be my first choice, fitting another motor in would be a major task as well. As I have no idea what part of the world you are in I can't make any recommendations. If Europe, I would probably contact Hilpert - Tonstudiotechnik, AEG/TELEFUNKEN MAGNETOPHON, not cheap, but correct.
Cheers
Alan
Repairing the servo would be my first choice, fitting another motor in would be a major task as well. As I have no idea what part of the world you are in I can't make any recommendations. If Europe, I would probably contact Hilpert - Tonstudiotechnik, AEG/TELEFUNKEN MAGNETOPHON, not cheap, but correct.
Cheers
Alan
Supply of SG4 chips and boards for EU and ROW
I have been supplying the SG4 chips and PCBs to the UK, EU, and also addresses further afield (Rest of World
). I have now run out of both chips and boards.
Before I order more parts I would like to know how many people are still interested in purchasing these as I do not want to be left with considerable excess stock.
Please PM me if you are interested.
Thanks
I have been supplying the SG4 chips and PCBs to the UK, EU, and also addresses further afield (Rest of World
). I have now run out of both chips and boards.Before I order more parts I would like to know how many people are still interested in purchasing these as I do not want to be left with considerable excess stock.
Please PM me if you are interested.
Thanks