Here is a graph of the motor itself ( same as a current waveform ). As one can see the power supply is near zero distortion to arive at this result. It is the motor for the Garrard 501. The TD124 will be very similar. Notice the 3rd harmonic is at - 68 dB. The motor could be called a 80Hz first order filter. Thus the harmless 4 th harmonic is attenuated below the 3rd. The 2nd and 4th seem to be the motor itself. If the motor coupling is too tight even the 2nd seems to be gone. Seems is the word, it's still there in the current waveform.The 501 runs at 52 Hz as this allows a better drive system. Rumble is - 79 dB weighted. It is idler drive using the Garrard 301/401 layout.The second is harmless in this amount as the effects run in phase with the rotor. This might also say why in music 2nd is almost harmless if kept to 1%. 3rd is harmful and causes vibration.
Is this the current spectrum by the Garrard 501 motor which is running on 130 Volt ?
Hello everyone,
First of all as this is my first post in your community my congratulations on this very extensive thread about the TD124.
Using a light bulb as a voltage regulator works great. As Nigel pointed out using a light bulb for dropping the mains voltage works well indeed. I can confirm that using a 40 Watt bulb drops my mains voltage of 230V to around 220V for my TD124. It is perhaps not as high tech but it works and is more compact then having a rheostat in your living room. As I want to get rid to some of the mains interference I was just wondering if I could add an extra neon bulb in // or a choke in series to make a passive filter or using a decoupling transformator (1:1 windings). Our mains is so polluted that one of our local cardiologist even had trouble configuring pacemakers during daytime...
I was even thinking of making an alternator with an AC motor driving the alternator (not very energy efficient and noisy)
Even listening to music during daytime is a challenge as it sounds flat! In the late evening / night things start to get better more detail more dynamics. This is not related to the quantities of ethylic beverages consumed as I did the test sober...
Any input welcome.
First of all as this is my first post in your community my congratulations on this very extensive thread about the TD124.
Using a light bulb as a voltage regulator works great. As Nigel pointed out using a light bulb for dropping the mains voltage works well indeed. I can confirm that using a 40 Watt bulb drops my mains voltage of 230V to around 220V for my TD124. It is perhaps not as high tech but it works and is more compact then having a rheostat in your living room. As I want to get rid to some of the mains interference I was just wondering if I could add an extra neon bulb in // or a choke in series to make a passive filter or using a decoupling transformator (1:1 windings). Our mains is so polluted that one of our local cardiologist even had trouble configuring pacemakers during daytime...
I was even thinking of making an alternator with an AC motor driving the alternator (not very energy efficient and noisy)
Even listening to music during daytime is a challenge as it sounds flat! In the late evening / night things start to get better more detail more dynamics. This is not related to the quantities of ethylic beverages consumed as I did the test sober...
Any input welcome.
Thanks. Here is the other famous drive motor measured as a current waveform, it was made in Belgium and is a new old stock sample. Notice how the 3rd is high ( very good for a synchronous, many are 100% worse ). The amplifier used is 0.05% THD and 90 Vrms ( 127 V is it's sensible max ). The power used about 1.26 watts ( 7 mA x 2 phases ). 45 RPM is via a nearly correct crystal instead of 3.2768 MHz usually used. The reason I say current measurement is if the amplifier has very low output impedance we don't see the truth. Even the current waveform can make it better than it is. That is no problem as it is easy to retain that using a series resistance. The light bulb or lamp doing the same. My scope is isolated so measuring the mains is possible, don't try this yourself unless very certain.
Do be honest I didn't see any real advantage with this motor in using an amplifier except easy 45 RPM. 4.433619MHz = 45.1 RPM
I measured an alternator once, it seemed to use saturation as crude over voltage limiting. Not ideal. If you can use my boost idea and a 60 watt lamp maybe that could really work? The thing to seek is the voltage is more stable after the lamp. My version had 253 Vrms ( 260 really, 253 is the suggested limit ).
BTW guys, my interest started in 1972 for this. A reviewer had wrongly described a Thorens TD125 ( Like a Linn ). I built his wrong idea and it worked fine ( 1990, completed the day my daughter was born, talk about a displacement activity, 28th December, used in the 501 ). The reviewer didn't realise the motor of the TD125 is not the one used in the TD160. The TD125 uses the lamp idea in a different way. If a TD125 doesn't work try WD40 first on the sliding contacts. I have a TD125 with original S shaped arm I am fixing for a friend. I have never seen this arm before, it's a beauty. I have seen an older version on TD124/135.
Do be honest I didn't see any real advantage with this motor in using an amplifier except easy 45 RPM. 4.433619MHz = 45.1 RPM
I measured an alternator once, it seemed to use saturation as crude over voltage limiting. Not ideal. If you can use my boost idea and a 60 watt lamp maybe that could really work? The thing to seek is the voltage is more stable after the lamp. My version had 253 Vrms ( 260 really, 253 is the suggested limit ).
BTW guys, my interest started in 1972 for this. A reviewer had wrongly described a Thorens TD125 ( Like a Linn ). I built his wrong idea and it worked fine ( 1990, completed the day my daughter was born, talk about a displacement activity, 28th December, used in the 501 ). The reviewer didn't realise the motor of the TD125 is not the one used in the TD160. The TD125 uses the lamp idea in a different way. If a TD125 doesn't work try WD40 first on the sliding contacts. I have a TD125 with original S shaped arm I am fixing for a friend. I have never seen this arm before, it's a beauty. I have seen an older version on TD124/135.
One idea you could look at is using the 115 V windings via 230 V. Try loosing let's say 90 Vrms. If we GUESS the load to be 18 watts it will be about 160 mA ( might be 100 mA or even 200 mA ). 30Vrms @ 160 mA = 200 R ( circa ) and 11 watts type for safety. If we take 150 Hz as a corner frequency c= 1/2Pi.fo.r, 1000 000/2x3.142x150x200 in uF, = 5.3 uF. 5x1uF ( 15 total )class X2 which is for mains use ( please check my maths ). 1 uF being a good price, e.g Panasonic class X2 . The resistors are in series with a capacitor to neutral after each capacitor. Ideally the last 20 Vrms is lost by a lamp. There will be a slight drop at 50Hz due to the filter. If adapting this idea to 60 Hz you will need a transformer, one for 2 x EL 84 could work. The loss at 60 Hz will be slightly more, 2 x 2.2 uF ( 6 x 2u2 ) should work. Remember 3 resistors need 15 uF if 50 Hz.
You might say is - 9dB @ 150 Hz worth the trouble? It is because at 250 Hz it is far more ( my house supply that is clean would be at >- 50 dB with this filter ). The mains generally has problems to 1 kHz. If you play with the capacitors and work in the greater losses you could do better. Ducati motor capacitors and other makes range in the 10 to 20 uF values. As these are for big motors I must assume this use is easier than their real use. Where they sit with regulations I have no idea ( class X2 is ideal ). Use the 230V types. Try not to use electrolytic types. I suspect my 3 x 200R + 5 uF is about as good as it gets whilst using a 1930's solution. Inductors could be used. That's going to cost too much.
You might say is - 9dB @ 150 Hz worth the trouble? It is because at 250 Hz it is far more ( my house supply that is clean would be at >- 50 dB with this filter ). The mains generally has problems to 1 kHz. If you play with the capacitors and work in the greater losses you could do better. Ducati motor capacitors and other makes range in the 10 to 20 uF values. As these are for big motors I must assume this use is easier than their real use. Where they sit with regulations I have no idea ( class X2 is ideal ). Use the 230V types. Try not to use electrolytic types. I suspect my 3 x 200R + 5 uF is about as good as it gets whilst using a 1930's solution. Inductors could be used. That's going to cost too much.
This idea could work. The Oneac version in the past claimed better, I have used them. I tried to build one of these. It wasn't easy. It is related to magnetic amplifiers.
Hammond Mfg. - Constant Voltage - Line Transformers - (CV Series)
This one seems worth the risk if the seller can hook it up with plug and socket ( it may already have them ). The Oneac was quiet. This one might need to be away from the listening area as they can buzz and get warm. Seems a very good spec and I suspect it is new. CVT's usually make motors quiet as the CVT saturation resonance is also a filter.
http://www.ebay.com/itm/SOLA-Type-C...651047?hash=item3ad4582aa7:g:ucMAAOSwFdtXxOP8
Here is a UK type, it isn't cheap. Good technical description. Many amplifiers might work worse with one. Great for turntables and class A tube amps.
http://www.aelgroup.co.uk/pdf/wp_hifi.pdf
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This is very much don't try this at home. I am using 2 x51K and 1K attenuator to show results. 1V circa 100 V. Before anyone wonders these are the bits I had so that's why these values. The Garrard 401 is not unlike a TD124. Very interesting results that on the whole are worse! As the motor peaks at about 150 Hz it is no surprise this filter has problems and has made things worse by + 18 dB. However the rest is very promising. My conjecture is a 50/60 Hz filter might be workable. Equally a 250 Hz one which I will try when time allows.
NO LAMP.
I would hope the Sola CVT from eBay to be the ideal result and be plug and play. It should look like my graph No2 with the 3rd harmonic at better than -34 dB regardless of where used. In fact a CVT is like a good verion of this idea, it resonates so as to provide the CVT function. The core even looks like a motor.
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A better version, notice the flat top is gone from previous posting. For USA use I wouldn't be confident that the driving transformer wouldn't change the results. This idea might adapt to TD124 ( Garrard 401 here ). Without a scope it's hard to be sure you are getting the right result. This result might be marginally better than the house supply taken as vibration effects. The heat output is high. I have always speculated that this might work. Nearly.
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Take it as a reasonable snap shot. The reading at the 5th harmonic is when averaging complete - 48 dB. The 3rd a tad worse than - 30 dB ( 29.3 dB ). Not a bad result and not a simulation. The centre line is - 34.38 dB on this graph ( the scope is still on so set to that ). The steps at 10 dB.
Ah, I see now.
The distance between the cursors is shown as the dB figure in the bottom margin.
All three pics have the same 10dB/div for the vertical scale.
The top test shows the 3rd, 5th, 7th, 9th and 11th all above -50dB.
I think we are all agreed that is pretty poor. Is this without the filtering?
The lower one in post2209 looks like all the 5th and higher are below -50dB.
It's the 3rd that is high.
Surely modifying that cascaded version could achieve more 3rd attenuation and give better results than the post2210 single filter?
Can I suggest keeping the cascade version, but changing the filter values to 330r+4uF followed by 500r+3uF ?
Could you post that result?
Yes, it's more capacitance: 7off 1uF X2 caps compared to 2off 2u2F X2 caps.
The distance between the cursors is shown as the dB figure in the bottom margin.
All three pics have the same 10dB/div for the vertical scale.
The top test shows the 3rd, 5th, 7th, 9th and 11th all above -50dB.
I think we are all agreed that is pretty poor. Is this without the filtering?
The lower one in post2209 looks like all the 5th and higher are below -50dB.
It's the 3rd that is high.
Surely modifying that cascaded version could achieve more 3rd attenuation and give better results than the post2210 single filter?
Can I suggest keeping the cascade version, but changing the filter values to 330r+4uF followed by 500r+3uF ?
Could you post that result?
Yes, it's more capacitance: 7off 1uF X2 caps compared to 2off 2u2F X2 caps.
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I am glad you saw that Andrew. As it is not a TD124 I didn't want to get in too far. I was rather alarmed at the rise in 3rd harmonic of the first idea. The next idea is a reuse of the capacitors. I wanted to show less can be more, or in some ways more. If people don't mind the heat given of and power used I suspect a 50 Hz filter might start to work. The 3rd harmonic is the major problem, alas I have made it worse. Due to phase shift the way the motor works as a filter is being defeated. If I can borrow a TD124 I will try harder. I will buy some bits to help it along. I suspect I will need some resistance post filter to help the two devices work together. I will continue to use 120V output as then using 230 V input should give circa 110V, my circa 245 Vrms is higher than most. This is where an analyser helps. Our eyes say I have ready won the battle on the oscilloscope and maybe I have. However if we add knowing how the motor is a filter the 3rd Harmonic is our focus. On this I failed. If I can get - 6 dB at 150/180 Hz I will be happy.
Though interesting I suspect that a Constant Voltage Transformer, now available for very little money on 'fleabay' will provide a simpler, and dare I say it, safer solution to those cursed with a poor mains supply.
Not only do they provide a constant voltage, but also, due to their resonant design, a lower level of harmonic distortion.
I suspect that only a regenerated, xtal controlled supply would be any significant improvement over a suitably sized 'Sola' or equivalent for driving a single phase motor. of the type found in many older turntables.
Not only do they provide a constant voltage, but also, due to their resonant design, a lower level of harmonic distortion.
I suspect that only a regenerated, xtal controlled supply would be any significant improvement over a suitably sized 'Sola' or equivalent for driving a single phase motor. of the type found in many older turntables.
The CVT is the ideal off the shelf < $500 solution that should sound better than the house supply. Even at 3 in the morning we don't get clean electricity. 100VA would be plenty. I suspect it needs to be in another room with a cable to the turntable as they buzz.
Since 1990 I have held the same view as you. This is a careful look at the mild possibility of a passive solution. It's a Venn diagram of what we need and what is workable. The two circles just touch if they do at all. If you look at a jet engine it's just a blow torch. Then you do the safety bit.
Since 1990 I have held the same view as you. This is a careful look at the mild possibility of a passive solution. It's a Venn diagram of what we need and what is workable. The two circles just touch if they do at all. If you look at a jet engine it's just a blow torch. Then you do the safety bit.
I am not sure about all CVT's, but the two SOLAs I've owned had waveforms that were not quite perfectly sinusoidal, they typically have at least several % of THD in the output - which is in many cases significantly better than the mains powering them..
http://www.emersonindustrial.com/en...ditioning/cvs_hardwired/cvs-hrdwrd-solahd.pdf
Surplus ones can usually be had for reasonable money on eBay.
http://www.emersonindustrial.com/en...ditioning/cvs_hardwired/cvs-hrdwrd-solahd.pdf
Surplus ones can usually be had for reasonable money on eBay.
At last a real TD124/II S No 30334. I can't say for sure all motors are the same. This one looks like ones I know.
This was my hunch and it worked first time ( 2 x 2u2 and 2 x 1uF ) . I suspect beginners luck. Whilst I agree with Andrew I think this result is good enough. The motor is silent and seems very low on vibration. I am using the lower 100 to 120 V range of the motor . Even the lamp works which was not true of the Garrard. Post 2209 shows typical mains at my house.
I have a busy weekend so this is the best I can do for now. Looks to me this is a winner if a slightly higher electricity bill is OK. I used what I have if wondering. 17 watt x 4 for the input and 17 watt x 1 for the output I would say as minimum. 470R + 6u4 + 470R. Could the USA 234 V be used ( Vacuum cleaners I seem to remember )? If your house is 230V perhaps 330R output.
This is not a bad result. It gets hot. I put the DCR of the motor in to give a point of reference. Considering the filter action of the motor the modification might not help as much as it looks at my house ( I have OK mains ). Where people have more mains wave distortion I think it could work. 10uF >400V motor capacitors seem ideal ( Ducati brand etc).It's a cheap circuit, using some care should be safe. Switch the whole circuit off when not in use. I would use 10 x 4K7 17W if you can get them, 11 watt if not. Mount them on bus-bars and hold them in free air. The capacitor well away to keep cool. Play with the final resistance to suit need. At 230V in it should be close to ideal. I suspect 105 to 115 V best. As it is lower distortion 115 V might work best.
TE CONNECTIVITY / CGS - SBCHE11 4K7 - RESISTOR, WW 11W 4K7 | CPC UK
I just did a current check and got 390 mA. One can use 20 x 10K 11 watt instead to give 500R ( paralell ). The cost to run about the same as a 100 watt filament lamp. These resistors below come in 5 packs. Do not be fooled by 100 watt resistors, they usually need heat sinks. Space the resistors at least as wide as themselves. The bus-bar can be any chunky piece of wire.
TE CONNECTIVITY / CGS - SBCHE11 10K - RESISTOR, WW 11W 10K | CPC UK
TE CONNECTIVITY / CGS - SBCHE11 10K - RESISTOR, WW 11W 10K | CPC UK