John
Please don't be cruel. I'll be very interested in your bridge amp providing the 110v rms out. Even without component values.
Regarding the oscillator, fine tuning a (lamp) Wien bridge produced less than 0.01% second harmonic which should be more than sufficient especially compared to 5-6% off the wall. I use an 8015 AVR with an EPROM based lookup table and DAC at the output port. Mostly for the convenience of a second phase being readily available at another port. So far i've only built step-up transformer based amps to produce the high output but since comparing this to a Valhalla decided that high voltage amp is likely a much better way to go. The Valhalla produces much better subjective dynamics and bass. I did draw a circuit off the Valhalla board hi voltage amp and disappointingly it is cap coupled to the motor. A dc coupled amp will presumably offer better performance but at the risk of frying the motor if anything goes wrong. I wonder how Lingo deals with that.
Any info?
cheers
peter
Please don't be cruel. I'll be very interested in your bridge amp providing the 110v rms out. Even without component values.
Regarding the oscillator, fine tuning a (lamp) Wien bridge produced less than 0.01% second harmonic which should be more than sufficient especially compared to 5-6% off the wall. I use an 8015 AVR with an EPROM based lookup table and DAC at the output port. Mostly for the convenience of a second phase being readily available at another port. So far i've only built step-up transformer based amps to produce the high output but since comparing this to a Valhalla decided that high voltage amp is likely a much better way to go. The Valhalla produces much better subjective dynamics and bass. I did draw a circuit off the Valhalla board hi voltage amp and disappointingly it is cap coupled to the motor. A dc coupled amp will presumably offer better performance but at the risk of frying the motor if anything goes wrong. I wonder how Lingo deals with that.
Any info?
cheers
peter
Tease over.
Peter,
The bridge amp produced up to 240 volts out. (120v each side).
It is a dangerous beast to get working.
It's imperfect, in that there is a slight crossover glitch between the top and bottom FET's, but if I remember rightly, it practically disappears when on load, with the correct power-factor correction.
If you are determined, send me a disclaimer and non-disclosure e-mail. Since you are a valve man, I'll assume that you know what you're doing with these lethal voltages, and will isolate accordingly.
I won't send a PCB though - that would just be too tempting
Cheers,
Peter,
The bridge amp produced up to 240 volts out. (120v each side).
It is a dangerous beast to get working.
It's imperfect, in that there is a slight crossover glitch between the top and bottom FET's, but if I remember rightly, it practically disappears when on load, with the correct power-factor correction.
If you are determined, send me a disclaimer and non-disclosure e-mail. Since you are a valve man, I'll assume that you know what you're doing with these lethal voltages, and will isolate accordingly.
I won't send a PCB though - that would just be too tempting
Cheers,
Implementation help
Dhaen,
Thank you very much for your interest, the pcb offer and the info. I've spent time to understand the garrard circuit, and the one you have is far above my head of electronic knowledge today. With the pcb you have, I only have to add the power stage, right? Would be it expensive in components?
Peter & Brett,
Thanks a lot for your information and scheme. I think I will build the scheme, but have some comments:
I don't think the thorens motor will need much power, but don't know the actual value.
I've found (with the 166) that with 220V the motor vibrates and make noises, and that in the 160 there is a resistor for lower the voltage. Putting a similar value solves the noise problem of the motor, so I'm sure that the motor is the same, it is for 110V operation, so I only have to reach this value in the ps.
Oscillator:
what is the minimum value for the trafo? is it necessary 50VA really?
What is the purpose of the 5k pot?
The non-linear element (the lamp) is just a 28V lamp?
The pulley I have is for 60Hz operation, so it has a smaller diameter. I've been thinking about it and maybe I keep it because the lesser the contact the lesser the vibration passed to the platter, right? Is because of this that the top-models has a very small pulley and just a wire instead of belt?
The values I will consider for 60Hz operation are:
R: 270 K
C: 0.01uF
I will use the 5532, because I already have one.
I like your suggestion about to put in a cap after the oscillator and put out the electrolitycs in front of the trafo. I don't know wich value should I choose,
any help??
Power Amp
If the purpose is to amplify the signal, here I can use any amp capable of manage a load equal to the trafo impedance and with the highest voltage swing possible, right? Any reason for the 3886? The distorsion of the circuit is given by the oscillator, by the amp, or by the trafo?
The 100K pot at the possitive input of the LM is a "volume" pot, isn't it?
Why could be better use a high voltage amp instead of a trafo?
Step-up Transformer
Can I simply use an ordinary trafo, but backwards? Yep, it's so simple...
Oh boy, toooo many questions today, sorry and many thanks for your help. I'm real analog, (I bought last week more than 100 very good lp's for 140 EURO) so why to buy a CD?
Thanks a lot
Dhaen,
Thank you very much for your interest, the pcb offer and the info. I've spent time to understand the garrard circuit, and the one you have is far above my head of electronic knowledge today. With the pcb you have, I only have to add the power stage, right? Would be it expensive in components?
Peter & Brett,
Thanks a lot for your information and scheme. I think I will build the scheme, but have some comments:
I don't think the thorens motor will need much power, but don't know the actual value.
I've found (with the 166) that with 220V the motor vibrates and make noises, and that in the 160 there is a resistor for lower the voltage. Putting a similar value solves the noise problem of the motor, so I'm sure that the motor is the same, it is for 110V operation, so I only have to reach this value in the ps.
Oscillator:
what is the minimum value for the trafo? is it necessary 50VA really?
What is the purpose of the 5k pot?
The non-linear element (the lamp) is just a 28V lamp?
The pulley I have is for 60Hz operation, so it has a smaller diameter. I've been thinking about it and maybe I keep it because the lesser the contact the lesser the vibration passed to the platter, right? Is because of this that the top-models has a very small pulley and just a wire instead of belt?
The values I will consider for 60Hz operation are:
R: 270 K
C: 0.01uF
I will use the 5532, because I already have one.
I like your suggestion about to put in a cap after the oscillator and put out the electrolitycs in front of the trafo. I don't know wich value should I choose,
any help??Power Amp
If the purpose is to amplify the signal, here I can use any amp capable of manage a load equal to the trafo impedance and with the highest voltage swing possible, right? Any reason for the 3886? The distorsion of the circuit is given by the oscillator, by the amp, or by the trafo?
The 100K pot at the possitive input of the LM is a "volume" pot, isn't it?
Why could be better use a high voltage amp instead of a trafo?
Step-up Transformer
Can I simply use an ordinary trafo, but backwards? Yep, it's so simple...
Oh boy, toooo many questions today, sorry and many thanks for your help. I'm real analog, (I bought last week more than 100 very good lp's for 140 EURO) so why to buy a CD?
Thanks a lot
The Thorens motor will work with 90v rms if you remove the resistor.
As i don't have a 160 anymore i'd suggest you have a look at the stated power consumption at the back of the unit and use a transformer with at least double that. Surely 20VA will be more than enough.
The 5k pot sets the feedback for oscillation. A scope can be very handy here as you need to monitor how the oscillation grows. Set it for around 2v p-p and a clean looking sine. In the abscence of a scope you can use one of the many scope/analyser progs which work with a soundcard. Because of the low frequency you'll be able to very accurately measure the harmonics in the output (that's optional)
28v 20-30mA seems to work very well. i used the first lamp i found and it was fine. the scope/ spectrum analyser will confirm this.
With a 100k input resistance the coupling cap value is non-critical. Just 1uF preferably non-polar will do.
You don't have to use 3886. I used briefly a Rotel power amp and a PP EL34 amp. The 3886 is damn convenient though.
The bulk of the distortion is caused by the step-up transformer. If you have one specially wound you may choose to go for more turns/volt than the min requirement for the core. It seems this will minimise the distortion. I ended up using a 50VA 220-20 v unit. At 90v the distortion is very low.
Yeah, the 100k is volume. Use it to set the output.
Good luck
peter
As i don't have a 160 anymore i'd suggest you have a look at the stated power consumption at the back of the unit and use a transformer with at least double that. Surely 20VA will be more than enough.
The 5k pot sets the feedback for oscillation. A scope can be very handy here as you need to monitor how the oscillation grows. Set it for around 2v p-p and a clean looking sine. In the abscence of a scope you can use one of the many scope/analyser progs which work with a soundcard. Because of the low frequency you'll be able to very accurately measure the harmonics in the output (that's optional)
28v 20-30mA seems to work very well. i used the first lamp i found and it was fine. the scope/ spectrum analyser will confirm this.
With a 100k input resistance the coupling cap value is non-critical. Just 1uF preferably non-polar will do.
You don't have to use 3886. I used briefly a Rotel power amp and a PP EL34 amp. The 3886 is damn convenient though.
The bulk of the distortion is caused by the step-up transformer. If you have one specially wound you may choose to go for more turns/volt than the min requirement for the core. It seems this will minimise the distortion. I ended up using a 50VA 220-20 v unit. At 90v the distortion is very low.
Yeah, the 100k is volume. Use it to set the output.
Good luck
peter
Thanks
I have downloaded the LM3886 data, and you were right: it's pretty convenient to build a simple amp as long as it is going to deal with one frequency. My only concern is if the load (the trafo) is going to be an easy load. A standard trafo has not 8 not even 4 ohms, is this a problem. I was just comparing to an audio amplifier feeding just a wire (like a trafo), wouldn't that increase the distortion??
Now it's time to make a PCB.
Thanks a lot for your support, it's greatly appreciated. I think you deserve your nickname.
I have downloaded the LM3886 data, and you were right: it's pretty convenient to build a simple amp as long as it is going to deal with one frequency. My only concern is if the load (the trafo) is going to be an easy load. A standard trafo has not 8 not even 4 ohms, is this a problem. I was just comparing to an audio amplifier feeding just a wire (like a trafo), wouldn't that increase the distortion??
Now it's time to make a PCB.
Thanks a lot for your support, it's greatly appreciated. I think you deserve your nickname.
You're welcome.
The transformer represents a very low load only at DC - you may be talking less that 1ohm for the primary. This is only a problem if there is any significant DC at output - 3mV in this case - so nothing to really worry about. At 50Hz (60) where you're really developing power the LM sees the impeadance of the motor stepped down by the square of transformer ratio - whatever is the impedance of the motor divided by about 100.
The transformer represents a very low load only at DC - you may be talking less that 1ohm for the primary. This is only a problem if there is any significant DC at output - 3mV in this case - so nothing to really worry about. At 50Hz (60) where you're really developing power the LM sees the impeadance of the motor stepped down by the square of transformer ratio - whatever is the impedance of the motor divided by about 100.
Thanks for the info on the trafo impedance, now my concerns are away.
The thorens motor is only 1.5VA, but I'll oversize the power amp, just in case I upgrade my deck or my motor someday. Depending on transformers price, I will settle on 30-50VA.
What I'm not sure yet is if I should include a speed change. I don't have 45 records, but who knows!! I don't think changing the speed very often would be a good idea with this circuit, but as I will have two standard pulleys (one for 50Hz, and the original one for 60Hz), maybe I should fit the two options and i will have the chance to buy some 60Hz motors in the future... Or just leave space to fit the new RC values for different pulleys-motors,... just thinking.
I have made the pcb layout, but for the NE5532 (dual), I will make it more neat and fit a 5534.
I know seems the same question as always but, what about the heatsinking requirements for the LM?
Just for the record, I've ordered the RB250 with the expressimo heavyweight and OL VTA. I hope that all this will result in a good deck to listen to my Prokofieff records.
The thorens motor is only 1.5VA, but I'll oversize the power amp, just in case I upgrade my deck or my motor someday. Depending on transformers price, I will settle on 30-50VA.
What I'm not sure yet is if I should include a speed change. I don't have 45 records, but who knows!! I don't think changing the speed very often would be a good idea with this circuit, but as I will have two standard pulleys (one for 50Hz, and the original one for 60Hz), maybe I should fit the two options and i will have the chance to buy some 60Hz motors in the future... Or just leave space to fit the new RC values for different pulleys-motors,
... just thinking.I have made the pcb layout, but for the NE5532 (dual), I will make it more neat and fit a 5534.
I know seems the same question as always but, what about the heatsinking requirements for the LM?
Just for the record, I've ordered the RB250 with the expressimo heavyweight and OL VTA. I hope that all this will result in a good deck to listen to my Prokofieff records.
Hi
What do you need a pcb for? A project as simple as this will take you an hour max to wire using vero board. No idea what the actual power dissipated in the Thorens will be, but with the Garrard the LM gets red hot with a respectable heatsink. No big deal to make it switchable for 45rpm, dunno if you'll find much Prokofiev stuff on 45 though
cheers
peter
What do you need a pcb for? A project as simple as this will take you an hour max to wire using vero board. No idea what the actual power dissipated in the Thorens will be, but with the Garrard the LM gets red hot with a respectable heatsink. No big deal to make it switchable for 45rpm, dunno if you'll find much Prokofiev stuff on 45 though
cheers
peter
Yes, it's a simple project, but I always spent a time thinkink about the layout even for a veroboard. Besides, my target is now to build a good power supply even for future projects. I'm trying to design a layout that allows for switchable RC constants, maybe a small "card" that could be plug to the board with this small conectors (I don't know the name, but are used for jumpers). You know, 60HZ? well, let's plug this card, now a bigger pulley? well, let's fit this one...
About the heatsinking, when you say respectable, with size are you refering to? 200*100mm?
My "spagetti" layouts fed me up, so that's why I now spend more time thinking than building. I'm becoming the saint Job.
BTW, yesterday I measured the mains distortion and was only 2%(at 19:30). Do you really think a "perfect" sinusoudal is going to improve the sonics? I'm going to build the ps so you will have then my comments.
Another thing (maybe related) I discovered is that the motor is noisy even stopped. I used a "stetoscopio" and a bzzz is heard when the motor is just conected. That bzzzz reaches the arm. When the motor is started and in normal operation, the bzzzz rises, but not much.
About the heatsinking, when you say respectable, with size are you refering to? 200*100mm?
My "spagetti" layouts fed me up, so that's why I now spend more time thinking than building. I'm becoming the saint Job.
BTW, yesterday I measured the mains distortion and was only 2%(at 19:30). Do you really think a "perfect" sinusoudal is going to improve the sonics? I'm going to build the ps so you will have then my comments.
Another thing (maybe related) I discovered is that the motor is noisy even stopped. I used a "stetoscopio" and a bzzz is heard when the motor is just conected. That bzzzz reaches the arm. When the motor is started and in normal operation, the bzzzz rises, but not much.
Raka,
You need not use the original strobe circuit. That is complicated by the need of the original to be mains isolated.
I still have 3 boards left, so you can have one if you'll use it.
Cheers,
Yes, it's the power stage you want. Really an amplifier of the required power feeding into a step-up transformer would be the easiest.
You need not use the original strobe circuit. That is complicated by the need of the original to be mains isolated.
I still have 3 boards left, so you can have one if you'll use it.
Cheers,
Thanks a lot for your interest, dhaen!
Well, your circuit seems a bit complicated today for me, but once I've studied the easier one, I will give it a chance to go. Do you have a simple explanation over the scheme? Does it have a strobe?
Of course I'd like to have one pcb, my only fear is if I know how to populate it
What's all that about mains isolation?
Well, your circuit seems a bit complicated today for me, but once I've studied the easier one, I will give it a chance to go. Do you have a simple explanation over the scheme? Does it have a strobe?
Of course I'd like to have one pcb, my only fear is if I know how to populate it
What's all that about mains isolation?
The 4060 is a binary divider with built in crystal oscillator circuitry.Raka said:Thanks a lot for your interest, dhaen!
Well, your circuit seems a bit complicated today for me, but once I've studied the easier one, I will give it a chance to go. Do you have a simple explanation over the scheme? Does it have a strobe?
Of course I'd like to have one pcb, my only fear is if I know how to populate it
What's all that about mains isolation?
The 40103 is a programmable divider, it's division ratio set by J1 to J8. It's output duty ratio is not 50% so the 1/2 4013 corrects this.
The 2/2 4013 is spare, so is used to reduce the number of links needed to change the frequency between 50Hz & 60Hz.
The TLO72 *1 1/2 & 2/2, and TLO72 *2 1/2 are active filters to turn the square wave into a sine wave.
The temperature compensation 4K7 NTC will not be necessary normally. It was used on the original because the whole case was a heatsink which could get very hot. It was to keep the output level stable for change of temperature.
Mains isolation:
Most home built equipment (wisely) uses mains isolation. This means that there is no direct connection between any of the internal circuitry and either of the mains wires. We use mains transformers for this purpose.
Commercial equipment often does not do this, but uses special and controlled techniques to ensure safety. Do not be tempted!
I will reserve 1 PCB for you, but before I send it, I need to know that you can benefit from it, and have a reasonable understanding and plan
Unlike Iraq, there is no time limitCheers,
Not so difficult
Thanks a lot dhaen,
Well, it doesn't look so difficult to build the circuit. As far as I understand now, your circuit achieves a square wave by means of dividers controlled by the crystal (and the 4013 as selector of frequency). After that, it's fed a led strobe by means of a transistor follower, and a filter that clenns everything to a trafo. Right?
The strobe light is a good thing to check the pulley. I'm planning (in long term) to change the motor, so a final check it's a good idea (but not essential if that makes this difficult)
The good point with your circuit is that the circuit is always of a fixed frequency and exactly 50Hz. That will avoid frequency variations. But what about the final distortion? Does the filter clean completely to a sine wave?
About buying the chips, any hint about where to buy and maybe code? I searched for 4060, but appeared many, I'm more used to analog components, 3055, 244, etc... any complete code for the dividers?
Thanks a lot dhaen,
Well, it doesn't look so difficult to build the circuit. As far as I understand now, your circuit achieves a square wave by means of dividers controlled by the crystal (and the 4013 as selector of frequency). After that, it's fed a led strobe by means of a transistor follower, and a filter that clenns everything to a trafo. Right?
The strobe light is a good thing to check the pulley. I'm planning (in long term) to change the motor, so a final check it's a good idea (but not essential if that makes this difficult)
The good point with your circuit is that the circuit is always of a fixed frequency and exactly 50Hz. That will avoid frequency variations. But what about the final distortion? Does the filter clean completely to a sine wave?
About buying the chips, any hint about where to buy and maybe code? I searched for 4060, but appeared many, I'm more used to analog components, 3055, 244, etc... any complete code for the dividers?
Dhaen,
Thanks for the codes searching, I will try also, but I'm a little bit ignorant about digital.
Will you then send to me the PCB? I would be 
to run my TD160 with your clean sine wave. I promise to use it properly and to inform you about the happines of my deck. I promise also no more than two hours and a half of a general description of my "news" LP.
Thanks a lot
Thanks for the codes searching, I will try also, but I'm a little bit ignorant about digital.
Will you then send to me the PCB? I would be to run my TD160 with your clean sine wave. I promise to use it properly and to inform you about the happines of my deck. I promise also no more than two hours and a half of a general description of my "news" LP.Thanks a lot
Happy thorens
Hi,
I've just finished the power supply!! I have to thanks to dhaen for his generosity and patience with his design and my private questions. I learn a lot with the people in this forum. Not only technically, but even more in the human aspect of generosity and help.
Peter, I also thank you very much for your help, I will use the 3886 amp scheme, so be ready for my questions
Well, after the credits , a brief descritpion of the system: The output of the oscillator has a distortion of .3%, which is fine with me. Then, an old Sharp receiver amplifies the signal passed through a cap and the speaker output is connected to a transformer and at last the thorens.
Well, the results. Before all this I noticed that if you use an stethoscope, a buzz is heard caused by the motor even when is stopped. If you feed the deck, the buzz is there. Now, with my brand new power supply, no buzz is heard when the motor is connected!!!!! I suppose this is good
The sound?? Do you want a description of the sound? You should look at the bags under my eyes. I stopped spinning vynil at one in the morning, last night.
Amazing.
Hi,
I've just finished the power supply!! I have to thanks to dhaen for his generosity and patience with his design and my private questions. I learn a lot with the people in this forum. Not only technically, but even more in the human aspect of generosity and help.
Peter, I also thank you very much for your help, I will use the 3886 amp scheme, so be ready for my questions
Well, after the credits
, a brief descritpion of the system: The output of the oscillator has a distortion of .3%, which is fine with me. Then, an old Sharp receiver amplifies the signal passed through a cap and the speaker output is connected to a transformer and at last the thorens.Well, the results. Before all this I noticed that if you use an stethoscope, a buzz is heard caused by the motor even when is stopped. If you feed the deck, the buzz is there. Now, with my brand new power supply, no buzz is heard when the motor is connected!!!!! I suppose this is good
The sound?? Do you want a description of the sound? You should look at the bags under my eyes. I stopped spinning vynil at one in the morning, last night.
Amazing.
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