You are absolutely correct Nigel, switching to the 4.433 MHz crystal frequency does drop the voltage to the motor. My experimenting and measuring showed only 65 volts hence the need to also change resistor R13 to around 15k to bring it back up to 85 volts. The motor will run at the lower voltage but will not start without a push.
My simple ( primitive) version works surprisingly well but I can see from your input that I should really make the phase cap switchable from 22 to 11 to further help smooth the motor. In spite of this however the motor in the AR seems just as quiet and smooth with the 'wrong' cap value but further tweaking can only improve things.
Cheers
Graham.
My simple ( primitive) version works surprisingly well but I can see from your input that I should really make the phase cap switchable from 22 to 11 to further help smooth the motor. In spite of this however the motor in the AR seems just as quiet and smooth with the 'wrong' cap value but further tweaking can only improve things.
Cheers
Graham.
As I thought an ECC81 ( using ECC85 as that is all I have , similar ) will not drive the motor directly . 30V rms is not bad ( 10 : 1 probe ) . The motor in 4K64 without the inductance . It is a genuine LP 12 motor from the old Belgium factory ( my spare one ) .
Motor is rotating albeit zero torque . If I make an external phase shift device I will try the direct coupled version ( hence 4K7 load as it is very like the motor static load ) . The distortion is OK and good a basis for feedback ( 14 % THD ) . Anode plates are not glowing red . 0.2 uF phase shift ( all I have to hand ) .
Considering the simplicity of this oscillator it is giving excellent performance . 0.25 % THD . The capacitors are 5% chosen at random . The purple resistor should be 318 K approximately for 50 Hz and I guess 910 K paralleled for 45 Hz . Notice an allpass filter does give a sine and cosine wave as proven by the maths ( 1.414 times larger ) . By combining the 180 degree section via 91K and 10 K a distortion null is created giving 4.1 Vms at 0.07 % THD . This would improve if 1N4148 was used in place of red LED's with reduced output . TL074 used as op amp . LED's are OK on temperature stability considering the cost , IN4148 perhaps less so . An ice cream put on the LED's took output to 4.21 from 4.1 V (null ) .
If I didn't make an error the DC residual is too great for direct coupling . A lovely powerful feel to the motor without sustained rotation using SVF oscillator . Output was 60 Vrms for 5 V input using ECC85 at 10 mA per phase .
Ok its still a bit to technical for me, but if you can say exactly what components I need to get & where to put them, do I need to remove any existing components or cut into the board at all ?
Will the switch be the same as the Linn or does that need to be replaced or a second one added?
If it is supposedly so easy & cheep to do this why didn't Linn do it in the first place....or is that a very stupid question
Will the switch be the same as the Linn or does that need to be replaced or a second one added?
If it is supposedly so easy & cheep to do this why didn't Linn do it in the first place....or is that a very stupid question
How I did it was to use 12 V to switch the 2 relays . In fact being you are UK also I used the switch on the mains socket to switch ( cheap and simple ) .
I am a little concerned you attempt this as it is a bit dangerous . Live anywhere near Oxford ?
Why didn't Linn do this ? Simply because it was not done in house . The crystal is not exact so maybe an idea they didn't want to follow ? Lingo isn't the one to copy . If people don't get bored I will try to perfect a Lingo for them . I am 80% there and got 63 Vrms from 2 x EL 84 today . The oscillator is fine . I am looking at a cathode follower now .
You need .
3.276mhz Hc 49/u Crystal
4.433619Mhz 30ppm HC 49US Low Profile Crystal
220nf 275v Class X2 Capacitor
2A SPCO Subminiature signal relays
HF7FD0121ZSTF 12VDC 12A SPDT Miniature Cube Power Relay
AC/DC Unreg Ptop Psu 12v DC 500ma
I am a little concerned you attempt this as it is a bit dangerous . Live anywhere near Oxford ?
Why didn't Linn do this ? Simply because it was not done in house . The crystal is not exact so maybe an idea they didn't want to follow ? Lingo isn't the one to copy . If people don't get bored I will try to perfect a Lingo for them . I am 80% there and got 63 Vrms from 2 x EL 84 today . The oscillator is fine . I am looking at a cathode follower now .
You need .
3.276mhz Hc 49/u Crystal
4.433619Mhz 30ppm HC 49US Low Profile Crystal
220nf 275v Class X2 Capacitor
2A SPCO Subminiature signal relays
HF7FD0121ZSTF 12VDC 12A SPDT Miniature Cube Power Relay
AC/DC Unreg Ptop Psu 12v DC 500ma
Thanks for that Nigel, as I understand it as long as the Caps are fully discharged (20 min?) It should be safe to tinker with?
I don't have much understanding of electronics but I can make just about anything, & have made valve amps, was a long time ago though!
So with this list of parts (all from the same source makes life so much easier) is it a case of swapping components, or is it a new bit of circuit thats being created?
& or where do they go ?
What & how is the AC/DC Psu used for?
You mentioned a Lingo are you building a DIY version? praps it might be better to wait till you get this sorted.
Are you proposing a kit or circuit diagram with list of parts? how would the circuit board be sourced.
sorry for all the questions.
Jay
I don't have much understanding of electronics but I can make just about anything, & have made valve amps, was a long time ago though!
So with this list of parts (all from the same source makes life so much easier) is it a case of swapping components, or is it a new bit of circuit thats being created?
& or where do they go ?
What & how is the AC/DC Psu used for?
You mentioned a Lingo are you building a DIY version? praps it might be better to wait till you get this sorted.
Are you proposing a kit or circuit diagram with list of parts? how would the circuit board be sourced.
sorry for all the questions.
Jay
Nigel, I have an old Axis PSU. Any idea to increase voltages to make
it powerful enough to start the heavier LP12 platter?
Jay, to be honest, if you really aren't experienced in electronics,
keep your hands off a Valhalla with voltages exceeding 300 V.
it powerful enough to start the heavier LP12 platter?
Jay, to be honest, if you really aren't experienced in electronics,
keep your hands off a Valhalla with voltages exceeding 300 V.
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The Axis was a weird turntable . So well engineered and yet was very hard to sell . The PCB very complex and seemingly well thought out .
The motor I think was the slightly cheaper version often talked about on on Forums ( RS sell it at about £40 ) .
Looking at this thread the 15 K might be it or the 3 K resistors . Maybe get the circuit from this guy ? It looks possible .
http://www.diyaudio.com/forums/analogue-source/76386-linn-axis-pcas011-power-supply.html#post896286
Jay if I can find my Valhalla I will play with R3 ( ? additional relay and resistor or relay section ) . The idea is to put a meter in the red or blue phase . The voltage required should compensate for the inductance at 67.5 Hz ( AC current range ) . This is more critical than people realize . 75 Hz I suspect is the resonance point of the Airpax motor ( Philips Belgium , it has had many names ) . That is OK as we want 67.5 for 45 RPM . I had the motor working nicely at 5Hz by mistake . Common sense says use the highest speed you can . I would say 130 V at 75 Hz are the upper limits . 130 V 50 Hz might give too much vibration even on ideal waves . On very sick phase correct waves at 63 V vibration was excellent ( 20 % THD ? ) . If I fitted a 78 pulley at about 32 mm if there is room ( 75 Hz ) . I guess 32 Hz for 33 1/3 and 43.3 for 45 . Almost suggests 45 rpm at 50 Hz would not be bad ( 27 mm ) . That would 86.7 Hz 78 which might be OK . 33 1/3 at 37 Hz . In my bones I feel you might win more than you loose at 37 Hz . That would still be 133.2 poles per platter rotation compared with 180 standard ( {250/ 33.33} 24 , 250RPM = 50 Hz ) .
The motor I think was the slightly cheaper version often talked about on on Forums ( RS sell it at about £40 ) .
Looking at this thread the 15 K might be it or the 3 K resistors . Maybe get the circuit from this guy ? It looks possible .
http://www.diyaudio.com/forums/analogue-source/76386-linn-axis-pcas011-power-supply.html#post896286
Jay if I can find my Valhalla I will play with R3 ( ? additional relay and resistor or relay section ) . The idea is to put a meter in the red or blue phase . The voltage required should compensate for the inductance at 67.5 Hz ( AC current range ) . This is more critical than people realize . 75 Hz I suspect is the resonance point of the Airpax motor ( Philips Belgium , it has had many names ) . That is OK as we want 67.5 for 45 RPM . I had the motor working nicely at 5Hz by mistake . Common sense says use the highest speed you can . I would say 130 V at 75 Hz are the upper limits . 130 V 50 Hz might give too much vibration even on ideal waves . On very sick phase correct waves at 63 V vibration was excellent ( 20 % THD ? ) . If I fitted a 78 pulley at about 32 mm if there is room ( 75 Hz ) . I guess 32 Hz for 33 1/3 and 43.3 for 45 . Almost suggests 45 rpm at 50 Hz would not be bad ( 27 mm ) . That would 86.7 Hz 78 which might be OK . 33 1/3 at 37 Hz . In my bones I feel you might win more than you loose at 37 Hz . That would still be 133.2 poles per platter rotation compared with 180 standard ( {250/ 33.33} 24 , 250RPM = 50 Hz ) .
Quick question for you Nigel. Over the weekend I intend to further refine my 'el cheapo' version of 2 speed Valhalla by adding the alternative motor phasing cap.
Can you tell me did you calculate the value of 0.11 for 45 rpm or experiment, or a lucky dip in your parts drawer ???
Cheers
Graham.
Can you tell me did you calculate the value of 0.11 for 45 rpm or experiment, or a lucky dip in your parts drawer ???
Cheers
Graham.
http://docs-europe.electrocomponents.com/webdocs/0211/0900766b802111e1.pdf
This motor is more or less the LP12 . Notice is says 0.18 uF 60 Hz . It is almost saying 0.11 uF will be about right . 0.15 uF is well worth trying first . I think I held it in my hand also to sense vibration . My recollection is 0.11 uF worked well and was easy .
There are two other methods . Manipulate the capacitor until voltages are about equal . That won't be far off . Take also the between phases voltage , 85 x 1.4 should be about right ( 120 ? ) . By Pythagoras 45 degrees is root / 2 larger .
Next using cheap isolating transformers use as I did a dual beam scope .
The final way is just match the voltage ratios of 0.22 uF 50 Hz . I suspect only the separate amplifier approach is definitive . The coils are identical so there isn't a fiddle factor on the blue phase allowing for capacitor effects .
If you reverse the phases you can hear how Pink Floyd did things . It is also a technique for recording damaged records . Then digitally reverse play them or tape recorder having the facility . For archiving sometimes this is done .
PT I only know by reputation . Possibly the same .
Let me know best R3 ( was it ) . I would assume 10% more for 45 would be good ( 95V ? ) . Same current used would be excellent on red phase 33/45 .
I just did a quick check of something . 50 / 0.22 = 227.3 , 60 / 0.18 = 333.3 67.65 / 0.15 = 451 . Whilst not proof it looks about right and 0.11 uF perhaps was the right side of wrong . 0.15 uF if starting again looks about right .
This motor is more or less the LP12 . Notice is says 0.18 uF 60 Hz . It is almost saying 0.11 uF will be about right . 0.15 uF is well worth trying first . I think I held it in my hand also to sense vibration . My recollection is 0.11 uF worked well and was easy .
There are two other methods . Manipulate the capacitor until voltages are about equal . That won't be far off . Take also the between phases voltage , 85 x 1.4 should be about right ( 120 ? ) . By Pythagoras 45 degrees is root / 2 larger .
Next using cheap isolating transformers use as I did a dual beam scope .
The final way is just match the voltage ratios of 0.22 uF 50 Hz . I suspect only the separate amplifier approach is definitive . The coils are identical so there isn't a fiddle factor on the blue phase allowing for capacitor effects .
If you reverse the phases you can hear how Pink Floyd did things . It is also a technique for recording damaged records . Then digitally reverse play them or tape recorder having the facility . For archiving sometimes this is done .
PT I only know by reputation . Possibly the same .
Let me know best R3 ( was it ) . I would assume 10% more for 45 would be good ( 95V ? ) . Same current used would be excellent on red phase 33/45 .
I just did a quick check of something . 50 / 0.22 = 227.3 , 60 / 0.18 = 333.3 67.65 / 0.15 = 451 . Whilst not proof it looks about right and 0.11 uF perhaps was the right side of wrong . 0.15 uF if starting again looks about right .
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Seems RV 1 adjusts the voltage . Surprised they didn't use 2 x 4060 ripple counter . I wonder if they wanted it to look complicated ? LM324 is a generic of the op amp used . R3 is to adjust the low voltage side current ( should be OK as designed ) . The switch is a neat idea . Bootstrap is missing a letter . Perhaps a resistor switched around RV1 to give the increased voltage at 67.65 Hz ( ideal 65.5 ) .
Now I look at it the flip flop is used for two circuits . Very economical if slightly more complicated ( 4060 also has flip flops , 2 off still looks better to me ) . Without playing with RV 1 I am not sure it is just a simple level control . Go gentle . 85V was the standard setting . Looks almost certain that's all it does in a practical sense . The switching possibly mutes it as it's other function , neat if so ?
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I don't think it was issued by Linn . Mostly the W08 rectifier and 47 R inrush resistor fail on Valhalla . The Axis was repaired by installing a new PCB with motor . That was not unusual .
My valve driven idea is too expensive I feel . I had a very good 41.2 Vrms waveform from an ECC 85 cathode follower . Off load 73 Vrms . It was 18 K at 160 V = 8.9 mA for the current setting cathode resistor . The g1 using 1 M to both 0 and 320 V and 0.1 uF input capacitor . I suspect ECC 82 a better choice and same values . Like using various transistors I doubt as a buffer it makes much difference if current is OK .
If set up with 2 x ECC 82 and 2 x ECC 83 I suspect it would be workable ( in bridge with 4 high gain voltage amps ) . Shunt feedback from motor to input to reduce sensitivity and get a bit of distortion reduction , nice double use of the output capacitor ( > 22 uF electrolytic ) . The signal would need phase splitting ( 0 + 180 , in addition to 0 + 90 required , thus 0 + 180 , 90 + 270 ) . This can be done using a long tail pair type ECC 83 splitter . This would be elegant ( like Quad valve amps , they use pentode ). Alas 6 db of distortion reduction would be lost . Better to use a double op amp inverter and 4 identical stages ( 2 per phase ) . There is one complication . The maximum heather to cathode voltage is 180 V for ECC 82 . 160 V is too close . The heater would need raising . That to me is the killer blow . Doubtless it can be done . It is tempting to think it could be strapped to g1 , If using 0 -115 , 0 - 115 ( 0 - 160 - 320 DC ) that would be possible . Also a resistive divider is possible . We have one piece of luck . The LP12 motor has separate coils . It could work is sine / cosine bridge .
This tool is handy .
Cathode Follower Output Impedance Calculator
My valve driven idea is too expensive I feel . I had a very good 41.2 Vrms waveform from an ECC 85 cathode follower . Off load 73 Vrms . It was 18 K at 160 V = 8.9 mA for the current setting cathode resistor . The g1 using 1 M to both 0 and 320 V and 0.1 uF input capacitor . I suspect ECC 82 a better choice and same values . Like using various transistors I doubt as a buffer it makes much difference if current is OK .
If set up with 2 x ECC 82 and 2 x ECC 83 I suspect it would be workable ( in bridge with 4 high gain voltage amps ) . Shunt feedback from motor to input to reduce sensitivity and get a bit of distortion reduction , nice double use of the output capacitor ( > 22 uF electrolytic ) . The signal would need phase splitting ( 0 + 180 , in addition to 0 + 90 required , thus 0 + 180 , 90 + 270 ) . This can be done using a long tail pair type ECC 83 splitter . This would be elegant ( like Quad valve amps , they use pentode ). Alas 6 db of distortion reduction would be lost . Better to use a double op amp inverter and 4 identical stages ( 2 per phase ) . There is one complication . The maximum heather to cathode voltage is 180 V for ECC 82 . 160 V is too close . The heater would need raising . That to me is the killer blow . Doubtless it can be done . It is tempting to think it could be strapped to g1 , If using 0 -115 , 0 - 115 ( 0 - 160 - 320 DC ) that would be possible . Also a resistive divider is possible . We have one piece of luck . The LP12 motor has separate coils . It could work is sine / cosine bridge .
This tool is handy .
Cathode Follower Output Impedance Calculator
This works . 4n7 was an attempt to use overall feedback ( let me know if you succeed , I was getting 28 kHz ) . Left it in place as unity gain is unusual for a TDA 2030 . Uses the oscillator previously posted . Distortion is from the modestly priced transformer . PCB from RS . Small TO 220 heat sink required . In reality probably as good as it needs in terms of distortion and might give the Lingo a run for it's money . Adjust output by inverting op amp gain formula .
The output is floating . You might put green 0 V to the centre of the output . It would then have trendy common mode cancellation .
On Valhalla looking at R 13 ( Not R3 , clean my specs I think ) that will affect output .
Jay . The AC DC PSU is to power the relays if Valhalla mod .
Pcb Open Mains Transformer 6va 0 9v 0 9v
Buy tda2030 online from RS Components
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I was rather intrigued by how nice the waves looked . Like a good valve amp the harmonics fall on an exponential curve more or less . This will sound very nice . It doesn't provoke much vibration due to the exponential decay . At 13.2 V DC +/- there is just enough output for 110V , the chip will take 15 V +/- . The motor is at about 45 C or less even at full power . This suggests 110 at 67.5 would be perfectly OK if required .
Notice how inefficient the transformer is used this way . The idea is to keep it out of saturation .
I also noticed the capacitor required changes with voltage when transformer coupled . Maybe that's why I used 0.11 uF ? Ideally use two amps as in my previous drawing .
Look how bad the mains is .
I did this project in about 1995 . This is the first time I have written it up . All from memory . The oscillator was a Wien bridge using RA 53 ( obsolete ) . This TDA 2030 I think was the spare from that project ?
Jay . Hope this isn't too far from your question . It is I suspect a better and safer option if anyone wants a Lingo on a budget . I will stick my neck out and say it is better . That is if you are like me , you would probably use 85 V . You have the choice , on Lingo you don't .
Just retraced my steps 18 years on . It was via a transformer which I guess must influence things ? Redoing it said the voltage is critical also to the decision . No idea if that is the same on a Valhalla ? 95 V was also 95V blue @ 0.22 uF 50 Hz . At other voltages 0.22 uF was not optimum , e g . 76 , 85 . I can see 0.22 uF is for maximum power at maximum voltage .
The reason I posted the home brew Lingo is I wanted to document it . I doubt the parts come to $50 ?
I can see that I will have to build a home brew Lingo, it looks like fun.
However in the mean time I am happy with my own cheap version of 2 speed Valhalla.
One interesting thing for you to mull over Nigel, seeing as how you seem to be the guru on this subject.
I went to the trouble of adding a switching function for the phasing cap so that I could use a 0.11 or 0.15 cap on 45 rpm instead of the existing 0.22.
Well the motor will not start on either the 0.11 or 0.15, it just sits there and vibrates.
It spins and runs fine if I give it a push and is nice and quiet but wont start.
I have removed them and gone back to just the original 0.22 for both speeds and it operates just fine.
The motor in the AR is a Hurst which is different to that in a Linn so maybe it would prefer different values, but having said that , it is happy on the 0.22 on 33rpm.
Go figure !!!!!
Cheers
Graham.
However in the mean time I am happy with my own cheap version of 2 speed Valhalla.
One interesting thing for you to mull over Nigel, seeing as how you seem to be the guru on this subject.
I went to the trouble of adding a switching function for the phasing cap so that I could use a 0.11 or 0.15 cap on 45 rpm instead of the existing 0.22.
Well the motor will not start on either the 0.11 or 0.15, it just sits there and vibrates.
It spins and runs fine if I give it a push and is nice and quiet but wont start.
I have removed them and gone back to just the original 0.22 for both speeds and it operates just fine.
The motor in the AR is a Hurst which is different to that in a Linn so maybe it would prefer different values, but having said that , it is happy on the 0.22 on 33rpm.
Go figure !!!!!
Cheers
Graham.
Hi Graham . I have a Garrard 501 PSU I have just repaired . Only a broken wire and from New York ! It has 160 V 67.5 Hz . If I pot that down to 85 V I will see what I can get .
The inductance of a motor is 2Pifl . That suggests for a 35 % increase in frequency one might need 35% higher voltage . At a guess because part of the load is resistance 15% would seem about right . The maximum output of a Valhalla will be on a good day 90 Vrms ( V supply in DC is 160 , / 1.7 = 94 Vrms ) . At the very least set the R13 to give 90 Vrms at 67.5 Hz . I also had the start problem . I always start at 33 1/3 and switch over , that seems to work . Lingo and Axis do the same I think ?
The inductance of a motor is 2Pifl . That suggests for a 35 % increase in frequency one might need 35% higher voltage . At a guess because part of the load is resistance 15% would seem about right . The maximum output of a Valhalla will be on a good day 90 Vrms ( V supply in DC is 160 , / 1.7 = 94 Vrms ) . At the very least set the R13 to give 90 Vrms at 67.5 Hz . I also had the start problem . I always start at 33 1/3 and switch over , that seems to work . Lingo and Axis do the same I think ?
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