After seeing Volken's page on cap tuning the Papst motor to work smoother in a TD124 I thought I'd give it a try. If the cap tuning doesn't quite get me where I want to be I'll resort to finding a 3-Phase motor controller and putting that to use.
But first I need to build up this TD124. SN 13943.
The original paint on this unit was less than acceptable. So I decided to refinish it. First, I used Aircraft Remover to chemically strip the paint off. Aircraft Remover (yes it is the product name) is popular among automotive painters and also aviation painters. Good stuff.
More info here:
13943
-Steve
Looking forward to seeing and hearing a lot more about this over the next few months. I briefly contemplated a Papst motor, and might still do it at some point as I have a table I am not too uncomfortable experimenting with.
I plan to keep this thread short. So I will cut to the chase and mostly focus on utilizing the Papst on this chassis. But at my site I'll document the entire build as I usually do.
At the moment I have a collection of capacitors in transit coming to me. And I'm assembling the unit now in anticipation.
-Steve
early implementations
To begin with it is necessary to refer to whatever wiring schematic might be available for getting this motor to work on the TD124. The only one around seems to be Thorens service bulletin Nr. 22 from October 1977
Here are pages 1 and 2 that I have been able to scrounge up. They are not very readable but seem to be the best copy available.
It is the 2nd page the is least readable. Apart from the need to translate, the photo in figure 2 is less than usable. Further, it appears to be of a TD124 mk2. I'm working with a mk1 and the voltage commutator is different in appearance. Although I expect function between mk1 and mk2 to be identical. I just haven't had a mk2 over here to look at up close.
next:
An English translation of this bulletin.
THORENS -- Service Information Nr. 22 Oct. 1977
Replacement Motor for Thorens TD 124
The continuing popularity of Thorens turntable TD 124 has led us to search out a solution for the replacement motor. We are therefore very pleased to finally introduce adequate replacement in the form of a motor manufactured by Papst.
Unfortunately, due to the completely different type of construction, and an alternative electrical suppressor circuit, the motor can only be operated with one voltage option.
To order, it is important to specify which kit:
3805-200 Kit for 200-240 V at 50 hz (with C = .47 uF) or
3806-110 Kit for 100-125 V at 60 hz (with C = 1.4 uF)
Figure 1:
Figure 2:
Figure 3:
The above figure 3 translation was hand drawn by yours truly. If anyone finds an error in any of the above I'd appreciate any comments or corrections you may have.
I have more but I'll put those on the next post coming up right away.
-Steve
To begin with it is necessary to refer to whatever wiring schematic might be available for getting this motor to work on the TD124. The only one around seems to be Thorens service bulletin Nr. 22 from October 1977
Here are pages 1 and 2 that I have been able to scrounge up. They are not very readable but seem to be the best copy available.
It is the 2nd page the is least readable. Apart from the need to translate, the photo in figure 2 is less than usable. Further, it appears to be of a TD124 mk2. I'm working with a mk1 and the voltage commutator is different in appearance. Although I expect function between mk1 and mk2 to be identical. I just haven't had a mk2 over here to look at up close.
next:
An English translation of this bulletin.
THORENS -- Service Information Nr. 22 Oct. 1977
Replacement Motor for Thorens TD 124
The continuing popularity of Thorens turntable TD 124 has led us to search out a solution for the replacement motor. We are therefore very pleased to finally introduce adequate replacement in the form of a motor manufactured by Papst.
Unfortunately, due to the completely different type of construction, and an alternative electrical suppressor circuit, the motor can only be operated with one voltage option.
To order, it is important to specify which kit:
3805-200 Kit for 200-240 V at 50 hz (with C = .47 uF) or
3806-110 Kit for 100-125 V at 60 hz (with C = 1.4 uF)
Figure 1:
Figure 2:
Figure 3:
The above figure 3 translation was hand drawn by yours truly. If anyone finds an error in any of the above I'd appreciate any comments or corrections you may have.
I have more but I'll put those on the next post coming up right away.
-Steve
First cap tuning session
From the top with platter removed.
From underneath.
Close-up detail on the wire-up at the commutator. The combined cap value in this is 1.43 uF. This was arrived at after trying five different cap values. I listened to each cap value while using a mechanics stethoscope. I did this by placing the probe of the stethoscope at various places on the Td124 chassis while running the motor at full voltage. But with platter removed and the idler tire held away from the driving step pulley / capstan.
I should note that the stethoscope indicates the propagation of motor vibes throughout the chassis and can indicate just where the motor vibes seem to travel to and where it is loudest and where it is softest. Very useful! In this session, and others I've done in the past, it was found that motor vibes were heard clearly on that area of the casting where the tonearm board mounts!
Cap tuning notes:
Cap value 1.5 uF per the service bulletin.
results: strobe = dark (does not light)
motor vibes: 2nd quietest
Cap value 1.72 uF
results: strobe = dark
moto vibes: much louder/stronger vibe and loudest of the session
Cap value 1.22 uF
results: strobe = dark
motor vibes: strong and comparable to the 1.72 session
Cap value 1.33 uF
results: strobe = dark
motor vibes: comparable to the 1.5uF setting
Cap value 1.43 uF
results: strobe = dark
motor vibes: lowest so far but still noisier than anything I've heard from an E50 in one of these chassis.
Now I'm back to square 1. With the strobe not lighting up, I think there must be something wrong in my wire-up. But I don't see where I've made any errors. Suggestions would be appreciated. My own thought is to try different resistor values at the strobe. At present I'm using the recommended value; 33k ohm. This value is recommended by the TD124 service manual and also in the service bulletin Nr. 22.
Perhaps I wired the strobe (blue wire) to the wrong tag on the commutator...but I can't tell that I did it wrong.
Oh, and there is no evidence to suggest a burnt out neon bulb. This one looks fresh.
Other notes:
Once I have a better functioning wire-up I will make some comparison test record plots of the silent groove track on hfn 001. compared to a TD124 with E50 and this one with the papst. While using the same arm/cartridge/signal chain. Right now I won't need a test record to know that the papst is operating quite a bit noisier than I can tolerate.
-Steve
From the top with platter removed.
From underneath.
Close-up detail on the wire-up at the commutator. The combined cap value in this is 1.43 uF. This was arrived at after trying five different cap values. I listened to each cap value while using a mechanics stethoscope. I did this by placing the probe of the stethoscope at various places on the Td124 chassis while running the motor at full voltage. But with platter removed and the idler tire held away from the driving step pulley / capstan.
I should note that the stethoscope indicates the propagation of motor vibes throughout the chassis and can indicate just where the motor vibes seem to travel to and where it is loudest and where it is softest. Very useful! In this session, and others I've done in the past, it was found that motor vibes were heard clearly on that area of the casting where the tonearm board mounts!
Cap tuning notes:
Cap value 1.5 uF per the service bulletin.
results: strobe = dark (does not light)
motor vibes: 2nd quietest
Cap value 1.72 uF
results: strobe = dark
moto vibes: much louder/stronger vibe and loudest of the session
Cap value 1.22 uF
results: strobe = dark
motor vibes: strong and comparable to the 1.72 session
Cap value 1.33 uF
results: strobe = dark
motor vibes: comparable to the 1.5uF setting
Cap value 1.43 uF
results: strobe = dark
motor vibes: lowest so far but still noisier than anything I've heard from an E50 in one of these chassis.
Now I'm back to square 1. With the strobe not lighting up, I think there must be something wrong in my wire-up. But I don't see where I've made any errors. Suggestions would be appreciated. My own thought is to try different resistor values at the strobe. At present I'm using the recommended value; 33k ohm. This value is recommended by the TD124 service manual and also in the service bulletin Nr. 22.
Perhaps I wired the strobe (blue wire) to the wrong tag on the commutator...but I can't tell that I did it wrong.
Oh, and there is no evidence to suggest a burnt out neon bulb. This one looks fresh.
Other notes:
Once I have a better functioning wire-up I will make some comparison test record plots of the silent groove track on hfn 001. compared to a TD124 with E50 and this one with the papst. While using the same arm/cartridge/signal chain. Right now I won't need a test record to know that the papst is operating quite a bit noisier than I can tolerate.
-Steve
The stock neon lamp requires about 180 - 200V to light, and the E50 when operated on 120V provides the required voltage off of an otherwise unused portion of the winding. The Papst has no such winding, but you could use a small step up transformer or try to locate a lamp that operates on 120V.. (Note you also have a wiring error - the lamp must be connected in parallel with the motor winding connection and this does not appear to be the case.)
thanks. Useful.
re; 120v to the strobe. Based on the way I've got it soldered, I'd surmise that the strobe is not receiving any juice. That tag I have the resistor soldered to must not be alive, presently.
re: wiring error.
Is it the schematic or is it just my wire-up? fwiw, I've had zero training in things electrical. Just figuring it out as I go. (bzzzzzappp!....) So far, no black smoke.
-Steve
Steve have you measured the capacitors on a LCR meter ?
Mine original 0,47 uf measured 0,417 uf !
It is important that the voltages on the coils have a equal voltage , I use a resistor extra for correction .
Have you checked the neon with a resistor on your powergrid ?
The vibration from the Papst is not the same as the E50 , I have my analog 3 phase powersupply almost finished , I made already measurements with the Omron inverter but get more unwanted vibration extra !
Next week I use my single phase turntable supply and try it on 110 Volts- 60hz to see what happens with your setup.
Volken
Mine original 0,47 uf measured 0,417 uf !
It is important that the voltages on the coils have a equal voltage , I use a resistor extra for correction .
Have you checked the neon with a resistor on your powergrid ?
The vibration from the Papst is not the same as the E50 , I have my analog 3 phase powersupply almost finished , I made already measurements with the Omron inverter but get more unwanted vibration extra !
Next week I use my single phase turntable supply and try it on 110 Volts- 60hz to see what happens with your setup.
Volken
Attachments
The schematic is fine, the wiring error is in the way you wired it - the neon resistor is connected to an open tag.
There should be a neon lamp in a bayonet base that operates satisfactorily on 120V, none of mine do, (OEM and European sourced replacements.) Otherwise you could find a neon lamp and socket that works..
One of these days I'll have to get a Papst Außenläufer to experiment with, I've even got a spare E50 in addition to the ones running my two tables. It occurs to me that 3 phase operation should provide the smoothest torque, talking of which reducing voltage slightly may reduce vibration operating in 3 phase mode.
strobe fix
Thanks kevenkr for pointing out my blunder wiring the strobe. I moved the resistor wire to the positive side of AC input.
After soldering and re-soldering 5 times, the wire insulation is starting to melt away from all the heating. Once I get this sorted out, I'll get some new hook-up wire in there and try to make a clean job of it.
Volken
re: cap values. I have a capacitance meter of the hand held and cheaply bought on ebay kind. I did check each individual capacitor prior to use. So far my supply of caps are within at least a single digit of its stated value. And the ones I've bought so far have a (stated) 5% tolerance of variation. When I add them together I should see the sum of these. Or so I think.
re: individual coil voltage. I'll have to figure out how to evaluate each individual motor coil before I can determine which value of resistor to use....and where. This sounds promising. I'll research the subject.
re: voltage control. I'm using a Viz Isotap model WP-26A mains isolator that has adjustable output by means of a step up transformer within it. I use this for all my turntable motor work. I bought it used off of ebay. It wasn't expensive, but probably a life saver at some future date. I'll try operating the motor at different voltage rates while listening.
guys. I really appreciate this input. Already I can see progress I might not have had without it.
-Steve
Thanks kevenkr for pointing out my blunder wiring the strobe. I moved the resistor wire to the positive side of AC input.
After soldering and re-soldering 5 times, the wire insulation is starting to melt away from all the heating. Once I get this sorted out, I'll get some new hook-up wire in there and try to make a clean job of it.
Volken
re: cap values. I have a capacitance meter of the hand held and cheaply bought on ebay kind. I did check each individual capacitor prior to use. So far my supply of caps are within at least a single digit of its stated value. And the ones I've bought so far have a (stated) 5% tolerance of variation. When I add them together I should see the sum of these. Or so I think.
re: individual coil voltage. I'll have to figure out how to evaluate each individual motor coil before I can determine which value of resistor to use....and where. This sounds promising. I'll research the subject.
re: voltage control. I'm using a Viz Isotap model WP-26A mains isolator that has adjustable output by means of a step up transformer within it. I use this for all my turntable motor work. I bought it used off of ebay. It wasn't expensive, but probably a life saver at some future date. I'll try operating the motor at different voltage rates while listening.
guys. I really appreciate this input. Already I can see progress I might not have had without it.
-Steve
Last edited:
Thanks kevenkr for pointing out my blunder wiring the strobe. I moved the resistor wire to the positive side of AC input.
After soldering and re-soldering 5 times, the wire insulation is starting to melt away from all the heating. Once I get this sorted out, I'll get some new hook-up wire in there and try to make a clean job of it.
Volken
re: cap values. I have a capacitance meter of the hand held and cheaply bought on ebay kind. I did check each individual capacitor prior to use. So far my supply of caps are within at least a single digit of its stated value. And the ones I've bought so far have a (stated) 5% tolerance of variation. When I add them together I should see the sum of these. Or so I think.
re: individual coil voltage. I'll have to figure out how to evaluate each individual motor coil before I can determine which value of resistor to use....and where. This sounds promising. I'll research the subject.
re: voltage control. I'm using a Viz Isotap model WP-26A mains isolator that has adjustable output by means of a step up transformer within it. I use this for all my turntable motor work. I bought it used off of ebay. It wasn't expensive, but probably a life saver at some future date. I'll try operating the motor at different voltage rates while listening.
guys. I really appreciate this input. Already I can see progress I might not have had without it.
-Steve
re: voltage input levels and the papst. While in 3 phase operation, (wouldn't that be nice, we think so far), adjustable voltage input seems promising. But just for the heck of it I tried it in the single-phase cap hack configuration we're using now. And that appears to work also. I adjusted voltage output at the isotap down in 5 volt steps while listening via stethoscope. I got as low as 90 volts and the motor appeared to operate normally, but with much lower noise levels. Dramatically lower noise levels!
Hmmmm. This is getting better and better. Might be a good day.
-Steve
But there is a problem. The above experimentation was with the platter removed so I could have access to the drive train while evaluating motor noise. But voltage level also affects motor speed, apparently. I can see this after assembling the platter and observing the strobe while operating the motor unit at different voltages. 90 volts will not bring the unit up to speed, at all. It looks as though I'm back to 115 - 125 volts of operation. At those voltages I can adjust the pitch control into a steady 33-1/3rd rpm.
And a 3 phase power supply sounds better in theory. I'm interested to find out how Volken resolves any current issues with his 3-phase power supply that is still being developed. And the 3-phase inverter that can be bought off the shelf and powered via single phase to operate in true 3-phase a 3-phase motor. More needs to be learned about these.
I suspect we are on the verge of opening up a new level of performance for one of these decks. We just need to learn more.
-Steve
Silent Groove plots
SN 13042 playing its first record...whilst wearing no paint. The silent groove plots are recorded using the same open box plinth standing on the same glass shelf on that rack. Same arm and cartridge. (Zeta / DL-103r std tip in Uwe ebony body)
Here is a side by side of the E50 plot (taken in TD124 sn 2729) and the Papst plot (taken in sn 13943)
There are some notable differences between the two players.
As far as early listening goes, the Papst powered player is sounding far better than it did a few years ago. This time the highs are not obviously rolled off. Mids are nicely articulated and fully present. Lower frequencies seem a tad more forceful. Just one album played; Paul Simon, There Goes Rhymin' Simon. Good sense of presence. Enjoyable.
I've got the IsoTap mains isolator set to deliver 125 volts. That seems to work best in this room/building where mains voltage tends to average 115 vac and with the occasional brown-out.
It's early. I still need to tweak this setup further and explore other options to supply power to the Papst. Will it be a single-phase capacitor hack job like the Thorens company suggested back in 1977, or will it be a true 3-phase power supply? Care to guess? I'll explore all options that I can. And please, suggestions are invited.
Fwiw, I'm kinda digging the bare aluminum look of this chassis.
-Steve
SN 13042 playing its first record...whilst wearing no paint. The silent groove plots are recorded using the same open box plinth standing on the same glass shelf on that rack. Same arm and cartridge. (Zeta / DL-103r std tip in Uwe ebony body)
Here is a side by side of the E50 plot (taken in TD124 sn 2729) and the Papst plot (taken in sn 13943)
There are some notable differences between the two players.
As far as early listening goes, the Papst powered player is sounding far better than it did a few years ago. This time the highs are not obviously rolled off. Mids are nicely articulated and fully present. Lower frequencies seem a tad more forceful. Just one album played; Paul Simon, There Goes Rhymin' Simon. Good sense of presence. Enjoyable.
I've got the IsoTap mains isolator set to deliver 125 volts. That seems to work best in this room/building where mains voltage tends to average 115 vac and with the occasional brown-out.
It's early. I still need to tweak this setup further and explore other options to supply power to the Papst. Will it be a single-phase capacitor hack job like the Thorens company suggested back in 1977, or will it be a true 3-phase power supply? Care to guess? I'll explore all options that I can. And please, suggestions are invited.
Fwiw, I'm kinda digging the bare aluminum look of this chassis.
-Steve
Steve, you might want to try the spring based motor suspension kit from hanze hifi in Holland. I have one I am going to install once I am physically up to doing it.
I think a 3 phase drive would be a worthwhile experiment as this should reduce torque ripple to some extent. Most of the reasonably priced drives have square wave outputs, so I am wondering if some inductors in series with the motor windings might be advisable. (Or maybe a second order RLC filter in series with each winding if this is not likely to kill the output stages in the drive.)
Siemens makes some very reasonably priced drives..
The aluminum colored chassis looks nice, perhaps a clear coat to keep it from oxidizing over time?
I think a 3 phase drive would be a worthwhile experiment as this should reduce torque ripple to some extent. Most of the reasonably priced drives have square wave outputs, so I am wondering if some inductors in series with the motor windings might be advisable. (Or maybe a second order RLC filter in series with each winding if this is not likely to kill the output stages in the drive.)
Siemens makes some very reasonably priced drives..
The aluminum colored chassis looks nice, perhaps a clear coat to keep it from oxidizing over time?
Operational notes, listening notes
Operational notes:
As a preface I should make some operational notes: I'm feeding it a solid 125 volts coming off the Viz Iso-Tap. And in this configuration, with the 1.43 uF cap values, the player is rather slow to get up to speed. Speed is fast enough to begin play after a few minutes, but it does take a full record side before it seems to truly lock in at 33-1/3rd. And from that point it holds steady. That's not what it should be. I can get an E50 motor to perform better in this respect.
There was a service bulletin that came out a couple of years after the Papst replacement motor was introduced. Bulletin Nr. 23. That message was that a number of Papst motors had left the factory with the wrong lube and would be slow to reach speed. The fix was to clean out old lube and install the correct lube to fix the problem. Perhaps that is what I'm dealing with here, or maybe it is something else. At any rate I did put some 20 wt lube into the upper bushing prior to installation. The lower thrust point has a dab of bearing grease put there by yours truly.
Listening notes: 2_17_2014
I spent a few hours listening today. Today's program list:
Brahms: Symphony No. 2, HVK/BPH cat DG138 925
Creedence Clearwater Revival (1st Album) Sundazed Remaster (Stereo)
Donovan: Sunshine Superman , Sundazed Remaster (mono)
The Doors: L.A.Woman (Butterfly Label from the original period
Donovan: Storyteller: MS Music Cat MUS (2) -001 Record 2 at 45 RPM (Steve Hoffman remaster)
Dave Brubeck Quartet: Time Out (Classic Records remaster)
Dave Brubeck Quartet: Newport 1958 Columbia CL1249 (mono)
Brian Auger's Oblivion Express; Straight Ahead RCA APL1-0454
The Doobie Brothers: Toulouse Street , Warner Bros. BS 2634
The Beatles: A Hard Day's Night; Parlophone (early seventies re-issue black label single box)
Regardless of the coming up to speed performance sn 13943 is sounding good enough to spend a day listening to it at length and in depth. Keeping in mind that the cartridge in use, a DL-103R with standard conical tip, but mounted in a Uwe Ebony body, has an identifiable sound that has certain limitations and certain pleasure points. It does not have the most extended upper frequency. It does have a meaty midrange and a solid, clean (but not quite lean) lower frequency. Nor is there any overt characteristic about it. It is hard to go wrong with one of these. And it is less fussy about record condition as well as some alignment adjustments like VTA/SRA, or Azimuth, for that matter. At least it is not as fussy as is a line contact stylus ... like those fitted by SoundSmith on their $250 option. So I made sure to include some rock titles from the sixties and seventies among the list of records played. And this was a nice day for listening.
On the whole this Papst powered TD124 was not at all veiled or obscured by extraneous noise coming from the motor and intruding by putting a blanket over the signal. Not like it had been the first time I tried it around 4 years ago. Rather it seemed to be enhanced when compared (by memory) to an E50 powered TD124 that I normally listen to (sn 2729). Transients were apparently quicker and sharper in initial attack. Whether that transient be a violin, an electric guitar or percolating bongos (Donovan) the beginnings of notes were sudden and palpable. Low frequency authority is increased. As is the visceral force that propels the music. Definitely, this motor unit has me moving my feet to the rhythms of rock records.
On the Brahms, which I listened to at the beginning of the session, I did not really notice anything missing. And I did appreciate tones and textures of massed strings as well as individual players. This is not to say that I heard everything "clearly" on this record. It is, after all, a DG pressing. But I was able to appreciate the performance, enjoy the colors of tone, and take note of the speed at which beginnings of notes did appear. I could use this to play classical records and be happy with it.
On needle drops, and in the blank spaces between tracks I listened for any trace of audible rumble, and heard none. Not even faintly. With the Brubeck records, which get played routinely over here, I was not missing any musical details. Not that I noticed. Cymbals seemed to float and shimmer after the initial sharp attack. Desmond's alto had the full clean airy 'cool' tone I'm used to. Wright's double bass was full with a presence that is felt as much as heard. Deep and with some string slap being apparent. Dave's piano was sounding as present as I've heard while using this cartridge.
The Creedence album. This is the first one from 1968, where on side one the first track is "I Put a Spell on You" originally written and performed by Screamin' Jay Hawkins. When Creedence does it, this is an energetic and full bodied performance. I always enjoy it. And I did this time too. Suzie-Q. Most memorable is the rhythm line that defines the simple repetitive nature of this tune and it seemed sharply present enough and with enough force behind it to move ones feet. Did anyone ever listen to the stupid lyric of it? Toward the end of it there are some Guitar chords which have an amped-up presence. Like the engineer in the recording studio turned up the microphone just for these notes. This you hear no matter what equipment being used, but here, this time, it was really there. Lots of presence.
Donovan Storyteller. This is a Steve Hoffman re-master. The first record is of Donovan's early attempt to become the Scottish Bob Dylan. I did not play from that. I went for the 2nd record in the set which has 4 tracks recorded at 45 rpm. I wanted to hear these to find out if there was anything more present about it. The 4 tracks; Hurdy Gurdy Man, Atlantis, Sunshine Superman, Mellow Yellow are probably Donovan's best regarded singles. They're recorded a bit on the hot side on this record. I was not disappointed. Propelling percolating rhythms. Sudden guitar strikes. Excellent presence. It might be that this cartridge, with this conical stylus is a good way to hear it. Yeah. It had me moving my feet whether I wanted to or not. But I wanted to.
I chose the Brian Auger record to evaluate this player's ability to bring across the driving rhythm of it. No disappointment. There is enough released energy coming out of this record to give the impression of conga drums virtually leaping out of the speakers sudden-like. It still does that.
To sum, I want to say that there is an excellent sense of presence and aliveness coming off sn 13943 with its Papst motor driving it. The motor does have an external rotor with a finned outer shape. You can hear the rotor beating the air from underneath. I only notice this when changing records and even then I have my ear close up and listening just for that noise. It is faint. Nor does this noise come across from within the electronic signal. This is just a bit more noise being heard from outside the player that doesn't really intrude on the listening experience. On this day it seems like this is a promising path to follow. Let's see if it isn't possible to get the motor to come up to speed quicker while operating even smoother. There seems to be promise.
Operational notes:
As a preface I should make some operational notes: I'm feeding it a solid 125 volts coming off the Viz Iso-Tap. And in this configuration, with the 1.43 uF cap values, the player is rather slow to get up to speed. Speed is fast enough to begin play after a few minutes, but it does take a full record side before it seems to truly lock in at 33-1/3rd. And from that point it holds steady. That's not what it should be. I can get an E50 motor to perform better in this respect.
There was a service bulletin that came out a couple of years after the Papst replacement motor was introduced. Bulletin Nr. 23. That message was that a number of Papst motors had left the factory with the wrong lube and would be slow to reach speed. The fix was to clean out old lube and install the correct lube to fix the problem. Perhaps that is what I'm dealing with here, or maybe it is something else. At any rate I did put some 20 wt lube into the upper bushing prior to installation. The lower thrust point has a dab of bearing grease put there by yours truly.
Listening notes: 2_17_2014
I spent a few hours listening today. Today's program list:
Brahms: Symphony No. 2, HVK/BPH cat DG138 925
Creedence Clearwater Revival (1st Album) Sundazed Remaster (Stereo)
Donovan: Sunshine Superman , Sundazed Remaster (mono)
The Doors: L.A.Woman (Butterfly Label from the original period
Donovan: Storyteller: MS Music Cat MUS (2) -001 Record 2 at 45 RPM (Steve Hoffman remaster)
Dave Brubeck Quartet: Time Out (Classic Records remaster)
Dave Brubeck Quartet: Newport 1958 Columbia CL1249 (mono)
Brian Auger's Oblivion Express; Straight Ahead RCA APL1-0454
The Doobie Brothers: Toulouse Street , Warner Bros. BS 2634
The Beatles: A Hard Day's Night; Parlophone (early seventies re-issue black label single box)
Regardless of the coming up to speed performance sn 13943 is sounding good enough to spend a day listening to it at length and in depth. Keeping in mind that the cartridge in use, a DL-103R with standard conical tip, but mounted in a Uwe Ebony body, has an identifiable sound that has certain limitations and certain pleasure points. It does not have the most extended upper frequency. It does have a meaty midrange and a solid, clean (but not quite lean) lower frequency. Nor is there any overt characteristic about it. It is hard to go wrong with one of these. And it is less fussy about record condition as well as some alignment adjustments like VTA/SRA, or Azimuth, for that matter. At least it is not as fussy as is a line contact stylus ... like those fitted by SoundSmith on their $250 option. So I made sure to include some rock titles from the sixties and seventies among the list of records played. And this was a nice day for listening.
On the whole this Papst powered TD124 was not at all veiled or obscured by extraneous noise coming from the motor and intruding by putting a blanket over the signal. Not like it had been the first time I tried it around 4 years ago. Rather it seemed to be enhanced when compared (by memory) to an E50 powered TD124 that I normally listen to (sn 2729). Transients were apparently quicker and sharper in initial attack. Whether that transient be a violin, an electric guitar or percolating bongos (Donovan) the beginnings of notes were sudden and palpable. Low frequency authority is increased. As is the visceral force that propels the music. Definitely, this motor unit has me moving my feet to the rhythms of rock records.
On the Brahms, which I listened to at the beginning of the session, I did not really notice anything missing. And I did appreciate tones and textures of massed strings as well as individual players. This is not to say that I heard everything "clearly" on this record. It is, after all, a DG pressing. But I was able to appreciate the performance, enjoy the colors of tone, and take note of the speed at which beginnings of notes did appear. I could use this to play classical records and be happy with it.
On needle drops, and in the blank spaces between tracks I listened for any trace of audible rumble, and heard none. Not even faintly. With the Brubeck records, which get played routinely over here, I was not missing any musical details. Not that I noticed. Cymbals seemed to float and shimmer after the initial sharp attack. Desmond's alto had the full clean airy 'cool' tone I'm used to. Wright's double bass was full with a presence that is felt as much as heard. Deep and with some string slap being apparent. Dave's piano was sounding as present as I've heard while using this cartridge.
The Creedence album. This is the first one from 1968, where on side one the first track is "I Put a Spell on You" originally written and performed by Screamin' Jay Hawkins. When Creedence does it, this is an energetic and full bodied performance. I always enjoy it. And I did this time too. Suzie-Q. Most memorable is the rhythm line that defines the simple repetitive nature of this tune and it seemed sharply present enough and with enough force behind it to move ones feet. Did anyone ever listen to the stupid lyric of it? Toward the end of it there are some Guitar chords which have an amped-up presence. Like the engineer in the recording studio turned up the microphone just for these notes. This you hear no matter what equipment being used, but here, this time, it was really there. Lots of presence.
Donovan Storyteller. This is a Steve Hoffman re-master. The first record is of Donovan's early attempt to become the Scottish Bob Dylan. I did not play from that. I went for the 2nd record in the set which has 4 tracks recorded at 45 rpm. I wanted to hear these to find out if there was anything more present about it. The 4 tracks; Hurdy Gurdy Man, Atlantis, Sunshine Superman, Mellow Yellow are probably Donovan's best regarded singles. They're recorded a bit on the hot side on this record. I was not disappointed. Propelling percolating rhythms. Sudden guitar strikes. Excellent presence. It might be that this cartridge, with this conical stylus is a good way to hear it. Yeah. It had me moving my feet whether I wanted to or not. But I wanted to.
I chose the Brian Auger record to evaluate this player's ability to bring across the driving rhythm of it. No disappointment. There is enough released energy coming out of this record to give the impression of conga drums virtually leaping out of the speakers sudden-like. It still does that.
To sum, I want to say that there is an excellent sense of presence and aliveness coming off sn 13943 with its Papst motor driving it. The motor does have an external rotor with a finned outer shape. You can hear the rotor beating the air from underneath. I only notice this when changing records and even then I have my ear close up and listening just for that noise. It is faint. Nor does this noise come across from within the electronic signal. This is just a bit more noise being heard from outside the player that doesn't really intrude on the listening experience. On this day it seems like this is a promising path to follow. Let's see if it isn't possible to get the motor to come up to speed quicker while operating even smoother. There seems to be promise.
I'm looking at the Hanze Hi-fi spring kit. I think I can reproduce it from off-the-shelf springs to be found at McMaster-Carr and I'll custom make some fitted washers to locate each spring. I hope Volken doesn't mind. But I know where I can get the parts fairly cheap. 😀 (fwiw I don't plan to sell any kits. Hanze Hi-Fi can do that. I'll just make what I can for myself.)
Now I'm kind of waiting to hear how Volken's experience goes with the 3-phase PS he's working on. I have no illusions about being able to cobble up my own circuitry on something as complex as a power supply. Not my comfort zone. I'll take a back seat and see what is possible for me to emulate. Siemen's inverters seem like a possibility but I'll need guidance if something more than a simple wire-up is required to get that working.
re: bare metal. Yeah. oxidation. It happens to aluminum. One possibility is that I can use a green scuff pad to keep it shiny on a periodic basis. But it would be better to seal off the surface some how. a coating of something. Or even plating.....
this is kind of fun.
-Steve
Ps: Kevenkr, get well soon. 🙂
Above photos display the Papst disassembled. What there is of it.
I had been dealing with really slow start-up times with the papst. And that was after I had done some capacitor tuning which resulted in a slightly lesser cap value that was recommended by Thorens. Fwiw, I had used the recommended resistor value at the neon strobe bulb.
After observing this while listening to the unit for a day, I decided to try two things.
1) The first was to clean and lube the motor. I had done this previously something like 5 years ago, but the motor had been stored in its box for those years and possibly might benefit from another clean/lube.
2) The second was to change the resistor value at the neon strobe bulb just to see if this altered performance in any way. And it did.
Getting back to the clean/lube at the motor, it did spin far easier after I gave it some fresh lube. I used 20 wt turbine oil in the bushing bore and a small dab of bearing grease at the thrust point. And, just for the heck of it, I put in a small drop of the same 20 wt lube there as well. After reassembly I could finger spin the motor and observe that it held the spin something like 4 times longer than before. With that much done, and the motor still wired to the chassis, I powered it up to see if this changed its behavior. But.....not really. It was still very slow to reach terminal speed on a cold start.
Getting to the the resistor value change. It occurred to me that green wire going to the motor, the resistor wire going to the neon strobe bulb, and the postive input from AC mains are all tied to the same tag on the Thorens voltage commutator board. Does this resistor alter voltage level not only going to the strobe bulb but also the motor?
I'm sure many of you guys can explain why it does. But for me I thought I'd simply try a different resistor value, a lesser value and then observe the strobe while powering the motor. I chose to go with roughly 1/2 of the recommended value. I soldered in a 15Kohm resistor to replace the 33kohm resistor. Actually, I replaced that entire wire (coded red) that goes out to the neon bulb.
Result: At a cold start I observe 3 minutes while the motor continues to get up to speed. By the end of those 3 minutes it does appear to lock onto 33-1/3rpm. So says the strobe. This is a significant improvement over what I'd been getting with the 33Kohm resistor. With that one it really took a full record side before rpm appeared to stabilize. So there was an improvement by making this one change. And I should note that apparent brightness of the lit strobe bulb did not change. Not so that I would notice.
Fwiw, I've already mentioned this previously, but I should mention it again, I'm using a couple of Viz IsoTap isolated power supplies. One to feed power to the turntable at the audio rack. The other I keep at my soldering station to protect me from mains voltage. Both of these units allow me to adjust voltage output from zero up to 150 vac. And it does this while operating off the mains coming into my building, which seems to deliver ~ 115. Presently I'm powering the Thorens at 125 V. If I chose a lower value, motor rpm would slow, if higher motor rpm would increase proportionally.
To sum;
This is still obviously a work in progress. Performance level isn't where I can accept it. Start-up is too slow. Heck, I can get an E50 to come up to speed in 10-15 seconds (in summer).
I suppose I could do some more cap tuning to see if any of the previously tried cap values, which resulted in noisier operation, will offer faster start-ups.
Otherwise, the turntable is sounding quite good right now and does hold a steady rpm throughout the day while I spin records.
So it goes.
-Steve
The resistor is there only to limit current to the neon lamp, if wired correctly it and the neon appear in parallel with the motor winding and AC mains, no motor current flows through it. It now appears correctly wired to me.
The cleaning and lube seem highly advisable after all this motor is probably 35+ years old. I believe this accounts entirely for the performance improvement you have observed.
I was a bit surprised at the design of the thrust bearing assembly - looks to me like there is considerable room for improvement. I can't imagine it is as quiet as it could be. The bushing in the stator assembly provides the only centering and the bottom of the motor is essentially floating. I assume the external rotor assembly is very carefully balanced otherwise I expect wobble rather than just vibration. On reflection I suspect it would be hard to modify that thrust bearing..
The cleaning and lube seem highly advisable after all this motor is probably 35+ years old. I believe this accounts entirely for the performance improvement you have observed.
I was a bit surprised at the design of the thrust bearing assembly - looks to me like there is considerable room for improvement. I can't imagine it is as quiet as it could be. The bushing in the stator assembly provides the only centering and the bottom of the motor is essentially floating. I assume the external rotor assembly is very carefully balanced otherwise I expect wobble rather than just vibration. On reflection I suspect it would be hard to modify that thrust bearing..