A Papst in a Thorens?
The story goes something like this:
In 1977, ten years after the TD124 had been discontinued, Thorens management worried that it could no longer supply new replacement motors for their once top-of-the-line player. The solution turned out to be the subject of this article. Thorens contracted with Papst to adapt one of their "Aussenlaufer" motors to function in the TD124.
Above photo: A 60 hz version of the Papst Aussenlaufer motor designated by Thorens for use in the TD124. It stands on chassis sn # 13943, which has been chemically stripped of its paint in preparation for a complete restoration.
About the Papst:
Thorens Service Bulletin Nr. 22, October 1977
(roughly)Translated into English:
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)
1.43 uF capacitance. This detail photo shows a combination of capacitors that add up to 1.43 uF. This value proved to be the quietest running in this test session. Quietest, but not really "quiet". But there is a problem with the wire-up. In this photo I have the resistor wire going to the strobe bulb soldered to the same tag as it would with the E50 installed. But the strobe bulb will not light up this way.
This is the first test session.
Results: Quietest motor operation was with a cap value of 1.43. This was determined using a mechanics stethoscope to listen at various points on the td124 chassis while the motor was in operation. I should note that when probe was placed in the armboard mount area, motor noise was as audible here as anywhere else on the chassis.
Strobe: remained dark and showed no indication of wanting to light up. Bulb looks ok (not burnt) . this part duplicates my earlier experience while using the service bulletin nr.22 a couple of years back. I'll explore more on this to see if alternate resistor values may make a difference...or if a different wire-up is needed.
Strobe fix: 2_16_2014
moved resistor wire to the tag receiving positive voltage. Previously, the resistor wire was soldered to the tag that is to be used when the E50 is installed. The strobe works this way with the E50 and not with the Papst because of a difference in coil windings between the two very different motors.
Regardless of what the plots say, early listening to one Paul Simon record (There Goes Rhymin' Simon) went well with the Papst powered sn 13943. Good energetic thrust. Nice deep bass. High frequencies were not overtly rolled off. Nice ambience. sparkly atmospherics as they should be on this record.
More to come. The silent groove plot suggests there is work to be done.
As a preface I should make some operational notes: In this configuration 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:
In this configuration 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 at all 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.
Transients were (possibly) quicker and (maybe) sharper in initial attack. (compared to E50 power) Whether that transient be a violin, an electric guitar or percolating bongos (Donovan) the beginnings of notes were sudden and palpable in the way that I'd expect a TD124 reproduce these. 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.
On needle drops, and in the blank spaces between tracks I listened for any trace of audible rumble. And I 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. Eugene 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.
Looking at the Papst close up.
These pieces appear to be in good order. The bushing bore was wiped clean with rolled up paper towel pushed through like cleaning a gun barrel, then followed up by Q-tip which came out clean. After minor cleaning with a lint free cloth, 20 wt lube was applied to the rotor shaft, liberally. A small dab of automotive bearing grease was applied to the center of the thrust pad and a drop of 20 wt lube for good measure. The motor was re-assembled and then displayed greater spin-down times.