I used a company called Wilkinsons in Lancashire England for my tt101. They have a JVC museum as it happens
Victor TT 101 vs TT 81
I am aware of some of the differences regarding the motors of these two units, but I was wondering if anyone had insights as to the differences in sound (if any) and the differences in reliability (I'm guessing the 81 being simpler might be more reliable, however, it seems to have the better motor). Any info will be appreciated.
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Hi, best groove It was a cut caused by a scrape that was under the solder mask, so a manufacturing issue. Nearly the entire trace was cut, except one small corner at the edge of the solder filet, which cracked right at the very corner causing the intermittent connection. The MN6042 is used in every Technics table that has digital pitch control. You are correct - not the SP-10 MKII. |
@lewm the situation went well for your TT101, the break of the pcb is deduced from what was caused? Old age, bad manipulation or something else? If I’m non wrong I read something of the chip developed by JP for the Technics but if I remember correctly it was for the MK3 much more complicated than the MK2 .... I remember well? |
After this thread died a natural death, I found JP Jones via this forum and via DIYAudio, as well. JP gained fame among DD-philes by deconstructing the single chip that makes Technics SP turntables run properly and without which they don't run at all. The chip is no longer available from any source, so JP is a life-saver of sorts. JP's chip is constructed from discrete parts on a small PCB that is no larger than the original chip when it is mounted on its PCB. What's more, JP's chip is a tad more accurate than the original in controlling speed. Anyway, I contacted JP, and he fixed my TT101, nearly two years ago. It's been running fine ever since. I was not wrong in my hypothesis, sort of. JP found a hairline crack in one of the PCBs in the TT101. A line of solder covers the crack such that when the board was flexed it caused a short circuit that was nearly impossible to see or detect, unless you knew where to look, which JP did. JP can be found on-line at Fidelis Analog, but alas he is apparently very busy these days. Still, you could contact him and ask. |
I used the Classic Direct base I do not know what it is? A company, a product or what? Do you have a link for me? I have thoughts of taking it back to Bill, now that the problem is sure to occur in his hands. He is a superb guy in all ways. However, I thought perhaps you may have a guy who is steeped in servo technology who might provide some insight. did you solve the turntable problem with Bill Thallman? |
Hi rgs, In the Vintage DD Thread, there are some Posts by HiHo https://forum.audiogon.com/discussions/vintage-dd-turntables-are-we-living-dangerously?page=12 who is very knowledgeable about all the Victor models made only for the Japanese market, and we discussed the QL66F among others. You started this Thread asking about the ’sonic’ differences between the TT-81 and TT-101. To me, there appears to be none. If, as it appears now....you are wedded to a Victor coreless motor.....that’s another kettle of fish altogether and I would strongly recommend that you wait for a good TT-101 to come along. Good luck...👍😎 |
Hi Halcro, Thanks for all the links you have provided. Although I had read them in the past, it was good to revisit. I was surfing the Vinyl Engine JVC turntable section and I came across the QL 66F. One of the threads you directed me to references your experience with a lower QL version (A5??), and how it impressed you. It appears the 66F was one of the last higher end tt JVC made. I don't care for its automatic controls, but it seems its motor borrows much the TT 101's tech, even more than the TT 81 did. The 66F also uses a coreless motor and servo controls. Have you ever had a chance to examine one? Reading a couple of threads on the net suggest that it benefits from a lot damping of the plinth. Considering it probably does not sell for much on the used market, I wonder how difficult it would be to remove its motor and motor electronics to use elsewhere. |
Dear HWS, Bill Thalmann's shop is about 20 minutes from me, and Bill has worked on my TT101, twice. Bill has also worked (successfully) on several of my other DD turntables and on one of my Beveridge direct-drive amplifiers. But when my TT101 was in Bill's shop (last year), the problem was intermittent, and the unit worked fine, for 2 weeks, on Bill's workbench. We could not make it fail over there. In my house, it was working OK much of the time but would occasionally malfunction in a way I will describe. In search of a cause, we (Bill and I) surmised that there was a bad solder joint somewhere. (This is after Bill had already replaced every electrolytic except one and also re-soldered many of the joints.) At that point, Bill was understandably rather tired of fooling with it. I am a fairly decent DIYer myself, but not with ICs and not so experienced with any sort of solid state gear. However, in my spare time and because I have other tt's to use, I went in there looking for possible bad connections. I suspected that there may be a cracked wire going into one of the many beige-colored multi-prong connectors that connect different PCBs to each other. Two in particular on the board that is tucked up under the top escutcheon, housing the servo mechanisms, seemed loose. So I cut off the beige connectors and hard-soldered those wires to the prongs. (Both are 4-prong connections.) Along the way, I also replaced the one electrolytic that Bill missed doing earlier; it sits alone in that servo board up under the top piece. The result of my labors was to make an intermittent problem into a permanent one! Here is the failure mode: The tt comes up to speed based on the tach reading "33.33", but very shortly thereafter, within less than a minute, you will see readings suggesting the speed is off, 33.32 then 33.34, etc, typically. At that point, the motor shudders significantly and shuts itself down; the platter coasts to a stop with no brake action. The tach goes blank, except for the decimal point. That's the story. This is what it used to do only intermittently. I must say though that I had not detected the motor shudder symptom earlier, but that may have been because the tt was then bolted into a sturdy and heavy plinth. To work on it on my bench, I built a lightweight jig which enables me to flip it upside down easily without risk of damage to the innards. The jig is supported only by 3 metal threaded rods, which is probably why the motor can shake the whole assembly. The bearing is dead silent throughout all this failure mode. There is no rubbing sound or other friction noises. My hypothesis is that the servo is failing in one of the two directions such that the correction mechanisms are fighting each other; that's how I explain the motor shudder prior to shutdown. I have thoughts of taking it back to Bill, now that the problem is sure to occur in his hands. He is a superb guy in all ways. However, I thought perhaps you may have a guy who is steeped in servo technology who might provide some insight. |
I am blown away by the amount of interest in these Victor motors. When they were selling them everyone wanted the Technics, or the Kenwood, or the Micro three arm, etc. One hearing and I knew these were special but stopped using it decades ago probably due to the really bad base and arm arrangement. I have never had to fix mine but I will tell you it does act up if you don't use it. When I took it out to mount in the new base it took almost all day for it to figure out how to run right and that was with me coaxing it along!! I've mechanically worked on it, changed the thrust disc, lubed and polished the shaft, etc. but have not had to do anything electrical to it yet. Someone mentioned Bill Thallman and while I don't know if he has ever worked on a TT-101 he is an electronics wiz-bang and I would trust him with mine. I have guys at the factory and I know a few engineers with the patience for this work but they are not experts on this item. HW |
VintageKnob is often an unreliable source. You can download the Service Manuals for both TT-81 and TT-101 units from Vinyl Engine http://www.vinylengine.com/library/jvc/tt-81.shtml http://www.vinylengine.com/library/jvc/tt-101.shtml which disclose that the 101 is coreless but not the 81. They BOTH however, share the bi-directional servo control (a Victor patent) which IMHO is one of the secrets to their exceptional performance. |
According to the specs at Vintageknob, it is Coreless, but with substantially less slots (24 vs 180) TT 101 http://www.thevintageknob.org/jvc-TT-101.html TT 81 http://www.thevintageknob.org/jvc-TT-81.html |
Henry, et al. I thought you told us long ago that the motor of the TT81, while it may or may not be absolutely identical to that of the TT101, is also coreless. (I made a claim that it was not, which prompted you or someone else to post a brochure on the TT81 that seemed indeed to say it had a coreless motor.) In your initial post on this thread, I am unsure what you are saying vis a vis the TT81, coreless or not coreless? I do tend to like coreless motors, too, based on the performance of my L07D, as compared to my other DD turntables using multi-pole motors. Heretofore, I thought the major difference between the two is that the TT101 has a
bi-directional servo, can correct speed if either too fast or too slow,
whereas the TT81 servo is only reading "too slow". A question, if not a plea, to HWS: Have you got "a guy" who can work on my TT101? I'd love to get it up and running, and I have a pretty good idea where the problem lies, just not the knowledge to identify it specifically and fix it. So far as I know, it does not need a new master chip, but I do have a few spares of those, if that were to be the case. Like Halcro says, I gave a spare chip to another frustrated TT101 owner in Germany, still waiting for his results. |
hwsworkshop well my ears tell me it means a quite a bit .... :^) @hwsworkshop Have you ever heard one of your tonearms in this fashion ? https://www.youtube.com/watch?v=HSZSzxnN1mg some fun many years ago now... |
I always use a solid base because I like to be able to lock the tonearm to the chassis the motor is in, that's me and probably means nothing. Besides, I new I was using my 12" 3D arm so it became a moot point to have arm changing capabilities, I just swap armtubes. If I new how to post a picture I would do it, it really looks great. HW |
Halcro, besides the aesthetics, was there any value in removing the "base" from the turntable? BTW, I like the design of your arm pillars. Any reason you decided to go with your own design as opposed to using the steel column "legs with spikes" sometimes seen in Japanese auctions sites?I didn't get a base with either of my Victors rgs.....just the motor units. And I wanted the freedom of mounting ANY arm of ANY length and ANY design.....so I think separate arm-pods are the best way to achieve this. I looked into buying existing arm-pods but their weight, height, design and cost were all inappropriate (most vintage arms have their wiring exiting their bases whilst most modern arms have their wiring exiting from above). There are also arms with VTA adjustment devices which need to be accommodated under their arms so I designed my solid bronze pods to accomodate all the vintage and modern arms I could know about. http://i.imgur.com/e3JxLkl.jpg http://i.imgur.com/WU5k38M.jpg |
Are there any parts you think are particularly important to acquire as spares?I think for both the TT-81 and TT-101, every part (including chips) is available (just Google the part No.). There is just one special power chip which is scarce and Lewm has snaffled up a bag-load of these, one of which he has kindly sent to Thuchan who needs it to complete his rebuild of a TT-101 I found him. Will be interesting to see if he ever gets it going...👅 |
Thanks for the info Halcro and HW. Halcro, to be honest, I have a bias towards coreless design (interesting you find it difficult to differentiate from the two...food for thought), but was concerned about the complexity of the 101 (more things that could go wrong). Reading from your prior posts, I realize the importance of changing the caps and re-soldering the old solder joints (specially when troubles surface regarding the latter). Are there any parts you think are particularly important to acquire as spares? HW, that is a very positive recommendation from you and the custom base is quite interesting. Did you try it nude with metal pillars/feet? If yes, was there any advantage or disadvantage to using your custom base? |
This is the motor unit and electronics of the TT-101 http://i.imgur.com/T1gijMr.jpg and this is the corresponding unit of the TT-81 http://i.imgur.com/fsVuGYu.jpg If you are aware of some of the slight differences in specs between them, I think the main practical differences are the 'coreless' motor of the TT-101 and its complex ability to adjust pitch in 1Hz increments. I have both units http://i.imgur.com/Xp97BF8.jpg http://i.imgur.com/2zjzhtS.jpg and cannot honestly say that I can hear the differences in sound. For the ease of repair and ownership....I would recommend to anyone contemplating buying, to find a good TT-81. You won't be disappointed. Here are two A'Gon Threads that you may find interesting.... https://forum.audiogon.com/discussions/vintage-dd-turntables-are-we-living-dangerously https://forum.audiogon.com/discussions/nude-turntable-project |