Vintage DD turntables. Are we living dangerously?

I think the chip was made by NPC, which stands for "Nippon something something".  I will check the label when I am able to get to it.  It is indeed a good idea to specify the maker when ordering, so as to be sure there is no confusion, even though there should be one and only one chip configured like the SC3042. (This is from memory, but I think correct. However, I could be thinking of the designation for the Denon DP80 chip, a more rare bird.) Whether that designation can optionally have an "A" after it, I do not recall.  My experience has been that several of the vendors that offered to sell me this chip have never ceased to email me to ask whether I want more of them or to try to sell me something else in the realm of solid state parts.  I probably get at least an email per week.  At the time, I just picked the seller who seemed to have the best grasp of the English language.

Henry, it's a 16-pin rectangle with 8 pins per long side.  You'd need a special soldering iron to de-install the old one and install a new one, or great skill with a conventional soldering iron.

Totem, Thank you for alerting us to the thread related to SP10 Mk3 speed regulation.  I've digested it thoroughly.  What I don't get is whether the guy who figured this out and went to the trouble of creating a PCB, on which to mount his circuit that replaces the single chip that "runs" a Mk3, is selling or is going to sell the PCBs along with instructions on how to stuff the board.  I would be interested for sure, as the owner of an SP10 Mk3 that I bought NOS and which works perfectly as is.  One cannot be too vigilant about potential maintenance needs. Plus he seems to infer that his circuit is actually more accurate than the original chip, although I don't know whether one needs to worry about a few Hz when the frequencies in question are in the millions of Hz.

By the way, a dirty little secret of SP10 Mk3 world is that the very same chip was used inside an SL1500 or SL1600 turntable, either of which is usually available for a few hundred bucks.  I know some guys who have stockpiled a few of those so to be able to repair their Mk3's.

rw, Thank you for doing the legwork to unearth the fact that it is the SL1300, and perhaps not the SL1500 or SL1600, that utilizes the MN6042 chip also necessary in an SP10 Mk3.  Sorry for my alphanumeric error.  I was going on second-hand info received from a fellow Mk3 enthusiast.

Totem, Please do keep us posted.  I am a buyer.

I am also thinking hard about sending my Victor TT101 to Germany so that Thuchan's guy can fix it, once and for all.  I got an email from Thuchan today; he is thrilled with the sound of his TT101.  This is a guy who owns some of the most expensive turntables in the world, so I take his praise for the TT101 very seriously.

Dear JP, Congratulations on your perseverance and genius in pursuing the Mk3 "problem" to its potential solution.  Now that you're here, and pursuant to Dover's lament and criticisms, did you mean to infer that the apparently increased accuracy of your circuit vs that of the MN6042 would confer a meaningful, not to say audible, improvement in the performance of the Mk3?  That would be really something to behold.  Like I may have said above, in reading your posts on Audiokarma, I was not sure that the few Hz by which your circuit "beats" the MN6042 in accuracy would necessarily translate to performance.  But this is also because I may have a misconception about the true meaning of those data points you posted.  Can you comment further?

Also, I will be contacting you privately about purchasing one of your boards.  Thanks again for your work.

Dear Dover,  To ask a question or to wonder is not to "trivialize".  The basis for learning is questions and answers. That's about all I can say to you that is not vitriolic.  I would hope that JP appreciates the fact that my earlier post meant him no disrespect at all.  In fact, I am rather amazed at his work, since failure of the MN6042 has been the downfall of many Mk3s.

Dear JP, I now see that you did in fact respond to my question about the accuracy of your circuit vs that of the MN6042.  Sometimes these threads move too rapidly for me to be current. I did wonder whether 262.XXX kHz was the operative number or whether it was the much higher frequency that gets divided to yield 262.XXX kHz.  Now I know it is the latter, which enhances the significance of the difference between your circuit and that of the MN6042.  What's additionally appealing about your circuit is the fact that if it ever should fail, it's fixable with parts that are readily available.

Totem and JP, As you also may be able to glean from reading Halcro's and my recent posts, a few years ago I was able to find and buy about 10 samples of the SC3042.  In the last few weeks, I sent two of them to a fellow aficionado in Germany, known to us as "Thuchan".  Thuchan had evidently purchased a broken TT101 with Halcro's help, and his tech determined that it needed replacement of SC3042.  Until this recent episode, I had no idea whether the chips I bought (from a vendor in Hong Kong) were genuine or even in operating condition, but Thuchan's tech got his TT101 up and running perfectly by virture of installing the chip I sent.  This is great news for me as well, because I have more SC3042 chips on hand. (By the way, I think they are still available from China and Hong Kong.)

My own TT101 has been "broken" too, since purchase about 3-4 years ago.  For that reason, I got it at a low price, approximately the value of the tonearm that came with it.  I happen to live very close to Bill Thalmann's shop in terms of highway driving, and Bill early on replaced all the electrolytics in my unit.  However, in Bill's shop, once the lytics were replaced, the TT101 refused to misbehave.  It worked perfectly on each of two visits to the shop.  In my house, it worked only intermittently, and every time I began to feel confident about it, it would go "on the fritz".  I tried all sorts of black magic to no permanent avail.  Then I started to try to trouble-shoot it myself. Suffice to say that in the process of trying to fix it, I converted the intermittent problem to a permanent and consistent problem.  Also, I am pretty sure at least that the problem is local to the PCB that contains the SC3042, although I lack the expertise to prove it's the SC3042.  (There's more than one chip on that board, and the others are not SC3042s.) However, Thuchan's tech tells us that his unit was misbehaving in a way similar to mine, so now I have hope that replacing the SC3042 may finally fix it.  How's that for a saga?

Bill worked on my SP10 Mk3 and on my Denon DP80. He's a great guy, and we are lucky to have him. Now that my TT101 is reliably malfunctioning, I hope to take it back to him for the 3rd time to finally trouble-shoot it. Either that or I may send it to Thuchan's tech in Germany, if the postage is not prohibitive in cost.

JP, Are you in the DMV area?  I'm watching snow accumulate on my car outside.

I do think there would be interest in an SC3042 PCB re-creation, certainly on my part and especially if the discrete circuit can outperform the chip.

PBN, FYI, you're looking at a coreless motor.  They are built quite differently from the iron core motors used in both Denon and Technics DD turntables, in that you see no iron poles wrapped in coils of wire and in that iron core DD motors tend to be oriented vertically, shaped like a cylinder, whereas the TT101 motor and other coreless turntable motors are oriented in the horizontal plane.  Further,  "pound for pound", iron core motors will tend to have more torque than will coreless motors.  Plus, the latter have more issues related to cooling.  All that said, and given that you may know all of the above, IMO, coreless motors impart a certain effortless and very musical quality that is rather addictive. Of course, my opinion is based on the Kenwood L07D sound, since I have yet to hear my TT101.  Whatever one may say about the Krebs mod, data or no data to support it, to my ear the Krebs mod makes the SP10 Mk3 sound more like the world's best coreless-motor-driven tt than like the world's most powerful iron-core-motor dd tt (which it also is).  (I've got a DP80, too.  I kept it over the SP10 Mk2, because I thought it sounded better.)

Isn't this stuff best posted on the "other" thread, sometimes known as "the thread" on MM cartridges?  Just sayin'...

Harold, Have you had a listen to that rig yet?  Seems like a great combination.

One of us (in the US) has to buy a Pioneer Exclusive P3.  That's the only one missing from our collective ownership. (I know that a few Aussies, like Downunder, have got them.)  God knows what surprises may be in store in terms of how a P3 can malfunction, and there is no service back-up at all outside of Japan.  That's "living dangerously" for sure. Up to at least a few years ago, Pioneer would and could service them inside Japan.

I just ordered my replacement feaux MN6042 from JP.  Since my Mk3 is working perfectly, Bill Thalmann advised me to just keep it for a spare, but it's tempting to wonder whether the Mk3 could perform even better with JP's PCB replacing the stock MN6042.

RW, Isn't that a sort of oxymoron: "lifetime warranty if you could get it to Japan"?  I knew a guy who lived in Tokyo and owned two P3s, but he would hand carry his P3 to the service center and pick it up after work was done.  I am not aware that they would be willing to accept shipments from other parts of the world, and then be responsible to pack and ship in return.  (On the other hand, I don't know that they wouldn't do that, either.) The fellow in question has since moved to Hong Kong and curtailed his vintage buying habits. (He had two Denon M100s, too. (Not sure that's the correct alphanumeric designation, but I refer to the BIG Denon.)

Thanks, JP, for your comment.  I guess the question is whether the superior performance of your chip would be audible, compared to the OEM MN6042 in my MK3.  I doubt we can ever know that, if the difference would be subtle, as I imagine it would be. Because one's aural memory is not trustworthy in matters such as this, where my Mk3 would be out of use for weeks until Bill would find time to make the change.  On the other hand, this means I need two of your PCBs, one to install now and one for that rainy day.

Another, perhaps lesser bit of news, but this time good:  My Victor TT101 is most likely fixed! I won't have it back in my house for 1 or 2 more weeks, but since I've waited to hear it for more than 2 years since I bought it, I can be patient a little longer. (I'd have to check back in this thread to figure out when I actually bought it; it's been that long a time.)

May a lotus bloom in your underwear, oh revered one.
None other than JP of Technics chip fame.

JP did a lot of work on my TT101.  We're still debugging it, or I should say that HE is still debugging it.  More anon.

Thanks for the offer, Peter.  I sent you a PM.  Just as an aside, isn't silver oxide a perfectly good conductor, which is partly why to use silver?  I know when Bill Thalmann worked on my DP80, he replaced all the OEM transistors with new ones, on the premise that the OEM ones with which he is familiar are prone to failure (although I don't think any of them had actually failed in my DP80).  I wouldn't be surprised if the transistors in the TT101 were of the same provenance as those in the DP80.

ps68, You've independently hit upon exactly the reason I went off on a craze over these vintage dd turntables.  In the end, the better ones are the best bang for the buck.  Plus, the drive and rhythm that they can impart to music are addictive and unique.  The best idler-drive turntables are of a similar flavor.

To all: The problem with my TT101 seems at the moment only to have been a tiny crack in the main PCB, right near the edge. JP thinks it occurred during manufacture, 30-odd years ago.  The circuit was only maintained by solder, and once the solder cracked (invisibly, I might add), the result was a fault in TT101 function that was manifested intermittently, depending upon stress on that PCB.  There was no need to replace the SC3042 chip in mine or indeed any of the discrete transistors.  Great work by JP to find this problem, only made possible by the fact that the thing finally malfunctioned in the presence of a smart guy who knew how to trace down the cause.  Other such problems are being searched for, just as a precaution before I get it back. I hope this is not premature, but I am very pleased.

PBN, Was reading your instructions to Aigenga with interest, since I think I may have a go at cleaning and lubricated the bearing in my unit, once I get it back.  Seems to me that loosening the plug, which I assume means turning it counter-clockwise, would have the effect of lowering the bearing/spindle/platter such that the outer edge of the platter might ultimately rub against the escutcheon that surrounds the upper level circuitry and the tachometer and switches.  "Tightening" the plug, which would make it move upward into the chassis, would seem to me to be the way to relieve that condition.  This, I think, is the opposite of what you wrote.  However, since you may have worked this out with your TT101 right in front of you, I am thinking that maybe I do not understand the anatomy of the TT101.  Please by all means correct me if I am wrong in my concept of the relationships among these structural elements.
Thanks.

Dear Peter,
Forgot about the rotor, which would be a fixed to the bearing/spindle assembly.  Thanks.  My Kewood L07D is built like that as well, perhaps this is common to all coreless motors that more or less copies of the original Dual coreless motor.  

JP is satisfied that my unit is ready to be returned to me, on Monday.

Golly; I was really typing fast.  Should be "affixed", not "a fixed".  Should also be "Kenwood", not Kewood.

Aigenga, Vibrations and EMI can come from the power transformer more than anything else.  It would not be much of a trick to re-mount it outside the chassis on a separate base.  And you might be able to do it with the rectifiers and filter capacitors that together with the transformer constitute the power supply. However, I would be very leery of moving those servo and motor control circuit boards off-chassis.  Peter already told me privately that he sees this as a bit of a problem with the TT101, whereas you may know that he did do it successfully for the DP80 in the context of his aftermarket plinth.  I too will be interested in his take on moving the circuitry off-chassis, once he solves the problems with his unit.

Note: "Made in Western Germany".  So that step-down transformer is at least 25 years old.  Not that there's anything wrong with that.  But this is to say that I don't think it's fair to dismiss ANYTHING made in China as "crap".  I've got two 117V to 100V step-downs made in China, both from the same source and of the same type, that are nicely made and have held up for more than 5 years each.  They don't vibrate or heat up during constant use.  The best bet is to make sure the step-down or -up is over-rated for the power demand.  As long as that's the case, you should be oK.

Ironically, there was once a time in the post-WW2 USA when Japanese-made products were looked down upon in much the same way as many of us now view Chinese manufacturing. 

Just for semantic reasons, I should have written "EVERYTHING", instead of "ANYTHING", in my comment above.  Of course, any one thing made in China could be "crap", but not everything is.

My experience agrees with JP's.  The OEM mat(s) on my Mk2A and Mk3 were identical, although I don't know the part number.

Peter, I thought I noticed that not one but several other ICs appeared to be used in the TT101. However, all seemed to be of the same type, based on cursory examination.  Is this the one you've now got?  How many would hypothetically be needed to re-do an entire TT101 circuit, assuming that one would need several of one kind?  Thanks.

Banquo, If you hear differences in the sound of your analog based on the brand and source of your step-down transformer, THAT would be worth reporting here, provided that the inferior sounding step-down was not in any way malfunctioning. Come to think of it, I am not sure that my SDTs were made in China; I only assume that to be the case, because isn’t everything these days made in China? Could be Japanese as well.

On a more newsworthy note:  UPS delivered my TT101 back from JP tonight.  It works!!!!!  Of course, it has worked in the past only to fail eventually.  But this time JP got to work on it when it was in failure mode, which allowed him to trace the problem to a probable source.  And he fixed that issue.  So I have reason to be optimistic.

Banquo, I am trying to figure out how to fit the TT101 into either of my two audio systems.  The question is complex, because the first thing I want to do is to audition my Fidelity Research FR64S tonearm, for the first time since I bought it several years ago.  It's ready to roll, on the QL10 plinth for the TT101. This means I want to use a low compliance cartridge, which means a low output cartridge.  That won't work on my basement system, because the phono stage there is strictly MM and I don't own a SUT.  Plus, I am very fond of the Lenco/Dynavector DV505 on that system. Upstairs, I have 3 turntables already set up. One of them will have to go into storage, most likely the Denon DP80.

Dear Tim (Pryso),
Actually I myself re-capped my SP10 Mk2.  And I did not replace diodes or rectifiers, as the Mk2 had no problems ever.  (I sold it after purchasing the Mk3.) When I acquired the Mk3, I did turn that over to Bill Thalmann who re-capped it and calibrated it as well.  To my knowledge, he replaced no other parts, but considering the cost of his work in that instance, he may have replaced other parts.  Somewhere in there, Bill also replaced the main chip in my Denon DP80 and all its electrolytics, too. In the process, he noticed that the discrete transistors in the DP80 were of a type he knew to be unreliable and also inferior to a modern equivalent part.  He then took it upon himself to update all those transistors in the DP80.  This brings us to the TT101.  So far as I know, none of the diodes in the TT101 needed to be replaced.  One might go to Schottky diodes, simply because they are the lowest in noise, but I am never going to open up my TT101 again, so long as it is working.  I am so done with fretting.  If one were to change the diodes, the new ones would likely have a different forward voltage drop than the originals. This would result in a very slightly different output DC voltage from the PS. You'd need to re-calibrate the voltages, at a minimum.  Possibly, you'd have to recalibrate the motor as well.  It's not trivial to do that. JP's philosophy is if it's not broken, don't fix it.  I went along with that.

I was thinking last night that we collectively have made the world much safer for vintage DD turntables over the course of this thread.  We now know about Bill, Peter, and JP.  We know we can get most of the supposedly unobtainable ICs and discrete transistors for the major brands.  Thanks to Halcro for starting us on this journey.

Today I went to buy a Boston Audio Mat2 for my TT101, only to find that it is out of production.  What are guys using? I really like the Mat2 on my Mk3 and the Mat1 on my Lenco.

Acman, In principle, I want your BA Mat2. However, being a computer klutz, I cannot figure out how to contact you from this website. When I click on your moniker, it takes me to a page that does not offer the possibility of sending an email. Further, JP seems also to be interested in your mat. Since he has been so patient and diligent in finding the gremlin in my TT101, perhaps I could do him a small favor in return by ceding my place in line to JP. So, you and JP can get together on that. If JP should change his mind, I do wish to acquire it. 

Of course, if my TT101 crumps again in the next few weeks, JP has to send me the mat, along with a crying towel.  (Joke alert.)

RW, I don't know about those Alibaba sources for an MN6042, but it seems to me that if you need MN6042 these days, it's a no-brainer to connect with JP and purchase his reconstruction of an MN6042 on a PCB made from discrete parts.  It outperforms the stock MN6042, and my direct experience tells me that JP will stand behind it, should you have a problem.  Moreover, having JP install it also gets you a calibration of the 3-phase motor drive in the bargain.  Obviously, I am not affiliated with JP in any way; I am just a satisfied customer.  (Sounding like a cheerleader, I know.)

All OEM electrolytics in all vintage audio electronics should go, IMO.

Acman, It seems JP has deferred to me.  I am still interested in your Mat2. Please do contact me, as I cannot figure out how to PM you.
Thanks.

Chakster, You could say I did that experiment.  I own one of each and have heard both on SP10 turntables.  The SAEC is very good, but I give a slight edge to the BA Mat2.  (So someone is wondering why I am looking for a Mat2, when I already own one.  Because the Mat2 that I own "belongs" on the SP10 Mk3.  I would like to find another.)  I can actually do the experiment again using the TT101.  There is no a priori guarantee that results would be the same.  And pigskin too.

Halcro, I note from the Top Class advert that was attached to a post here that the Victor pigskin mat is actually a 2-part affair, where the pigskin goes on the platter, and the lucite mat goes atop the pigskin.  Thus, the surface that contacts the LP is actually lucite.  I gather you and the other fortunate few who own the Victor pigskin are using ONLY the pigskin, no lucite.  Yes?

Chakster, I had never heard of an SP20 before your post.  My Googling shows a photo of something that looks like a black SP10.  No outboard PS is shown in the photo, but that wouldn't necessarily mean that none was ever supplied.  Does yours have an outboard supply?  If yes, then it seems the SP20 was a black SP10 Mk2.  If no, then I would liken it to an original SP10, not quite as great as a Mk2.

I've never tried a Micro CU500 platter mat. Nor do I even know anything about it, except that by name it would seem to have been made by Micro Seiki, out of copper.  Does the "500" indicate weight, in grams? I tend to think that metal mats are of a kind, in terms of sonics.  Except maybe copper sounds different from whatever alloy is used in the SAEC SS300, or stainless steel, used on the Kenwood L07D.  Weight of the mat might be a factor, because one TT101-user reported that his TT101 did not like a heavy metal mat.  (Perhaps the motor needed calibration; a motor that is out of calibration will exhibit subpar torque. I know this from JP's work on my TT101.)  However, 500g is rather light for a metal mat.  Some monsters made of copper by TTW were as heavy as 4 lbs, nearly 2 kg.

Thanks, RW. So maybe SP20 is a black version of the original SP10.

Peter, On your system page, I see the SP10 Mk3 in a beautiful wood plinth reminiscent of Albert Porter's plinths.  Is that your new one or is that an older photo?

How's it going with the TT101?

Forgot to say that my TT101 is running but not "up and running". Time got away from me this weekend, and I have yet to mount a cartridge. I did install the chassis into the QL10 plinth, which I have modified extensively with metal arm board and metal re-enforcements underneath the MDF stock plinth, to add mass and structural rigidity, and constrained layer dampening.

Has anyone unearthed any data on the Victor UA7045 tonearm, particularly its effective mass?  I have an FR64S mounted on the Victor plinth, but I might want to go back to the UA7045, if it would be a better match for a higher compliance cartridge than is the FR64S.

2.7 kg!!!!!!  That is nearly doubling the weight of the entire platter of an SP10 Mk2.  I would never do that to any DD turntable.  You could probably get away with it on a Mk3, because the base platter weighs 22 lbs to start with.  The servo is tuned to the rotational mass of the platter. You may well have enough torque to get that much extra mass moving, but you are probably losing something in terms of performance.  Perhaps Peter and JP can chime in on this subject.  Lots of modern day users of vintage DD's do these things. Keep in mind that M-S made the mat for their belt-drive turntables. In any case, I won't be looking for a CU-500 for my Victor.

The SP20 sounds like an economy version of SP10 Mk2.  You sacrifice 78 rpm, probably some electronic sophistication, and the cost of an outboard chassis, to save some cost.  I'm sure it's excellent.

Ok. If you guys sanction the use of platter mats that are way heavier than the original mat, some even as heavy as the platter upon which they sit, I must be off base. I was given to believe from reading on this subject that the servo action was tuned to the rotational mass of the "platter", which must of course include the mat. As an aside, it is gratifying to know that Nelson Pass is into vintage DD turntables enough to use one at an audio show.

For clarification, when you say that Pass uses an 8kg stainless steel platter, do you mean that he puts an 8kg ss mat on top of an 8.8-lb platter on an SP10 Mk2? (Because 8.8 lbs is the weight of a Mk2 platter, IIRC.) So, here you’re going from probably around 10 lbs total (accounting for the weight of the OEM platter + OEM rubber mat) to a total weight of more than 28 lbs (OEM platter + 19.4-lb ss mat). Is that what you meant, JP? I think at that point what must happen is that rotational inertia takes the place of servo action much of the time.

This has nothing to do with wearing out the bearing, by the way. I am wondering how it affects the servo.

By the way, I have no doubt that metal mats can sound great; I just think that the Boston Audio Mat2 sounded more neutral than any metal mat I have tried, albeit none of them weighed 19 lbs.

And finally, here I am talking about a TT101.  Someone said he tried a heavy metal mat on his TT101 and was not enthused.  Has anyone else got an opinion?  I think Halcro has a copper mat on his TT101. One potential advantage of the copper mat on TT101 is that it would act as a shield to block EMI coming up from the motor.  I made a shield for my L07D out of TI Shield placed under the platter "sheet" (as Kenwood calls the stainless steel mat), and it seemed to remove a coloration that was not noticeable until it was expunged. Lots of L07D owners do something like that. The coreless motor stator and rotor in both the L07D and the TT101 are oriented such that there would be a possible field projected upward toward the platter surface.  Does this make sense, JP?

When I owned "only" the SP10 Mk2A and the Denon DP80, both in very similar slate plinths, I gave a slight edge to the DP80 and eventually sold the Mk2A.  But I agree, the Mk3 surpasses both by a considerable margin.  Prior to applying the Krebs mod to my Mk3, I would have said that the L07D was slightly preferred, not that I could hear anything wrong with the Mk3. The two were just different flavors of goodness. The Krebs mod seems to make the Mk3 sound as fluid and open as the L07D with slightly more "drive" than the L07D.

JP, can you amplify on your cryptic comment about the effect of a heavy platter mat? "Drive gain"?  I was thinking last night that I wished I could modify my statement that a heavy mat might mess up the servo mechanism. Obviously it's also about the motor and its torque.  I thought that the original designers had to match platter inertia with torque and servo action, a triumvirate of factors.

Also, you guys, my concern about a heavy platter mat was not about bearing wear.  It was about the possible effect of a very heavy mat on speed accuracy and constancy. See above.  I'd give the CU-180 a try on the TT101, based on Halcro's comment, but pigskin too. 

JP, Thanks very much for your informative response. If you ever do get to do some additional experiments with DD’s toting heavier-than-OEM platters, let us know. 

Here is a question that maybe Totem or Peter can answer, particularly Peter: Will a TT101 fit into a plinth made for a DP80? Here I am asking only about the hole in the top deck and the placement of the bolt holes. My DP80 is sitting in a very nice slate plinth cut for it. I might like to try the TT101 in that same plinth, but not if it requires modifying the slate. Obviously, I could just try it, but that requires me to do work.  Hate that. Thanks.

Yes, I measured the circumference of both, and I noticed that the TT101 casing/shield has a larger circumference by about ~1.5", which, divided by pi, would be consistent with an ~0.5" difference in diameter.  I had hopes that the Denon cut-out would accommodate this slight difference, but I can see why it would not; the bolt holes run pretty close to the circumference. (I supplied the water-jet guy who cut the plinth for my DP80 with a template I made according to a factory drawing. He did a superb job.)

I do have the QL10 plinth for my TT101.  I replaced the MDF tonearm mount board with one made from aluminum.  I then also re-enforced the remainder of the plinth with slabs of aluminum bolted to the bottom, wherever there was room.  One large piece of alu runs across under the tonearm mount opening, and a large bolt conjoins the piece under the chassis with the new aluminum mount board,which is drilled and threaded to receive the bolt.  Thus I've increased mass, ridigity, and created a little constrained layer dampening, between MDF and aluminum.  We'll see how that sounds.  In my opinion, the plinth is where Victor really dropped the ball by comparison with Technics, Pioneer Exclusive, and Kenwood.  It's nothing much by itself. Same goes for Denon with the DP80, which is why I am sure your DP8(?) is a huge upgrade over the stock DP80 plinth

I have a longtime friend who is a professional machinist, owns a large business making scientific equipment.  At his home, he has a machine shop that is beyond belief, analogous to what we would do with unlimited resources to put together a vintage audio system.  He has huge lathes that are no longer made and every possible accessory for them.  And he loves to mess around.  If I ask to use his equipment to drill or cut, he ends up taking the job over from me, and does the work far better than I could ever hope to do.  So, it was really he who made all the aluminum parts for the QL10 plinth. Then we get stoned.

I've had two days listening to the TT101.  I am beginning to actually believe that it is going to work consistently.  Saturday I listened to it for a few hours with the OEM rubber mat.  Then today all day, I switched to the SAEC SS300 mat.  This combo is a winner.  This turntable is wonderful.  I can only directly compare it to my highly tweaked Lenco, because it is in my basement system feeding the Bev speakers.  I think it has a lower noise floor than the Lenco.  I am using an Acutex LPM320 cartridge, which I am quite used to hearing in the Lenco, but the FR64S tonearm, which I have never heard before. To my ears, the Acutex, which I always liked a lot, sounds even better in the FR64S on the TT101 than it did in the DV505 on the Lenco.  Still using the DV 505 headshell on the FR64S. I expected a problem with mismatch between compliance and effective mass, but that cannot be happening because the low bass detail is superb, not overblown, and my Transmission Line woofers are not "pumping", which they would be wont to do if there were very low frequency resonant peak.  (The TL cabinet affords no dampening of spurious woofer motion.)  This is not just another good turntable. Julie London at 45 rpm is crystal clear and highly musical. LA4 on direct to disc recording just blew me away.  Sarah Vaughn singing a ballad moved me to tears. Here's to JP.

Cheers to you as well, JP.
Just to bump this thread, which to me is more interesting than "what cartridge to use on a Reed 3P?", I will add after another night of listening to a wide variety of LPs, good and mediocre in sonic quality, that this combo of TT101, SS300 mat, FR64S tonearm, and Acutex LPM320 cartridge is THE quietest vinyl set-up I have ever heard.  On better LPs, one could easily convince oneself that one is listening to a CD, except unlike CDs, which have a "noiseless floor" that seems to lie above the musical noise floor, this combo gives you ALL the lowest level musical cues (which CDs mask, usually).  On top of that, you get that fluidity and effortlessness that I now think may be characteristic of coreless motors (and the SP10 Mk3 with Krebs mod).  I am going to try other mats, of course.  For starters, I can borrow the Boston Audio Mat1 from my Lenco, which is sitting next to the TT101.  If I can find a pigskin, I surely will try it.  And I may shell out for the reproduction of the CU-180.

Peter, It's more like "TT101 vs Mk3 vs L07D".  There are too many other variables to reach a scientifically objective conclusion, especially since the conclusion is unavoidably subjective.  I am thinking the TT101 does crush my Lenco, and I am a little sad about that.  Like the Lenco a lot.  As I tried to say above, the Mk3 and the L07D are sitting side by side in my upstairs system (very modified Sound Lab 845PX), whereas the TT101 and Lenco are downstairs (Beveridge 2SW).  No two of them are using the same tonearm and cartridge, either. 

I saw Halcro's latest plinth-ification of his TT101 on his photo website. Fantastic work.

Totem, Don't scald yourself on my account.  Science conquers superstition, I hope.

No one really knows.  There's the rub.  The idea is to stabilize the stator (in the Mk2 and Mk3) so as to lessen the effect on the stator of torque inputs prompted by the servo sensing a speed inaccuracy.  The thesis is that very minor displacements of the stator due to torque input lead to spurious or unnecessary further speed corrections, which results in the colorations that some hear with the big Technics DD turntables. You want all the energy to go into the rotor (which essentially IS the platter). Newton's Third Law of motion says that there must be an equal and opposite force (torque) on the stator; the attempt is to cancel the effect of that force.  How this is achieved is a proprietary secret, apparently. Before I re-assembled my Mk3, after getting it back from Bill Thalmann who did the Krebs mod on it, I could easily see that "something" had been done to the structure around the stator, but nothing was obvious about it. Richard Krebs tells me privately that he experimented extensively before arriving at his solution, even ruined a Mk3 in the process, I think he said. I'm sure he's here somewhere.

Henry, As I now understand it, the 300 series Acutex's are induced magnet types (of that I am certain), but the later end of run 400 series cartridges are conventional moving magnet types.  So, it would not surprise me if they sound very different. I own a 420 and a 412, but I have never heard either one.  The LPM series has an optional "headshell", which word I put in quotations, because it does not look like a headshell, more like a P-mount.  This is called the "Saturn V".  The LPM320 has a compliance of 42, which makes it even more strange that it works so well on the FR64S.  Using the Saturn V mount with the LPM320 would reduce the total effective mass by at least 5-10g, so it may be worth trying to re-mount my LPM320 into the Saturn V.  (I've got one.) Based on a OEM compliance of 42 and an estimated effective mass of (FR64S plus DV505 headshell plus LPM320 in conventional adapter) at 30g, I calculate an expected resonant frequency of around 5 Hz.  Maybe this is cool, as long as the LP does not have a warp or the floor does not shake.  My best guess is that because the 320 is now pushing 30 years old, the compliance is reduced from its OEM value due to aging of the suspension, which may be working in my favor on the FR64S.

Either you or your machinist is very talented to have made that beautiful and probably effective mounting system for your TT101. Congrats.

JB, I am glad you are happy with the Krebs mod; I've been touting it for months after hearing how it positively affected my Mk3.  I was previously a skeptic. As far as I know, the mod is less expensive when applied to the Mk2 vs the Mk3, so doing it on a Mk2 is even more of a no-brainer.  Also, it will get even better over the first 20-50 hours of use.  At first, I was not sure whether I was really hearing it or whether it was partly my imagination and listener bias.  Then after 10 hours or so and counting, all self doubts evaporated.

I shouldn't have written that "no one really knows" the nature of the Krebs mod.  Obviously, Richard and Bill do know.  But they ain't talkin'.

My experience agrees with what Richard wrote about "run in".  As I wrote earlier, the differences were at first subtle and now obvious-er and obvious-er.

JB, I have a feeling that the results with the Mk2 might be more profoundly positive than even what I am hearing from the Mk3, if only because I think I could hear a low level gray-ish coloration with the Mk2 that is likely to have been fixed by Krebs-izing.  With the Mk3, I did not hear that coloration a priori, but the mod has resulted in a greater sense of fluidity and open-ness, less of a clinical sound, if that metaphor works.

Yes, So far as I know as told to me by Lloyd Walker himself, the platter of the Proscenium is one giant slab of lead. 

On the safety of a lead platter.  The Walker Audio tt uses a solid lead platter.  They coat it with something that both imparts a nice black shiny smooth finish and probably makes it safe to handle. One might inquire with Walker Audio how they do that. Just a thought.  Also, Fleib, wash hands before eating.

My other question about a lead platter is how do you assure that it maintains its shape around the spindle, were fit is critical to keeping the platter level?  I don't know what Walker does; perhaps in their case the spindle is cast into the platter as one piece.

The question remains, what is "encapsulating" the lead platter of the Proscenium?  Possibly Walker now plays down the lead platter for fear of either having violated some environmental regulation or for fear of being singled out on that same basis.  Given that the Proscenium turntable now retails for over $100,000, the platters are not likely to end up in some toxic waste dump, not until Armageddon, anyway.