Regarding the inertia of the platter & servo mechanism, Yamaha GT2000's original platter is ~5.5kg, but Yamaha offered as options a vacuum platter mat (~2.2kg) and a gunmetal platter (~18kg). So if you used the vacuum mat with the gunmetal platter, you'd be at roughly four times the original platter's weight. The shape of the gunmetal platter is the same as the original aluminum platter's shape, so presumably the inertia to weight ratio would be about the same too.
So at least in this case, the manufacturer did not consider a very wide range of weights to be a problem. |
"What are the measurable physical properties of lead that could support the contention that it is superior....."
Weight, density, damping coefficient? We're talking about the transmission of vibrations through a material(s), and this stuff isn't exactly unknown.
If you affect the torque to weight ratio of an existing motor system, then you might screw up performance? That rates a duh.
Lead doesn't hold shape and is normally used between pieces of more rigid material. It's extremely affective at killing vibrations. If the idea is to match the record impedance with the material directly under it, then lead is a good choice as sandwich material.
Perhaps Trans Fi type spikes is a better choice? I think Naim Audio has a similar scheme. I've never used them. |
Fleib - both the Final designer and Goldmund have clearly stated their design goals. In the Final design their goal is to dump excess energy from the stylus/record interaction to ground as fast as possible. They eschew any form of soft materials - rubber, plastics etc. Kenwood had similar goals with their L07D.
Goldmund have a similar design goal of dumping energy to ground as expoused in their publications on their mechanical grounding systems. If I recall correctly Goldmund's use of lead in the platter was more about adding flywheel mass than the damping properties.
As far as the Transfi goes, I have listened to it at length on both an SP10 & Garrard 401 ( with $15k of arm& cartridge ) and in both instances it was vastly inferior to either a copper ( TT weights ) or stainless ( L07D ) mat, missing big chunks of information and smearing notes.
Unfortunately with mats most folk use them like cables - as bandaids for system deficiencies rather than try to work out the best solution. |
Fleib - both the Final designer and Goldmund have clearly stated their design goals. In the Final design their goal is to dump excess energy from the stylus/record interaction to ground as fast as possible. They eschew any form of soft materials - rubber, plastics etc. Kenwood had similar goals with their L07D.
Goldmund have a similar design goal of dumping energy to ground as expoused in their publications on their mechanical grounding systems. If I recall correctly Goldmund's use of lead in the platter was more about adding flywheel mass than the damping properties.
As far as the Transfi goes, I have listened to it at length on both an SP10 & Garrard 401 ( with $15k of arm& cartridge ) and in both instances it was vastly inferior to either a copper ( TT weights ) or stainless ( L07D ) mat, missing big chunks of information and smearing notes.
Unfortunately with mats most folk use them like cables - as bandaids for system deficiencies rather than try to work out the best solution. |
Regarding additional platter weight affecting performance, there was discussion of this in the past and I remember at least Lew and I participated in that.
The manual for my SP-10 Mk2A states its performance has "stable load characteristics up to 1 kg tracking force". It also suggests the quartz phase-locked system and DC servo motor torque can maintain rated speed even if 500 tonearms of 2 g. tracking force could be positioned simultaneously.
That seems clear to me that a new platter or heavier mat up to 1 kg heavier than the original platter/mat should operate normally. |
It occurred to me that the Walker Audio Proscenium famously employs a huge lead platter, nothing but lead. No CLD or anything. In keeping with my previous post, I must maintain my nihilistic position whilst making any point, but I could say that to my ears the Walker does not commit the sins that Geoffkait has assigned to lead per se. Does anyone think so? Most think it's one of the best sounding tt's ever made, in fact. (I don't own one.) This does not necessarily prove Geoff is wrong or that lead is a panacea, either. |
Dover,
Interesting impressions of spiked mats. I'll keep that in mind, although you repeat yourself. Once should be sufficient?
" their goal is to dump excess energy from the stylus/record interaction to ground as fast as possible."
Exactly how is that accomplished, by using a mat of dissimilar mechanical impedance of a record? That doesn't take vibrations to ground, a high percentage will reflect back to haunt the stylus.
This is from a 1987 interview of Pierre Lurne who worked for Goldmund and was responsible for the design of the Studietto table:
http://www.stereophile.com/interviews/pierre_lurne_audiomecas_turntable_designer/
"From the Minimum turntable in 1979, through the second turntable which I designed for Audioanalyse in 1981 and now to the Audiomeca J1, I used the same concept of mechanics. I'll begin with the platter. I agree with other designers that methacrylate is the best material for a mat, and the shape of the platter is the same as the Minimum, which is to say that it is a little concave: it slopes from the outer rim to the center at an angle of 0.30$d. I decided on this form from a statistical survey of a large collection of records. There are actually two sheets of methacrylate, either side of a solid, 8mm-thick piece of lead, giving a total mass of 8kg.
"This construction is something very special. If you know the velocities of vibration in methacrylic and in lead, you can calculate when the vibration is reflected back to the stylus. First, the vibration induced in the record from the stylus tracking the groove goes through the record into the methacrylate, then to the lead, and so on. Each time the vibration is transmitted from one material to another, there is reflection and transmission, and the time taken for each reflection to return to the stylus can be calculated. You need not have all these delayed signals reach the cartridge at the same time. You then get the same effect as with the acoustics of a room with square dimensionsβone big resonance. This is no good, and in addition, when a large reflected vibration reaches the stylus, the tracking is instantaneously different. But if you take care of the spacing in time of these delayed reflectionsβdo you understand the concept of the 'Gold Number?'βthen neither the music nor the tracking is affected, not at the beginning of the record or at the end.
"We use lead because it almost behaves as a 'magic material.' It has high mass, it has good damping with low-Q resonances, and it has a very low speed of vibration. If vibrations enter the lead center of the platter, they leave considerably later, much lower in amplitude."
Regards, |
Dear Richard, For further clarification and to expound on your post above, the current Artisan Fidelity Sp10Mk2 Technics Sp10Mk2 replacement platter (~5kg.) is comprised of a magnesium alloy based lower segment and pure Copper upper section. The platter's internal cross section features concentric damping provisions to help tame stray resonances. Initially, the platters used a slightly heavier (+.4kg.) aircraft aluminum lower section but was eventually replaced by magnesium alloy possessing superior damping characteristics.
Pryso, Acute observations regarding the robustness of the factory Technics Sp10Mk2 A's DC based motor, indeed it (including supporting bearing architecture) is easily capable of accommodating a heavier platter and/or mat over stock. For reference, the factory Mk2 platter weight = 2.9kg. and a respected replacement platter mat, say for example the well known vintage Micro Seiki CU-180 weighs in around 1.4kg.
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Chris74.
Thanks for the expansion of details on your SP10MK2 platter.
Further, I agree on the robust nature of the bearing assembly. Both it and the MK3 are substantial indeed.
Geoff.
I see two main structural paths in a TT... One from the record upper surface, thru the platter, bearing, plinth (or shelf for those of us who prefer au naturel ), arm, cartridge and stylus. "The loop path"
The other, from the record surface to Mother Earth "The ground path".
For now, ignoring suspended TTs
I have used lead extensively in my TT designs, but it has always been to " laminate" these two paths and has not been inserted into either of them.
I have found this methodology to work well.
Cheers. |
Last month Lew brought up an aspect of performance that we read little about, speed correction timing.
"It's also the case that the L07D servo was deliberately designed to exert a much looser control on the speed than does the Technics servo, for one example. I think it only activates when there is +/-3% speed error."
Maybe it's my imagination, but I've heard this difference between my Kenny and other direct drives. Any thoughts on the timing of speed error control?
Can properly functioning non quartz servo controls outperform some quartz locked counterparts?
Regards, |
Fleib.
To add a little more to your question. I took a lot of notes when upgrading a customers LO7D. One surprising observation is that the motor stator is rubber mounted via grommets. Such that it is possible for the stator to twist a little backwards in an anticlockwise direction when applying torque. This would seem to be counterintuitive but it is there in the design.
I don't know about the 3% servo thing, but it has been quoted many times in various posts. If this is how it is built, it would be a reasonable assumption that it is effectively open loop once up to speed. In this way it is relying on the synchronous motor's innate speed accuracy and the platters inertia to maintain the correct RPM.
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07-13-15: Richardkrebs
Fleib.
To add a little more to your question. I took a lot of notes when upgrading a customers LO7D. One surprising observation is that the motor stator is rubber mounted via grommets. Such that it is possible for the stator to twist a little backwards in an anticlockwise direction when applying torque. This would seem to be counterintuitive but it is there in the design.
I don't know about the 3% servo thing, but it has been quoted many times in various posts. If this is how it is built, it would be a reasonable assumption that it is effectively open loop once up to speed. In this way it is relying on the synchronous motor's innate speed accuracy and the platters inertia to maintain the correct RPM. Richardkrebs, It is staggering that you would be performing turntable modifications without a thorough understanding how the TT works. It is fanciful to speculate that the Kenwood engineers designed "slippage" when torque is applied by using rubber grommets. It is more likely that they employed the grommets to reduce mechanical and/or electric noise within the suspended board and coils. To help you understand the L07D servo operation, here is a link to the owners manual - http://www.vinylengine.com/library/kenwood/l-07d.shtmlPage 4 gives you an overview - the L07D uses a dual mode speed control system - if the speed error is below 3% the phase is controlled with a wide lock range and large phase gain. If the speed error exceeds 3% the servo controls speed rather than phase, and applies higher torque. When the servo mode switches from phase to speed control, the coupling changes from DC to AC to minimise influences from the motor drive circuit and motor offset. Clearly the L07D relies more on platter inertia and phase locking for coping with stylus drag unless the speed error is very high. This is quite a different design to the Technics SP10 solution which relies on a much more aggressive servo speed control system with the DJ market in mind β the ability to start and stop on a dime was more important to the Technics engineers than the Kenwood engineers. I have listened to many L07Dβs and SP10mk3βs at length and in my view the difference in servo design and implementation forms a significant difference in presentation, particularly in timing and coherency. |
Dover, I've got a fully refurbished L07D sitting right next to a Krebs-modified SP10 Mk3 which I bought NOS (before replacing all electrolytics and having Bill Thalmann perform the Krebs mod). These are easily the two best turntables I have ever heard in my system, yet they sound very subtly different. Before the Krebs mod was performed on the Mk3, I would say the difference between the two was greater than it is now, in favor of the L07D. But of course, there are more differences between the two than those having to do with the drive system: The tonearms, tonearm wire, and phono cartridges are all different as well. They both feed into the same Atma-sphere MP1 phono stage. But it's fair to say that prior to the Krebs mods, I tended to favor the L07D (with an EMI/RFI shield installed between motor and underside of platter). The Krebs mod keeps the virtues and advantages of the Mk3, absolute firm sense of pace, while ameliorating the rather "clinical" nature of its sound, as compared to the L07D, which might in fact err on the side of romantic but intensely "musical". (I distrust that word, too.) These days, I could live with either, happily, but might now give the edge to Mk3. The Krebs mod is transformative.
Richard, I had reason recently to disassemble my L07D motor and then put it back together as well. I do not recall seeing any rubber grommets. What I did see were some nylon grommets and some brass grommets, neither of which afford much elasticity. Is it possible that the motor you looked into had been "messed with" by someone, some time in its past? If you look at the service manual, and if you consult Howard Stearn, the L07D guru who lives in Virginia, you would get confirmation that the grommets should be nylon or brass. Howard talked me through the rebuild process. My memory may be playing tricks on me re the rubber grommets, but I believe this is the case.
Fleib, For all I know, Pierre Lurne' is a genius when it comes to platter design, but I am no fan of any of the turntables with which he was associated. The ones I've heard (Audiomeca, Goldumund Studio, etc) all "suffer" I think both from speed irregularity and an overly spring-y suspension. They are kind of a yin to the yang of direct-drive turntables. |
Dover,
"with the DJ market in mind". I trust you were referring to radio station DJs, which were a market for early Technics DD tables, not dance club scratch/mobil DJs. I've read many false assertions the Technics SL-1200s were designed for dance club DJs. I believe the SP-10 and SL-1200 series were designed in the '70s, a time before dance club DJs evolved.
I don't mean to sound picky here but I hate to see the DJ misrepresentation continued for any newbie readers here who may not be familiar with DD design and development. |
Lew
The rubber grommets look original.
I will PM you a pic of the stator to compare with yours.
Inserted in the centre of the grommets is a small metal tube stand off to prevent the grommet from being crushed when the bolt is tightened.
There are also a couple of nylon? stand offs to prevent the rotor from contacting the stator windings when the platter isn't in place ( partial mag lev feature)
Anyway, slight stator rotation is permitted by this arrangement and if original it is an interesting design decision. |
Lew,
When Lurne was working under contract for Goldmund I imagine there were constraints. The T5 linear arm wasn't held in the highest regard and the DD suspensions were problematic with any arm substitution. Many users including myself defeated the suspension. The Studio came with alternate springs, but most users were clueless about how to substitute.
This is the first I've read of problems with speed stability. These are quartz locked with a JVC motor. Perhaps you're referring to the earlier Pabst motor, but the ones I've heard didn't seem to have speed problems if everything was functional. The Reference was servo controlled belt drive.
Lurne is probably the most copied TT designer in audio. Not sure which Audiomeca you're referring to, but take a look at this design including the suspension:
http://www.tnt-audio.com/sorgenti/belladonna2_e.html
Regards, |
Fleib,
Many years ago my friend took his bog standard L07D over to Richardkrebs who at that time had a heavily modified Goldmund Studio. Despite the Goldmund having had many power supply and other modifications and an ET2/Monster Alpha cartridge and the L07D a cheap moving magnet - the L07D highlighted significant speed problems in the Goldmund, particularly in timing and coherency. The Goldmund by comparison sounded like it was lurching around and struggling to get over the line. This is what I believe prompted Richardkrebs to dump the Goldmund for the SP10mk3 that he now runs. I believe that Goldmund had the JVC motor.
I have heard the Krebs modified SP10mkII and to my ears it is similar to the Goldmund Studio, well down in performance compared to the L07D and SP10Mk3, again in loss of timing and coherency. I think it is significant that both the L07D and SP10mk3 utilised higher mass platters than their earlier DD's to assist with speed stability.
And yes by DJ I meant radio stations and the need for quick and accurate queuing.
One further thing to be aware of - out of the five people I know with L07D's, only one has had no "apparent" problems - quartz locking not working properly, hum, noise being the most common issues. So when we audition some of these decks today it is possible that we were not hearing them optimally as they were designed simply due to ageing and drift in components.
Lewm I have heard both the L07D and SP10mk3 with and without the Krebs tweak and agree with your summation, the proviso being that the TT's have been serviced thoroughly and are performing to spec. Bear in mind though that the SP10 requires a lot of work to get it sounding ok - new plinth, mats etc.
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Dover,
Can't say I accept your anecdote about the Studio as being typical of performance. I've heard a few and your description of "lurching around" suggests a malfunction or improper set up. I no longer own a Goldmund so I have nothing to defend, as audiofools typically do. The Studio isn't an easy table to set up. Your description suggests lateral movement from the suspension and/or platter wobble. If the table had the T3 arm that could have been a source of the problem. I didn't use their arm. I had a Zeta.
The DJ comment was Pryso's. Actually, the 1200 came out in the early '70s and was a consumer deck as were all with the SL designation. It was adopted by both the broadcast industry as a cheap backup deck, and mostly by the dance music DJ's. This was a time before digital and using a record player at a dance was typical.
Technics was aware of their sales and the use of the 1200. They redesigned the deck in the late 70's specifically for DJ use. Still light enough for portability, yet ruggedized and practically shockproof. The SP25 and 1200MKII are the same deck. The SP25 is for console mounting or in a separate plinth and the 1200 is a DJ deck. That's the way it is. How do people think the 1200 got the way it is, by coincidence?
Regards, |
Fleib, My gross impression of the Audiomeca that I heard on many separate occasions was that it suffered from what I now think of as an ill of belt-drive, maybe a stretchy belt or maybe its bouncy suspension. Some in those days used a compliant belt and mounted the motor on the stationary chassis whilst the platter was suspended, a great set up for speed variation as the platter suspension responded to the environment. However, this may be unfair criticism, since I do not know how the motor was mounted in the Audiomeca. Anyway, the sound was "woolly", for want of a better word.
Dover, My Mk3 is mounted in a ~100-lb slate and cherry wood plinth, and I have implemented a massive bearing damper much like that used by Albert Porter in his Panzerholz plinths. Of course, the L07D plinth I've left alone, apart from updates to the feet. |
Hi Lewm
Great to hear your LO7D is up, running and sounding so good. That you prefer it slightly to the technics Mk3 is also interresting.
Me, still using the Pioneer Exclusive P3 most of the time and its sounding absolutely superb.
cheers |
An update on the lead under-mat project. I've determined the lead sheet I'm using is not completely flat. This is made from flashing for roofing. I don't know about other types of lead sheet.
I think casting a lead mat is the way to go, but I haven't started that project. A 2mm lead mat should weigh about 1Kg so weight might not be prohibitive? Combined with a 3mm top mat close to the mechanical impedance of a record, might yield great results.
Regards, |
Downunder, As the Krebs mod breaks in, the Mk3 pulls slightly ahead of the L07D. By the way, my L07D has never been a problem as far as getting it up and running. My lamenting has been in relation to the TT101. I've had two L07Ds and no problems with either one. |
It's been a couple of months and nothing stands still so I wanted to note that I replaced the feet under my naked (to a point) TT-101 with Mapleshade Heavyfeet (I use 4, three supporting the edges of the tin-can bottom and one in the center of the can to damp it.
I was using smaller brass points and sorbothane and brass cups. The new feet go right into the mdf shelf of my Solidsteel wall shelf. Much better vibration control, almost no noise from a tap test to the mdf shelf. Results in a nice increase in transparency of sound-image.
On a totally different track: the forthcoming Technics DD turntables with advanced motors may be just the ticket for a worried owner of golden-age technology like me. I am hoping that there will be a better SP 10 unit in store. Does anyone have the inside scoop? |
Possible "scoop" on the new Technics: From the drawings, it appears to have a coreless motor, a la my lovely L07D and the cantankerous TT101. That would be great. Furthermore, the magnets appear to be attached to the underside of the platter at its outermost perimeter, with the coils in fixed position beneath them, which would tend to benefit torque. One can only hope the thing will not cost $50,000. |
Forgot to ask: I have reached the end of my rope with the TT101. In my efforts to fix it, I have achieved one thing; the fault is now constant, not intermittent. The good news is that this may make it easier for a really good tech to diagnose the problem, which I think is related to malfunction of one of the two opposing servo mechanisms. So, the question is, has anyone identified a tech who is well versed in these particular issues? |
the fault is now constant, not intermittent This is good news Lewm. At least a Tech can now 'trouble-shoot' it for you. Can you describe the exact symptoms....? |
hi Lewm, You could try talking to the guy, Dave Brown, who fixed my tt 101. He wasn't taking new clients last I checked about 6 months ago, but he might be more open now. He's already famillar with the table and has perused the manual, so that saves a lot of time. You can find his contact info here. Good luck. |
Thanks, Halcro and Banquo. To answer Halcro, the symptom is as follows and as I described it before, except now that it is constant, I can make more complete observations: The tt starts up fine. The tach will show it ramp up to the 33.33 display, but within usually less than a minute at speed, the tach will start to display errors, e.g., 33.34, 33.32. Very shortly thereafter (within several seconds), the power goes away and at the same time I now see that the motor assembly "shudders", vibrates enough to shake the chassis, just before power goes away and tach display will go blank, except for the decimal point. The brake does not activate; the platter coasts to a stop, as if one pulled the plug, but the Power light is on and the decimal point remains lit. I suspect that the shutdown is a safety mechanism that saves the motor from damage. |
I would call your attention to the Yamaha GT2000L and the Pioneer Exclusive P3 on eBay right now. Both are in the USA. No connection to me. |
Sadly.....I think I have to admit that Tommy of TopClass is correct in his assessment which inspired this Thread. But perhaps mainly in relation to the Victor TT-101...π± My TT-101 has been with my Tech for over two months because it suddenly developed speed issues (on both 33.33rpm and 45rpm). He has replaced five chips without any success and as all the electrolytic capacitors have previously been replaced as well as all the soldering...he has nowhere else to go. He has already spent too many days (and money) trying to wade through the complexity of this particular turntable. Compare that to the comparative simplicity of the TT-81 which does exactly the same job (albeit without the coreless motor) and I mourn the opportunity Victor spurned by not adding the TT101 motor to the TT81 electronics...π© I found a TT-101 for Thuchan who has had his Tech in Germany trying to get it working for nearly five months..... Thankfully the TT-81 sounds just as impressive and I have heard that the TT-71 also performs well. I have lived with the TT-101 for 3-4 years and have loved it....but it is no longer in my future. I lived dangerously during that period and unfortunately those who still own 'fully functional' TT-101s must hear the clock ticking.....π |
The Pioneer Exclusive P3 does not have a straight arm wand. The straight arm wand does sound a lot better than the S. Something you can find in Japan for time to time.
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Halcro and Lewm
Bad news re the Victor 101.
Halcro and I have the same tech. He did mention when I had a problem with my P10 last year that the Victor 101 was incredibility complex. The Pioneer otoh was straight forward and quite simple it is circuit. Fingers crossed my P3 continues to give me great service. |
Downunder, I'm confident that your P3 will keep going...and if it doesn't, it will be easily rectified by Chris Kimil. Despite the fact that I have to agree with Tommy about the 'risks' involved with TT-101 ownership....it is NOT because of the scarcity of new parts available. Every chip, transistor, and capacitor for the Victor is procurable. The problem with the TT-101 is simply its complexity. I believe there are few risks involved with ownership of any of the other Victor models and there are hundreds of Denon DDs available on the used markets as well as a seemingly endless supply of Yamaha GT-750 DDs from Japan. I have just brought in a Victor QL-A7 from Japan for my son (who has recently dived into HiFi and vinyl). Listening to this in my system (with a Signet TK-3Ea/155Lc cartridge) was a sobering experience. This $600 table literally shamed the belt-drive Raven AC-2 loaded with mega-dollar arms and cartridges. It also sounded stunningly better than my 'nude' TT-101 and TT-81 Victors (also with their mega-dollar arms). This salutary experience has caused me to reflect on the wisdom of my 'nude' turntable mounting. The heavy wood plinth of the QL-A7 combined with the four large mildly compliant feet appear to bestow upon the performance, a depth and palette somewhat greater than is extracted with the steel cradle and spiked feet of my 'nude' mounting. Changes are in the wind....π |
Henry
Good to see you coming over to the Pioneer way of thinking. DD with integrated plinth and more sophisticated suspension as you go up the food chain.
There is also a QL-A75 with 980LZS cart for sale in Sydney - you might want to pick that up
http://www.stereo.net.au/forums/index.php?/topic/88966-fssyd-victor-ql-a75-direct-drive-turntable-with-stanton-980lzs-cartridge-and-100v-stepdown-transformer/
Enjoy |
Regards, Halcro: Congratulations on the TT-71. The deck is capable of demonstrating the qualities of alternate mats, have fun! (Nice cartridge / stylus too).
Peace, |
Oh yes Professor....
I have already settled on the thin Jico suede mat as a 'delicious' match.
However my son will have to do with the thicker Jico mat...π
I know you prefer an alternate mat with your TT-71....
Shane...that Victor is twice the price I paid for the QL-A7...which also comes with a 2 year Guarantee from HiFiDo....π
I also don't recognise that arm whilst the A7 comes with a rather fine Victor arm...πΌ
I do think the TT-81 with its bi-directional servo control is potentially better than the TT-71 (or at least as good) so there is no way I am ridding myself of it and the three bronze armpods.
Rather...I need to examine how I can create a cradle with more mass to test whether my theory is correct...? |
Halcro, get yourself either a single purpose turntable wall shelf (like the Solid Steel that I use) and spike the turntable to it, or a good stand and an isolation pad like an SRA or Symposium. I would put my naked TT-101 against any plinthed DD and be sure of a favorable outcome. |
I have experience with the JVC QL-A7 and QL-7, both using TT-71 motor unit. Great for the money. But the gems, as far as pure turntables are concerned, are actually in the integrated turntables such as QL-Y7, QL-Y66F, QL-70A, etc., all have coreless motor and smooth sonic. The QL-Y66F is the same as QL-70A, except one with electronic arm and the other is manual. Electronic arms are not reliable unfortunately but the motor unit is stable and reliable. It's high time for people to look into those and install your arm of choice. If all integrated DD turntables have an armless version, history could be rewritten. But audiophiles usually overlook them because they want to use their own arm and I don't blame them. But they're missing out on gems.
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Correction: the model should be QL_A70, not 70A. I have keep these model numbers straight in my head. :)
Sorry for the confusion.
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Correction of correction. Oops. The above should read:
"I should have kept these model numbers straight in my head."
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hi hiho, It's high time for people to look into those and install your arm of choice. I've actully been eyeballing the victor ql a95 (same motor as the tt 801 and can be used in conjunction with the ts1 vacuum stabillizer) for a year now, but the arm issue has kept me from pulling the trigger. I assume that one cannot just put whatever arm one wants (leaving aside geometry), due to the electronics in the table? Can you please elaborate on what might be involved in installing a different arm on one of these integrated tables? thanks. |
Banquo363,
I never had a QL-A95 so I cannot be sure. Most of these tables have ribbon cable connectors from tonearm to the main board so you can disconnect them and the table will work manually. You can just add a armboard to cover the hole and a cut out for your am. The mod should be reversible. Most JVC arms are 10" so a typical VPI 10.5 or similar should work. I have the a QL-Y66F and the automatic electronic tonearm never works right so I uninstalled it by disconnecting all the ribbon connectors and I just need to machine a piece of armboard for it. Another approach is to make a larger plinth and so you can keep the stock arm and mount another arm in the back. The A95 plinth seems to use a lot of wood around the motor unit so adding arm shouldn't be too hard. The stock arm seems like a mechanical arm and should be reliable, unlike the electronic one that uses field coils to adjust VTF and azimuth and damping. The Y66F arm on mine was a nightmare! The Y66F is a bargain, arm or no arm.
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Some pictures of the QL-Y66F showing the tonearm attachment.
http://photoshare.ru/photo11191273.html
http://stat001.ameba.jp/user_images/20140126/12/kzaxiom/eb/3f/j/o0800060012825505017.jpg
Cut away picture of A95:
http://audio-heritage.jp/VICTOR/player/ql-a95.html
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The best example about integrated turntable is the Lenco. Most Lenco models are integrated tables with stock tonearm but once audiophiles ditched the arm they are liberated and you can find all the creations in LencoHeaven site. I wish people start paying attention to other DD tables. Even with the Technics SL-1200MK2, people replace the stock tonearm.
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But the gems, as far as pure turntables are concerned, are actually in the integrated turntables such as QL-Y7, QL-Y66F, QL-70A, etc., all have coreless motor and smooth sonic. Hiho, I'm not sure what you mean by "integrated turntables"? The QL-A7 I bought for my son has the tonearm integrated with the table and has an electro-mechanical device integrated into the plinth which operates the armlift up and down....and also automatically lifts the arm and stops the platter at the end of the record. All without interfering with the structural integrity of the arm itself...π Forgive me if I'm wrong....but I thought that only the TT-101 had the coreless motor? |
Aigenga, Halcro, get yourself either a single purpose turntable wall shelf (like the Solid Steel that I use) and spike the turntable to it, or a good stand and an isolation pad like an SRA or Symposium. I would put my naked TT-101 against any plinthed DD and be sure of a favorable outcome. You're right of course and this is indeed a recommended method IF one has a dedicated rigid wall shelf like yours. The problem occurs in a situation like mine where the shelf is shared and not dedicated...or where the shelf is heavily loaded because of the mass of the armpods (again like mine). Mass-loading a shelf induces stresses within the shelf strata and these stresses (mainly the tensile ones) induce low-frequency 'noise' or vibrations in the shelf material. A massive plinth can help absorb these vibrations without itself resonating especially if the plinth is mounted on slightly resilient feet. A very low-mass plinth (like my steel cradle) is easier to precipitate into its resonant frequency and steel spikes do little to hinder this. Most turntable manufacturers are aware of this structural feedback issue and attempt to combat it in various ways like mass, sprung suspension, air isolation feet etc. Rega believes a low-mass plinth (or even skeletal) is best when mounted on compliant rubber feet. This structural feedback issue is so important that Mark Doehmann has designed his new turntable with a Minus K stand inbuilt into the plinth. At any rate, I have been doing a lot of testing lately and, because I can do nothing about my shared shelf and its mass loading....I need to try and devise a solution to creating 'mass' for my cradle situation...πβοΈ A tricky problem.... |
Halcro: "I'm not sure what you mean by "integrated turntables"?"
Integrated turntable just means a turntable comes with its own tonearm, unlike TT-101 or Technics SP-10 that allows you to use your own tonearm.
The QL-A7 qualifies as an integrated table, the same as a QL-7. It is essentially a TT71 with a semi automatic tonearm that has auto armlift at end of record and auto stop. The "A" means automatic version of the QL-7. I owned both QL-7 and QL-A7. They were my introduction to JVC turntables. Their later integrated turntables feature coreless motor that has a sound my ears are more cottoned to, such as QL-F6, QL-Y7, QL-Y55F, QL-Y5, QL-Y66F, etc... and the aforementioned flagship integrated table QL-A95.
Back to the QL-A7, the later integrated turntables are rather more complicated as they are completely automated with electronics that can adjust VTF, antiskating, damping, all on the fly with knobs on the front, like the one in the QL-Y66F. Very complicated electronically. It's great when it works right but it's a nightmare when it goes berzerk as it can kill your cartridge by applying too much tracking force by crushing the cantilever! For that reason I much prefer an old school tonearm like the one in the A7. Underneath the plinth of the Y66F, it has many ribbon cable connectors connected to the main board so it's a bit more complicated than the A7. Installing your own tonearm is doable but just have to be more careful.
The turntable section of these integrated units are very reliable, never had any problem with them. The electronic tonearms are a different story. If I can choose, I would like to have a QL-A70 as it has identical 14" platter and motor drive as the Y66F but with a more traditional tonearm. But the Y66F is more common and easier to find. Due to finance, laziness, and simplifying my life, the only table I am using these days is the QL-F6 with its stock tonearm mated with a Signet cartridge, hence my lack of participation in forums. It sounds satisfying to me. But the QL-A70 is always on my mind... I still have a beater Y66F in storage that, hmmm... I should put it into good use one day...
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Halcro: "Forgive me if I'm wrong....but I thought that only the TT-101 had the coreless motor?"
No, TT-101 is NOT the only JVC turntable that uses coreless motor. Look up some of the above models I mentioned.
I had a QL-Y7 briefly and sold it as a favor to a non-audiophile friend to replace his QL-A7 and he told immediately the sound is smoother with the same cartridge. I trust non-audiophile's ears than audiophiles, to be honest. Of course one can always argue they use different tonearms and it could be the attribute to the sound. But turntables with coreless motor that I heard have a fluid sound that I like and it's different from typical DD tables, a la Technics, almost like a belt drive but more concise and stable. That's just my own impression. YMMV.
There's a German JVC collector "JVC_graz" in some internet audio forums is very knowledgeable about all the different JVC models. Here's a picture of his collection of integrated tables.
http://www.vinylengine.com/turntable_forum/gallery/image.php?album_id=106&image_id=8637&view=no_count
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Great information as usual Hiho...π
The Victor world is indeed convoluted and full of gems..
What Signet cartridge are you using?...just out of curiosity...
Regards |
So Hiho,
If one wanted a Victor coreless motor unit which shared the dimensions of the TT-81/101 and had all the operating controls on the platter unit itself (like the TT-101)....I assume that these are not available as 'stand-alone'?
Is there a model in your integrated list from which I could remove the motor unit as a 'drop-in' for my TT-81/101? |
Halcro,
I have thought of the same thing before but JVC made their integrated turntables rather hard to do that because the circuit boards are laid out all over the place and wires are like spaghetti. After some research I believe the QL-A75 is the closest to what you are talking about. It's probably the simplest construction as the top plate or chassis contains all the controls and the circuit boards are all under the top plate so making plinth cut out a lot easier. I never owned one but I have similar QL-Y55F with the electronic tonearm but the main board took up the whole width of the plinth underneath. The QL-A75 is almost top of the line and I am sure it's a great performer even with its stock tonearm, which is an old school mechanical one so that's good.
Here are some pictures from a Japanese website:
http://blogs.yahoo.co.jp/gt2500jzz/34155439.html
The QL-A75 is rather hard to find though. And the A-95 is even harder!
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Another approach is to make an armpod or island for a tonearm, preferably 12", that can just swing over to whatever table you will be using. Of course, you have to remove whatever compliant footers so it wouldn't affect VTA or geometry. Pretty much the same concept as your "nude" approach. This way, you are not affecting the resale value of your stock table. Just another thought.
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