Wednesday, February 26, 2014

Vantage Audio Reference Systems

Vantage is a servicer of Technics turntables including SP10, and they also have many kinds of parts.

Located in the UK.

Monday, February 24, 2014

uncentered record wow

The discovery of the high wow measurement had me arguing with the seller, who agreed to take the turntable back (though for awhile I though he had changed his mind…leading to great angst).  I was getting mentally prepared for shipping LT-30 #1 back to the seller this week.

Then on Friday night after work (actually, the wee hours of Saturday morning) it occurred to me that some of the wow could be caused by the record being off center.  I recalled once reading that this could produce more wow than turntables themselves.

So I watched the Dr Feickert record playing.  I could clearly see the correlation between off center movement and the back and forth movement of the arm.  As the arm moved outward, the pitch went up, and vice versa.  I reversed the record 180 degrees and saw the exact same pattern.

So then I took the test disk and played on the Lenco L75.  Not only was the wow measurement not smaller, the flutter part (as measured by the IEC number of PlatterSpeed) was significantly worse.  Then my second LT-30 measured the same as the first.

Sometime on Saturday afternoon I emailed the seller and told him it looked like I was wrong, the turntable did not have excess wow at all.  I told him I'd check it out some more and if I couldn't find anything else wrong I'd close the eBay case on Monday.  I tried to leave the turntable on overnight (but turned it off without thinking) then just left the platter spinning for a couple of hours and repeated the measurement on Saturday afternoon.  Same measurement as before (it did not seem to be affected by having the turntable warmed up).  Then I watched the entire 3150 Hz track on the Dr Feickert record play.  No change from the beginning of the track to the end.  Not wanted to unnecessarily worry the seller any more, I closed the case on Saturday night.

Sometime on Saturday I re-discovered the page on off-center wow written by REG of The Absolute Sound.  This is worth reading a bunch of times, as I did.

Now I'm kicking myself because for the same price as all the turntable's I've purchased, I could have gotten a refurbished Nakamichi Dragon CT (computing turntable) which I saw listed at Audiogon.  That would make far more difference in measurable wow than any difference reasonably well working turntables and the very best.  It would leapfrog from the pitch stability of most turntables (which turns out to be about the same…simply due to off center wow) into 10 times closer to perfection.  If I really cared about pitch stability, and knew what I was doing, that's what I would have done (though I might have balked at the asking price of a refurbished CT, $3800).

Modern turntables have been pushing weighted wow and flutter down below 0.04%.  Meanwhile, the best you can do from a typical record, like the Dr Feickert test record for example, is about 0.12% or 0.16%.  The off center wow simply overwhelms any wow produced by nearly any turntable.  The raw number is even worse, I was seeing total pitch variation on the order of 0.8%, but the weighting filter used to create the weighted wow measurement drops that down to 0.12% on the basis that wow at 0.5Hz is less bothersome than wow at higher frequencies.

So why bother making or having a turntable with low wow?  REG points out the disconnect, turntable manufacturers know this problem…they have to take special measures (not using normal records) to measure wow, such as making a special painted platter to be measured optically.  And yet, nobody except Nakamichi has even tried to make off center wow reducing turntables.  Nakamichi, alas, didn't sell many of these incredible turntables, they likely lost a lot of money on the project, and thus a market for center wow eliminating turntables was never established.  People go on today ignoring the problem, comparing the wow of top turntables such as Gyrodec and SP 10, as if it matters when they both have wow 10 or 20 times lower than the off center wow of typical records.

So then why am I bothering with a speed stable (0.001%) SP 10 Mk2a when my records will have 0.8% recurring speed errors?

I am very disappointed by all this.  But meanwhile, I do have speculative explanations of why people have so easily ignored wow from off center records and meanwhile obsess over the trivial wow and flutter of most turntables.  The one obvious thing, of course, is that wow at 0.5Hz is indeed less audible than it would be at higher frequencies (and before going too much higher, we'd start calling it flutter).  I can hear the 0.5 Hz wow on a test signal, but it was hard to tell on actual music.  The second thing is that since off-center wow will occur on all turntables (except Nakamichi), people will tend to associate the sound with the record itself, rather than misperformance of the turntable.  We will simply never know how good our records would sound without the off center wow.  The third thing is that the off center wow modulates other wow components at higher frequencies, making THEM (or what we think they are) more audible.

As we can hear music below the noise floor, paradoxically it appears we can spectrum analyze very small wow components at higher frequencies even in the face of the large wow at 0.5Hz.

It would be even more paradoxical to believe that with all this wowing going on, we can hear tiny difference between turntables in their ability to correct the speed allegedly at the start of or after heavy groove modulation.  But I still think this is true.

I believe record would sound hugely better with off-centeredness lowered from about 2mm (typical) to 0.02.  And that center correction would reduce the apparent magnitude of higher frequency wow and flutter as well, and turntable speed correction effects, a huge win all around.  But most audiophiles including me have never heard this.

(I once attended a meeting where the Nakamichi turntables were being unveiled, and I recall the CT 1000 being played.  It was a noisy meeting and I suspect I wasn't paying enough attention to hear any huge difference.  So…Nakamichi's turntable failures are partly my fault as well.)

Wednesday, February 19, 2014

PlatterSpeed Specs on LT-30 #1

[Update: all these numbers are mostly explained by off center wow, which is typically 10 times greater than good turntable wow, see the next post.  There appears to be no serious problem with the LT-30 #1 after all.  It measures no worse than my other turntables, in fact the Lenco which seems to sound the best measures the worst.]

frequency:    3150.2 Hz (excellent, strangely)
max deviation (raw)   -0.39%/+0.38%
wow (DIN 2-sigma) +/- 0.12%
wow (DIN dynamic) +/- 0.08%

The wow is clearly dependent on platter angle, first it goes up, then it goes down, as the platter turns.  It is very audible to me.  The mean 3150 is strangely correct but the high is at least 3165 and the low is at 3135 (this is worst case in a 10-20 sec recording).

I would call this cogging to the extent that an entire pole or set of poles in the motor is working at significantly diminished capacity.  When the platter position dependent component is removed, the resulting wow and flutter is quite small, with the maximum deviations being 3155 and 3145.

This is obviously a problem which needs to be repaired, and the turntable is basically useless until it is.

I think I got a warranty on this.

Monday, February 17, 2014

More turntables, and my Lenco enlightenment

I did have a lot of audio stuff I wanted to do on the second weekend of February.  Typically when I have too much stuff on my mind I want to do, nothing actually gets done.  But not this time.

I started by moving the Classe CP35 preamp to the master bedroom, replacing the Acurus L-10.  Despite having better measurements, and the advantage of a "bomb proof" circuit with attenuator at the input (before any amplification…this may sound obvious but it is not always done this way, and the Classe does not, so input to the Classe must be limited to 3.5V RMS or thereabouts…hence the model number?) I actually like the sound of the Classe better.  Long ago, the Classe replaced the Aragon 28K in my then main system--the bedroom system.  And the Aragon is a far better preamp that the L-10 objectively and subjectively and build-wise.

But the main reason why I decided I needed the CP35 in the master bedroom was that it has stepped attenuation which ensures perfect tracking in both channels.  That's a very important thing if you are making digital copies of analog recordings, which is a main feature of the new "analog pod" at the south side of the master bedroom.  This started with the turntable (currently Mitsubishi LT-30) and the high resolution digital audio recorder (Alesis Masterlink).  But the pod already had my Nakamichi RX-505 (though it wasn't yet hooked up).  And I added a tuner (a Yamaha TX-1000).  These are all top or nearly top models of their kind.  And now they are all hooked up to the Classe CP35 (well, actually the dB systems preamp is hooked up, not the turntable as such).  Also the CP35 sends the audio from whatever is the selected device to the main portion of the bedroom audio system, which is in the northwest corner of the room.

Back in the day when I was using the L-10 preamp, I had simply dialed in the correct gain from phono preamp to masterlink, dialed in the balance point as well (which was not perfectly centered, because of mistracking in the potentiometer).  There was only one thing to record, so that was that, and if I needed to change the level through the speakers I could do that through the main system.

Now standing in front of the analog pod I flip through the different sources either for listening or recording, so it's convenient to readjust the levels for the different sources.  Eventually I hope to memorize the optimal recording levels for each source, and the Classe will make this possible, but even now it's not hard to find a good level (which is much easier than re-discovering the optimal channel balance each time you change the level as is needed with analog volume controls).  Somehow with a digital volume control, even though in principle you can't dial it in exactly, it is much easier to dial in within it's level of precision, and do so time after time.

That work combined with an evening at the Symphony (where they played Dvorak's New World Symphony) made for a good Saturday.  Actually I didn't get the FM antenna set up until Sunday morning.  This was far trickier than expected, high and flat against the wall didn't work well.  I tried several alternatives, ending up with a drooping line across the south wall, which still doesn't work as well as my antennas in the living room.  Which is strange because the bedroom faces my favorite FM station KPAC, whereas the living room is on the opposite side of the house.  The antenna may need more work.

Meanwhile I played a record or two on the LT-30 and copied the Scarlatti recording to CD.  The Musical Heritage Society recording of Scarlatti did not reveal any of the wow that I now believe this turntable has.  Unfortunately, the last recording I played on Sunday night, Rick Wakeman, did reveal the wow and the recording was made almost unlistenable.

I also discovered a wonderful tape inside the Nakamichi and played it many times.  It's a recording of electronic and dance music from KSYM several years ago.  I tried to tune in KSYM on the bedroom tuner and basically it's not worth listening to that way because of high noise in mono only (though I did listen several times).  My best antenna for KSYM is  at the NE corner of the living room, and it is hooked up to the Kenwood KT-6040 which has been turned off because it can't be adjusted right as the display is hidden by other equipment.  It had been in use a few months ago, but then somehow some key adjustments were changed, and it wasn't working right, and I couldn't figure out why, so I simply flipped the Sonos input over to the Pioneer F-26, connected to the best-on-KPAC antenna, and listen to that anywhere in the house.  On KPAC, and on that antenna, the F-26 sounds best anyway.  But that means right now I don't have good KSYM.  I had been thinking KSYM had less power than before, but it comes in fine in my car radio, it's just my master bedroom seems to be in a radio shadow.

Even if KSYM had been coming in well, however, (and I intend to fix that and subscribe to KSYM) on Sunday they did not seem to be playing the wonderful kind of music on my tape, which I listened to over and over and danced to.  So I was glad I had that tape!  Taping FM radio, a civil right which was won in court long ago, is a wonderful thing to be able to do.  You can time shift and even make party tapes and the like!  Note that you don't necessarily have these freedoms with digital sources.  I copied the tape to digital on Monday morning.  It sounds great in Dolby C playback, but I can't remember how I recorded it.  I was thinking of making digital copies with Dolby C, Dolby B, and no Dolby.  I'm also learning about a bunch of artists I'd never heard about before.

Anyway, I was by then into the doldrums of Sunday afternoon, and what to do next.  But I quickly started building the new equipment stack to support the Lenco.  The Krell FPB 300 is forming the base of the platform, with protective felt on top.  On top of that I have Marantz 2270, rescued from the bottom of a vintage equipment pile in the Laboratory.  Turned with the backside forward, and I set everything up for Phono 1 and 2, which I can reach over and change when needed.  Then I took off the Lenco platter and wondered about shipping bolts.  I looked up on VinylEngine and learned that the two red bolts around the motor are shipping bolts, which can either be loosened or removed.

Then without doing more online research, the mounting of the Lenco plate to the plinth seemed wrong to me.  So I removed the two metal plates that hold the plinth on.  Only then did I go back online and fine that those metal plates were part of the Lenco suspension, and without them the bottom panel (a thick piece of particle board) doesn't stay on.  Oh, well, I also found that many people remove the bottom plate and shims anyway, so I did just that.  I put the Lenco with bottom and springs removed on top of the Marantz 2270, which only gets barely warm (about 93 degrees) but I've decided must only be turned on when listening to records.

I also hooked up my second LT-30 to the Marantz receiver, but haven't listened to that much.

The arm on my Lenco has very flaky mounting, it hinges but can also wobble somewhat.  I suspect it has V-blocks in almost useless condition, sort of working but not very well.  It is also missing the tracking force weight and was missing the anti-skate assembly.  But no worries about the M91ED cartridge and "new" stylus (aftermarket) included, I didn't care what happened to them..  I found that I could balance the arm with the weight nearly all the way forward.  So I figured that just pushing the weight all the way forward would give about a couple grams of tracking force, and that would be fine.  (I only learned days later that the M91ED is not supposed to be tracked with more than 1.5 grams of force.)

I took the almost unlistenable copy of Emerson Lake and Palmer Tarkus and played it.  And it was like the first time I had ever heard that record.  For the first time, and completely unlike when I played it in the bedroom on the first LT-30, it made sense musically.

Then I played Peter Sprague Dance of the Universe, and it also sounded more musical than ever before though I'd say the bass player still sounds a bit out-of-tune…but I remembered that exact sense of intonation from the Peter Sprague concerts I went to.

I was expecting some kind of revelation from running an idler turntable again, and especially a Lenco (since I had good experience with Lenco in the 1970's).  But this exceeded expectations.  Not only was the Lenco more musical than any source I've had in years, the difference between it and my currently working direct drives is huge and obvious.

Actually, I think my #1 LT-30 is not working to specs, and it probably wouldn't sound so bad if it were.  But I have to believe that even if it were working to specs, it would not sound as musical as the Lenco.  During the following week, I played records on the Lenco and the #1 LT-30.  Records on the LT-30 sounded ok a few times, but sickly on others (and I think it's getting worse).  Every single record played on the Lenco has been a musical delight and revelation, despite the lousy tonearm and cartridge.

During the following week, I investigated tonearms, and decided to get a 12 inch Jelco SA-750L, mounted in a large base from Moldovia (where an ebay seller lists a large variety of possible bases).  On Friday I ordered the base after assurances that the seller would make it for the 12 inche Jelco and use American Walnut veneer.

Thinking I might like to have an idler automatic turntable in the bedroom also, I bid and won an ebay auction for a nice working Benjamin Miracord Elac 50h turntable.  With the Elac, I will not have to get a new arm.  Of the mainstream changers, I'd always thought Elac was the best, better than Dual or Garrard.  The Elac also features a special Papst motor which has spinning rotor on the outside for less cogging, and it has a platter as heavy as the Lenco if not more.  (The 12 inch Dual turntables also have about equally heavy platter.)  What I really hated about the 1209 I had while in college was the small platter AND the "mat" which consistent of rings cemented to the platter.  Those rings did not support the record very well, and a buzzing record contributed to bad sound.  Well it turns out the 1219 also has a similar looking platter, with integral rubber rings to support record, which I would not want.  But the 1229 has a full platter mat which might be removable.  So the 1229 might be OK too, but they typically go for even higher prices now than Elac, for reasons only of popularity.  I lost a few bids on 1229's, but would rather have Elac anyway.

I then won a second auction for a cheap 50h with no base for spare parts.  The working 50h I won has a modified arm with aftermarket balance dial.  I could replace that with the original counterweight from my second 50h.

On Wednesday I received the shipping clamp for the SP 10 turntable.  On Thursday I sent it to the seller of my SP 10 by Express Mail.  (The seller received it on Friday.)

So my collection of turntables now includes:

Linn Sondek LP12/Valhalla/Ittok (needs motor repair)
Sony PS-X800 (not working)
pretty Mitsubishi LT-30 (has motor problem)
dented Mitsubishi LT-30 (not yet fully tested)
Lenco L75 (a musical revelation!  But arm not fully functional)
Technics SP 10 Mk2a with Obsidian Base and EPA-100 arm (not yet received)
Benjamin Miracord Elac 50h (not yet received)
spare Elac 50h for parts

It remains to be seen whether SP10 or L75 will win the honors of being main living room turntable.  I might keep the other one in the living room also (SP10 for rock and Lenco for classical?) or I might end up putting the SP10 in the bedroom (all the better for copying vinyl to digital).  The EPA-100 arm features auto liftoff so it would make as good a bedroom turntable as any.

On the following Saturday I attended River city Audio Society meeting, which was as wonderful as ever.  This time was mostly playing vinyl records, and Gene had brought his Technics (looked like 1200).  It sounded mostly ok, but I thought I heard some speed instability even before I saw what the turntable was.  Gene said later that the table sounded better than it had sounded last time, when he felt it sounded old and tired.  After that, I got home and played two records on the #1 LT-30.  They both sounded pretty bad, so I'd have to say my LT-30 is actually far worse than Gene's Technics.  (Gene's favorite personal table is a Garrard 301 for which he sold his Scoutmaster.)

By Thursday I was able to set the tracking force on the Lenco with a digital gauge.  It appeared that my original setup wasn't too bad with tracking force just over 2g, but I needed to lower that to 1.5 at most.  Unfortunately the tracking force varies across the record and also at different heights and the gauge itself seems a bit taller than a single record.

On Saturday I tried to set up a replacement tracking force weight for the Lenco using a 5g weight and some dental floss.  I ended up using tyvek tape instead of dental floss.  But rather than allowing the arm to be more stable (so it wouldn't rock but simply hinge), the weight only made the situation worse.  Or I made it worse trying to attach the weights.  I ended up removing the 5g weight and repeating my original setup but with gauge.  But fiddling this much with the arm seems to have made the damping blocks even worse and it tends to rock more easily than before I started trying to use tracking force weights.  What it really needs is full disassembly and repair with new V blocks, but I don't want to bother with all that since it's going to be replaced soon anyway.  But I was strongly tempted to remove the Ittok from my Linn and use that instead.

But instead I got to setting up my super tweeters again, and that makes for another story.

Friday, February 14, 2014

Analog preserves micro time

It hit me while listening to my Lenco L75 playing Rick Wakeman, which was virtually unlistenable on my Mitsubishi LT-30 because of wow (I think it's not working to spec, even, so lets not judge all LT-30's let alone all direct drives on that example).  But the Lenco has been a revelation of sorts, I really do hear far more from this analog source than anything else I've had…even if the source material is below spec (and I've been using my least well regarded records until I ensure everything is working ok).  Rick Wakeman plays with pitch a lot, but if you can't follow his play, it sounds all flat.  Did I hear him scratching?  Never heard that previously.

My idea is best stated like this: When two different instruments begin creating a sound at slightly different moments, what are the possible differences in the relative time they can start?  Well on an analog system, there are infinite possible time differences (perhaps down to some level of quantum time…or quantum something).  With the digital system, there is always a finite number (just as there are a finite number of different voltages, whereas an analog system can have infinite levels of voltages down to some quantum level).

(Not, eventually the instruments on parallel analog and digital systems catch up.  It's merely the first instant of information that is truncated.)

But unlike the different voltages, which may be to some extent (I've long accepted that we can hear at least 20dB into noise level, it may be far more in real life situations) affected by noise, so that we can't hear all possible differences in voltage, there is nothing (well except our own physiology again, but differently) to prevent us also from hearing infinite differences in time, or at least being able to detect and correlate them with other things…to create a different sonic experience (for example, in a spatial image).  And that being able to be influenced by such a difference, if not be aware of it as such, might get down to very small levels too, not exactly quantum levels, but very small, far smaller than digital systems.

Very high frequency delta sigma systems, like DSD, preserve time better because the time start rate is the bit rate, 2.88 Mhz for DSD (or the corresponding fraction of a second).  In that sense, these systems ARE far more like analog.  I had never thought of this before, and have been critical that DSD doesn't actually deliver high (voltage) resolution in upper frequencies.  Of course DSD is quite complex and may have other issues too…  But in preserving start time, it is far superior to PCM digital systems.

Conventional PCM can go to 96kHz or 192kHz in consumer, that's far higher temporal resolution then the 44.1 Khz of CD Quality digital, though not in the league of delta sigma systems.

Wednesday, February 12, 2014

Another Great Audio Site

It's interesting.  WhatsBestForum, founded by Steve Williams.

Here he describes the creation of his new music room in Southern California.  Leaving behind a cavernous "dream" listening room in the Bay Area, Steve loves his new house and planned community in his cherished Souther California, but finds he can't build an outdoor building for his new music room.  So he builds a music room inside the existing house, by taking the top of a living room with 20 foot high ceilings.  The resulting room is small by the living large standards you might expect him to have (guy with megabuck system, megabuck house, etc) but Steve puts so much effort into refining the acoustics (with hired professionals) he finds the result even better than his last room which would be a dream for just about any audiophile.

The thing I like is this: it's only about 50% or so larger than my puny living room.  So there is hope!

(When there is money, there is always hope.)

More serious and more informative that Cat's site, though possibly less entertaining.

Blog(s) on turntable motors

An intrepid set of audiophile investigators has begun carefully measuring and deconstructing turntable wow and flutter on famous turntables of various designs, including Linn LP 12, Technics SP 10 Mk2, Technics SL 1200 (best selling turntable, and available for two decades), EMT, and others.  The effort that I am aware of started in 2009.  (Perhaps there are other such efforts out there.)

Actually, I first started reading a blog about this on VinylEngine, and the blog I was reading was actually a  derivative blog of comments the original blog (that I know of) hosted at Pink Fish Media.  I found the derivative blog quickly informative at the beginning, but then after a few pages it occasionally degenerated into accusations of conspiracy and claims of counter-conspiracy.  I still found it entertaining, if less informative, but ultimately the site administrator closed it to additional comments.

So then I flipped over to the original blog, such as I know it now, and it starts more slowly, and has the horrible misfeature that many of the pictures are no longer shown since they were hosted by a site that no longer supports them.  But flipping to the end of that original blog, and I believe it is still open and growing at 42 or so pages when I last looked, it did contain interesting and informative comments about  turntable drive systems, additional measurements, and so on.  I haven't read it all, but it does look worth reading, but I have to flip over to the other blog to keep the pictures in mind.

(The original site on Pink Fish Media might show the pictures if I become a member, so I'm going to do that.)

Friday, February 7, 2014

Turntable Adjusting

Time flies when you are messing with a turntable.  On Monday night I thought some of the bass was excessive, suggesting either feedback or arm resonance.  On Tuesday, I had difficulty determining which of those, or neither, was true.  It might have simply been the recording I was listening to.  But then later, I decided that worse than feedback, I seemed might be having a serious tracking error issue.  On Wednesday morning I was playing Peter Sprague again, and in the final grooves it seemed to be silently skipping, sliding back a groove or so but without any obvious tick or pop.  THAT was an issue that immediately needed fixing, I decided, and no more records until it is fixed.

The first thing I did Wednesday night was to check the level.  I had leveled the table on Sunday night using a very small level of unknown quality.  I couldn't find my regular level, or my bubble level.  So on Wednesday I bought a level, and used it on Wednesday night.  I had leveled the table correctly on Sunday with the little level I had found then.  (The Rear feet are cranked up nearly an inch, it seems, but that's what it took!)

Then I checked the arm balance, and stylus force.  All were OK.

Then I got out an anti-skate test record, which has a 1 inch blank surface near the end of the record.  There was no skating whatever, suggesting my cartridge alignment was OK.  And since there was no skating force, that could not explain skipping anyway (regardless of how correct the alignment is, but it *is* probably correct anyway).

So then I got to something I've wanted to do for a long time.  I adjusted the height of the cueing mechanism.  The owners manual tells you to adjust this, and it should be set for 3/16 of an inch.  But when I turned the screw, nothing happened.  So I decided to take a chance and turn the screw all the way.  The screw came out!  Then I looked under the screw, and there is a little collar that the screw goes into.  When you tighten the screw, it's supposed to lift that collar flush with the surrounding metal (which is as far as it can go).  When you loosen the screw, it's supposed to fall back.  But it wasn't falling back.  The solution was to put the screw back in, and push the screw down.  With several pounds of pressure, it finally moved the arm to change the cueing height.  At first, I adjusted it a bit too low, then I adjusted just slightly higher than 3/16 of an inch (to allow for thicker records), and that worked great.  Turning the screw clockwise works great for raising the cueing, but counterclockwise requires a push so that the collar actually moves down.

Then I noticed something really weird.  When I had the cueing too low, the blank record now showed considerable skating towards the center of the record.  That would suggest that the arm had been made too long.  When I finally got the cueing adjusted right (just slightly more than 3/16 of an inch) there was no skating again.

So it seems the cueing adjust screw actually adjusts the arm tilt rather than the cueing arm itself!  Actually the manual does not even call this the cueing adjustment, they call it the stylus level adjustment.  Small changes in arm tilt affect (by a very small amount) the length of the arm when the stylus touches the record.  If I understand this correctly, it suggests my cartridge alignment is very exact, because even a small error introduces significant skating, and I have none.

I had some idea that adjusting the cueing was beneficial in this way: the cueing had been set so high that the cueing mechanism was actually pushing the arm up at points when it was in the groove.  That could explain the mistracking.  I'm not sure this is true, possibly the mistracking (which I thought I heard while in the bathroom) was just hearing the repeats in the music.  I had not tried to replicate the mistracking before I started testing and adjusting (because I wanted to get the job done, and I knew some things needed adjustment anyway).

The rest of the adjustment mainly involved getting the arm to land precisely in the arm holder after automatic arm return (this turns out to be VERY important on this turntable) and to get it safely into the lead in groove on automatic start.  These two adjustments require very fine screw turning, and they are said to interact (though I didn't notice much interaction, per se).

Here is why you need to get the arm to land precisely in the holder when it returns.  If the arm doesn't land precisely in the arm holder, it will get bumped either toward the record or away from the record.  Then, the arm will no longer be perpendicular to the arm rails.  So then if you put the arm on the record, when it lands (or before it lands) the servo mechanism will try to correct by moving the arm base.  This could cause the stylus to fall off the record (not good).

Now I had noticed from Sunday night that the servo mechanism was turning on above the record surface.  That could cause the arm base to move before the stylus falls into the groove, which is inconvenient if not dangerous.  I tried unsuccessfully to adjust that.  Actually, this particular adjustment was covered by what looked like factory applied black tape, which I needed to peel off.  That black tape is on both of my LT-30's.  Anyway, I peeled off the tape, but the small phillips screw underneath could not be turned by any reasonable amount of pressure.  I gave up, not wanting to break the arm.

But after I had adjusted the cueing height, the servo engagement system fixed itself.  Now the servo turns on at the moment the stylus reaches the grove.  That means even if the arm is not correctly perpendicular, it will fall where you want it, and not servo to some other position (which could be off the side of the record) before reaching the groove.

Then one more adjustment, because I actually feared all of the above (while useful) would not actually solve any mistracking problem (if there had been one).  I tried adding more mass to the headshell to change the arm resonance.  I first tried using the 4g weight, but that was too much because I could not get the arm to balance.  But the 2g weight worked fine.  I'm not sure if this is helpful, it seems I can see more relative arm to stylus jiggling than before.  But I think that might be good if previously the jiggling was at too high a frequency.

I've noticed no more mistracking.  But it sometimes seems like the turntable might be adding wow and/or flutter, despite the servo lock light being on, and the turntable not being affected by a little extra finger drag.  I've gone ahead to buy the Dr Feickert test record from Hong Kong through ebay as it is apparently not sold in the USA (not online anyway).  That should give me some objective results for wow and flutter and arm resonance.  An arm resonance could also be adding wow and flutter.

Friend came over on Thursday night and we listened to two records together.  She noticed nothing wrong and said it sounded great.  It's great to have a working turntable!  It's great to have friends too!

Servicing SP 10

One of the great advantages of buying an SP10 Mk2 or above is that these were very popular turntables, at least by high end audio standards.   That translates into incredible support today, almost 30 years after the launch of the SP10 Mk2.  People are talking or will talk about them everywhere, discussing all aspects of use and refurbishing.  There are companies well known for servicing SP 10's, which is something I intend to do soon (but hopefully not because the turntable has stopped working well).  Here is a list of well known SP 10 shops:

1) Bill Thalmann at Music Technology in northern Virginia.

2) Steve Dobbins (mostly known for high end plinths)

3) Sound HiFi in UK

Here's the blog where I found these names.

I like the idea that the SP 10 bearing is supposed to be user serviced, because that means it is user serviceable!  (And not some bit of magic that requires you to find a guru in Xanadu.)  The main thing required is cleaning (with alcohol q tips) the bearing and then adding oil, or just adding oil if the bearing is clean and in use.  The factory specified oil is Technics SFWO 010.  Technics does not supply this anymore, but claimed-identical products are available in many places, include, where I just bought some.

KAB reveals that they learned from Technics that the oil is actually a synthetic diester oil blend known as Anderol 465, used for impregnating sintered metal bearings and parts on aircraft (!)

Others have suggested various alternatives, like synthetic 5-50W oil.  What definitely should not be used is 3-in-1 in the red can because it gets gummy, but 3-in-1 in the blue can (for medium electric motors) is said by some to be ok.  Seems like Technics was using the best possible product though.

Tuesday, February 4, 2014

Spinning Vinyl Again

I've been spinning vinyl again, and loving it.  The sound is pretty much the best I've ever had, with minor issue that will be explained below.

My vinyl spinner is a straight line tracking direct drive table from Japan in 1980, a Mitsubishi LT-30.  My first unit worked fine out of the box, even though the ebay seller had not bothered to remove the platter or secure the linear tracking arm with the factory shipping plates.  The arm makes a very soft tick or bump sound just before it moves while tracking the record.  I have a recollection of a straight line tracking table in the 1980's doing exactly the same thing, and I think it was a Mitsubishi, and the reason I did not buy it, even though way back then I didn't really think it was such a big deal.

Anyway, I spent a week after unpacking the first LT-30 not actually playing music through it, just testing how well it tracked records, and adjusting the user accessible adjustments.  I wanted to be sure it was OK before mounting my Dynavector Karat 17D2.

In fact, the last weekend in January, when I received the first LT-30 on Saturday, was very busy and productive.  As usual, I hosted a discussion and movie party on Sunday from 3-9 PM.  I spent most of Saturday preparing for that by cleaning up the living room, which was filled with stuff I had been working on (including the Sony PS-X800 turntable I had attempted to fix).  I needed to install the new set of UPS batteries in the Pure Audio UPS, move the UPS back into position, and set up the stack of components that rests on top of it (which had been strewn about the living room).  That included exchanging the Acurus A250 tweeter amp (which has waaaaay too much power for my Elac ribbon tweeters) with a Parasound HCA-1000A (which has less power, higher bias, circuit design done by John Curl and approved by my friend Tim as being the best possible, and is direct coupled).  I wanted to set up the Parasound also, but I found out that it wasn't working.  Then I found the problem, a blown line fuse, and recalled the experimentation with the PS Audio Power Plant Premier when I had an APC Smart UPS 1500A on the same multi room AC circuit.  The two power conditioners on the same circuit were fighting each other, my equipment was buzzing, especially the Parasound amp, then the fuse blew.  I don't think there was actually a problem with the amplifier.  Anyway, it turns out the Parasound uses a 3/4 inch line fuse, and all my line fuses were 1+ inches.  After putting more than an hour into the effort of getting the Parasound running again, I simply abandoned that project, but put the Parasound in the new equipment stack anyway, with the old Acurus taken out to my climate controlled storage building called Lyndhurst, where I had also gone to retrieve the Parasound.

With all that, and the party preparation, it was a wonder I even got the turntable unpacked, but I did, and started the testing and setup process.  I was actually spinning vinyl before the end of January, as I had promised a friend at the River City Audio Society meeting, but wasn't actually playing music from it until the following weekend.

I tried to get some answers on the arm ticking/bumping sound from a thread at AudioKarma during the week, but no answers yet.

Then the following weekend I finally got vinyl spinning AND sound playing.  Though it started with another busy Saturday.  I went to computer club meeting and gave a Kurzweil demonstration.  Then I had dinner.  Then I went to the San Antonio Symphony to see and hear a semi-staged production of Rusalka.  Then I went to the supermarket and did the shopping I had been postponing all week.

Finally I got to the actual vinyl playing setup on Sunday.  The first step was getting AC power to the related components (turntable, DB-8HG phono module, and Acurus L-10 preamp).  I though about various temporary solutions, but then jumped right in to what I wanted to do, taking a chance it would work, and it did.  I cut a hole in the back of my drawer/shelf chest, in one of the shelves.  That hole would allow me to put an AC power strip on that shelf, and run all the cords to and from it.  I was initially thinking I'd need a saw, and that would create a huge mess, and I'd have to move all the equipment (lots of it) off of the chest so I could move the chest out from the wall to vacuum up all the saw dust.

Fortunately, it turned out that the back panel of the chest is basically just cardboard, and it cut fairly easily with a utility knife.  I did take all the electronic equipment off of the chest anyway, to vacuum it off, and set it back with even more equipment on top.  But I didn't have to mess with the turntable or the piece of slate beneath it.  (Actually, I had already done this equipment vacuuming and setup BEFORE I was faced with this problem of cutting a hole or not.  So I REALLY did not want to move the equipment off AGAIN.)

Then the next problem was getting power to the power strip.  The hole I cut was not large enough to squeeze the power strip through, and just pushing the cord out from the hole I couldn't get it to go anywhere where it could be pulled out and attached to another cord to be connected to the main equipment strip.

The solution to that problem was cutting a short piece of string, and then attaching a metal object (actually, a cat nail clipper) to the string, and lowering it down from the top of the cabinet, I could then pull the string through the hole.  Then I could tie the string to the power cord of the outlet strip, and pull it back to the top of the cabinet, where I could attach it to another cord (I found the perfect 8 foot 14g cord in my cord box) to reach the sub-strip next to the TV.  THAT second strip connects to the main Monster Power strip that powers all my AV equipment, and that main strip is connected to my 20A dedicated AC line.

It also turned out to be easy to get all the equipment cords run through that hole just by lowering them from the top of the chest.  The plugs almost seemed to magically appear in the opening, and I pulled them in one at a time.  I connected the three things I needed to run right away, plus the three others I will be using in the future: the SAE impulse suppressor (a friend insists I use this when I copy his out-of-print records to digital for him), the Alesis Masterlink recorder (which I use to records LP's and cassette tapes), and the Nakamichi RX-505 cassette deck (which I can use to play cassettes I'd like to copy to digital, or just play cassettes).  So the metal outlet strip is nearly full now.

Once I got everything hooked up to AC power, I had to connect the interconnects.  I didn't use anything too fancy, but I did have a 1.5 foot length of premium OFC interconnects I got at CES in 1989 to connect the DB-8HG phono stage to the Acurus L-10 preamp, which then drives a pair of cables the 25 foot distance to my level-boost preamp, an Aragon 28k, which then drives my MSB PAD-1 analog to digital converter, which feeds AES/EBU to my system Tact preamp.

(And despite all that, despite all the long cables and multiple in-line buffers, all my care in AC connection and cabling shows itself as zero noise and zero buzz when listening to phonograph records).

I first played the Peter Sprague album I had been using for testing and setup purposes (because I considered it expendable).  Actually, this turned out to be a marvelous record, and all my messing around with it (even using the *gasp* cheap phono cartridge which came with the table) didn't seem to have hurt it at all.  Then I tried some Emerson Lake and Palmer.  First, Pictures at an Exhibition, then Tarkus.  I liked the Peter Sprague better.

The weekend ended well.  I texted my friend and she wanted to hear over the cell phone but I was hydrating in the kitchen and missed her call.  While I was hydrating in the kitchen, I used Sonos to pipe the sound from the bedroom turntable into the living room.  The Sonos system in the bedroom takes as input the tape outputs of the Aragon 28K used to amplify all analog sources to suitably high level for the MSB PAD-1 digitizer.  But the tape outputs are at just the right level for Sonos as they are not amplified to that high level.

Actually, before I even started on this project in earnest, something else happened.  I won my ebay auction bit on a Technics SL 1000 system, include SP 10 Mk2A turntable, Obsidian base, and EPA-100 arm.  That is the turntable I hope to use in my living room, with the Lenco L75 as an alternate (for testing or backup).  Since winning that bid, since before winning the bid actually, I've been talking with the seller about the details of packaging.  I had already ordered a shipping plate for the Technics motor on the expectation of winning this table, which has been a dream table for me for decades.

I never believed that direct drive tables, the better ones, are lousy sounding.  My previous favorite table, the Sony PS-X800 is a nice direct drive with wonderful sound.  Likewise my new LT-30.  When I mentioned my belief to an audiophile friend years ago he quipped "so where is your SP 10?".  Well I didn't have an SP 10, and I'd be the first to concede it could be an even better sounding motor than the one in the PS-X800.  So now I will have one, with a fine arm also, and I even believe the Obsidian base has been unfairly maligned--it would take considerable effort to make a better plinth, and the Obsidian can likely be made better without starting over (I hope) mainly by adding bottom decoupling (i.e. damping feet).  Anyway, the motor is superb and the plinth with dustcover will be very convenient until I get another one.  There is no reason to believe the Obsidian base is inferior to the base of the LT-30 or the PS-X800, in fact it's likely to be better than those, with the only weakness being the lack of damping feet.

So I've been very excited about winning my "dream" table.  Meanwhile, I just barely managed to check out the second LT-30 I bought for backup, parts, and experimentation during this weekend.  It was actually Monday afternoon by the time I quickly unboxed it and plugged it in.  And I discovered quickly the turntable didn't even turn on when I flipped the on switch (at the arm holder).  Later on Monday I opened an eBay "case" and sent a message to the seller about the claimed-to-be-working turntable.  But Monday night I took the bottom off the unit, and quickly discovered the problem.  The actual power switch was loose and was not getting enough push from the cam that was supposed to be pushing it.  I tightened the switch, and the turntable worked.  I put a record on it for testing (this time, I chose the Emerson Lake and Palmer Tarkus, my least favorite of the 3 records I played Sunday night) and it worked perfectly.  Despite the arm base seeming even looser than on the other LT-30, and despite the table generally seeming in slightly poorer condition, the arm does not make the ticking/bumping sound that the one in the bedroom does.

Anyway, I'm glad I had the opportunity to take a look at the bottom of the LT-30.  It is far simpler than the PS-X800 and looks like it can be much more easily serviced and experimented with.  I should be able to figure out how to fix that bumping sound.

But I've not heard any ill effect from the arm movement on my speakers.  What did strike me as being slightly wrong were the loud pipe organ bass notes from the Reference Recording of Respighi's Church Windows.  Right now I don't know whether the lumpy bass was caused by the arm/cartridge mismatch (I think the Dynavector 17D2 cartridge needs much more effective mass than the current arm and headshell provide) or by acoustical feedback.  It will be important to find out.  I can fix the effective mass problem by using a heavier headshell, like one of the Sumiko headshells I must have somewhere. I loved those Sumiko headshells, but I was forced to use a lighter headshell in the PS-X800 because it's auto-balance system didn't seem to be able to balance correctly with the Sumiko headshells anymore.

If the problem is acoustical feedback, I'm not sure it can be as easily fixed.  The table sits on a 50 pound piece of slate on the chest.  The chest is very strong vertically but can be made to twist horizontally by a millimeter or two.  If there is an acoustical feedback issue, it is most likely from this horizontal twisting.

It had been sometime during last week that I decided to go for my "dream" SP 10 turntable.  I had been looking at SP 10's and Denons on eBay and in discussion forums for the past month.  Finally, it was the sense that I really need to follow my bliss that got me going.  I'm a serious audiophile, and I take turntables pretty seriously, I think that rotational speed is very important, and I think direct drive is basically the way to go for best performance.  So why did I not have an SP 10 already?

But actually, I've had a number of conflicting feelings.  Not that belt drive is superior, but that perhaps the DC direct drive used by Technics isn't the best.  The audio salon I worked at in the 1970's sold Denon turntables, and pushed the line that Denons were better because they used AC rather than DC motors.  We also said that the DC motors worked on a series of pulses (I now think this part is likely incorrect).  I haven't compared the two myself (we didn't have a Technics in store, we had only Denons and our Mitch Cotter base had a Denon 6000 on it, only now I learn that the official version used the Technics).

But as I was looking at auction sites and reading blogs, it seems that the SP 10 MkII is generally regarded as being better than most Denons including the 6000, and about on par with the DP 80 (which I had never heard of before this month).  The only Denon which might actually be better would be the very very expensive Denon DP 100.

The Technics also has other things going for it.  They sold many of these tables, so service and reconditioning is widely available, and in fact the turntables are easily serviced.  Checking and oiling the bearing is the first think any new owner can do.  Denons are more like closed systems.  You don't touch the bearing at all, in fact it isn't even well known what the Denon bearings are actually like; they're a black box to most people.  So it looks like servicing a Denon would be far more difficult and expensive.

I also like the idea of the separate power supply.  And my newfound thinking, from reading the likes of Arthur Salvatore and listening to idler drive maniacs, is that speed constancy requires good torque.  SP 10 MkII and MKIIa, and MKIII are the torque champions!

I'd also been a little upset to learn that Denon went to using PWM to generate the sine waves used in it's turntables.  I generally think of PWM as an inferior system; it's been poorly used in tuners and amplifiers over the years anyway.

So it was actually only this month that I've moved over to the Technics camp.  Not very long ago, I was  criticizing the use of DC motors as in the Haiku Fan that I returned because it was too noisy.  But then I started learning that DC motors were not so necessarily inferior.  For example, Michell went to DC motors for their latest Gyrodecs, and users say universally and unequivocally that the DC motors are better.

Nevertheless, I had been continuing to look at auctions for the Denons.  Not only have I learned that the DP 80 was a successor to the DP 6000, but also the DP 75, which has better specs than the DP 80 but made to a slightly lower price point.  Either DP 80 or DP 75 would do for a nice contest with the SP 10 MkII.  But by most accounts, the MkII would probably win, and the MKIIA should be even better.