How much does rock-solid speed stability cost?

Thanks, everyone, for your thoughtful replies.

Twl, as usual, you are a fountain of useful information. Your explanation of cogging makes sense. I'll do some reasearch into DC motor-based tables. I'll also look into tables with heavy platters.

For those of you that commented on off-center holes, I see that occasionally, but not often enough to explain what I hear.

Violaguy, I am a former musician (trombone), though I haven't played in many years. I played in high school and college. I don't know if I have perfect absolute pitch or not but I'd say I have very good relative pitch, at least. I'm sure I could distinguish between A440 and 441. Thats about 1/8" on a trombone slide. A good trombone player is a lot more accurate than that - I'd say accurate to at least 1/32". I know what you mean about variations in dynamics and overtones. I love hearing the overtone beats of a piano chord, for example. That type of variation doesn't bother me at all. However, that's not what I'm hearing. I'm hearing real changes in pitch. I have heard variations in CDs but always assumed it was due to the master tape. Most CDs are fine. I've found the more overtones an instrument, or voice, produces the less likely it is to cause noticable flutter. It's the pure tones that get you.

From what you all are saying I think it's going to cost quite a bit to achieve the pitch stability I need. I'll keep my eye on the classifieds. (The SL1200 is going back to Crutchfield!)

The 1200 has close to perfect pitch stability--that's why is preferred by a lot of musicians that use "inferior stereo systems". I really like how it flawlessly keeps the beat of complex rhythm patterns of *salsa* music. Most belt drives don't cut it in this department. Something's not right here...

You could be mistaking eccentricity for pitch, as someone else pointed out. Nakamichi used to make a TT that adjusted the record's spindle so that it would play concentric. Perhaps it should be on your short list. Get back to us and send us some pictures!

Psychicanimal, I'm not trying to be contentious but rythmic patterns don't show up the kind of pitch variation I'm talking about. Sustained pure notes do. I listen to mostly jazz and classical which show this effect quite often. I've had the SL1200 for about a week and have played around 50 records on it. Most don't have any eccentricity at all. I vaguely remember the NAK deck. Early '80s, I believe.

Psychicanimal, I thought you might be interested in a recent development. I've been using a Shure V15VMR with the SL1200. I had been using the VTF set at 1.5g, as recommended, when using the dynamic stabilizer and a target VTF of 1g is desired. With this setup I could hear pitch variations on pretty much every record.

Next, I tried disabling the stabilizer and setting the VTF to 1g. Whoa! Much better. Tracking is not so good on warped records, though. This got me to thinking, maybe the stabilizer in subtracting more than .5g. I re-enabled the stabilizer and set the VTF to 1.7g which should give a net VTF of 1.2g, which is near the top of the recommended range for the V15. I suspect the actual VTF is less, but I don't know of a way to verify this. Anyway, the pitch variation is almost completely gone! I still hear it on records with off-center holes, but a good record sounds fine. I've changed my mind on the SL1200. I think I'll keep it:)

Anybody know why this is so? I know the V15 is high compliance. Could the suspension, in a lightly loaded state, been resonating to cause a sound like flutter?

Nighthawk,

I also use the v15vxmr and have noticed the difference the tracking force can make when using the stabilizer. I could be way off, but I think of it much like the loading of the suspension on a car. I think of the little brush as a spring. If the tracking force is light, as shure recommends, there is less loading on the stabilizer and it's "shock absorbtion" is slower to react or has a greater distance to move, however you want to look at it, but the effect is that some of the load is taken off the cantelever. When we set the VTF higher we have forced the loading on the stabilizer and also the cantelever so the whole mechanism is quicker to react and get back down in the groove because it doesn't move as far vertically. BTW, I also notice more sibilance with the lighter VTF.

In anycase, I agree that it does sound better with the stabilizer in place and with the higher VTF.