Grado "wobble"...?

Make sure that your tonearm has an effective mass of
12 to 17 grams with optimum performance at 14 grams.

John

I am no expert but I have owned quite a few Grado's from the Signature 3 to the Sonata!! A great series of cartridges! However, I have had, in all my Grado's two that had the wobble. I cannot explain it but I could not remedy it. It JUST appeared. I understand that it may have somthing to do with the compliance of the cartridge and tonearm.

I have owned four Grados all in all from the Black, Blue, Plat., now a VPI Sonata. In a nutshell, yes the wood bodies wobble as you put it, the only time I have noticed this was with the wood bodied carts., namely the current Sonata. I have it attached to a Rega 250 arm. The only time I observed said phonomena was while playing the HIFI test record, you know the torture tracks, for cartridge compliance. Well the whole body started vibrating laterally, but the stylus never moved. John Grado explained that the Reference/Statement cart.s have just one resonance point above the coils in the "body" of the cart. This is what I saw, as far as what is happening with your playback I do not know. I hope your experience with the Prestige Grado does not effect your decision for a later upgrade, possbily to the Platinum and beyond.

I have only a little to add. Never owned a Grado- always kind of wanted one. I have had a Rega table for six years (rb-300 and 900 arms) and I have heard that rega arms are especially bad for the 'Wobble'... ie. the people who say great things about the cartidges don't use them on Rega arms. There can be a compliance issue but I think Rega uses an odd grounding scheme and Grado does not shield their magnets on the motor which can lead to the 'wobble'. I have never heard of a 'fix' for it. Check out the vinyl area at audio asylum. There probably hundreds of posts on this. Good luck

I should probably clarify a few things. First, the cartridge wobbles only rarely: three records so far, out of several thousand. On all the others it performs far better than a $40 cartridge has any right to.

Also, I've tried to find some common denominator regarding these 3 records but have come up with little so far. Each has a very slight bit of warp, but no more than many others in my collection. Two are 45 RPM, one is 33 RPM. None has vast dynamic shifts. But these 3, for whatever reason, all cause the cartridge to wobble every time I try to play them, while (so far) no other records in my collection seem to. And one of these records (I don't recall playing the other two) played fine, no wobble, when the cartridge was in the Thorens arm.

Thanks for the tip regarding this question at Vinyl Asylum.

I've experienced this phenomenon on several Grados, all the way up to a Reference/Reference model in a JMW 10.5 arm. It is consistent in the fact that the same records always induce the wobble and, yes, it seems to happen more often with 45 rpm records than with 33 1/3. It's something Grado owners simply have to learn to live with, apparently. At least I've never been able to stop it. And yes, it's annoying.

For the record, it's the Grado "Wiggle".
And yes, mine did it too (I always thought the damn thing would bust loose and leave a huge scratch on my LP -it never did...)

The problem is one of improper cartridge/arm matching.
Grado cartidges will resonate visually and audibly (check out what your woofers are doing during the "dance"...).
Your amp is reproducing that stuff!

As "jlazart" accurately points out, you need a medium effective mass tonearm or a tonearm that utilizes dynamic damping to get the best out of the low compliant Grados. Arm/cartridge matching is critial to getting the best performance and sound out of an analog front-end.

Hmm. Though I know very little about this stuff and am highly math-phobic, I ran a calculation according to the figure on Galen Carol's "tonearm/cartridge capability" web page and came out with a resonant frequency of 8.635, which though lower than the recommended 9-11 range doesn't seem to miss by much. I didn't think the Grado's compliance of 20cu was considered "low." But admittedly I have a lot to learn in this regard. Thanks for all the help so far.

OK, I've had a chance to look through the archives at VA, and am more confused than ever. Some posters there suggested that the wobble was due to unclean vinyl (my soul, perhaps, but never my records). Others suggested that the VTF was set incorrectly (I'm at 1.55g; Grado recommends 1.5). Still others suggested that the 'arm/cartridge match was improper. This last point is what has me still concerned.

Factoring in an effective mass of ~16.5 grams (11 g for RB-250, 5.5 g for cartridge, plus some miniscule amount for two mounting screws), and Grado's published rating of 20 cu for the cartridge, I calculated the Grado/Rega resonant frequency at about 8.6 Hz. The chart at the bottom of Van den Hul's phono FAQ webpage essentially confirms this.

Is this really too far outside the recommended 9-11 Hz range?

And, isn't the problem that the Grado has slightly too *high* a compliance for my 'arm, rather than too *low* a compliance?

It seems that Jlazart's recommendation of a total effective mass of ~14 g is spot-on, but also that I'm in the ballpark. So I have to think the Grado wobble (or wiggle) is due to something other than 'arm/cartridge matching, at least in my case. (My latest theory is that the slightly wider grooves of a 45 RPM pressing and/or the wider lead-in grooves prove difficult for the Grado to track.)

I'll certainly look for something a bit lower in compliance when I upgrade (soon).

Thanks again. Sorry to beat this topic to death--just trying to learn something from it.