Just Another Groovetracer Fan

If I were in the VERY enviable position to purchase an RP8 or 10, I'd have not even bothered trying to upgrade a lesser model. With the GT subplatter, the difference was very big, but that being said, I did it because it brings the table closer to what the RP8 or 10 comes with in the stock form. They also have dual pullies, a much better plinth, and what my P3 can't begin to compete with is the tone arms on those models. At the end of the day, I aspire to get to the sound that an RP10 can deliver. The only way to get to that sound is to buy one. I know myself well enough to know that even after I purchased the GT products, the curiosity and desire to have the best I could afford would push me into the arms of an RP10 anyway. Thats just me though. There's no way any amount of modification I could do to my P3 that could keep me from still wanting the 8 or 10.

 

Good points J.D. I haven't heard the RP 8 or RP10, because they were out of my price range back then. I owe it to myself to hear how big the difference is and my dealer has them. I also love the look of the P9 and would not hesitate to pick up a good used one there. Then there are the beauties over at Vinyl Nirvana...

 

I've been very happy with my current config over the last two years, haven't changed anything since, and see no reason to, audio nirvana achieved. The vinyl front end now rivals the digital mastering rig. I also have the TangoSpinner triple brass pulley with three of their silicone belts, and the Michell VTF adjuster, I think that's all the mods.

 

I've heard the RP8 here in the city. It's magnificent. I'm not the biggest fan of the plinth design and the detachable parts, but that's for purely aesthetic reasons and I'm probably in the minority on that one. It's a beautiful turntable in its own way that's just better in so many ways to the P3 I'm using. The sound was just very refined on it. It's the kind of turntable you'd want to build around. Especially if you're one of those "source is the most important part of the chain" guys. I think I'm turning into an "everything matters" guy. All the parts play on the others abilities. Turntable, amps, speakers... It all just seems to be of equal importance to me. Anyway, good luck and enjoy whatever it is you buy!

 

Rotational stability is a function of the bearing and platter system. The subplatter is the component with the smallest effect of the lot. The main bearing of many turntable designs could support a platter directly, and does so in many designs. Most notably in direct drive models. The rotational stability is achieved by a smoothly rotating bearing and a platter that has some mass, especially at its outer edges. That should also be balanced well to work optimally. Many makers of belt driven tables choose to split the platter into two sections consisting of a main outer platter and a smaller inner subplatter. That is so they can locate the motor under the platter which has several advantages. It protects the motor, pulley, belt, subplatter surface system from dust and allows for a smaller overall footprint for the turntable. Rotational stability in platters is most effective at the outer edge, where inertia and speed are greatest. That is why Rega has concentrated mass there. The subplatter adds some mass but it is rather inconsequential at that proximity to the bearing.

Rega's philosophy about light and stiff designs isn't a philosophy as much as a design goal. It's an engineering specification that was implemented in their designs as they found that it improved the sound of the tables. When they change the subplatter material in their higher end models, it isn't about the subplatter materials mass or about adding mass. It is about creating an ideal interface between the subplatter and the main platter to form a more precise fit there, allowing the two pieces to perform as one. I went over this in detail in another thread.
-Bill

 

Interesting observations, but that is not what is actually happening. Rega uses a completely different subplatter and platter, which are engineered together in their upper end designs. It isn't just adding an aluminum subplatter. The platform surface of these are machined to fit into their platters on the RP8 and RP10 tables. It is only the lower tier models that have a molded cap that centers their single layer glass platters. Using the phenolic platter and the single layer glass platter does lower the cost of the lower tier tables, but performance is still very high. The RP8 and RP10 platters use contoured platters with weight evenly distributed and concentrated around their perimeter. These were designed to have a precise fit onto their machined aluminum subplatters.

Rega subplatter, nor aftermarket subplatters are designed as you suggest. All subplatters consist of at least two pieces, an axle and a platform. The axle is machined and hardened steel on the Rega subplatters and I suspect it is as well on other brands also. It could be made of some formulation of stainless steel alternatively, but that is a bit trivial in this application. Axels are pressed into the platforms, no matter whether they are phenolic or aluminum or unobtainium. Rega bearing wells are brass and have a ball bearing resting in their base. The well is bathed in oil and the axle is inserted to form the complete bearing. Most aftermarket subplatter makers are not offering complete bearing assemblies, rather just the axel part that you drop into the existing bearing well on a Rega deck. No way can you guarantee higher tolerance bearings without making both halves of the bearing. Further, the Rega bearing design uses a ball bearing on which the axle spins and a heavy oil film between the axle shaft and bearing wall, so it is suspended by hydraulic pressure rather than the bearing surfaces having direct mating contact. There are bearings made that use either very thin oil or are made from oil impregnated bronze, or even have a teflon mating surface, all of which would have more significant wear from more direct interfaces, but that is not the case here.
-Bill

 

I love the engineering behind all of this. It's even more enjoyable to read about the mechanical engineering than it is the electrical engineering behind tube amplifiers and the such. Reading circuits, and the parts and pieces that are inserted into the circuits to deliver a very specific grade of sound is pretty great stuff.
But for me, at the end of the day, it just comes down to the simplicity of liking what I hear, or disliking it. A subplatter, no matter if it is an insignificant engineering alteration to a much grander system, when changed out made my turntable sound better. I don't even care if it's no better than a bandaid. It was so simple. I changed it. The pitch stability changed for the better, and that was that. I just liked what I heard. I easily go down the rabbit hole of the ins and outs, the engineering, the cost, the this and that of this audiophile labyrinth. And there is a great value to doing that. You learn so much!!! Endless learning
But sometimes it's as simple to me as, "well, does it sound better or not?"

 

I bought an RP3 with an Exact2 and TTPSU. I then added a white belt which was a bit of an upgrade. Nice table, really enjoyed it.

A few years later I bought the Reference sub-platter from Groove Tracer with the ruby bearing. Incredible difference. This led me to purchase the Delrin platter and then the counterweight. This is a transformed table. I love playing LPs on it and I don't lust for another player. It sounds so good with my Decware ZP3 phono preamplifier into my Decware Torii Mk III amp. I'm a happy LP spinner. I recommend the Groovetracer products without hesitation.

 

Your post is very interesting. The company that did the restoration of my Thorens TD 160, is Vinyl Nirvana.

The restore is beautiful, could not be better!

The TT has all the nice standard features that come with the Midnight Edition. It is a lot of stuff. I have a optional record weight from them.
Now, they also offer a counter weight as an option. It looked like a well made counterweight was already on there. I just assumed that the counterweight option was more "audiophile" looking, than serving any practical purpose?

What would I expect a counterweight to do except sit there, it's just a piece of metal? What would be the difference between an audiophile piece of metal and the standard piece of metal that is on a reasonable quality turntable arm (Rega/Moth 202 w/upgraded Cardas Wiring)?

From your post, sounds like something worth checking out, down the road.

 

Not directed at me, but I see two differences:

Optinising the weight or the counterweight allows the counterweight to sit as close to the pivot point as possible.

Also, most of the better counterweights have an Allen bolt to secure the weight to the arm. This should reduce resonance .

 

The GT products seem to do the job and are of an extreme high quality. it is still a shame that Rega does not include better quality sub platter and bearing on a $1K turntable. At the volumes of product they sell the cost of these upgraded parts would not be that much to include them.

 

I am not exactly sure about the physics, but I read that having an "underslung" counterweight like that offered by GT and Michell (where the weight is all 'down low' instead of being equally distributed) changes or improves the way it tracks. It's going to affect the centre of gravity etc. But I also read another article saying that underslung counterweights were a waste of time, I'll see if I can find the link... All I know in my case is that it definitely improved tracking.

Underslung tonearm Counterweight - truths and myths to know about

 

The counterweight that is already on the Rega/Moth tone arm is carved from a block of aluminum, is anodized black (it may be paint, don't know for sure) and it has an Allen bolt set screw.

I'm thinking that where the counterweight sits, might have something to do with it?

If it were better closer to the pivot point, it might be thinner, it it were to be made with a denser aluminum alloy. It could also be a larger diameter which would allow it to be thinner.

Although I may have missed them, I can't seem to remember reading any threads that said much about counter weight upgrades?

It would be interesting to read some before/after opinions.

And, a little science too, if possible?

 

Article was very interesting, I tend to go with the more dense counter weight being smaller and having a lower moment of inertia.

It would be most effective with dense metals, like Tungsten, Gold and Uranium.

 

I bought the GT subplatter and platter a few years ago and the counterweight and clamp this year. While all of these upgrades improved the performance of my P3 (2000), I noticed the biggest improvement from the counterweight. It tracks much better, giving more detail and less inner groove distortion. I would strongly recommend all of these products for anyone with an intermediate level Rega turntable.

 

for someone who has been there n done it, i would say go for it man.

last year, i bought a 6mths old Rega RP6 fm UK and then go onto to Groove Tracer n got the
Delrin Platter, Subplatter n Underswung Counterweight, for my ears it was literally a day and night improvement
overall, a mind blowing experience with no regrets.

 

I finally succumbed and ordered the GT record weight too, to add to the counterweight and reference sub-platter on my RP6!

 

I was searching Groovetracer threads and just found this one. I recently upgraded to a GT sub on my Rp6 and am still blown away with the difference in makes. Not subtle at all. Incredible.

In terms of the counterweight and platter—I assume these aren't quite as big of a sonic shift? Or are they? Which would you prioritize?

 

The GT counterweight is fantastic, didn't notice much of a difference in sound, but it now tracks everything much better. I have the GT reference sub and counterweight on my RP6, but didn't bother with the platter as I like the standard glass platter and saw no reason to "upgrade". Reached my TT audio nirvana about five years ago and not felt the need to upgrade anything else since. Also have the Michell VTF adjuster and the TangoSpinner triple pulley with "Opal" (silicone) belts. It's a superb turntable now (AT150 MLX cart).