[nanbil]

OK, I'm thinking about placing two (one on the top side of the plinth and one on the bottom side of the plinth) grungebuster washers between my Audiomods tonearm and my Rega P7.  The Audiomods tonearm uses the older style (RB 300-600) locknut system rather than the current three point attachment system.  I know that the internal diameter is 24mm and would prefer to use the thinner (.8mm) size.   Any thoughts?

Additionally, I'm curious as to your thoughts about decoupling the P7's ceramic platter from it's metal subplatter using an additional grungebuster washer (size 50mm OD and 40mm ID)?

Thanks

Bill   

[watercourse]

I made a washer for the arm just like you are thinking, but only on top of the plinth, also a collar between the base and the arm itself. I used standard thickness. Works just as well as you would expect too, although the collar was not that effective as the arm was raised off the base and didn't contact it much. You'll have to adjust VTA, obviously.

[Herbie]

Hi, Bill. Grungebuster materials like washers and Dots are virtually always beneficial in and around turntable plinths. With washers you don't get a thorough decoupling as long as the parts are still coupled together via bolts or screws, though the washers do help tame micro-vibrations of and between the parts.

As an interface between ceramic platter and metal subplatter, a Thin black grungebuster Washer should do superbly.

Steve Herbelin
Herbie's Audio Lab

[nanbil]

Steve my thought is to decouple (as much as possible) the arm from the plinth and hence the reason for using the washers on both sides of the plinth.  On the P7 the motor is attached to the bottom of the plinth and I believe that the bearing is attached to the top-my thought was to try to decouple the arm from both sides. 

Additionally, what is the difference between the white grungebuster washers and the black ones?

[Herbie]

Addressing the arm from both sides is likely to be more beneficial than from just one side. Thin Black grungebuster Dots are a little more firm than the regular thin off-white Dots. Either should do very well between platter and subplatter, but I think a thin interface with just a little compliance would be best.

Steve
Herbie's Audio Lab

[nanbil]

Ordered!

[watercourse]

Please report back Bill!

[watercourse]

Oh, forgot to mention one more thing: I have been using HAL-O jr. dampers on the Audiomods counterweight stub and the armlift base, as well as the external DIN connector, with excellent results as well. The arm is more controlled without losing delicacy, previously uncontrolled distortion that added a tiny bit of treble edge is no longer noticeable, unless it's supposed to be there. Similar to the results of silicone fluid damping with my WT arm.

http://herbiesaudiolab.net/jr.htm

The dB neutralizer sheets also worked extremely well when I had the carbon fiber braces on my P5, to tame any resonances in the brace and plinth. I'm using it with my current table, the Simplex, with similar benefits. Along with liberally applied grungebuster sheet material on the plinth near the bearing, on the motor housing, and the arm pod for the AM arm.

http://herbiesaudiolab.net/gb.htm

[nanbil]

Watercourse-as you know I've been in Hawaii for the past month-due to be home soon-so I've not had the chance to give a full evaluation.  What I can say is that initial listening has been very promising.  Did the HAL-O Jr replace your bluetak?

[watercourse]

For all those that don't know: Bill has been tirelessly locating and safely disposing of unexploded WWII-era ordnances in the islands for the past month, keeping us all safe. I salute you, Bill. 

The HAL-O did not replace the blutak, but TBH, I never noticed any benefits with the blutak. With the HAL-O, each one has had subtle, but additive benefits. I initially put on one the counterweight stub to add weight, but noticed that it improved the sound. Then I added one to the arm lift, then the DIN connector, and the DIN cable itself.

[nanbil]

Funny Watercourse-

OK, I've spent a good bit of time listening to modded P7, and I have to say that I'm impressed with the decoupling effort-the effects are subtle but clearly audible.  The bass has a bit more slam, depth and definition, the soundstage also has opened up a bit-interestingly more with depth than width (my soundstage was pretty wide to begin with).  The biggest benefit is a smoother top end-I love the Denon DL-S1 but it can be a tad unforgiving in the top octave or so-violins in particular have a smoother, less metallic quality.  Overall I'm very happy with this mod-I won't be taking it off.