Vintage DD turntables. Are we living dangerously?

Fleib,
Speaking of assumptions.....I'm assuming that you don't actually own a periphery clamp as I do...❓
You are probably correct in that the use of one together with a centre clamp/weight applies pressure more evenly across the record/platter interface.
However I have found that the sound quality is deleteriously affected if the clamp is used with any pliable platter mat.
When used with a solid mat (metal, glass, plastic) or no mat at all....the peripheral ring does iron out the three seriously warped records I own whilst appearing to have little to no affect on the sound quality.
When used with a compressible mat however, like rubber, felt or leather...the peripheral clamp on my turntables, manages to suck the 'very life' and essence out of the reproduced sound...😱

I am not saying that thin suede mats (because I have found it critical to always have the 'cut' suede side rather than the tanned leather side facing upwards) are the answer to every platter on every turntable...👀
It didn't improve my Raven AC-2 when placed on the copper-faced platter nor did it improve the sound when placed on top of the Micro Seiki Cu-180 platter mat.
I think all these things are system-dependent but as I started this discussion topic within a Thread by saying.....the cost of trying these suede/leather platter mats is small enough (for the possible gains) to warrant experimentation....😎

Halcro,
Interesting observations about periphery clamps. When a vacuum system is over applied it has a similar deadening affect, at least to these ears. Using a reflex clamp in reflex mode can have the same affect, depending on what's under the record and the rest of the record player. A combination of an over-damped tonearm (SME V - too much silicon) and a physically stressed record will sound dead as a doornail. Combine this with a ponderous sounding belt drive and it's torturous.

The best I've had is a Goldmund DD platter w/Goldmund clamp used only to hold the record in place. There was also a Goldmund mat made of methacrylate. Sota had what they called a Supermat that seemed like a similar hardness and was slightly concave. This would help flatten a record and compensate for outer groove brightness if clamped hard enough, but one had to exercise restraint.

All this leads me to believe a Delrin type acrylic or possibly carbon, and an unstressed record is the best.
I'll give away the deerhide - better results with a hard rubber mat.
Regards,

Fleib, I own a SOTA reflex clamp. On my SP10 Mk3/Boston Audio Mat2, I just sit it on top of the label, and I do not activate the clamp. I figure it weighs about 200g, give or take, and that is "enough". For my L07D, I own the OEM peripheral ring and the center record weight (which is quite heavy). When I listened with both devices in place, the veritable life seemed to have been squeezed out of the music, like toothpaste out of a tube. After more experimentation, I use nothing at all on my L07D, no clamp, no weight, no ring. Love it to death. There are no rules for this I guess; it's very subjective.

Lew,
I think there are similarities here. Have you tried the peripheral ring with the Sota clamp?

Matching the mechanical impedance of the record seems like a good idea, but only if vibrations are not reflected back. I think that's why a 5mm carbon mat is more affective than 3mm.
Griffithds likes the Funk Firm mat that purports to do just that - prevent reflections from coming back to smear the sound.

Perhaps using a metal platter or mat is a better match for slightly stressed vinyl? I use neither, but considering your and Halcro's posts, it seems logical.

Think I'll try the Achromat next. Maybe I'll take some sheet lead to a machine shop and have a thin undermat made.

Regards,

Fleib, What I wonder about is whether the stainless steel platter sheet of the L07D becomes a negative, when the LP is pressed firmly against it, since by all rights you'd think that immobilizing the LP with a ring and a weight should be a good thing to do. I probably should play with other platter surfaces, but the L07D design does not make that so easy to do. However, I can try the ring plus the Sota clamp.

On another note, I just had my SP10 Mk3 updated a la Krebs. The preliminary results are surprising, in that I really did not think much could be done to make the Mk3 sound any more lively and coherent than it does/did prior to the upgrade. Now I may be a convert. More anon, when I have had more time to listen.