Albert Porters after market panzerholz plinths

Dear Mapman: Speed accuracy and speed stability is IMHO a critical main target in any TT design but seems to me that in the best TT set ups ( either drive mechanism. ) that is not any more an issue, I can be wrong but that's what I think.

What I don't know for sure because I never measure it is that if my vintage BD and DD TTs are right on original specs as my today TT designs ( that I assume are on target in this regard. ).
All in all I don't heard/precieve any trouble with my units regarding speed accuracy or stability.

Regarding DJ the main problem is that DJ's needs heavy torque ( at any " moment " ) with the TT and very fast start/stop TT characteristics and I don't know yet any BD that can meet DJ needs job.

regards and enjoy the music,
Raul.

I'm still not getting it.

I believe a table spinning at a constant speed has 0 acceleration. Acceleration occurs as the table gets up to speed and prior to playing. So I'm not sure I understand how the higher mass plinth can enter into this. If teh plinth does not move or rotate during playing at target speed, then it should be fine I would think.

Also my understanding of the panzerholz material used in aLBERTS plinths is that it is very rigid but lower mass than comparable standard wood materials, so I'm not sure that adds up either.

I could see the value of the plinth using that material in theory again if the intent is to isolate from vibrations from the motor or perhaps even otherwise. No doubt any kind of motor used to drive a table produces vibrations, so perhaps the tonic is in teh specific cases where this is an issue otherwise, though I am skeptical it is an issue common to all tables in particular those already designed out of the can to deal with the issue.

I will also add that I cannot imagine a case where applying a more massive plinth properly can hurt, and they are very nice looking for sure!

Mapman, You are quite right that not all that torque is used during play. We like to think that some torque now and then is needed to maintain speed stability in the face of stylus drag, which can vary in degree related to the tortuosity of the record groove. Torque is also in play when the platter goes off speed for any other reason, like due to cogging, etc. I never saw anyone put any numbers on these forces, so I don't know how great or small they may be. If we ever had any real facts to go on, we would not need to have these rambling discussions.

Also my understanding of the panzerholz material used in Albert's plinths is that it is very rigid but lower mass than comparable standard wood materials, so I'm not sure that adds up either.

The Panzerholz used in Albert's plinth is very dense. It is made up of European red beech plies compressed under high pressure into a sheet about 1 1/4" thick. It's density is on the order of 85 lbs./cubic ft., which makes it heavier than than all but the densest exotic hardwoods.

John

i own 2 vintage tt's with Dobbin's plinths; a Garrard idler drive 301, and an Technics SP-10 Mk3 DD. i did also have a Dobbins plinth'd SP-10 Mk2.

so why do these plinths improve performance over the basic stock tt or OEM plinths?

my opinion, already touched on by others here, is that 60's, 70's and 80's 'even SOTA' tt's had their strengths and their 'areas of potential improvement'. obviously the strengths were that much more R&D could be directed to building motors since these companies were much more able to spend that money than the typical tt builder of today. OTOH their weaknesses were that the case work was an afterthought in comparison. system performace (cartridges, arms, phono stgaes) did not necessarily reveal limitations of the build quality back then.

it's not simply adding mass, or adding isolation. it's more a matter of engineering the precise plinth construction that will optimize the drive system. what is the best combination of materials put together in a particular way to allow the tt to have maximum livelyness, low noise, and drive which sounds the best.

i know that Steve Dobbins built many dozens of plinths before he sold his first plinth for the SP-10 Mk2. he did the same for the Garrard 301, and then again for the SP-10 Mk3. i know he experimented with many materials and ended up with a constrained layer design. eventually on the Mk3 he discovered that (in his opinion) mounting the Mk3 with the casework still in place compromised the performance due to the high torque of the Mk3 motor. the original casework allowed 'flex' and a slight smearing of the sound. eliminating the case and mounting the Mk3 'nude' inside the plinth performed better.

not every plinth designer necessarily agreed with Dobbins on that issue.

in any case; it should not be surprising that 30+ year old casework could be improved upon.