One turntable with two arms, or two turntables with one each - which would you prefer?

"Panzerholz is not stable -it can warp"

In all the years I have known of B25 Panzerholz ply ,

I have never seen anything even remotely to suggest

it is unstable or will warp. 25 mm and up in my experience is VERY stable to the point of being used

structuraly in many building applications . I have used

pieces removed from the base of massive machinery shipped in the late 70’s that were stored in the factory basement left leaning against a cold damp concrete floor in winter and hot humid in summer for almost 4 decades with zero warps or instability.

The layers of BEECH [its not birch] are layered between with the resins. The vacuum and compression leaves the Beech impermiated with the resins throughout. I simply cannot see any scenario in the home or shop that could cause an inch or more thickness of what is essentionly more phenolic resin than wood now warp or not be stable. Loft condos use it for self supporting stair structures. As far as sealing it, my experience tells me the edges seal themsevles when the blade heats and seals as it cuts. You can literaly polish it to a shine exactly as you would the paint on a car with a polishing compound.

Im with pindac on this claim in my experience for certain. Too many critical items are being made from it whom would not do so without data and reason to hang their shingle on.

Beech B25 Panzerholz, are you talking about the same thing. As my experience mirrors Pindacs and I know of no one elses whos doesn’t...Just know what Ive seen and experienced and never seen proof to refute it...

I find that Pz warps only when left unsealed. Is your experience otherwise? Thanks!

Yes. Panzerholz is hard to get in New Zealand.

I purchased from the importer, checked the flatness of the raw material and found the sheets were not dead flat.

Basically I had to laminate 2 pieces, choosing adjacent material and inverting one so that when I laminated the 2 pieces the warp was eliminated. We are talking half a mm across 12 inches, but for me thats too much - I want the arm and bearing to be precisely on the same plain. And I would not want to machine the material flat and disturb the surface - hence the lamination process seemed the best option for me to resolve the warp issue.

Soundwise used as an armboard it damped resonances very well compared to my usual gunmetal armbands. for example it worked well with my FR64S, but these results can be very much dependent on the turntable itself and how the armbands are terminated. For example on my reference TT the armboards are terminated with a 60kg SPZ ( superplastic zinc alloy ) plinth that is as dead as a dodo - on this specific TT the panzerholz armboard is inferior to the gunmetal.

Beech B25 Panzerholz, are you talking about the same thing

Never used these words - have no idea what you are referring to.

Beech B25 Panzerholz, are you talking about the same thing

"Never used these words - have no idea what you are referring to."

You said Panzerholz and that you used it and it warped.

I assumed then you knew enough about this product that you would know it comes in either B15 or B25. Either 15 layers of Beech veneer per 25 mm thick or 25 layers per 25 mm thick.

I reiterated the word beech as even in this thread others claim its birch wood.

Sorry, I would assume anyone familiar with the product would know exactly what I was refering to...apologies

As far as the panzer armboard being inferior to the gunmetal on a specific table. I can see that preference. Very dead plinth the liveliness that the metal brings would be missed by some so balance is a key here. Its a valid point one must be wary of over deadening in this application where one surface meets another for preference. As far as being out less than half a mm. Its sheet goods not d4s finished stock. For armboards some surface milling like any othe material be it aluminum , brass, stainless, ebony etc. etc...that would be a basic step.

Non of those materials come without the same variations in raw standard plate or bar uniformity.

B25 was what I used.

The 40mm compressed bamboo ply I used was dead flat - really impressed with the quality and easy to refinish the surface if required. I used a 60ft bed CNC router used for yacht manufacturing and it knackered the cutter - its a tough material.

Very dead plinth the liveliness that the metal brings would be missed by some so balance is a key here. Its a valid point one must be wary of over deadening in this application where one surface meets another for preference.

or the deadness of Panzerholz could be missed.

My reference TT was specifically designed in the 70’s as an energy dissipation device.

The primary material used, SPZ, was a specially formulated engineering supermaterial, developed in the 1970’s in Japan for earthquake proofing buildings, that has superplasticity at room temperature - any vibration or energy between 10hz to 100hz entering the material disappears through grain sliding at a molecular level. It is no longer available - too expensive to produce.

The secondary material gunmetal is a high lead content naval bronze and was specifically chosen to encourage the transmission of unwanted energy from the arm to the SPZ slab with minimal backward reflection. Having a propagation speed of 2 materials close together improves damping ( sometimes referred to as bi-metallic damping ) and more importantly minimises backward reflection of energy at the material junction - in this case minimises backward reflection into the arm/stylus.

In layman’s terms the greater the disparity between 2 conjoint materials in terms of energy transfer and propagation speeds of any disturbances, the worse the damping and backward reflection is. Something to remember when you are combining different materials in a turntable structure.

Soft material like Panzerholz can absorb a lot of surplus energy, but at some stage that energy has to go somewhere, eventually the unwanted energy will be released in an.uncontrolled manner in terms of time - leading to a smearing of the leading edge in replay.

Ideally you really want a path to ground for the unwanted energy rather than a temporary sink.