08-26-13: Richardkrebs
From reading here it seems that those that prefer hard supports make them all out of the same material. I believe that this arrangement can be improved, if your goal is to wick energy out of the TT structure. By using, say, three identical hard feet you are creating multiple paths to the shelf (ground). This is the electrical equivalent of an earth loop.
This is certainly not new.
The seminal article for mechanical grounding in audio equipment as applied to turntables was the Technical Report by Martin Colloms of the Goldmund Reference published in Volume 51 of The Absolute Sound magazine in 1988. Colloms undertook a complete dissection of the design of the Goldmund Reference including the single point grounding methodology that Goldmund employed. I would highly recommend anyone interested in TT design obtain a copy for reference. Some of these mechanical grounding principles were deployed to their entry level products such as the Goldmund Studio that richardkrebs owned.
Each time there is a change in materials some energy passes through and some gets reflected back. For example if you have a mat on a platter, then some energy will pass through from the mat to the platter, but some energy will reflect back to the record/stylus and smear the sound. This is basic materials engineering.
Providing properly designed pathways to drain unwanted energy from the stylus, record interface through the platter to ground in order to prevent coloration from energy reflecting back into the record and stylus has been around since the 60's, moreso in Japanese audio circles.
The Final Audio Parthenon from Japan released in 1971 is essentially a nude turntable with defined energy paths from stylus to ground. The designer Kitamura explains that the amount of energy generated by the interaction of stylus and groove is much higher than required to drive the coils, and therefore unless the balance of energy is drained to ground, it rebounds and resonates the turntable, arm and cartridge, superimposing resonances back into the playback. This is documented in a review of the Final Audio TT in TAS Volume 8 #30 in 1983. The absence of resonance, which results in a clarity and density of tone unparalleled by other TT's I have auditioned such as the Goldmund, Micro Seiki's. SP10's, L07D's etc is one of the primary reasons I purchased the Final Audio Parthenon.
08-29-13: Ct0517
If I understand you are using three leg supports under your triangle TT.
One is the "alpha" leg the leader for energy transmission, while the other two are slower followers? Are you not worried about energy in the plinth getting built up in those two areas with the pvc legs? Did you have a way to test this other than by listening?
08-29-13: Richardkrebs
Like your Alpha leg analogy. Actually, with the other two feet, we are trying to block energy transmission as much as possible although in practice I doubt that this can truly be done.
Actually it does work.
With electrical grounding the signal always finds the path of least resistance.
With a mechanical ground, as discussed, providing a single path to ground results in a cleaner dissipation of energy. Mechanical resonances and disturbances will find the path of least resistance to some degree, but there must be a logical path in terms of materials selection, transmissibility etc from platter to ground to minimise backward reflections. In the richardkrebs example the resonant behaviour of the hard footer will result in a specific resonance absorption and transmission/reflection profile, whereas the soft feet will attract a resonance absorption and transmission/reflection profile that is quite different. If one were able to put together a mathematical model of the structure and materials composition, then minimising the resonant behaviour and backward reflections can be calculated quite easily and would be more reliable than listening since no system exists without colourations due to room or other equipment..
