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----- Original Message ----- From: "Ron Fial" <[log in to unmask]> > Has anyone tell us what they mean by a 'clean' 78, or a 'cleaned' 78. > It makes more sense to have a contest between machines after agreement about how the 'clean-ness' of a 78 is measured. I am no expert, but here are some possible criteria, and I suppose you could give a numeric weight to each measurement to come up with a cleaning 'score'. I am sure there are many other measures that could be taken, like actual signal to noise ratio and the like. > > 1) presence of dirt or microscopic metal particles in the groves. > > 2) Lowest noise levels in a quiet section of grove. > > 3) Lowest ionic contamination ( part of the 'cleaned' record is dipped into distilled water and stirred. Then the ohmic resistance of the water is measured, the resistance will drop due to ionic contamination). > > 4) The record after cleaning sounds better, has less distortion, less residual noise in quiet parts of the grove. > > 5) The record after cleaning has shinier surface. This could be due to dirt removal or actual surface > polishing, but this could be due to residual oils or soaps also, which is probably not a good result. Of all of these, #4 is the only one which has any actual applicability! #2 is part of #4...#1 and #3 are of interest primarily to research chemists, unless any become catalysts for the chemical breakdown of shellac..and #5 can be easily simulated with a can of black Shinola! Steven C. Barr