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Richard Hess: > My biggest concern is gap-loss in normal pro-machine > repro heads. I think that's probably the limiting factor. Sorry no. The wavelength on the tape stays the same irrespective of the duplicating speed. So when duplicating at 64X the original speed by running the binloop master recorded at 3 3/4" speed at 240"/s then the replay gap in the loop bin master machine isnŽt any better than around 2 ”M. Which is the same gap width as is used on the Studer A80MR master maker running the tape at 3 3/4" speed to get you to at least 16 kHz. The losses occur in the inductance of the playback head at 2.5 mHy resonating with the loading capacitance. So youŽll see buffer amplifiers in the headstack with say 2" maximum of unshielded wire connecting the replay head to the low capacitance input buffer to get the LC resonance as far up as possible. Normally the loading input resistor of the buffer amp is set to get you some free eq loss compensation at approx 1.2 MHz to help compensate for the spacing loss between the tape and the head due to the air that is moved with the tape running past the head. I know since I worked with professional duplicating of cassettes for more than 15 years of my life and I rebuilt 6 Ampex BLM 200A from 32X duplicating speed to 64X speeds and I had to figure out all the gotchas myself. No rocket science for sure since everything that goes at 1X speeds works at 128X speed too. -- Best, Goran Finnberg The Mastering Room AB Goteborg Sweden E-mail: [log in to unmask] Learn from the mistakes of others, you can never live long enough to make them all yourself. - John Luther