First do no harm. The responsible preservation and conservation of heritage master tapes.
Think that master tapes are best played back on the same equipment that originally recorded them?
The science proves otherwise. Legacy tape recorders should never be used to play back valuable master tapes.
All heritage tapes are slowly deteriorating from age-related chemical degradations. Huge numbers of Mylar (polyethylene terephthalate) film based tapes exhibit an oxide binder chemical degradation (called soft binder syndrome) that can render them un-playable without special treatment.
Acetate film based tapes can suffer from another degradation that makes them turn brittle and fragile. Using studio recorders having forced-guidance tape paths, fixed-pin lifters, or unnecessary path elements like erase and record heads for playback can damage or even destroy irreplaceable master tapes.
Minimizing playback distortions.
Revealing the true sound quality hidden in a master tape requires a playback hardware platform that is contributing no additional distortion.
There are two predominate distortions introduced in analog tape playback. The first is time base degradation, known as wow and flutter and pitch change. It’s observable as unwanted frequency modulation and shift.
Mylar-based tapes stretch (change in length) under tension. This makes recording and reproducing analog audio signals on these tapes challenging if you want to preserve the recording's time base accuracy. The solution was a servoed constant tension transport. Further reduction of time base corruption is accomplished by improving the mechanical quality of the transport mechanism. This approach is costly, but the results are audible.
The second distortion is amplitude response error, observed as a non-linearity of signal magnitude plotted across the frequency spectrum. Once again, perfecting the mechanics of how the tape travels over the face of the reproducing head is the critical first step in controlling this distortion. Only after this is accomplished, should one turn to improving the playback electronic circuitry.
Both of these distortion types are easily measured with suitable instrumentation. Both are readily detectable by trained listeners.
Meet the reproducer, a reference-quality tape transport mechanism optimized for playback.
We manufacture state-of-the-art analog tape playback systems for sound recordings archives. Some of the design objectives behind our products are outlined here.
We know that achieving the lowest time base corruption requires a servo constant-tension, servo capstan, precision guidance transport design fitted with high precision headblocks employing no forced guidance. Further, our reproducers make the headblocks rapidly interchangeable and also offer easily adjustable tape tensions and capstan speed trim.
Proof of performance.
FFT spectral analysis can quantify the time base accuracy of any analog audio tape transport. As suggested by Dale Manquen, a 12.5 kHz carrier signal that is four times higher in frequency than the historic wow and flutter measurement standards is used. This permits wide-band flutter analysis that includes scrape flutter, once erroneously believed inconsequential to the perceived sound quality of recorded music.
Reference-quality playback electronics.
With a reference-quality transport contributing near-perfect tape guidance with exceedingly low scrape flutter generation and high dynamic azimuth stability, optimal playback can be realized through low-noise, low-distortion playback electronics that accurately follow the established equalization curves.
Audition our state of the art solutions.
We began our work designing and building state-of-the-art analog magnetic tape reproducers back in 1987, making 2019 our thirty-second year. Please get in touch to learn more about our Model One and Two reproducer systems (use the form below).
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