GennLab Standard Alignment Cassettes

Each Cassette Tape is a Full-track Master tape (not a copy). Cassettes are recorded OFF SHELL (except azimuth, 5 Hz RAMM and 1 kHz Track Alignment Tapes) using an OTARI 0.15" (3.81mm) Reel-to-Reel MX-5050BIII-F-P4 Production full-track tape recorder and professional test equipment from NEUTRIK. The Capstan motor of the tape recorder is controlled by digital Quartz- Locked PLL. This can work at standard speeds with 0.01% accuracy, and at any speed from 1-7/8 to 30 ips using an external clock generator. If required a cassette can be recorded
at 30 IPS.

Reproduction or Playback Head of the tape recorder is a 4-track 4-channel head to measure Level unevenness @ 400 Hz.
PLEASE NOTE. Level unevenness is checked totally across the tape (not along the tape) before recording. Tapes with difference in Level more than 0.4 dB are discarded.

Reproduction Equalization is calibrated using a Constant Magnetic Field Transducer which has been designed by GennLab.

Handling of Alignment Tapes.

PLEASE NOTE
All test tapes are consumable items. They will not last forever, However careful use will ensure the anticipated lifetime is achieved. Alignment Tapes should always be handled extremely carefully.
A single Test Tone is recorded on each tape at the Level corresponding
to the Equalization curve.
Test tones need to be recorded on separate tapes.
Firstly: to speed up adjustment process.
(It is faster to change a cassette than to rewind it to find a required portion on the tape),
Secondly: to ensure the safe guard and longevity of the tape which is most important.

The lifetime of any Alignment Tape depends on the number of playbacks and rewinds. The physical pressure from capstan-pinch roller pair and tape guides demagnetizes the tape (it is assumed that you have demagnetized the mechanism of the tape recorder prior to tests).
With a single tone recorded on each tape, every time a cassette is placed in a deck stopped and subsequently removed, the tape should only be continued to play back from that location on the tape from when it was stopped and removed.
When you reach the end of the test signal on the tape, rewind the entire cassette at once
This should be recorded as "1 full pass", and so on up to 50 full passes, which is the normal lifetime of any Alignment Tape.
After 50 passes, accuracy of the recorded signal level of the Level and Frequency Response Tapes is out of specs, and the tape is not usable anymore for fine adjustments.
The Speed tapes are stretched (especially by double-capstan mechanisms), and they give readings lower than actual speed. Speed of decks adjusted using such tired test tapes is higher than nominal.
The Stretched Azimuth tapes give unstable and uncertain readings.
Each Tape is a Full-track tape, but it should be played back in one direction.
Use the labeled side of the cassette only.
Change the side of the cassette for Reverse PB adjustments only (Nakamichi DRAGON etc.). Multiple rewinds from one tone to the other tone recorded on the same tape on inferior cassettes found on the market will decrease lifetime of those tapes dramatically and will not achieve normal lifetime expectancy of 50 passes.

Please note, GennLab tapes are recorded on new RTM, TDK, MAXELL, TEAC, SONY or US-made AMPEX 472 professional tape.