What do you need to know if you are using in-cassette duplication?
If you are duplicating tapes using an in-cassette duplicator, there are a few important things you should know.
The overwhelming majority of cassette duplicators operating at 4×–16× speed were designed for copying speech programs, not music. According to their datasheets, their frequency response does not extend beyond 12 kHz. In reality, it often doesn’t exceed 10 kHz, due to magnetic head wear and improper adjustment.
Another reason for the poor quality of duplicated tapes is the master cassette, whose frequency response is already limited. On top of that, the hiss of the master cassette is inevitably added to all duplicated tapes. Even using chrome master cassettes rarely improves the situation significantly.
The only way to achieve more or less acceptable quality with in-cassette duplicators is to record tapes using a mastered digital source. However, very few devices support this option. Keep in mind that you can speed up your program on a computer without quality loss at 4× speed if you use an audio interface that supports a 192 kHz sampling rate. For 8× speed, an interface supporting 384 kHz would be required—which is rare and quite expensive, if you can find one at all.
A checklist for those using in-cassette duplication
It is possible to achieve excellent recording quality using cassette decks, but there are several important things to consider.
- First, you still need to check every duplicated cassette, as occasional recording issues can occur. This is caused by the inherent imperfections of cassette mechanisms. For this reason, it is essential to have a separate quality control deck. Checking tapes on the same deck used for recording is not recommended. This mainly relates to azimuth (phase) alignment and transport speed. When you record and play back a cassette on the same deck, phase and speed will always seem perfect—even if the deck is poorly calibrated. Incorrect recording azimuth leads to high-frequency loss, making tapes sound dull.
The most common defects are: missing channels (there are four of them on each cassette), speed deviation (lower or higher speed), azimuth related phase shift, reduced recording level, and poor frequency response.
- Second, magnetic head wear is a critical factor. Many decks available on the second-hand market have already transported thousands of kilometers of tape, resulting in heavily worn heads. This will not improve over time. While head wear is less critical during playback, it is crucial when recording. Replacing the head can help, but only if you know how to properly align and adjust the new one.
- Third, recording speed matters. Beyond knowing how to adjust speed electronically, it is essential to keep the mechanism clean to ensure stable tape transport. If cleaning doesn’t help, you may need to replace pinch rollers, belts, or even drive motors.
Why is pancake duplication better?
What is good about the pancake duplicators we use at GoTape? They are free from the imperfections of cassette mechanisms. The tape transport is designed similarly to reel-to-reel recorders, which makes wow and flutter (speed deviation) negligible and keeps all channels precisely in place on the tape. All cassettes are recorded using a single magnetic head, ensuring that every copy is absolutely identical.
