The format page for 0.15 inch wide tape has a drawing (click for large version) that clearly shows that mono cassettes have one wide track and stereo cassettes split this track in half and add a small guard band. Most mono cassette recorders follow this format. It turns out that the mono Marantz PMD201 uses a two-channel head and records dual mono. Most other mono recorders seem to follow the standard.
While this is a theoretical problem, few if any good mono recorders are available for reproducing these tapes anyway, so most of us in the domain transfer field use good quality stereo machines for all cassette transfer work. (more…)
There has been some discussion recently about the 4-channel cassette recorders that were used for court reporting and other logging- or court-reporter-type applications. It seems that the players only have one output and can select any combination of one or more playback channels into that one output.
This monitoring topology is actually identical to two 1-inch 40-channel reel-to-reel logging machines I have where one can listen to any combination of one through forty tracks on a single output. (more…)
The discussion of what bias frequencies were used over time keeps recurring. Special thanks to Jay McKnight of Magnetic Reference Lab, Tom Fine, and Brian Roth for input to this list. I posted this to the ARSC list, but wanted to include it here as well. This knowlege is useful for those who wish to archive the bias along with the audio for future application of time-base-error correction tools such as the Plangent Processes.
In the early days, apparently wire recorders used bias as low as 30-40 kc, but Jay McKnight recalled in the pre-Ampex days, 60 kHz was common.
The Ampex Standard was 100 kc up to the MR-70. (more…)
It seems some people new to tape are confused over how to align a tape recorder. This is the abbreviated version.
If you want to record on a tape recorder (and I do not recommend doing that these days as you’re just generating more tapes that will need to be transferred later) the first thing to do is get the playback correct.
- CLEAN the machine. (more…)
I received an email asking me to discuss tape splicing. Most of my work is now repairing old splices so I try and butt them together as best I can in an Edi-Tall block and use the blue Quantegy splicing tape (which will become harder to find with Quantegy exiting the business). I will not be evaluating a replacement for several years as I bought a large supply a few years ago. (more…)
I received the following in an email from a person only identified as Ross. I thank him. He sent me the following in reference to this post. concerning Philips and PoziDriv screws as used on Nakamichi Dragons and other Japanese equipment. I, too, have a set of Hozen drivers which I obtained from www.escience.ca (more…)
The question seems to regularly arise on mailing lists and chat rooms about Dolby and dbx plug-ins. I don’t think it will happen and I added that comment and some hopefully helpful operational hints to my noise-reduction page, here.
There have been rumours that Nakamichi used a different cassette standard than the other manufacturers. This is not really the case. Everyone thought they were using the same 3180/120 or 3180/70 microsecond equalization as specified in IEC Pub 60094-1, 1981.
As I understand the history, both Nakamichi and STL in the late 1970s discovered that when they made calibration tapes based on the published time constants in the standards, their response showed that the then-common BASF alignment tapes were approximately 4 dB high (hot) at 16 kHz.
It is assumed that BASF, who made the calibration test tapes made an error in calibrating their reproduce heads’ response in one of two areas: (more…)
A client phoned me and said a cassette he was playing started to shed in his machine and he stopped and took it out. He sent it to me and as I pulled a little bit of clear leader out of the middle of the tape, this is what I found:
Notice how the complete strips of oxide exist on their own, independent of the clear “leader” to which they previously were attached. (more…)
Demagnetizing tape heads and recorder parts is a ritual of magnetic recording. If any part that touches the tape is magnetized beyond a certain level it will begin degrading the tapes played on it.
While early machines may have had an issue with magnetization, most late-model machines rarely become magnetized. The source for real information on this is Jay McKnight’s Magnetic Reference Lab Web site. (more…)
