Bigmark said:
406/407 are bias equal to ampex 456 grand master.
the replacement equal to Maxell UD-35-90
is the 642-151111 available as we speek....
In dought contact Quantegy
www.quantegy.com.au
and ask the techs......
It is true that Quantegy 642 is the recommended replacement for UD 35-90.
However, the general idea behind the responses was to recommend a backcoated high output tape, equivalent to XL1 35-90B rather than UD 35-90. The recommended replacement for XL1 35-90B is Quantegy 407. Maxell made this recommendation when they announced that they would no longer make open-reel tape.
Quantegy’s 642 is their closest match to UD 35-90, but it is inferior in every way… output, dynamic range, etc. On the other hand Quantegy 407 is in the same league as, but superior to XL1 35-90B.
If it wasn’t clear, IMO, no one should be using non-backcoated tape for serious high fidelity recording, unless their machine is so old that backcoated tape is not an option.
For
the Akai GX-270 and other Akai decks from this era it is better to set the tape selector switch to “Wide Range” and use 407 or better. On the latest generation of Akai decks and many other brands, the bias setting has a continuously variable knob rather than having a simple switch. It can be more finely tuned to a tape per the manual.
Bias is a tricky subject. As tape speed increases the difference in bias becomes less between tapes. So on some half-tracks @ 15 ips the factory recommendation for 1 mil may include 3M 207, Ampex (Quantegy) 407, Maxell XL 35-xxB, UD, Sony DUAD and TDK AUDUA, all to be used interchangeably because the bias is “close enough.”
Of course most agree that it’s best to select one kind of tape and have the bias finely tuned. But even that only opens another can of worms because people disagree on optimum bias for a given tape. Some even bias by ear, listening for the lowest noise/lowest distortion sweet spot.
Bias has enough wiggle room for people to choose a tape that sounds good to them with the machine set just as it is. Different people will choose different tapes, and some find better tapes than the factory recommended. Noise reduction makes the wiggle room even greater.
For example, the only tape recommended in the early Tascam 388 manual was Maxell UD 35-90. People guessed that XL1 35-90B and Ampex 407, 457 would be even better, and those are what many people used. Factory recommendations are just a good starting point. It’s like the default settings in your PC’s BIOS… it’s safe.
Believe me, it was as controversial 20 years ago as it is in this digital age, so this isn’t entirely due to the “lost art” factor.
