
cjacek
Analogue Enthusiast
I asked Dorsey about the SM911 bias, compatability thing and here's what he replied with:
>Scott, you say in the article that you would not recommend SM911 on a
>TASCAM 38 but that the SM468 would be fine. Why ? Both of these tapes
>are the same operating level and bias is close, like 1db difference.
MOL on 911 is actually higher, so you can use it at higher operating
levels. The bias required is MUCH higher. Yes, the "overbias" number
is similar, but that is not a measure of bias, that is a measure of how
much over the 10KC peak you need to go to set the bias properly. You
will find if you set the bias that the peak on 911 is higher than on 468.
>Isn't SM911 a drop in replacement for the Quantegy 456 ?
For some value of "drop in." BASF used to claim it was "bias compatible"
with 456... but no two batches of 456 were even bias compatible with one
another. It's more or less in the ballpark as far as bias and operating
level goes, though.
>The TEAC
>80-8, TASCAM 30, 40 and 50 series and some others were setup for the
>456. It then figures that the SM911 would work too and so would the
>SM468.
Some of those machines have a very narrow range of adjustment, and on
machines that way, 911 might be a better bet. You'll know this is
the case if you try and set the bias with another tape and can't find
the peak.
--scott
--
>TASCAM 38 but that the SM468 would be fine. Why ? Both of these tapes
>are the same operating level and bias is close, like 1db difference.
MOL on 911 is actually higher, so you can use it at higher operating
levels. The bias required is MUCH higher. Yes, the "overbias" number
is similar, but that is not a measure of bias, that is a measure of how
much over the 10KC peak you need to go to set the bias properly. You
will find if you set the bias that the peak on 911 is higher than on 468.
>Isn't SM911 a drop in replacement for the Quantegy 456 ?
For some value of "drop in." BASF used to claim it was "bias compatible"
with 456... but no two batches of 456 were even bias compatible with one
another. It's more or less in the ballpark as far as bias and operating
level goes, though.
>The TEAC
>80-8, TASCAM 30, 40 and 50 series and some others were setup for the
>456. It then figures that the SM911 would work too and so would the
>SM468.
Some of those machines have a very narrow range of adjustment, and on
machines that way, 911 might be a better bet. You'll know this is
the case if you try and set the bias with another tape and can't find
the peak.
--scott
--