
cjacek
Analogue Enthusiast
Can someone please tell me exactly what "BIAS" is as it relates to that little switch on some open reel recorders ?
Thanks!
Daniel
Thanks!
Daniel

The Ghost of FM said:If we're talking about a switch, it means that the deck holds 2 separate bias setup levels on it's internal circuitry and allows the operator to switch between the two setting when using different formulations of tape.
Many consumer decks from Teac offered this on their latest models which allowed the user to switch between normal 456 type tapes and EE type tapes which had a higher output capability.
The current TASCAM BR20T, deuce has dual position switching also and this is for 456/499 switching, I believe.
Cheers!![]()
cjacek said:Thanks Jeff but technically speaking what is "bias" exactly and how does it work and can any deck that has a bias switch be set up for any tape formulation ? Thanks!!
Daniel![]()
The Ghost of FM said:That's a very different question.
Bias is like the heater current used in tubes.
The bias warms up the tape electrically and allows for recording to be made with near zero distortion.
Depending on tape formulation, speed, track width and electronic limitations of the deck in question, differing amounts of bias can facilitate higher recording levels which will get you quieter recordings, hiss wise and broaden the dynamic range capabilities as well, before gross and audible distortion kicks in.
Here's a link that explains this in better detail then I have time to type.
http://www.vaporpark.com/invboard/index.php?act=ST&f=12&t=211&
Cheers!![]()