Bias
2If you're looking for some literature, I could likely get you some if you're serious. You should definitely read about it and other basic tape machine maintenance before you spend the money on one. They are a lot of work to keep up, especially if they aren't that great (and considering 1/2" 8 track isn't a professional format, the machine probably isn't awesome). I should know - one of the machines I own is an Otari 5050 8 track.
Bias, in general, is a large AC signal riding a high frequency signal. It's purpose is to keep signal away from the areas of tape recording that are the least linear. It depends on what machine and, more specifically, what tape you are using. Manufacturers have optimal bias current settings for different types of tape. That being said, the setting is still up to the engineer. The effects of bias are very compromising (i.e. at one point, you may have the lowest amount of 3% 3rd harmonic distortion, but your high frequency saturation may be too high for your taste).
There is a chapter on tape machines in Glen Ballou's "The Handbook for Sound Engineers." It is expansive and pretty heavy, but it contains about all you need to know. Go to the Focal Press website to get the best price on that book (it's probably around $80). Another great source is a paper by Jay McKnight (of Ampex and MRL fame) called "Tape Recording Equalization Fundamentals..." which can be found at http://home.flash.net/~mrltapes/equaliz.html
Sorry, I don't know how to do the one-word-red-font-link thing.
Also, there is an old book that I have found to be extremely helpful (albeit pretty technical) called "Elements of Tape Recorder Circuits" by Burstein and Pollack. I think it's from 1956 or 1957. Might be hard to find, but they have a great chapter on bias.
Alright, I think that's enough geeketry for now. Let me know if you have any other questions about where to find good info on tape machines. Good day.
Bias, in general, is a large AC signal riding a high frequency signal. It's purpose is to keep signal away from the areas of tape recording that are the least linear. It depends on what machine and, more specifically, what tape you are using. Manufacturers have optimal bias current settings for different types of tape. That being said, the setting is still up to the engineer. The effects of bias are very compromising (i.e. at one point, you may have the lowest amount of 3% 3rd harmonic distortion, but your high frequency saturation may be too high for your taste).
There is a chapter on tape machines in Glen Ballou's "The Handbook for Sound Engineers." It is expansive and pretty heavy, but it contains about all you need to know. Go to the Focal Press website to get the best price on that book (it's probably around $80). Another great source is a paper by Jay McKnight (of Ampex and MRL fame) called "Tape Recording Equalization Fundamentals..." which can be found at http://home.flash.net/~mrltapes/equaliz.html
Sorry, I don't know how to do the one-word-red-font-link thing.
Also, there is an old book that I have found to be extremely helpful (albeit pretty technical) called "Elements of Tape Recorder Circuits" by Burstein and Pollack. I think it's from 1956 or 1957. Might be hard to find, but they have a great chapter on bias.
Alright, I think that's enough geeketry for now. Let me know if you have any other questions about where to find good info on tape machines. Good day.
Bias
3danielruder wrote:If you're looking for some literature, I could likely get you some if you're serious. You should definitely read about it and other basic tape machine maintenance before you spend the money on one. They are a lot of work to keep up, especially if they aren't that great (and considering 1/2" 8 track isn't a professional format, the machine probably isn't awesome). I should know - one of the machines I own is an Otari 5050 8 track.
Bias, in general, is a large AC signal riding a high frequency signal. It's purpose is to keep signal away from the areas of tape recording that are the least linear. It depends on what machine and, more specifically, what tape you are using. Manufacturers have optimal bias current settings for different types of tape. That being said, the setting is still up to the engineer. The effects of bias are very compromising (i.e. at one point, you may have the lowest amount of 3% 3rd harmonic distortion, but your high frequency saturation may be too high for your taste).
There is a chapter on tape machines in Glen Ballou's "The Handbook for Sound Engineers." It is expansive and pretty heavy, but it contains about all you need to know. Go to the Focal Press website to get the best price on that book (it's probably around $80). Another great source is a paper by Jay McKnight (of Ampex and MRL fame) called "Tape Recording Equalization Fundamentals..." which can be found at http://home.flash.net/~mrltapes/equaliz.html
Sorry, I don't know how to do the one-word-red-font-link thing.
Also, there is an old book that I have found to be extremely helpful (albeit pretty technical) called "Elements of Tape Recorder Circuits" by Burstein and Pollack. I think it's from 1956 or 1957. Might be hard to find, but they have a great chapter on bias.
Alright, I think that's enough geeketry for now. Let me know if you have any other questions about where to find good info on tape machines. Good day.
Thanks!!!