Bias before Record Level?

[witchfeet]

Hi. I'm learning to set up my Otari 1/2" 8 track. I calibrated my meters and think I did it correctly. I set the Repro level and EQ with my MRL fine I think. My problem comes when I'm trying to get the record level and bias set. I'm trying to use +9 tape with the Otari and it seems like I can get enough level to the tape no problem with the SRL button in. The thing is, if I set my record level up this high and then go to bias, the peak is off the meters. Should I reduce the record level to get the bias in range of the meters, set bias, and then go back and set record level?

Also, I've had a tech who worked for Otari, and a couple other people tell me my machine should be just fine running +9 tape, but I've also read others say it's a no-go. Should I switch to 911 or 456? I have one reel of older 456 lying around, but I'm scared to put it on the machine for fear of sticky shed. I also have three reels of 499 and two reels of GP9. All used, but very lightly, maybe two or three sessions each I was told. They were a gift of sorts for some design work I did for an acquaintance at a discounted rate.

Thanks in advance for any help! I was pulling my hair out the other day.

[tactics]

The thing is, if I set my record level up this high and then go to bias, the peak is off the meters. Should I reduce the record level to get the bias in range of the meters, set bias, and then go back and set record level?

Make sure you have your calibration happening in the correct sequence first.
From your question it sounds like you are biasing after setting the record level ?
Or do you mean repro level? Bit confusing.

You can reduce the 10k tone from the oscillator during biasing if it is off the meters scale.
The peak point is what you need to see to set the overbias.
Make sure you return the oscillator to the correct level for your record calibration though.


Google search tape machine alignment for the correct alignment procedure.

[crow]

After years of reducing the generator level in order to see the bias point, an experienced tech told me not to, and said that I should be reducing the record level instead. I took him at his word, and now use two little screwdrivers at once to jockey with the record level and bias pots simultaneously, and it works fine.
That being said, I never noticed any adverse effects from doing it the other way, and depending on specific tape machines and test tone generators, it could be no difference at all.

Regardless, it's important to calibrate the repro path first, since you'll be using it to examine the record path.

Also, I used +9 tape on my mx5050 1/4" machine and liked it just fine, although folks tend to agree that 456 etc. Sounds more "tapey". My 2 cents: I really like the ATR tape at +9, although it seems to be really forgiving of levels.

Hope this was helpful! Holler with any more questions.

[witchfeet]

The thing is, if I set my record level up this high and then go to bias, the peak is off the meters. Should I reduce the record level to get the bias in range of the meters, set bias, and then go back and set record level?

Make sure you have your calibration happening in the correct sequence first.
From your question it sounds like you are biasing after setting the record level ?
Or do you mean repro level? Bit confusing.

You can reduce the 10k tone from the oscillator during biasing if it is off the meters scale.
The peak point is what you need to see to set the overbias.
Make sure you return the oscillator to the correct level for your record calibration though.


Google search tape machine alignment for the correct alignment procedure.

I have a few different references for the procedure, although some say to set record level first and then bias and some say the opposite. I think I got my answer though from the other poster. Thanks!

[witchfeet]

After years of reducing the generator level in order to see the bias point, an experienced tech told me not to, and said that I should be reducing the record level instead. I took him at his word, and now use two little screwdrivers at once to jockey with the record level and bias pots simultaneously, and it works fine.
That being said, I never noticed any adverse effects from doing it the other way, and depending on specific tape machines and test tone generators, it could be no difference at all.

Regardless, it's important to calibrate the repro path first, since you'll be using it to examine the record path.

Also, I used +9 tape on my mx5050 1/4" machine and liked it just fine, although folks tend to agree that 456 etc. Sounds more "tapey". My 2 cents: I really like the ATR tape at +9, although it seems to be really forgiving of levels.

Hope this was helpful! Holler with any more questions.

Perfect. This is exactly what I was wondering. I have been setting the repro w/ the MRL first, but my problem was setting the record level before bias, and then having the bias peek off of the meters. So I think I'll reduce the record level to get the bias peak to overbias. Then I'll go back and set record level. I have a few different documents, some saying set record level first, then bias, and one the opposite.

Thanks for the reassurance. I should be set now.

Any tips on biasing or do most of you just stick with the standard overbias per tape type on each track? I've heard of some people biasing differently on each channel depending on what is going to be recorded on that track.