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Maybe I missed it, but I sure did look.  Are there any instructions on how to use the calibration tape?  The Otari MX-55 manual says they assume you want everything calibrated to +4dBm and gives instructions on how to do that using the calibration tape.  Is that the right answer?  I received 6 tapes yesterday, and so far all I have done is set my machine's flux to 250 and set the equalization to IEC and let 'er rip.  Judging by the Otari VU meters reading the playback head with the 3 tapes I have played so far, all appears right in the world.  I also have really good readings on my Ampex 350 VU meters.

We did a brief instruction in past newsletters, which are not very easy to find:

Part One

Part two

Thanks Doc, I appreciate the links.  What is not clear to me is that if I end up having to tweak my deck in order to get 0 on the VU meters at all the different frequencies, will that only effect the IEC playback or will it have changed my NAB playback as well?  For the here and now, when I make a recording and play it back, I believe it is very accurate to the source.  And this is true using various different tape formulations.  I would hate to make any adjustments that would change something for the worse when I play back tapes I have already made.  Any thoughts on this would be appreciated.

How the calibration effects all playback on a machine depends on the machine itself and whether you're using the internal playback electronics of that machine or not.

If you're using the stock playback electronics of any machine, you should check first to see if you have settings for IEC and NAB or just IEC or (quite often) just NAB. If you have a switch that allows you to choose between these two different playback equalization curves then that switch is connecting one of two circuits (either active or passive). So when you do adjustments to one circuit, it doesn't effect the other. Some machines have an actual circuit board that has to be exchanged to switch from IEC to NAB. Others with microprocessor controls can be switched with the touch of a button.
In any case, NAB and IEC are different enough that a second circuit is needed.

My Otari MX-55 has a switch for IEC or NAB.  The manual doesn't address performing calibrations for each standard which made me wonder if I adjusted the calibration for IEC if it would somehow affect the NAB settings.  Since I don't see where there are different trim pots to adjust for IEC vice NAB settings, I can't help but think if you change those settings it will affect both IEC and NAB.


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