Recording current calibration

Technology
1

Hi All,

Every DCC service manual is referring to 4822 397 30264 9.6kHz 0dB reference tape. I was thinking of the possibility to recreate such a tape on the audio recorder (analog). Despite the audio head has a gap between left and right channel, it should be enough to cover at least 5 out of 9 DCC tracks. But there is a problem. DCC Standard does not list, what flux corresponds to 9.6KHz 0dB level. They are referencing to the calibration tape, but what are the characteristics of this tape standard does not show. Unfortunately there are missing pages, so maybe this information contained there (BTW does somebody know why are some pages missing? Is theree any chance to find them? They contain many useful information especially in the ITTS section).

I was thinking of using prerecorded tape as a reference for recording level, but it is not allowed - standard also lists that prerecorded tapes can be recorded within -4…+4dB relative to reference 9.6KHz tape.

I’m wondering, what methodology of recording current calibration are people using in the absence of the reference tape? Currently I see the only ± working method is to use a new DCC deck with very minor head wear and use it as a reference for recording level. And it seems almost impossible because finding new DCC deck looks almost impossible (just find working one is a pain).

Thanks,
Alexander

2

Alexander,

I am not sure what you are trying to do here. It read it as if you are trying to calibrate the analog playback part of a DCC deck, but I could be very wrong here.
If you are, then this is the head situation:

DCC kop track layout
DCC kop track layout452×848 73.7 KB

So in my humble opinion you can just use standard analog calibration cassettes here.

I am not sure about the fluxivity ‘standard’ in normal analog compact cassettes, because I read different stories. ome mention 160 nWb/m, but I also read about the later standards of 200 or even 250. I am not knowledgeable enough in the ACC field to advise you there.

-Philip.

3

I’m pretty sure the analog reference tape is just that: an analog cassette. I think the service manuals refer to it as Philips SBC420; maybe that will help you find more information about it on the internet. Those are now rare as hen’s teeth, so you probably won’t find one for sale online buy you might find other reference cassettes or you can make your own, based on the calibration of your analog cassette deck.

I don’t remember the exact numbers but the DCC System Description has detailed information about the magnetic specifications of DCC tape. As I understand it, it is basically identical to video tape.

===Jac