Calibrating a deck recording

[Alex SE]

about type2 needing more bias than type1 and metals even more... yes, it's this way and the bias difference is just big, it's a substantial difference.
.

OK, so generally the one should (but not necessarily) use a tape which have a flat FR, obviously ferric.

If I understand correctly, type I cassettes requires the least bias. Then why set external bias pots in the middle? That way there is a limited amount of positive bias to add and it can be insufficient for biasing some type II and type IV tapes, while the same amount of negative bias that will almost never be used. I would say, if adjusting internal bias pots using type I cassette it would be better to adjust external pots to, say 2200 hours instead. That way there would be enough of a negative bias to add by using external pots and more of positive which can be needed for type II and type IV tapes.

I mean, just thinking loudly. Please, correct me if I'm wrong.

BTW, I'll check if I can find some TDK Power tapes for a decent price. Just bought 6pcs Maxell XLII90, for about 31,5€/34$ incl. P&P, which is not bad at all I think. Hope that they are as good as previous models.

 

[vince666]

If I understand correctly, type I cassettes requires the least bias. Then why set external bias pots in the middle? That way there is a limited amount of positive bias to add and it can be insufficient for biasing some type II and type IV tapes

I guess I need to be more clear...

the actual bias value you have while setting your bias knob depends also on the tape type the deck is set to.

example... I insert a type1 tape and the deck shows "normal" on the display... then a few things are automatically set to normal mode... i.e. PB EQ set to 120us , bias set to normal range, REC gain is set for normal tapes range and REC EQ filters for normal tapes are enabled.
And the actual bias values will range from min to max but still within the normal bias range.

example n2... I insert a type2 tape and the deck shows "chrome" on the display... then, automatically, PB EQ is set to 70us , bias is set to chrome range, REC gain is set to chrome tapes range and REC EQ filters for chrome tapes are enabled.

example n3... I insert a type4 tape and the deck shows "metal" on the display... then, automatically, PB EQ is set to 70us , bias is set to metal range, REC gain is set to metal tapes range and REC EQ filters for metal tapes are enabled.

Then... your "center" (or 12 o'clock) fine bias setting (but bias settings in general) does change automatically together with the tape type... so, your center knob bias value when you insert a type1 tape is different than the center knob bias value when you insert a type2 tape and it's different than the center knob bias value when you insert a type4 tape.

So... my previous point was that, since most type1 tapes (or all of them if you exclude the very old ones) work within a relatively narrow range on your fine bias knob (when the deck has detected a normal tape) , it's not really needed that you try to center the range on the knob because it won't happen that you set the knob to the minimum or to the maximum and you aren't still OK to correctly bias a ferric tape.
But, since both type2 and type4 tapes might happen to need some very different (fine) bias settings, it might happen that if you don't set things properly you might not be able to properly bias certain "extreme" models.


Anyways, I meant the black magnetite XLII-S , not the more basic XLII.... the XLII-S might need some more bias than the XLII.


PS: I am not a great fan of TDK and especially of their later budget models... i.e. , the shells of the later CDing2 (and which were used on more of their later models) are really bad... very cheaply made and lacking the needed consistence and precision... i.e. I own a few late version CDing2 where the guide rollers at the lower corners of the shell aren't well centered then they turn wobbly. On some other of those shells, the two halves of the shell don't match precisely! So, be careful with such later cheap TDK models.

 

[Alex SE]

... so, your center knob bias value when you insert a type1 tape is different than the center knob bias value when you insert a type2 tape and it's different than the center knob bias value when you insert a type4 tape.

And that's the answer I was looking for! Another weekend - another knowledge Thanx!

Anyways, I meant the black magnetite XLII-S , not the more basic XLII.... the XLII-S might need some more bias than the XLII.

I know which one you was meaning, I have 34 of XLII-S, just mentioned that I've recently bought couple of XLII in a black shell/green wrap. Don't know how good they are, but a price was OK.


*still can't figure out how to remove wraps from them

PS: I am not a great fan of TDK and especially of their later budget models... i.e. , the shells of the later CDing2 (and which were used on more of their later models) are really bad... very cheaply made and lacking the needed consistence and precision... i.e. I own a few late version CDing2 where the guide rollers at the lower corners of the shell aren't well centered then they turn wobbly. On some other of those shells, the two halves of the shell don't match precisely! So, be careful with such later cheap TDK models.

TDK's was my favs until they made those blue SA and when railroading started. After that I've used D for everyday using/recording (when I couldn't find UR) and a Maxell became my preferred tapes.

 

[vince666]

just remove the wrap on each kind/version of those you own more than one cassette and try them all.

That's the best way to learn/know about your tapes and about your deck.
You can do FR plots...
Must only explain you how to measure MOL and you'll know if you are biasing them right.
But, even if you don't know the actual MOL, biasing tapes with the 315Hz or 400Hz output/sensitivity peak method as I just told you in the past will bring you in the ballpark of the optimum bias point for each tape there.

 

[vince666]

just as an example...

these are all cassettes, all different brand/model/year, which I use to check/align recording parameters on my own decks.
they are quite enough to make statistics about calibration parameters so that i know what tape can be a good reference for a given purpose... i.e. highest or lowest bias point, highest or lowest sensitivity, etc.