Alignment tape size question (1.5mil on decks designed for 1mil)

Blue Jinn

Rider of the ARPocalypse
I missed a screaming deal on two 1/4" MRL tapes on Ebay 7.5 ips and 15 ips 250nWb/m. Per MRL they record on SM911.

I found this Fostex All-in-one Calibration Tape, Measuring Tape 38-19 cm/S | eBay instead, which is pretty good deal and both speeds. It's recorded on SM468.

Two questions:

All the 1/4" decks I need to calibrate specifically recommend 1mil tapes, and both the MRL and the one from Nikolektro are recorded on 1.5mil. For playback, I'm assuming 468 or 911 isn't going to matter. but does the thickness? My 22-4 really doesn't like the thicker tape.


Reel deep thoughts...
I wouldn’t sweat it. You’re not setting tensions with the cal tape, just trying to line up levels across all tracks.


Rick Ruskin
The 1 mil vs 1.5 mil thing is a red herring. 1 mil tape gives a slightly better head rap, making it easier to get slightly higher measurable specs. The actual audible performance when using 1.5 mil tape of the same oxide type is negligible.