3M 250 and Ampex 456 1" Tape Bias and Levels

RandyRhoads1981

RandyRhoads1981

New member
I just purchased some 1" 3M/Scotch 250 Tape.
I've been using Ampex/Quantegy 456 and my machine(Tascam MS-16) is
calibrated/biased to this at +6db. I know 456 is +6db. I've read 250 is too.
But when I recorded a 1kHz tone for setting the record level,
it was reading -3VU on the 250 but 0VU on the 456. Why is this?
Also, is the 250 Bias Compatible to 456?
How many db should I overbias?
 
RandyRhoads1981 said:
The Tape is great. it doesn't shed t all.
I was weary at first, but they are wonderful.
I read a sticky shed list a while back and I didn't see 250 on there.
I did see 226 though.
Does anyone know the difference between 250 and 226?
Click to expand...

3M 250 was a good tape. Came out around the same time as 456. But yes unfortunately it is susceptible to sticky shed. It's not bias compatible with 456, but when biasing it’s the same amount in dB down from peak. For your machine that would be –3 dB using 10kHz @ 15 ips.

3M 226 is their answer to Ampex 456. When 456 began to dominate the market 3M came out with a bias compatible tape with basically the same output and characteristics of 456. 226 was a great tape, but one of the worst for sticky shed.

There are a few reasons why you may see a couple dB low on playback with 250.

250 is technically a +6 tape, but it’s not as hot as 456, so the repro level has to be bumped up a bit in calibration. Incorrect bias level can also cause lower output. Finally, sticky shed manifests itself in different ways. It may or may not slow or stop a transport. That depends partly on whether you’ve got stationary or rolling tape guides… basically how much friction in the tape path to begin with. The most common sign of sticky shed is low output. The condition prevents optimum tape to head contact, which results reduced output. So it could be any one or all of these things affecting output.

206 and the 1-mil version, 207 are probably the best tapes left from 3M/Scotch. They're +3, but basically bias compatible with 456. Most importantly they don't have stick shed.
 
Beck said:
3M 250 was a good tape. Came out around the same time as 456. But yes unfortunately it is susceptible to sticky shed. It's not bias compatible with 456, but when biasing it’s the same amount in dB down from peak. For your machine that would be –3 dB using 10kHz @ 15 ips.

3M 226 is their answer to Ampex 456. When 456 began to dominate the market 3M came out with a bias compatible tape with basically the same output and characteristics of 456. 226 was a great tape, but one of the worst for sticky shed.

There are a few reasons why you may see a couple dB low on playback with 250.

250 is technically a +6 tape, but it’s not as hot as 456, so the repro level has to be bumped up a bit in calibration. Incorrect bias level can also cause lower output. Finally, sticky shed manifests itself in different ways. It may or may not slow or stop a transport. That depends partly on whether you’ve got stationary or rolling tape guides… basically how much friction in the tape path to begin with. The most common sign of sticky shed is low output. The condition prevents optimum tape to head contact, which results reduced output. So it could be any one or all of these things affecting output.
Click to expand...


Thank you. That was the exact answer I was looking for.
I just purchased 2 more 3M 250 reels and one of them appears
to be shedding. They're guaranteed not sticky, so I can get my money back
or exchange it for another, but that still really sucks.
It sheds in the upper corner of a tape guide and then
forces the tape off the path! Even older shitty 456 doesn't do that!
So... Perhaps the first 2 Tapes that I thought were "good", may
be heading in the same direction?
The newer Ampex/Quantegy 456 always works great and is very consistant.
I guess I'll just stick with that. Unfortunately, It's getting really hard to find.
 
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