Using a test tape at the wrong speed

[ruffrecords]

I need to calibrate the replay chain of a cassette recorder that has a 35uS replay equalisation and runs at 3.75 ips. However, the only calibration cassette tape I have is recorded at 1.75 ips and is for a 70uS replay equalisation.

My brain hurts from trying to work out how to convert the levels from this test tape to the expected levels when played at twice the speed and with half the time constant replay EQ.

Help!

Cheers

Ian

 

[Tubetec]

Page 10 here theres a comparrison table for using test tapes at different speeds ,
Only goes to 3.5ips though .
https://www.mrltapes.com/choo&u.pdf

 

[ruffrecords]

Page 10 here theres a comparrison table for using test tapes at different speeds ,
Only goes to 3.5ips though .
https://www.mrltapes.com/choo&u.pdf

If I read that correctly I can use a 70uS test tape at twice the normal speed in a 35uS replay chain and set for flat response and it will be correct (just the frequencies will be doubled)

Interesting.

Cheers

Ian