Bottlehead Forum

Other Gear => Reel to Reel Tape => Topic started by: porcupunctis on September 14, 2014, 04:14:51 PM

Title: Mrl number
Post by: porcupunctis on September 14, 2014, 04:14:51 PM
I just placed my order for the 1500 tape mod.  I have one mrl test tape that I use for my Tascam 32.  21 24 is the number.  7.5 is IEC2, 250 nWebers.

Will this work for the 1500?  At least for 7.5ips.
Title: Re: Mrl number
Post by: Doc B. on September 14, 2014, 06:01:50 PM
Yes, IEC2 is the same thing as NAB. What we call IEC with respect to the Tape Project is IEC1, also known as CCIR.
Title: Re: Mrl number
Post by: Big Al 954 on September 14, 2014, 07:46:04 PM
There is a handy table in this MRL publication on using different test tapes for different speeds / EQ

http://home.comcast.net/~mrltapes/eq-shift-tables.pdf


Page 7 has the table for 7.5" NAB to 15" CCIR (IEC 1).
 You would also need to compensate for your tape being 1dB lower at 250nW and CCIR is at 320nW

Fluxivity Conversions are in this MRL paper
http://home.comcast.net/~mrltapes/choo&u.pdf

Title: Re: Mrl number
Post by: porcupunctis on September 15, 2014, 02:41:06 PM
Thanks Doc and Al.  Looks like with a little compensation on the meter this will take care of most of my calibration needs.

If I calibrate the deck at 7.5 ips,  won't the deck be pretty well tuned for 15 is and 3.75ips as well?

Title: Re: Mrl number
Post by: Big Al 954 on September 17, 2014, 01:29:19 AM
Hi Randall,
It would be best to adjust at each speed individually if the 1500 permits this.I have only ever worked on Studers,Revox,Otari,Ampex ,MCI and Nagra decks so I really don't know the capabilities of a 1500.

The different speeds have different turnover frequencies for the Eq. The MRL table is compensated for these  differences to allow a user with one tape to use it for different speeds and eq standards. If the 1500 deck is limited in the Eq adjustment, then I would optimize it for the primary speed that you intend to use and compromise for the lesser used speeds or go all the way and build an Eros tape head pre ( free plug for Doc).
Let us all know how you go
Cheers