Technics 1520 instructions are a bit different from this, Richard. Your way is pro-grade industry standard for 10kHz with 3dB overbias (Jay McKnight and I prefer 1kHz peak-bias, the "old-school" method). The Technics 1520, which was marketed as a high-end consumer deck but embraced by some professional users, is specifically designed to tweak bias and record-EQ at -10VU after getting in the range from the machine's 3-way bias and eq switches. The instructions are simple and laid out in the manual. If Sammy has a 1520 manual, I'm not sure where he's running into trouble. You cannot set the playback EQ without taking off the bottom panel of a 1520 and knowing what you're doing, with a service manual at hand. So HIGHLY NOT RECOMMENDED for a newbie. That said, it's never a bad idea to run a MRL tape and see how close to flat your machine's playback is. Specifically, you should write down VU levels at 10K and 1K. They should be flat or very close to flat or your record tweaking won't render a flat playback.
Quick recap of 1520 record-setup:
1. look in manual and find tape type, set bias and EQ switches accordingly.
2. set meter switch to -10
3. set monitor to input
4. turn on internal oscillator, to 1kHz
5. adjust line-input level so VU meter reads 0 (actually -10 but scale has been 10x in step 2)
6. put machine into record with desired tape type (as Richard says, NOT an MRL or pre-recorded tape, obviously). Don't forget to turn both channels' record-engage switches on.
7. switch monitor to tape.
8. adjust bias tweakers until VU meter reads 0. If you're adjusting more than a quarter-turn either way, something's wrong. Switch the bias switch until you get closer to 0. A very few tape types are out of the machine's range, but not Q632.
9. switch oscillator to 10kHz.
10. adjust record EQ to get VU meter to read 0. Again, if you can't get it there in a quarter-turn one way or another, something's wrong. Switch the EQ switch until you get closer to zero.
11. take machine out of record, turn off oscillator, set VU meter switch back to normal.
I guess I should also say to make sure you are monitoring off the main (2T) play head and not the quarter-track head.
Sammy, just to be clear -- if you don't see controls for oscillator frequency, two bias tweak pots and two EQ tweak pots on the front panel, above the VU meters and record/playback level controls, you do not have a 1520, you have a 1500 or 1506. Those machines cannot easily be tweaked. You can optimize those machines for a single particular tape type, but you need to do inside the machine and you need to know what you're doing and use a service manual.
-- Tom Fine
----- Original Message ----- From: "Richard L. Hess" <arclists@xxxxxxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Saturday, February 02, 2008 2:37 PM
Subject: Re: [ARSCLIST] Setting bias and EQ on ANY recorder
At 11:51 PM 2008-01-31, Sammy Jones wrote:
> From: Sammy Jones [mailto:sjones69@xxxxxxxxxxxxx] > Subject: Setting bias and EQ on Technics 1520 > > > My problem is in setting the EQ and bias properly to record on this > tape. This is my first time recording tape on a machine with settable > bias and EQ, and the Technics service manual does not specify how to do > this. I've found some information on the web for bias setup, but not > EQ.
I have placed a simplified set of instructions in my blog http://richardhess.com/notes/2008/02/02/aligning-a-tape-recorder/
Please let me know if you have any questions -- I'd prefer you ask them in the comments section of the blog.
Cheers,
Richard
Richard L. Hess email: richard@xxxxxxxxxxxxxxx Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX Detailed contact information: http://www.richardhess.com/tape/contact.htm Quality tape transfers -- even from hard-to-play tapes.