pishta
New Member
Ill jump in and add a few thoughts. I rearely record on a 2 head anymore once I got a 3 head, and even that is not enough by itself as it need an external bias trimmer or some sort of E.C.C.S (Hitachi) or Dolby calibration tones with L and R adjustments (bias in my mind). If its a 3 head with just a record levels, its a waste of a good transport. Get in there and find the bias trimmer on the mainboard, pull it out and wire it into the front panel with a little knob and wires back to the solder spots on the board. Get the same ohm scale linear potentiometer so you cant go crazy with the bias as a very little makes alot of difference. My first was a Akai M-50 (Or was it a Teac?) that had the bias control and monitor switch. Incredible as you can flip the monitor switch back and forth between the input source and the taped content with a millisecond difference in time in the cassette as the tape is traveling from record to play. You then set the record levels to match the volume and the bias to match the "tone" of the music. Dont use Dolby when doing this! The bias will make the content 'soft' or 'hard' or grainy if your a photographer. you want to match your blank tapes playback as close tot he sources as you can, but alas even on a 3 head, there was a little bit of 'shallowness' to the recorded content and no tweaking can fix that. You can just make it out switching between source and tape but in its own playback, you wont notice it. I have since graduated to a Sony TC-K71 that has the early production Canon sourced discrete record and playback head stack. Each head has its own adjustablility inside the head mount, the latter half of this models run was made with a Sony sourced sandwich cemented head. You almost never have to change this paired setting but I had an open record head so I had to replace it, disturbing the factory mating of the heads. I used a lego brick (!) to place on top of the 2 heads to make sure they were level with each other and even used 4 long pieces in a trapezoidal diamond shape to get them aligned with each other (They stay parallel when you close the diamond around the head pair..both showed errors off my eyeballing method). As a final test, I played a clear CBS recording (thought it was a high quality commercial tape) of a tape that had a lot of sizzling extended high notes, Pump up the Jam by Technotronic.
. I then played the tape with a set of JVC earbuds and a plastic phillips head screwdriver (not magnetized!) to adjust the azimuth on the fly. I tweaked the azimuth about 1 degree, just a little to get the highest highs sizzling and then tweaked the height screw to get the tape to show no curls on the guides with a flashlight and a pair of 10X loupes. Went back and forth until the head was straight up and down, the tilt was level and the azimuth was the highest highs. After that I recorded some high frequency tones and adjusted the RECORD head to get those same highs playing across the already adjusted PLAY head. It took only about 1 degree of turning of the record head adjustment to get the highs singing. checked azimuth one more time on a oscilloscope and the line was a flat 45 degree with just a touch of adjustment needed, really just seating the screwdriver in the slot. I then put a dab of pink fingernail polish on the screws to set them. Once all that was done, I made a test tape with the corrected speed in 330, 1K, 10K and 12Khz at 0, -3 and -10 dB source levels. I can use this tape later to check up on the transport or meter movements. Read the F'n manual (RTFM) that came with your deck! I have a Teac V615 that states the record level on a type I should be a +6! Happy taping!
