Strange reel-to-reel record/playback speed problem..

Discussion in 'Tape Recorders' started by Matt_Trix, Jul 31, 2005.

  1. DogsoverLava

    DogsoverLava Well-Known Member

    Joined:
    Jun 21, 2014
    Location:
    Vancouver
    Home Page:
    but wouldn't we see the variability occur in both modes (record and play?) And why not friction if record mode (which also "plays") brings the record head in contact with the tape causing additional tension/friction -- could this not account for the variation happening in record mode only?
     
  2. Kurt Foster

    Kurt Foster Distinguished Member

    Joined:
    Jul 2, 2002
    Location:
    77 Sunset Lane.
  3. DogsoverLava

    DogsoverLava Well-Known Member

    Joined:
    Jun 21, 2014
    Location:
    Vancouver
    Home Page:
    I did not know that (about the record head). Thanks for expanding my understanding there. Makes me wonder about residual magnetization.... is that a thing?
     
  4. paulears

    paulears Well-Known Member

    Joined:
    Feb 7, 2014
    Location:
    Lowestoft - UK
    Home Page:
    If you buy a tape deck on Ebay with a fault that means it records and replays at 10" per second - if this is your only tape deck, and you don't swap tapes with anyone else, you will NEVER notice it.

    Residual magnetisation is a real, and very important thing. Years ago, every serious tape user, amateur and professional had a degausser. You regularly cleaned the heads, guides and capstan with isopropyl alcohol, then demagnetised the heads. The magnetisation actually starts to erase a tape when played, gradually reducing it's level every play, and the magnetisation also prevents full depth recordings, and the sound suffers, especially at the top end where the depth of tape saturation is lower. You also need a calibration tape that you use to make sure your tape head gap is at exactly 90 degrees to the tape edge. Again, if this drifts off through vibration, or rough handling, it needs adjusting. The starting position at a recording studio meant you spent ages each day cleaning and aligning all the recorders so they could swap tapes happily from machine to machine. Cleaning and form filling was a really big part of the job, but an amazingly important one.

    You can buy degaussers on amazon and Ebay, and they're not expensive - but beware, as incorrect application can increase the magnetisation if you don't do it properly.

    One really good thing you can do is to record some test tapes. They will be subject to any problems your own machine has, and of course will be your own standard - replay on somebody else machine not aligned the same will not works so good.

    Record some tones. pick a low middle and high. Adjust the record level to hit the 0VU marking on the meter for each one. On replay you can check the purity of the sound. Wow and flutter will be very obvious. Level changes will also show up. Ideally replay of each tone will show you the frequency response is constant. There will be differences. Keeping a record will show you drift - usually the HF is coming down. Cleaning and degaussing indications. White noise is also quite useful for adjusting the azimuth - the brightest and cleanest top end is when the head gap is perpendicular to the tape. If you never share tapes with another machine. Having your own unique alignment is not necessarily a bad thing.

    These test tapes will also let you keep an ear on other issues. Some designs have a clean tape path. The supply spool has a constant torque, and the tape is held tight against the heads by the steady back tension and the capstan/pinchwheel just drives it through. These machines tend to have a gentle curve to the two or three heads top assist the pressure. Other designs may have little levers with tiny felt pads that push the tape into contact with the heads. The steady tones often allow you to hear a kind of fluttery sound as these pressure pads skip and hop over the surface when their springs are weak.

    My essential tool kit for a reel to reel was a small screwdriver to adjust the head azimuth, a degausser, bottle of alcohol, cotton buds and a lint free cloth. A cocktail stick is also handy for removing bits of built up oxide from the guides. Sadly, if I was buying a reel to reel machine now, I'd have to add a jewellers eye glass to be able to get my eyes close in - my glasses would be no good whatsoever!
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice