Track 1 isn't as loud as other three

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blueberry

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After recording on my tascam porta07 cassette four-track, which is four years old, track 1 is noticeably quieter during playback than the other three (all things being equal). All tracks play back fine, however, on tapes I've made six months or so ago. So, it seems the problem occurs during recording and not during playback. What is unusual is that track 1 is the one I use least often.

I clean the heads after every hour or so of use. I've never demagnetized, however.

Can someone tell me what the likely problem is? Is it something I can fix or do I have to take it in to be repaired?

Any help will be much appreciated.

Blueberry
 
To verify the nature of the problem, record about 30 seconds of the same signal (test tones, a sustained synth note, whatever) on all tracks at the same time.

Play it back and check the levels of each of the tracks on your meters... there could be a 2-3 db difference between tracks, but if track 1 is off by more than that, it's definitely a problem. If you're sure you've cleaned the tape thoroughly, then it's likely due for a trip to the repair shop... demagnetizing wouldn't have *that* dramatic an effect, and if your heads were magentized, the high-freq would drop on all tracks...

Bruce Valeriani
Blue Bear Sound

[Edited by bvaleria on 10-02-2000 at 21:59]
 
Bruce is right. Don't try to fix it yourself. It may be a head alignment problem that is best left to a tech.

Mark
 
bvaleria said:
if your heads were magentized, the high-freq would drop on all tracks...
Click to expand...

Not nessecarily. The different parts of one head can have different magnetization. But a big magnetization of just one track would probably be heard by more of the high frequencies going away each time you play the track.

Dirt or bad head alignment is good guess. Try cleaning the head first, with q-tips and cleaning alcohol.
 
Not nessecarily. The different parts of one head can have different magnetization. But a big magnetization of just one track would probably be heard by more of the high frequencies going away each time you play the track.
Click to expand...

That's certainly true on 24-track (or more!) analog machines, where the physical distance of the head is wide enough that it could be magnetized differently at different points, but on a 4-track with a 1/4" headspan - not likely!!! :)

Either way - I think it's a tech issue that needs repair - doesn't sound like a maintenance problem...

Bruce Valeriani
Blue Bear Sound
 
If you've never demagnetized , as you claim, then do it. If that doesn't help, take it in for repair. Make sure you demag properly or you'll really screw things up!

Mark
 
bvaleria said:
That's certainly true on 24-track (or more!) analog machines, where the physical distance of the head is wide enough that it could be magnetized differently at different points, but on a 4-track with a 1/4" headspan - not likely!!! :)
Click to expand...

On a multi-track tape head, each channel is as magnetically separated from the others as possible. This is to minimize cross-over. So yes, its likely. But as I said before, this doesnät sound like a magnetization problem at all.
 
Regebro...

Hmmm... I've never ever heard of the that... there is a guardband - a width of unrecorded tape between adjacent tracks - in order to prevent channel crosstalk, but no special magnetic-shielding between channels on the heads....

The heads themselves are made of magnetically-soft alloys, tending to resist magnetism in the first place, but residual magnetism still occurs.

Do you know how this shielding is accomplished?? This is something new...

Bruce Valeriani
Blue Bear Sound
 
Well, the guardband is the prime example of that.
The whole head is designed so that magnetism from one channel should not cross over to another. If it all were just one piece of metal, then you would be correct in that you couldn't have magnetism in one channel, but then you'd have a mono recorder. :)


[Edited by regebro on 10-04-2000 at 13:53]
 
Regebro...

I have to disagree with you here, the design of the head, including the guardband is designed to minimize channel crosstalk, NOT channel magnetism... not the same thing at all... again... the head as a whole is made with a magnetically soft alloy, but there is no channel-specific resistance to residual magnetism...

Anyways... this is getting kinda off-topic! Cheers!! :)

Bruce Valeriani
Blue Bear Sound
 
bvaleria said:
the design of the head, including the guardband is designed to minimize channel crosstalk, NOT channel magnetism...
Click to expand...
Which of course, in a magnetic recording medium, is exactly the same thing...

There must be something wrong with my explaining skills... :)
 
*SHEESH* C'mon, think about it!!!

The guardband is an area left on the *tape*, not the head............. For example, if I degauss the head improperly and pull away too quickly, I could easily leave some portion of the head MORE MAGNETIZED than another portion - IF the head is large enough (as in 24+ tracks) that the damaging magnetic field does encompass the entire head surface.... if I then record on the machine with the partially magnetized head - the guardband area of the tape will still protect against any crossover from channel to channel, but say tracks 1-5 will be dull-sounding due to partial magnetization.... Ged'it?!?!?! If not, I give up... it doesn't really matter anyways.............

*I* can't be clearer than that!!! :)


Bruce Valeriani
Blue Bear Sound
 
Thanks for all the helpful responses. Will take it in for repair.

blueberry
 
It is correct that with a degausser you can not cause magnetization in one track only. But there are other ways of making heads magnetic than a degausser. Since you obviously won't believe me, maybe you will beleive Magnetic Reference Laboratories, makers of the reference tapes that everybody loves and uses? (Throwing in a desperate measure of authority here... :) )

"It may happen that an associated amplifier draws current through the head, either all of the time, or during power-up or power-down. We have had reproducing-head magnetization that seemed — as best we could find — to be caused by occasional current pulses from an integrated-circuit pre-amplifier on power-up or power-down"

"Note that on a multi-channel recorder it is probable that the magnetization problems will be different on the different channels. So all tests have to be done on every channel that you care about. This may be a blessing in disguise, because you may find that some channels are not magnetized, and serve as reference for the magnetized channels."

http://home.flash.net/~mrltapes/
 
Reg!! That's exactly my point... magnetization may be different on different channels... what I was trying to get across above is that channel crosstalk is a different problem than magnetization - and they aren't necessarily related, as one of your posts implied....

Sounds like we are arguing the same point now... I'm not trying to out-theorize you (I know I'm right!!!) :) I checked out the URL - it doesn't dispute the point I made above at all - it actually parallels it...

Anyways I hate arguing this theory crap - takes time away from making music!! Let's agree to ask Scott Dorsey in RAP sometime - he'll probably set us BOTH straight!!! :)

Peace bro...
Bruce

[Edited by bvaleria on 10-06-2000 at 11:37]
 
The advice from MRL is dealing with large format machines, as this is what they commonly deal with. For a single track to be magnetized in a cassette four track you would have to have a intense magnetic field with a 1/32 of an inch diameter, which is not likely. Most likely when an edge track goes out (like track 1) either the mechanical alignment is wrong or the head is worn out. I have no idea what an alignment tape for an cassette costs but I would think its probably not very economical to get a cassette four track head, its probably a large percent of the machines value. In a pinch, you could adjust the head for maximum output off of the tape.
 
bnewsom said:
For a single track to be magnetized in a cassette four track you would have to have a intense magnetic field with a 1/32 of an inch diameter, which is not likely.
Click to expand...
In fact, that is exactly what is happening if you get an electrical spike through just one of channels.
 
You're right, I just don't see how this is a likely cause of the problem with the tascam 4 track
 
It isn't!

Thats one thing everybody has been agreeing on the whole time. :)
 
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