fostex a8 head performance

G

goldtopchas

New member
OK, I just bought a fostex a 8 really cheap. I had to clean the heck out of the heads. They had a dark colored residue all over them ,as well as the capstan and pinch roller. The record/playback head looks like it might actually have some corrosion on it.I recorded the same audio on all the tracks to compare playback quality.Tracks 1-7 sound a little muffled compared to track 8, which is much brighter and higher output during play back. The tape I got with the machine is really old ("leave it to beaver" stock) It's actually 2 track and must be 7 1/2 IPS. I have some quantegy 456 on the way though.
My question is this.... Is it likely that the head is shot... or could this be an issue with calibration or head alignment( since it sounds fine on track 8??)
Can I use some sort of fine polish to clean off the surface of the head???
By the way, this forum is FANTASTIC!!! A wealth of information, even for die hard analogue fans like me. Thanks!!!!!!
 
It almost sounds as if the noise reduction was bypassed for track 8 for sync track purposes and thusly, why you got more highs on it as the Dolby C noise reduction was off.

Check the switch on the back for this setting and suspicion of mine. :cool:

As to cleaning the head further by polishing it, this is something more akin to what a technician could do by actually re-lapping the head to give it back its original contour or shape and that may also be a more effective way of grinding off the corrosion or rust that has settled on the head.

Ordinarily, the A8 did not have a fantastic high frequency response as it only ran at 7.5 ips and the Dolby C has a way of killing your highs if the calibration is off at all with internal bias, level and eq settings.

At minimum, a calibration would be a good thing to get done to it as that procedure will give it a tune up and get it back closer to its original specs and having the head re-lapped would truly complete the tune up and set you back a couple of hundred bucks by the time you're done at the service depot.

Cheers! :)
 
This deck doesn't have any switches on the back, just one on the front for
NR in/out. Is there an internal set up for switching it off??
And has anyone had any luck polishing heads that appear to need heavy cleaning?? If so, what would you use?? I don't wanna pay someone $100.00 an hour to do this if I absolutely don't have to......OK, I know I'm cheap!!!
 
The head could always stand to be cleaned again,...

but I'd almost guarantee you that it needs calibration, and that's a factor in your sound quality. Most decks this age will have drifted pretty far off spec, if like most home recording rigs, it has not been calibrated in a very long time, if at all. I have not bought an 80's deck that did not need calibration when I got it.

You cant tell anything about record/reproduce quality until you test it with the proper new tape. Also, you can't tell much about a head's record/reproduce characteristics until you have all the circuits calibrated properly.

'Nuff said. :eek:
 
OK, I'll have to agree with you . I did some initial recording with the old tape, and although it seemed a little muffled, at least it worked. NOW when I try to do the same thing again,(still the old tape), I get recording level, but when I try to play back, there's nothing there.... no meter movement... no audio output whatsoever...
Do you think I damaged it with the old tape? Or did something fizzle out just because it wasn't used for so long? I guess it's off to the shop it goes...I'll try it again when my new tape gets here just for kicks.
THANKS for your advice!
 
You wouldn't damage the deck with the tape,...

but you may get more dirt on the head from older tape. Also, you have to be sure you're threading the tape properly, because any improper orientation of the tape would cause problems. The common mistake is to have the backing side of the tape against the head, instead of the oxide. Check cleaning and the most basic and simple things first. Double check everything. Don't make any hard & fast judgments based on tests of an unknown ancient tape. Get a fresh tape before drawing any hard conclusions. :eek:

It sounds to me like you may have the tape threaded upside down, or wrong in the tape path so that the tape presents itself upside down to the head. That description of "muffled" is just too telling.

Tape threading/tape orientation: check it. Have you threaded a reel recorder before? Do you have the manual, picture or diagram?

You gotta start by scrutinizing the most basic things, before moving to higher levels of complexity. Tape quality, tape threading, head cleaning. Then there's patching, routing, level setting. Then maybe alignment & calibration. Start at the basics, & work your way up. :eek:
 
Does your deck offer any type of monitoring switch facility to listen to either Input or tape? If so, it might just be in the Input position while the tape is playing and explain why you're not hearing the recorded results!

And, from what you described, it doesn't sound like oxide shedding to me.

Cheers! :)
 
My apologies!!!! I finally had a revelation and tried it with the tape flipped over...it works. I could have sworn that I read on here somewhere that the shiny side goes toward the head!!!!!! I still haven't figured out how it got reversed though????I've been running the reels in the same process the whole time. (haven't removed them from the machine.)It will really only thread a certain way over the guides...to do it wrong is about impossible.
I had to flip one of the reels backwards..then rewind the whole thing to correct it. Either way I pretty much feel like an idiot for wasting your time...
Thanks for your info... and patience!!!!
 
Aha! Just as I suspected.

It's not as hard as you think to get the tape wound upside down. What usually happens, is that the tape gets threaded normally, and then you inadvertently introduce a 180 degree twist into the tape, just right of the right tension arm. Then, the tape is affixed to the reel, and upon Play motion, the tape is handily wound onto the takeup reel upside down.

Don't say it's tough, it's very easy to do. I've even done this once with 1/2" tape, and you'd surely think it's "impossible" to do that with 1/2", but it happens. With 1/4", it much easier to do this.

If this mistake wasn't that common, I couldn't have guessed it, or written this post, but I did.;)
 
Just to let you know, got my new tape today and it seems to be working fine.
Although track 8 is still brighter and real hot. If I record at 0 db, it plays back at about +3 or +4. I'm inclined to agree that it must have the NR defeated on that track. I think I'll get it serviced,calibrated, and put back to stock. It should perform nicely. Thanks for all your good advice.
 
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