Fostex A Model 20 "crackling" on channel 1

blumediaprojekt

New member
I just picked up a nice condition Fostex Model 20 today. I'm hearing some "crackling" on channel 1 when I playback a recording. Its dynamics/loudness follows the dynamics of the recording --> loud deep electronic kick drums for example.

Any ideas on what this may be?
 
So many possibilities...are you sure you didn't overload the input? Bad jack (open it up and wiggle connections around)? Have any DeoxIT to spray on the contacts?

Have you tried pulling the amp cards out and cleaning the contacts with DeoxIT?

Those are the places I would start.
 
The deox was the first thing I thought of. I should go get some. There was no overloading going on.

Thanks for those tips, I'm going to try to get to it today.


-adam
 
Clean the heads and demagnetize if you haven't already..... I know I sound like a broken record but demagging is NOT optional.



AK
 
Last edited:
Is the tape is good condition? My R8 used to crackle on channel 1 back when the reel tables were too high. The transport would actually warp the outside of the tape where channel 1 was recorded, resulting in a crackly sound.
 
Good point, AK.

blumedia, heed that.

I just conquered the wierdest problem on my 58 that was the result of magnetized heads...It was truly wierd.

Demag...with a real demag unit.
 
Is the tape is good condition? My R8 used to crackle on channel 1 back when the reel tables were too high. The transport would actually warp the outside of the tape where channel 1 was recorded, resulting in a crackly sound.

The transport seems to be running well. The machine packs tape way better than my E16 does. The tape is also brand new RMGi 911.

I've never demagged before, but I'll follow the directions I've got.

I feel like this machine was a pretty good deal.

$150 included the machine, a han-d-mag, and a fresh roll of 911. I even got the original receipt. It's super clean and the heads look completely new, I just gotta get this crackling thing worked out and I'll be a happy camper.

Oh yeah, and the red leds at the top of the left meter aren't working but I've got the ouput of the machine going right into my monitor control (Presonus Central Station) which has fairly decent LED meters so it doesn't matter much I guess.

Thanks again for everyone's help so far. I'll check back soon.
 
Another connection to clean, the head connector sockets if it has them. I remember reading somewhere somebody that was having poor signal quality. They removed the head cover to access the multipin connectors for the heads, disconnected them, put some DeoxIT on them and connected/reconnected a couple times and the problem was fixed.

Keep us posted! ;)

BTW, that does sound like a good deal! Is the 911 running clean in the tape path?
 
Another connection to clean, the head connector sockets if it has them. I remember reading somewhere somebody that was having poor signal quality. They removed the head cover to access the multipin connectors for the heads, disconnected them, put some DeoxIT on them and connected/reconnected a couple times and the problem was fixed.

Keep us posted! ;)

BTW, that does sound like a good deal! Is the 911 running clean in the tape path?

The 911 seems to be running just fine. I de-mag'd everything and it didn't seem to change a thing. I don't have any deoxit so I've got to find some. I'm hoping that may solve this.

The machine is so damn "like new" but has been sitting in storage for the last ten years. I have a feeling that the deox will probably fix things.


What doesn't make sense to me is that the bias, etc adjustments are under a panel on the bottom of the machine- leaving no obvious way to adjust them while being able to keep things connected and playback going. Am I missing something here?
 
What doesn't make sense to me is that the bias, etc adjustments are under a panel on the bottom of the machine- leaving no obvious way to adjust them while being able to keep things connected and playback going. Am I missing something here?

Isn't this unit able to be operated horizontally?
 
I recorded in a little sample of the left channel versus the right. Keep in mind that this machine has not been touched in probably over 10 years so it definitely needs bias'd, aligned, etc... along with any other tune-up/clean-up.

Here is a zip file containing a sample recording from a song I'm currently working on. The left and right channels are separate files.

http://editorial.b-mp.com/tape_crackling.zip
 
Back
Top