Low End Static

[leddy]

Hi folks.

I noticed on my Tascam 22 on very quiet passages that I was hearing something that sounds like static at pretty low frequencies. Like moving around in a leather chair kind of noise. Pretty far in the background, but audible enough to annoy me.

I tested a couple of things:

I plugged in headphones and cranked the volume. With no tape loaded (and holding up the tension arm) I hit play and also record and listened. No noise.

Then I loaded a tape that I did not record on that machine (an MRL test tape). Cranked the volume; no noise.

Loaded another tape. With nothing coming in the line-in, I hit record. There's the noise.

So it appears it's coming from my machine during record.

Any ideas? Tomorrow I will clean & demag, etc, though I do that fairly often so I doubt that's the issue.

Thanks.

 

[sweetbeats]

leddy, could the noise also be described as "boulders" or "rocks" knocking against each other?

If so, and maybe even if not so, it could be a bias issue. Have you set the bias on your 22 for the tape you are using?

 

[leddy]

Yes, I think you could describe it like rocks hitting each other. I have not set the bias. I have the manual, but the trimmers do not seem accessable.

Is it normally pretty easy or pretty difficult to physically reach the trimmers in most machines? From what I can tell, they are on a board that faces down with only about an inch clearance to reach under. There's hardly any way to see what I'd be turning. I'd have to really take the machine apart to get at it comfortably. That doesn't seem right. I'm beyond my comfort level feeling like I'd risk doing more harm than good without some guidance.

 

[Tim Gillett]

Low frequency noises in record suggest a magnetised head. Try carefully demagnetising the record head.

 

[sweetbeats]

Low frequency noises in record suggest a magnetised head. Try carefully demagnetising the record head.

Good-good-good. Yeah, right on.

Magnetized head(s) can and will make all sorts of wacky noises...right AK? I have had wierd clicking noises to low fequency pulses from improperly demagging my heads and improperly bulk-erasing tape...just not being thorough enough.

Leddy, IIRC you have a good demag unit and have probably already done a good demag job, but take 5, 10, even 15 seconds of probe time for each head (not head stack, but each little strip on each headstack...I don't remember if you have a 22-2 or a 22-4, but for the 22-2 that would mean the erase head has two actual "heads" (little strips) to do, and so on with the sync and repro heads...the 22-4 would have 4 each, etc.)

Try that.

It still sounds like bias to me, but Tim is right on to make sure that you do a good demag job first, always.

I don't have a 22 manual , but the 22 and 32 decks share a lot of similarities, so I'll take a stab and say that the cards and trimmers are on the bottom of the deck facing down. You have to get the bottom panel off and that may mean pulling the other dress panels off. I say it is important to set bias...what kind of tape are you using? "Back in the day" my understanding is that techs would set bias with each roll of tape unless they knew the tape was from the same batch...that may be on the extreme for the likes of you and I, but if you have never set the bias on your 22 it could easily have drifted over the years and/or it has been set for a different tape than you are using and improperly set bias can severely impact the performance of your deck. If you do the demag thing thoroughly and you are still hearing boulders, I suggest it is time to get your hands dirty or take your 22 to a trusted tech and get the bias set.

You would need to lay the deck on its back. Different deck's adjustments are more or less accessible depending on how "professional" the deck is, but IMHO the 22 and the 32 are pro/semi-pro decks clothed in semi-pro/consumer-grade skin and lack some pro features like being syncable, but the rest of the tape path, reel motors and so on are good quality; able to produce very fine results. So, yeah. It is a bit of a pain in the 20 and 30-series to get to the adjustments, but they are there.

 

[leddy]

I spent more time demagging. The noise is still there...

Sweetbeats, I believe you right that I get at the trims via the bottom. I'm checking it out right now. Removing the feet loosens the bottom panel. I think it will come off. I'll report back.

 

[leddy]

I can be dense sometimes. All the trims are right there...

 

[sweetbeats]

SWEET!

I know what you mean...I'll get all wigged out before I give myself the chance to realize it is easier than I think...

Anyway, what kind of tape are you using?

Let us know how it is going.

 

[leddy]

I'm using LPR35. The machine is spec'd for a 1mil tape so I don't think I have too many options. I have one roll of 3M 996 that sounds better to my ears, but it's 1.5.