Topic: Demagnetizing Cassette Deck Heads

[Albix714]

I need to demagnetize the heads of a Nak Cassette Deck 2. I found this info and I'm wondering if it's correct or if anyone has anything to add. Thanks.


Demagnetize Erase and Record Heads 
 

1.   Use a commercial tape deck demagnetizer. 
 
2.   With the deck off, turn on (or plug in, if the demagnetizer doesn't have a switch) demagnetizer away from deck, other audio equipment and tapes. 
 
3.   Slowly move tip of demagnetizer toward head. 
 
4.   Make sure the demagnetizer doesn't touch the tape head (the magnetic field will cause it to try). 
 
5.   Slowly move the tip back and forth across the tape head for a few seconds. Get close to the head without touching it. 
 
6.   Slowly pull demagnetizer far away from head. Unplug demagnetizer after demagnetizing both heads. 
 
 
  Tips: 
 Look for a demagnetizer with a plastic-coated tip. 
 
 Only demagnetize if you start to hear distortion on your tapes. 
 
 A hi-fi shop might also demagnetize your heads for you. 
 
 
  Warnings: 
 Used improperly, a demagnetizer will increase head magnetization. 
 
 A demagnetizer can damage tapes, speakers and other audio equipment. 

[Lil Kim Jong-Il]

Yes that is right.  I recall the exact same directions came with my demagnitizer.   I have an old-style sony wand and I never noticed the sort of magnetic field that would pull the tip toward the head.

[Patrick]

I've got a TEAC demagnetizer that I use on my 4 track Reel to Reel. 

The damn thing is pretty powerful, actually.  And it is true, it WILL swipe a tape of its contents, one of the many reasons  digital technology took over!

[BobW]

about three layers of good, thick packing tape or a dip or two in tool rubber insulation paint on the tip always worked for me.

These work, as well (and they get more laughs in the shop...):

[heath]

just keep any and all media away from the thing.  unless you want to bulk erase, of course

and make sure you follow the rule of pulling away slowly.  over-exaggerate it.  Pulling away quickly can re-initiate a magnetic charge.

h

[Albix714]

Thanks for alll the tips!!! Much appreciated.

[zowie]

I never noticed any difference in sound from demagnitizing my cassette decks.   Matters more for R2R.

[BobW]

I never noticed any difference in sound from demagnitizing my cassette decks.   Matters more for R2R.

Heavy use and chrome tapes make it more important.

If you hear it, it's likely in the top end.

[heath]

just wanted to add a link to the best demag'er I've found.

http://www.blevinsaudio.com/handmag.html

[rocksuitcase]

I'm working through a bunch of Cassettes circa 1982/3 on a borrowed Nakamichi LX-5 (from raoulduke-TY!) and started wondering about demagnetizing this thing. Almost all the tapes are Maxell XLII's and seem to have similar tonal characteristics, even with about three different mic set ups. I have been cleaning the heads and pinch rollers after about every 5 tapes since the first cleaning. The first cleaning did remove some heavy black dirt, then following the tape runs, the dirt is brownish but not too much.

After a cleaning I ran a GD show which of course is two tapes per show. set one tape has some awful low frequency distortions which none of the other tapes exhibit (edit to add the set 2 tape was passed through after the demagnetizing). So upon hearing that, I realized I had not demagnetized yet after almost 20 tapes being run through. i ran my Realistic demagnetizer on it and the rest of the run didn't appear to have those sound issues. (about 4 tapes so far). I am about to run the problem tape again to see if another pass post demagging will help it. My overall goal has been to not run them through more than once, and if they are not tails out to side A, i run Side B first etc, no extra crossing of the tape heads with the over 30 year old tapes.

Should I be concerned about the problematic tape? did I erase some of it with magnetized heads? Ho often would someone suggest I use the demagnetizer? do you think I am cleaning too much, or not enough?
Should I be heating these babies up in a toaster oven like has been suggested on the JGB forums or what Rob Eaton did for the Betty boards?
I also have one of those Discwasher cassette demags taoes colored red.

What do you guys think?
So far They are mostly sounding great given their age! I have been storing them as best as one could over the years, including a 8 year stint at my mothers in a totally Air Conditioned environment while I was on tour in the 90's and never really had a space of my own to store them in.

[raymonda]

Demagnetization should only be needed after 25 to 30 hours of play, with sometimes after 50 depending on the type of tapes used. Whether it is cassette or R2R, all players will require demagnetizing. Demagnetizing more than that will most likely have the opposite effect and cause you to magnetize your heads.

The tape that has the distortion may not have been caused by you but rather it may have been an "in the field" user error of clipping the mic preamp, thus causing distortion. Most tapers have been guilty of this at some point. The taper might not have padded down the signal and clipped the heck out of his preamp. One way to tell is if he has the encore on the first tape. If that sounds clean, as well as the second set, then in all likelihood it was an "in the field" error.

Those are some great years to have and much needed, especially if it is with something other than Nakamichi 100 or 300 and if the were FOB. Even Senn. 421 or 441, would be preferred. Of course Nakamichi 700 or 1000 were also preferred. That is not to say that Tony S. didn't pull some great 300 tapes back in the day. He had it figured out and some of his 300's are the best recordings using these mics that i have heard.

BTW, I had a friend who recorded with Nuemann KM84's, however, because he sent a too hot signal to his D5 he has hundreds of hours of recordings that are distorted and these were years from 1982-1990. I was doing a bulk transfer and was extremely disappointed with the recordings. A clean recording using a cheap mic is always preferred over one that has clipping. I eventually gave up on the transfers due to poor results.

[rocksuitcase]

Ray, thanks for the input. Oddly enough I was invoking your name in text to another taper buddy just yesterday- as both of us had Mark for a mentor.

I will be sending these recordings to either raoulduke or kindms to do the post processing; we have a game plan that I will take them off using the Nak's and send the raw files to them; any that are quality enough to be upped, we will. For instance, I notice there are no audiences of GD 1982-08-04 on the LMA; mine was done with Beyer M 201's (which Mark recommended we buy/use) in the 100 sections about 25 feet from the stacks, not as nice as an FOB, but surprisingly nice. The tape in question is 1982-08-03 Starlight theater, and I was plugged into someone's Nak 300's into my D5 (I know who, but won't say here as I have never seen any of his recordings or his name on the LMA).

Back OT, and I welcome other input based on cleaning or demagnetizing (i.e. any specific brand fluid to rec re: head cleaner or pinch roller cleaner?) should I even touch the pinch rollers? that is a topic which has more than two sides to it! I do feel that your advice is more like what it was, that the lead deck on this tape (Nak 550) was set too high for side one of set 1, as side 2 has almost none of the same "distortion". After further listeing, I feel your intuition is accurate. I may try to run side A back through just to see. Of course, I am worried about too many passes of the masters and or not wanting to harm or use the NAk LX-5 for anything other than taking off the masters one pass at a time.

As I told raoulduke, I am notorious for killing cassette decks (as kindms!).

Thanks again Ray   

[raymonda]

The Beyer 201's in the right place can get you some fine results. It will be a great addition to the archives.

[rocksuitcase]

I'm being surprised by many of these Beyer recordings. Back in the day, possibly due to playback limitations, we though the Nak's were "better" sounding, and we had improved our overall approach, mic and deck wise by 1983, so many of these 1982 tapes never got too much play. we always made several first gens on one pass once we got back home, and the masters were rarely, if ever, played after that.

Once we get the project ready for upload, I will start a thread on it. it looks like 13 1982 shows, and about 40 1983's.

[raymonda]

That's great.