Tape Head Demag Video

[MylesBAstor]

http://www.youtube.com/watch?v=PrEFrZy6JQo&feature=fvst

 

[Steve williams]

Good video. I didnt recognize his demagger

I use a HanDMag

 

[MylesBAstor]

Good video. I didnt recognize his demagger

I use a HanDMag

Steve:

The guy in the video said it was a Nortronics demagnetizer.

 

[Steve williams]

I guess the question needs to be asked.....

how often does one demag their player?

according to some, every 50 hours and IIRC Paul Stubblebine from the Tape Project says not at all. Im sure there must be a happy medium somewhere in between.
I was interested that in the video he says not tomtouch the heads with the demagger. Some say to gently touch the heads. The strength of the magnet in the HandMag is such that when it gets close to something metal it is attracted like a bee to honey and sometimes becomes imposible not to touch the heads.

 

[MylesBAstor]

I guess the question needs to be asked.....

how often does one demag their player?

according to some, every 50 hours and IIRC Paul Stubblebine from the Tape Project says not at all. Im sure there must be a happy medium somewhere in between.
I was interested that in the video he says not tomtouch the heads with the demagger. Some say to gently touch the heads. The strength of the magnet in the HandMag is such that when it gets close to something metal it is attracted like a bee to honey and sometimes becomes imposible not to touch the heads.

Steve,

Check in the archives-raised that question when the forum first began. See:

http://www.whatsbestforum.com/showthread.php?85-Tape-Head-Demagnetizing&highlight=demagnetizing

Rich Brown and Charlie King are of the mind between 50 and Paul. One thing Charlie pointed out is that the heads must be demagged when installed.

 

[Steve williams]

I remember that thread. So how often do you demag.

 

[MylesBAstor]

I remember that thread. So how often do you demag.

Less and less as time goes on.

Probably closer to the 100 hr or so mark.

I understand both arguments, the anti-demags being that you can screw it up as much as help the heads unless one can measure the residual magnetism with a magnetometer (and it would have to be pretty sensitive).

 

[Steve williams]

i asked the question because like you i demag less and less because of underlying concern that I might do more harm than good.
the video was interesting because he said excessive head magnetization will reduce transient response

 

[stellavox]

Demagnitizing heads

Let me repeat my response to the original thread on this:

I think this demag thaang may be overrated.

From my perspective, a head can (only) get magnetized in two ways. Exposing it to some fairly large external magnetic field, or applying some kind of electrical impulse to its coil. If you believe this then to mitigate "one", I'd keep anything that could be magnetic - like (magnetized?) tools as far away from the heads as possible. As regards "two" it seems that the only way you might screw this up is possibly removing/inserting a headblock with the power on.

I've actually never come across or "heard" a magnetized head. When working on a deck, as a matter of course I do demagnetize everything in the tape path when finished and before loading the "first" tape - especially (expensive) calibration tapes. If you think about it also, most well designed heads are quite well shielded, with pretty narrow "windows" - the only place where magnetizing flux can actually get in. You'd have to have a pretty strong field in close proximity to the head to do anything "permanent". Of course I have reversed the connections to my preamp (tape head to output instead of the input) and recorded hum and noise on the tape when "playing around" wondering why I wasn't hearing any signal. And of course the tape I was playing was a WONDERFUL dupe - what an as*****.

AND LET ME NOW ADD TWO ADDITIONAL THOUGHTS:

Regarding the comment that too much demagnetizing might do damage - Hmm.

I forgot to mention that when demagnetizing I ALWAYS do it with the (at least one wire per channel of the) head DISCONNECTED from the electronics.

Think about this - a demagnetizer generates a GIGANTIC AC signal in the head - (both are only trying to do what it they are supposed / designed to do) - a signal maybe orders of magnitude larger than EVER encountered when playing a tape. As this signal is WAY more than the electronics expect OR may be designed to handle, I can understand that the process COULD damage electronics and more frequent demag more-so.

That's why I've found I only have to do it once.

And another thing - a demagnetizer generates an AC field, so theoretically it CAN'T leave any residual effects (on a head). HOWEVER, you shouldn't position it near a head when switching it on or off - especially off, as a residual pulse from switching off a demag coo close to a head could magnetize it. Therefore I always make sure that my demagnitizer is 2 or 3 feet away from the headblock before switching it on or off.

And of course; please don't have any tape "lying around" when you're playing demag games!

Charles

 

[MylesBAstor]

Let me repeat my response to the original thread on this:

I think this demag thaang may be overrated.

From my perspective, a head can (only) get magnetized in two ways. Exposing it to some fairly large external magnetic field, or applying some kind of electrical impulse to its coil. If you believe this then to mitigate "one", I'd keep anything that could be magnetic - like (magnetized?) tools as far away from the heads as possible. As regards "two" it seems that the only way you might screw this up is possibly removing/inserting a headblock with the power on.

I've actually never come across or "heard" a magnetized head. When working on a deck, as a matter of course I do demagnetize everything in the tape path when finished and before loading the "first" tape - especially (expensive) calibration tapes. If you think about it also, most well designed heads are quite well shielded, with pretty narrow "windows" - the only place where magnetizing flux can actually get in. You'd have to have a pretty strong field in close proximity to the head to do anything "permanent". Of course I have reversed the connections to my preamp (tape head to output instead of the input) and recorded hum and noise on the tape when "playing around" wondering why I wasn't hearing any signal. And of course the tape I was playing was a WONDERFUL dupe - what an as*****.

AND LET ME NOW ADD TWO ADDITIONAL THOUGHTS:

Regarding the comment that too much demagnetizing might do damage - Hmm.

I forgot to mention that when demagnetizing I ALWAYS do it with the (at least one wire per channel of the) head DISCONNECTED from the electronics.

Think about this - a demagnetizer generates a GIGANTIC AC signal in the head - (both are only trying to do what it they are supposed / designed to do) - a signal maybe orders of magnitude larger than EVER encountered when playing a tape. As this signal is WAY more than the electronics expect OR may be designed to handle, I can understand that the process COULD damage electronics and more frequent demag more-so.

That's why I've found I only have to do it once.

And another thing - a demagnetizer generates an AC field, so theoretically it CAN'T leave any residual effects (on a head). HOWEVER, you shouldn't position it near a head when switching it on or off - especially off, as a residual pulse from switching off a demag coo close to a head could magnetize it. Therefore I always make sure that my demagnitizer is 2 or 3 feet away from the headblock before switching it on or off.

And of course; please don't have any tape "lying around" when you're playing demag games!

Charles

Thanks Charlie for sharing your thoughts!!!

 

[Steve williams]

it only corroborates what i have felt. Thanks Charles.

i would rather replace heads on a prn basis than demag and run the risk

 

[flez007]

I was just about to start a new thread with the "to demag or not to..." headline...in my case, and following again the expert words of Bruce, Ki and Charles, I did demag the Nagra T to bring it back to life! I am converted!

 

[c1ferrari]

Excellent

I was just about to start a new thread with the "to demag or not to..." headline...in my case, and following again the expert words of Bruce, Ki and Charles, I did demag the Nagra T to bring it back to life! I am converted!

 

[Fred]

Interesting therories here guys. I play my decks around 30 hours or so a week. I try to keep my heads very clean. With the use of a dental mirror and flashlight I inspect them every Saturday morning when I do a ritual dusting of the components. I find that I clean the heads and tape path around every two weeks and the urge is to demag after those cleanings.

From my own experience, I find the decks sound as good as they're going to after the cleaning and demagging. And on those rare instances when I skip the demagging part and just clean the heads I find the sound not as tonally balanced. Maybe it's all psychological though as I'm talking small differences.

 

[jcmusic]

If memory serves me right most Akai decks had glass heads!!!