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337alant
17-04-2017, 16:07
Hi Pop pickers :D
Just a bit of R2R learning see below Video of the basic procedure for demagnetizing your tape heads and guides for those who may not have done it before:)
https://www.youtube.com/watch?v=PrEFrZy6JQo
http://mrltapes.com/mcknight_demag.pdf

Some important points to note! :eyebrows:

- do not have the machine plugged in or switched on during demag
- do not do the demagnetisation in the same room as any of your tapes or in the vicinity of anything that would be effected by a strong magnetic field.
-Thoroughly clean all of the tape heads guides and capstan before demagnetization.
-Use 99% isopropanol and cotton buds to clean everything and wipe from side to side on the tape heads not up and down.
- do not touch the tape heads with the demag
- plug the demag onto an un-switched extension lead that is known to be reliable and can not switch off during the demag process, its very important that you do not loose power whilst demagnetizing as you could leave your tape heads permanently magnetized if you do
- make sure you are a minimum of 4 feet away from the tape heads before you switch on or off the demag unit
- Once you switch on move very slowly into and away from the tape heads
- I prefer to demag all the guides and capstan first then the errase head followed by the record and replay heads last
- I have heard some distinct improvement in sound quality after demagnetization

I use one of these Han-De-mag units :rolleyes: its expensive and an absolute animal :eyebrows: and if you buy one make sure its the 240v version not 110v
http://www.ebay.co.uk/itm/HAN-D-MAG-international-studio-tape-head-demagnetizer-115-or-220-volt-BRAND-NEW-/221248600430?hash=item338371b96e:m:mhz4QIBKXccRbGu I3SzmHXw

But these are fine too
http://www.ebay.co.uk/itm/Analogue-Studio-Cassette-Tape-Head-Demagnetiser-/231985622670?hash=item36036bae8e:g:aEQAAOSwT6pVjV5 g

I also have a magnetic flux indicator for checking my tape heads and only demag when there is a reading
http://www.ebay.co.uk/itm/HAN-D-MAG-HAN-D-KIT-studio-head-demagnetizer-magnetometer-probe-strips-NEW-/221181056937?hash=item337f6b17a9:m:m7JVJdQZIowZWfK 6jU9so9Q

Alan

Barry
17-04-2017, 17:04
I use an old Wright & Weaire (Ferrograph) head defluxer. Think I paid about 25 for it. I like it because it has an on/off button integral with the coil.

http://www.mullardmagic.co.uk/ferrograph-wright-weaire-defluxer-1950s-boxed

(Mine is newer looking than this: it has the Ferrograph sage green coloured housing.)

337alant
17-04-2017, 17:11
Barry yes Ferrograph made some nice equipment, I bought a lovely distortion analyser from them recently

Alan

337alant
23-07-2017, 09:48
Just a bit more info on this subject from MRL who do know a thing or two about tape :eyebrows:

http://mrltapes.com/mcknight_demag.pdf

Alan

Cas
23-07-2017, 12:55
Just a bit more info on this subject from MRL who do know a thing or two about tape :eyebrows:

http://mrltapes.com/mcknight_demag.pdf

Alan

Thanks for posting this but I have to admit I stopped reading when I reached this statement in the heading of the piece.

" Here is what we think we know "

topoxforddoc
23-07-2017, 13:47
Cas,

Whilst people might argue over how often this needs doing, I don't think that may would argue that it damaging the heads and tape guides intermittently. The problem is that metal components esp tape guides and the heads can get magnetised by the travel of the tape. If there is a small magnetic field in the tape path, this can lead to losing some subtle loss of the high freq signal on your precious tape. That may not matter, if it's just your mix tape sourced from other media, but it does matter if it's a precious master tape.

Charlie

Cas
23-07-2017, 17:11
Cas,

Whilst people might argue over how often this needs doing, I don't think that may would argue that it damaging the heads and tape guides intermittently. The problem is that metal components esp tape guides and the heads can get magnetised by the travel of the tape. If there is a small magnetic field in the tape path, this can lead to losing some subtle loss of the high freq signal on your precious tape. That may not matter, if it's just your mix tape sourced from other media, but it does matter if it's a precious master tape.

Charlie

I hear what you say but.................

Barry
23-07-2017, 17:50
But what about the 20uT of the Earths magnetic field? :D

337alant
24-07-2017, 07:59
Thanks for posting this but I have to admit I stopped reading when I reached this statement in the heading of the piece.

" Here is what we think we know "
Cas
Of course Demagnetisation is completely optional and there are obviously lots of conflicting views on this subject.
I always do when I get a new recorder and then periodically after that but not rigidly to any hours count.
I have a least on 2 occasions cured audible noise on playback of 2 different machines so in my mind I know it can work.

Cas
24-07-2017, 10:35
Cas
Of course Demagnetisation is completely optional and there are obviously lots of conflicting views on this subject.
I always do when I get a new recorder and then periodically after that but not rigidly to any hours count.
I have a least on 2 occasions cured audible noise on playback of 2 different machines so in my mind I know it can work.

To me this sounds like a sensible option, if you are hearing recording problems that were not there before then hit it with the demagnatizer, or if
it is an old machine give it a demagnatize before using it for the first time.

Life really is to short to follow a process every so many hours that after reading loads about still sits in the demag or not to demag camps.

337alant
25-07-2017, 17:48
I also check for magnetism occasionally as well and if there is no significant reading then I would not bother

This is a check on a Tascam BR20 - zilch ;)

https://farm9.staticflickr.com/8646/15813344266_0ae342a76e_k.jpg (https://flic.kr/p/q6nwjE)sticky11 (https://flic.kr/p/q6nwjE) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr

Alan

Cas
25-07-2017, 18:32
I also check for magnetism occasionally as well and if there is no significant reading then I would not bother

This is a check on a Tascam BR20 - zilch ;)

https://farm9.staticflickr.com/8646/15813344266_0ae342a76e_k.jpg (https://flic.kr/p/q6nwjE)sticky11 (https://flic.kr/p/q6nwjE) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr

Alan

Can I ask roughly after how many hours use is there zilch, and what is that gadget you are using, and where can one be obtained ?

Barry
25-07-2017, 19:26
http://www.ebay.co.uk/itm/HAN-D-MAG-HAN-D-KIT-studio-head-demagnetizer-magnetometer-probe-strips-NEW/221181056937?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

337alant
26-07-2017, 02:37
http://www.ebay.co.uk/itm/HAN-D-MAG-HAN-D-KIT-studio-head-demagnetizer-magnetometer-probe-strips-NEW/221181056937?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649


Yes that’s the one and the DeMag I use, the indicator is a Gauss meter.
They have gone up quite a bit since I bought mine but they are excellent

There is no straight answer to how many hours I'm afraid ?.
The last I noticed some magnetism on my Studer was after removing the head block to adjust the capstan roller pressure. Whilst I had the block out I thoroughly cleaned and polished the heads when I put it back together I noticed a little magnetism but it could have been caused by a little carless use of the Allen keys to remove the head block and adjust the Capstan roller solenoid.
Anyway after a demag - Ziltch :D

Alan

Cas
26-07-2017, 10:37
http://www.ebay.co.uk/itm/HAN-D-MAG-HAN-D-KIT-studio-head-demagnetizer-magnetometer-probe-strips-NEW/221181056937?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

Thanks for that, believe it or not but I already have a demagnetizer, so it would be just the magnetometer I would be after.