Demagnetising tape heads?

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Demagnetising tape heads?

Postby Alistair » Wed Nov 13, 2013 12:15 pm

I've got a couple of Space Echo's I use a lot, and recently I've been needing to clean them a lot more often. Eg, every 5 hours or so to ensure good volume on the echos. I use to be able to do it every 40-50 hours and they were fine.

Thinking they probably just needed a bit of extra maintenance beyond cleaning the tape path, I purchased a hand held demagnetiser/degausser.

I've followed the instructions below, and everything is much much much worse. Even without a tape on the machine, the level of noise and hiss is incredibly high- controlled by the Echo Volume knob (as far as I am aware, just a mix knob after the replay heads).
I'm assuming I have somehow magnetised the reply heads, and they are playing back white noise.
Any ideas on how I have cocked this up (and what I can do to fix!)


These are the instructions I followed.

1) Turn the power off on the tape recorder or duplicator. Demagnetizing with the power on can damage the circuitry.
2) Turn the demagnetizer on well away from tape or tape machines (3' or greater).
3) Move the demagnetizer in so the tip contacts the parts of the tape recorder or duplicator you are trying to demagnetize. You want to do the head(s), guides, and (if you have a strong enough demagnetizer) the capstan.
4) Move across the surface of each part and from one part to the next very slowly and smoothly. If you slip and move fast, go back over that part.
5) After you have gone over the surface of every metal part in the tape path, very slowly and smoothly move the demagnetizer away until you are at least 3' away.
6) Turn the demagnetizer off.
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Re: Demagnetising tape heads?

Postby Ben M » Wed Nov 13, 2013 12:51 pm

Hi Alistair, sorry to hear bout this.

Referring to point 3 -
Alistair wrote:3) Move the demagnetizer in so the tip contacts the parts of the tape recorder or duplicator you are trying to demagnetize. You want to do the head(s), guides, and (if you have a strong enough demagnetizer) the capstan.

In the past when I've used demagnetisers I've never touched parts of the heads or any other part... just hovered an inch or so around them.
This may be the reason you're having the problems. Just my guess.

Someone else may be able to expand on this.
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Re: Demagnetising tape heads?

Postby Alistair » Wed Nov 13, 2013 12:53 pm

Thanks Ben.
My demagnetiser has a rubber sleeve over the tip so I think it's ok. I have tried hovering a few mm off the heads, or contact with the rubber. No luck either way!
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Re: Demagnetising tape heads?

Postby Drumstruck » Wed Nov 13, 2013 1:03 pm

What Ben says.... when I had a demagnetiser (years ago) the instructions were very firm that you don't touch the head with the probe - the closer you could get the better the demag job. All the other stuff (turn on at a distance / turn off when close) is what my unit said too.

You could remove the heads and take them to a toolmaker's shop - they generally have an industrial demag. unit....
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Re: Demagnetising tape heads?

Postby Thirteen » Wed Nov 13, 2013 1:07 pm

Do both machines now have the same noise issue?
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Re: Demagnetising tape heads?

Postby Alistair » Wed Nov 13, 2013 1:29 pm

Thanks guys.

Steve- I'm not brave enough to do the other machines considering this is the result.
I suppose it could be a very big coincidence though.

Is there any lasting damage I can cause through demagging incorrectly? As long as I don't do it to a live machine or turn off the power when close the heads it should all be fixable yeah?
If so, I'm prepared to test it on the other machine.
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Re: Demagnetising tape heads?

Postby Ben M » Wed Nov 13, 2013 4:35 pm

I'd would try the second unit but without touching the heads.
I find that very strange that they'd say to do that.
I'm just going by what my experiences are but I was taught to wave the wand around gently...hovering in no particular place for too long...and don't touch the heads...with the walking in and walking away as well.
I'm no expert on damagging so would be good to hear more opinions. I've never heard of touching the heads with demagnetisers.
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Re: Demagnetising tape heads?

Postby Thirteen » Wed Nov 13, 2013 7:34 pm

I would be leaning toward the coincidence theory.
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Re: Demagnetising tape heads?

Postby Alistair » Wed Nov 13, 2013 11:42 pm

Yeah, I believe they only recommend to touch the heads as there is a rubber shield over the demagger- that way it gets very close but there is never metal on metal contact.

I'm not brave enough to do the other unit just yet- I've got some shows over the weekend that I need at least one space echo to work for!

I read that I can magnetise screwdrivers with a demagnetiser by touching them to the tip and then turning the unit off- I can't get this to work either. I'm wondering if there is an issue with the demagnetiser or perhaps it's just too weak to do anything. It was just a cheap ebay job, $30 with shipping.

http://www.ebay.com.au/itm/400076917722 ... 1439.l2648
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Re: Demagnetising tape heads?

Postby otto ruiter » Thu Nov 14, 2013 6:40 am

The Annis Model 220-S (Short) Han-D-Mag is the go.

http://www.rbannis.com/products/handmags.html
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Re: Demagnetising tape heads?

Postby Alistair » Fri Nov 15, 2013 5:15 pm

Well.... Very strange coincidence seems to have won the day. Steve wins!

I demagged my 555, and it's working perfectly. I cleaned and checked voltages and starting experimenting on the RE201, all to no avail. Took it into another room, just in case it was the power point, and it worked perfectly...
Turns out it's actually interacting rather strangely with just one of my guitar amps. It's fine plugged into any other amps, and other Space Echos are fine plugged into this amp, but they just don't get on together.

Which is made odder by the fact they did last week, but don't anymore!

Over summer I think the RE201 might get a good clean and recap etc., but for now it's ok. Odd things.
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Re: Demagnetising tape heads?

Postby jasound » Sat Nov 16, 2013 7:55 pm

Speaking of a clean up and recap who is the tape echo tech to go to in Sydney?
My RE201 is going fine but I have a Korg Stage Echo that cuts out for half a second intermittently when feeding back on itself. It's a great machine, much longer delays than the 201, and it does sound on sound.

Has anyone bought echo tapes and pads from the local EBay seller EchoFix ,Is it good loop tape?

Thanks.
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Re: Demagnetising tape heads?

Postby Alistair » Sat Nov 16, 2013 10:06 pm

I've bought parts and tapes from Echofix. Really nice guy and very helpful.

First lot of tapes were great- second lot of tapes didn't seem to last quite as long. But whether that's also my machine starting to need some TLC I couldn't say. The tapes look identical though so I imagine they are.

Parts were very high quality. I got new felts and a pinch roller and it made a huge amount of difference.
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