Bulk eraser mistake?

johnfs19

New member
I am somewhat new to analog recording and recently bought a bulk eraser from E-bay. I tried it out today using a circular motion on both sides about 20 sec each side. My question is did I improperly erase the tape, because now I hear a low frequency womp..womp womp now. I tried to erase it then with the tape deck to record no signal and still I hear the noise. I have a 10 and a half inch reel of tape I wonder if I ruined it because of this noise that I can't get rid of? thanks for any help.

John
 
Did you shut the bulk eraser off while it was still on the tape? You are supposed to pull it away very slowly, about 3 feet away, then shut it off.
I made the mistake of turning it off once while still on the tape and I too ended up with the womp womp...
 
If it was a handheld bulk eraser, perhaps it just wasn't capable of doing a large reel evenly. When you switched on the the degausser was it away from the reel and you brought it in to do the circular motion and then pulled it away before switching it off? If it is switched off when still near the reel it could possibly impart some magnetization that may yield what you got.

I have a tape degausser from years ago that was designed for larger reels...... (keep credit cards with magnetic strips far away)
 

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Both good points. I never tried metal reels. I would think that would impact the results
 
I have a tape degausser from years ago that was designed for larger reels......

I keep hoping to find one like that at a decent price in good condition, since now I have a lot of 2" reels, which I wouldn't ever try to erase with anything smaller...other than using the deck, but I would rather have a quick bulk demag.



Both good points. I never tried metal reels. I would think that would impact the results


Did you decide that Indie place just wasn't for you now that RR is gone? :D ;)

I don't think the metal reels are a problem, since they are aluminum, and are not affected.
Not sure if they "block" the demag in any way though.
 
I think I turn it off when it was still very close to reel instead of moving it slowly away and turning it off. And yes to both I had a metal reel that I was doing with and yes that was was a hand hand version demagetizer. So is my tape worthless now?
 
Hit it again...tun it on from 2' away...bring it in slowly, then do a slow spiraling motion over the reel...then bring it 2' away...and then turn it off.

Which demag unit is it?
The only one that might work if you use the heel of the unit, instead of the probe side...is the Han-D-Mag.
http://www.rbannis.com/files/han-d-specs.pdf
They have a lot of kick.

If it was one of those small probe demags...forget it.

Just of out curiosity...why didn't you just erase it on the deck?
Do you have like dozens and dozens of tapes that need erasing...and you wanted to do it in bulk?
 
I think I turn it off when it was still very close to reel instead of moving it slowly away and turning it off. And yes to both I had a metal reel that I was doing with and yes that was was a hand hand version demagetizer. So is my tape worthless now?

The tape might be fine if you get everything re-arranged properly, but a smaller magnetic field will be more work and finesse
 
Did you decide that Indie place just wasn't for you now that RR is gone? :D ;)

Well, I know who they are : ) hahah You only got a year on me here, but no, I haven't been active here other than catching threads from web searches.
 
The model was made by Radio Shack "Archer". Anyways I was trying it out not that I have a bunch of tapes.Can you explain what you mean by? "The tape might be fine if you get everything re-arranged properly, but a smaller magnetic field will be more work and finesse". I was thinking of another alternative is to simply place a magnet on top of the tape and running the tape fast forward. What do you think?
 
You can search deguass tape reel;
https://youtu.be/x3ozPmZmrtU

I've never done a cassette and this vid seems "quick". I usually go closer to a minute on 7" reels - most of that is the exit process. Mine is a quarter the size of the large photo above - with the spindle in the upper corner. Somehow the cats dropped it 5-foot from a shelf

I wouldn't put a magnet anywhere near heads and transport. I'd just refine what you tried. I think I tried a 24' CRT TV once, but don't remember if there was any success. Record hot on a section and see how quite it is after the erase
 
The model was made by Radio Shack "Archer".

I kinda figured it was one of those consumer-ish deals.

Running tape against a magnet will do nothing for you...but go ahead...you won't make it worse.

Your problem...IMO...is that the RS degmag did splotchy job, maybe it just doesn't work good anymore...and it left those magnetic "bumps" on the tape...too strong for your tape deck NOT to be able to remove them...or for the RS unit to remove them, even though it left them there.

I think the only thing that will work is a stronger, more uniform magnetic field with a better degausser, and the right procedure.

So I'm kinda curious...if you don't have a bunch of tapes to erase...why did you buy a bulk tape eraser? :)
I can see you getting a demag unit for cleaning the deck's transport and heads...one of those with a wand/tip...but what did you need a bulk eraser for?
 
The idea of an AC (alternating current) bulk tape eraser is to scramble the magnetic orientation of the oxide particles which I believe somewhat reduces the chance of passing on a magnetic flux to the tape heads. If you run a permanent magnet along a steel screw driver shaft several times in the same direction, the screw driver shaft will become magnetized.

I remember having a 60's vintage 3" reel to reel tape recorder (Lafayette I think) that had a small permanent magnet prior to the record head that when the recorder was put in record the magnet swung in to contact the tape to erase it. Was not 'HiFi' by any means.
 
My Dok 9020v has a deguass button. ahah. I don't want to try it and mess up all six heads.

My understanding of the bulk erase mystery, is that it's all in the oxide flip-flop as you slowly reduce the influence of the external magnetic field. Not just one orientation of the polarity, but one more polarity flop ????
 
I have the Annis Han-d-Mag and Ampex HD-16 hand degaussing tools as well as an Intec hand-held bulk tape eraser unit.

I also have these two vintage Ampex bulk tape eraser units; an SE-10 and some unknown tabletop model. Never used these Ampex units. The SE-10 is for 1" NAB reels and is fully-automated:

IMG_7812.JPG

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Bulk Eraser Duty Cycle warning & Radio Shack Bulk models

Hi guys,

I`m new to the forum but not so new to Hi-Fi and guitar/pro-sound electronics - I own/operate a very small custom build, restoration and repair of vintage gear primarily vacuum tube stuff - but recently bought an Otari MX5050 BII2 from good ol' Ebay and it was terribly packaged and boxed - arrived where none of the transport buttons worked - turned out the fold out circuit board in the back had a 1/4" hairline crack lower right corner through the mounting screw hole separating one small trace - that was the problem. Fixed with some precision scraping and very careful soldering of a 3/16" 24 gauge pre-tinned solid copper wire. Lots of other small issues mostly cosmetic (missing & incorrect screws all over the place, missing bottom legs and back rubber feet, side panels falling apart -some missing paint around head cover and the transport button white lettering and symbols for FF/Rewind & Play barely visible. Legs, Rubber bumpers/feet & side panels will be replaced - Legs & Side Panels got some raw 3/4" Solid Mahogany precision cut that I will finish in a deep darkish Red Mahogany color using bright red, brown, yellow & black wood dyes, shellac seal coat, wood grain filler mixed with dark walnut & merlot red stain - finally a semi-gloss or gloss spray lacquer (Dyes, stains and lacquer need to do some experimenting on scrap mahogany to get right mixes). Will post final before and after in separate post in correct area

But for bulk erasing and tape head demagnetizing - - the Han-D-Mag is the best by far head demagnetizer but as a handlheld tape eraser - not so much - someone here said - too small a magnetyic field - I used the smaller Radio Shack bulk eraser years ago for analog and digital tapes (home audio cassettes, 8 tracks, small reels and VHS) and work (data cassettes, data discs, floppy, 3 1/2" and even hard drives) - didn't own large reels at the time (7" & 15") - that nulk eraser - which I think was rated at 4 amps with a 1 minute on 20 minutes off duty cycle died in a basement flood. The one I bought recently (waiting for delivery) is the "Radio Shack Improved" 9 Amp version - bigger, stronger 1 min on and 40 minutes off if memory serves - was upgraded primarily for video tapes (VHS, Betamax) wider tape, more information on tape at much higher "digital video" frequencies.. I purchased this one for its more than double power rating (4 vs 9 amps). But I also wanted to point out how important it is to pay attention to those duty cycles - if you leave the expensive HanDMag or the much less expensive Radio Shack hand-helds on much beyond their 1 minute duty cycle (duty = "powered on") ands/or you don't let them rest / cool down for duty off cycle - these will either fry and become totally useless or they can degrade considerably with possible shorted windings - generating more heat in shorter duty cycle time with less effective magnetism.... For the most-part all these things are - are AC transformers with low resistance loads on the secondary windings basically creating a transformer with a short circuit on its output. The more expensive commercial bulk erasers have protective current limiting circuitry and many I think have an automatic duty cycle - where they turn themselves off at the end of a programmed duty cycle - these others are controlled by the user - and can and will literally burn up if left in the on position too long - back in the day - the UL wasn't as strict as they are today - these things would never get UL approval if they were made today - I had a cheapo radio shark head demagnetizer that almost set my apartment on fire back in 1979 - it was a 1960's model - later ones may have had some type of basic thermal bi-metal safety that opened if overheated but did not reset as reliably - so again if u didn't follow duty cycle warnings even if it didn't melt down most times it would not function after one or maybe a few overheats - not until much later did they consider more sophisticated protection circuits and by then these were made/used primarily for the video cassette or commercial ones for the data industry. I was looking to by a tape tension gauge there are dozens of sellers with brand new Sony tape tension gauges for $25-35 - took me an hour to find out that this tool was designed specifically for sony video cameras and players - won't help much with audio world - although I did pickup a pair of new commercial grade spring scales (2 lb & 10 lb) off Amazon for $20 each - perfect for the Otari 5050 series - I'll let u know how the Radio Shack 9 Amp bulk eraser works out when it comes in - and thanks for reminding me about the 3 foot distance for the on and off cycles.. BTW my Han-D-Mag I bought second hand because the seller included the same brand Magnometer - has anyone used this and if so what should an Otari set of heads, rollers, capstan read when in need of demagnetizing (BAD) and after a successful demag what should the magnometer read? (GOOD)
 
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