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Subject: Re: [Mellotronists] MK2 Spkr.Magnet Question

From: Jerry Korb <jkorb@...>
Date: 2003-10-14

 

kenmerb@... wrote:

 In a messagedated 10/14/2003 1:34:10 PM Eastern Daylight Time, charel196@...writes:
Iwas telling a buddy today about the inner workings of the MK2 and
he asked me a question I didn't knowthe answer to...since there were
2 speakers on each side of the tapesin close proximity to them what
kept the magnets of the speakers fromerasing the tapes?(even
gradually over time)
________________________Ken Merbler Added : ___________________

This is a good question.  I thinkit's because the magnets are ∗at least∗ far enough away from the closesttapes so that they receive no damage.  I know that the magnets posea significant risk to those close tapes when changing the tapes. When I changed mine on MKII #247, I was warned about the tendency of loosetapes "diving" to the speaker magnet if given a chance, and this does erasethem.  So, when I changed my tapes, I used a towel and a plastic bowlover the speaker magnet on each side, as shown on my web site.  Butas far as tape erasure from normal use, I would say  that it's nota problem by design, although it looks like it would be. Ken M.

_______________________________________________________________

Greetings All,

The MK-I/II speakermagnets are low enough and  distant
enough not tocause any gradual degredation of tapes.
During normaloperation ..... If a tape breaks,it will brush past
the magnet andpartially erase the tape. LH Tapes 1-4 from
Gordon's ex-MK-Ihad noticeable drop-outs of audio.
Someone/somethingwasn't careful.....

The inverse squareslaw of physics applies to light , electricity,
and magnetism.  Ken M. was taking the proper precautions
during MK-IItape change.  I probably would have unbolted the
Wharfedales tomake 100 % sure.

BTW, the JKMK6has magnets even closer to the bottoms of
the M400 tape-frameswithin. No problems seen in two years +.
I installed mu-metal(mag. shield) adjacent to the spkrs.
to preclude afuture disaster. My pro-active policy of safety.

That's why we'Tron users cannot stress enough the need to
keep headblocksdemagged,non-magnetized hand-tools,
electrical precautionswhen installing headblock cable,
yada,yada, yada.....

Cheers, Jerry K.
(MK-I #124, 14,500lines of flux within Spkr. RS/12/DD model. )