Hi-
Attached is a pic of my modified headblock setup. It shows the added resistor, maximum shield microphone cable (thanks Parts Express), phono connector, and grounding solder tab. Yes, I also modified the preamp box with a phono jack.
I bought enough cable to re-wire all the audio paths in my machine.
I didn't try to re-use the original headblock plug & jack, but I did keep them.
One thing to check: make sure the headblock is isolated from any part of the of the frame below it. It must not make contact with any part of the frame, or else noise will result. In other words, both plastic rollers must be present for ground isolation, and to allow left-right movement of the headblock. And, the headblock hold-down clips should all have plastic isolation washers.
Good luck on your 'tron adventure!
-Bruce Daily
#1221
--------------------------------------------
On Fri, 5/25/18, fazeka@gmail.com [newmellotrongroup] <newmellotrongroup@yahoogroups.com> wrote:
Subject: [newmellotrongroup] Head block to preamp cable replacement
To: newmellotrongroup@yahoogroups.com
Date: Friday, May 25, 2018, 2:46 AM
Hi all,
I will be adding a 47k
resistor to my M400 preamp input to minimize the chance of
magnetization of my heads/potential erasure of tapes. I want
to also do another form of preventative maintenance and
replace the head block to preamp cable to avoid cable rot
which I also understand can magnetize heads and lead to
partially (fully?) erased tapes, as
well.
Sorry for the following
ignorant questions but what kind of cable? Any specific
specification? What gauge AWG? Single conductor shielded?
Spiral, braided, foil shield? How about Belden 9965 or 9961?
Coax (RG-59/U)? Other?,
Cheers,
Chris
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