Marrshall amp custom mod front panel

N_Cook

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Aug 18, 2010, 6:02:28 AM8/18/10

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This on a 4100/JCM 900 but presumably found on other wide cab valve amps.
Front panel replaced with translucent smoked brown plexi-glass and Marxhall
white 3D
logo over it, reflective "silver" lining to the rear panel and running
without screens or
retainers on the valves , for visible effect. But heavyish plexiglass sheet
only relying on a few glue spots onto the rexine covering, itself glued to
not much woodwork. So nothing much holding it in place, now a few glue spots
have failed . Any ideas on how to make a firmer fixing without drilling
holes through the material. There is white trim around top and sides of the
plexiglass , bonded to it, that could perhaps hide fittings

hr(bob) hofmann@att.net

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Aug 18, 2010, 3:34:04 PM8/18/10

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Lots of epoxy

Ron

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Aug 19, 2010, 6:48:30 AM8/19/10

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velco

N_Cook

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Aug 19, 2010, 7:15:32 AM8/19/10

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Ron <r...@lunevalleyaudio.com> wrote in message
news:AoOdneYFbfZilvDR...@bt.com...

The owner was aware of it being loose (1.2Kg) and he is going to sort it out
by gluing back, apparently he's done it before, so not my pidgeon.
He reported that over time whereas he was comfortable with 1/3 vol clean ch
setting , he reckons that imperseptibly over years he now needs 1/2 vol
setting.
3x ECC83 , generic recommended gain 1.6
these measure
v1 / 1.3,1.4
v2/ 1.0,1.2
v3/ 1.2,1.1

would that accord with people's experience here, av 1.2 over 6 triodes would
account for that gain drop?
4x EL34 all fine at 13 to 14 at 59 to 66mA

Back to wrestling with a 7.5 inch guage 12V,60 amp ride on train loco

Ron

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Aug 19, 2010, 10:45:03 AM8/19/10

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On 19/08/2010 12:15, N_Cook wrote:

> He reported that over time whereas he was comfortable with 1/3 vol clean ch
> setting , he reckons that imperseptibly over years he now needs 1/2 vol
> setting.

That's pretty common among guitarists ;)

Paul Hovnanian P.E.

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Aug 19, 2010, 6:01:35 PM8/19/10

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Glue (use the special plexiglass bonding solvent) some plexiglass blocks
around the periphery of the panel, hidden by the white trim. Drill these
blocks (before gluing) for mounting screws that thread into the cabinet.

Alternate to drilling the plexiglass blocks: Fashion some clips (metal)
that thread into the cabinet and grab the blocks.

--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
You're only supposed to blow the bloody doors off!

N_Cook

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Aug 20, 2010, 4:00:25 AM8/20/10

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Paul Hovnanian P.E. <Pa...@Hovnanian.com> wrote in message
news:4C6DA9BF...@Hovnanian.com...

Whatever the glue is , it is fine on the plexiglass. What has failed is the
surface , only, of the rexine has sheared off. So perhaps baring back to the
underlying wood is all that is needed. On the other hand there is a
noticeable bowing in the plexiglass , perhaps 1/4 inch over the length,
presumably due to heat, helping to shear any bonds on the sides

Arfa Daily

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Aug 20, 2010, 9:37:44 PM8/20/10

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"N_Cook" <div...@tcp.co.uk> wrote in message
news:i4j3pf$1ul$1...@news.eternal-september.org...

I would first make sure that none of the ECC83 anode load resistors have
gone high, if you feel that the gain is definitely down.

Arfa