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Marrshall amp custom mod front panel

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

Reply to
N_Cook
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Lots of epoxy

Reply to
hrhofmann

velco

Reply to
Ron

amps.

Marxhall

sheet

to

spots

the

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

Reply to
N_Cook

That's pretty common among guitarists ;)

Reply to
Ron

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:Paul@Hovnanian.com
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You're only supposed to blow the bloody doors off!
Reply to
Paul Hovnanian P.E.

amps.

Marxhall

sheet

to

spots

the

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

Reply to
N_Cook

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

Reply to
Arfa Daily

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