Marrshall amp custom mod front panel

N

N_Cook

Guest
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
 
On Aug 18, 5:02 am, "N_Cook" <dive...@tcp.co.uk> wrote:
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
Click to expand...
Lots of epoxy
 
On 18/08/2010 20:34, hr(bob) hofmann@att.net wrote:
On Aug 18, 5:02 am, "N_Cook"<dive...@tcp.co.uk> wrote:
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

Lots of epoxy
Click to expand...
velco
 
Ron <ron@lunevalleyaudio.com> wrote in message
news:AoOdneYFbfZilvDRnZ2dnUVZ8l-dnZ2d@bt.com...
On 18/08/2010 20:34, hr(bob) hofmann@att.net wrote:
On Aug 18, 5:02 am, "N_Cook"<dive...@tcp.co.uk> wrote:
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

Lots of epoxy

velco
Click to expand...

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
 
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.
Click to expand...
That's pretty common among guitarists ;)
 
N_Cook wrote:
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
Click to expand...
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
------------------------------------------------------------------
You're only supposed to blow the bloody doors off!
 
Paul Hovnanian P.E. <Paul@Hovnanian.com> wrote in message
news:4C6DA9BF.76D8B511@Hovnanian.com...
N_Cook wrote:

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

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
------------------------------------------------------------------
You're only supposed to blow the bloody doors off!
Click to expand...

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
 
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:i4j3pf$1ul$1@news.eternal-september.org...
Ron <ron@lunevalleyaudio.com> wrote in message
news:AoOdneYFbfZilvDRnZ2dnUVZ8l-dnZ2d@bt.com...
On 18/08/2010 20:34, hr(bob) hofmann@att.net wrote:
On Aug 18, 5:02 am, "N_Cook"<dive...@tcp.co.uk> wrote:
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

Lots of epoxy

velco


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
Click to expand...

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
 
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