Custom back panel idea for twin reverb.

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dragonbat13
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Location: Southwest Louisiana

Custom back panel idea for twin reverb.

Post by dragonbat13 » Mon Sep 04, 2017 1:13 am

I realize that the best thing is to try it, and I probably will. But has anybody ever taken the two back panels off of a twin reverb and replaced them with one big panel with an oval in the middle, ala dumble cabinets? My main concern is cooling. If anything I bet it would make the back of the amp look nicer. Right now I am going for the Eminence Swamp Thang/Texas Heat combo. My amp is missing the original panels. I would be keeping the original panel cutout at the top of the amp for the switches and ventilation.

Anybody know of this being done or have some links or something?

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martin manning
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Re: Custom back panel idea for twin reverb.

Post by martin manning » Mon Sep 04, 2017 9:36 am

Interesting idea. I think as long as you maintain the gap between the top of the panel and the chassis, and the area of the oval vent is say 2x the area of the gap (no problem there), cooling won't be an issue. The gap will add to the effective acoustic vent area, of course.

dragonbat13
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Location: Southwest Louisiana

Re: Custom back panel idea for twin reverb.

Post by dragonbat13 » Tue Sep 05, 2017 1:15 am

I am gonna try it sometime in the next couple of weeks. plan on getting an 4x8 sheet of panel for the back wall of my electronics desk so I can try it then.

Whats going on with this amp is I am reversing a few mods I did a long time ago to try and make the twin into something its not. I removed the pair of 5881 tubes, installed four and put a new balanced JAN phase invertor tube. I pulled two vintage 30's out and am gonna try a Eminence Swamp Thang/Oxford combo, then a Swamp Thang/Texas Heat combo.

Any idea what kind of port area I should shoot for? I can add the gap at the top with the oval in the back.

Bill Moore
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Re: Custom back panel idea for twin reverb.

Post by Bill Moore » Tue Sep 05, 2017 3:35 pm

I have no scientific reason, but I use the diameter of the speaker horizontally and 1/3 vertically. Seems to enhance the bottom end, more than you might expect.
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Leo_Gnardo
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Re: Custom back panel idea for twin reverb.

Post by Leo_Gnardo » Thu Sep 14, 2017 11:54 pm

dragonbat13 wrote: But has anybody ever taken the two back panels off of a twin reverb and replaced them with one big panel with an oval in the middle, ala dumble cabinets?
Yes, deafinitely. Sort of more a rounded off rectangle in the middle but no matter. I used a nice piece of oak-faced half inch ply, relieved the edge area a bit so it would sit squarely on the supports, added an extra support across the bottom plus a couple of stiffener slats. Loaded the twin with a pair of Eminence Texas Heats, and that's all she wrote ... customer was very happy with the extra warm low end, and lack of rattling & buzzing mechanically. It's a good move!
down technical blind alleys . . .

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xtian
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Re: Custom back panel idea for twin reverb.

Post by xtian » Fri Sep 15, 2017 4:10 pm

I decided to keep my '71 Twin Reverb, so I made the missing back panels from 1/2" birch ply and vinyl.
IMG_8440.JPG

Also spent some time with a toothbrush and 409 cleaner and removed the years of dirt. Shiny!
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I build and repair tube amps. http://amps.monkeymatic.com

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