Will an 18 watt standard combo chassis fit in a Bluesbreaker

[dbruno]

Looking to reconfigure my 2x12 18 watt combo into a Bluesbreaker size cabinet. Anyone done this? Easy conversion? Thanks.

[guitarmike2107]

Depends on which Bluesbreaker cab you are going to use and which chassis you have, make sure the panel cut out is the same width and you just mount it to the rear baffle.

Easily done

The one thing to watch out for is make sure the speaker magnets are not too close to the power valves. i.e. more than an inch is preferable

[dbruno]

I have Graydon's combo chassis and it's in a Swanson 18 watt cab now. The Swanson cab has ears inside the cabinet itself that the chassis mounts to. I'm looking at a Mojotone bluesbreaker combo cabinet. I believe the Bluesbreaker chassis was mounted to the back panel. The chassis length is the same though.

[neikeel]

I have three Marshall type combos. a 1x12 made by Reason (uses the 4 through chassis screws into captive nuts inside and a couple of captive nuts on the chassis through the back panel that is 25" IIRC.

The BB is a large Mojo one which ss very wide - at 32" it is wider than a stock 4x12 (30") and pretty heavy (same size as the 60's BBs). This uses the four screws through the back panel into the flanges on the chassis. These are so big that they will accommodate a 100watt chassis. Personally I find it a bit cumbersome but you need this size cab if you use KT66 in a JTM45 type head.

I have a 'no name' 2x12 that I have put my 18watt into which is 28" wide and it does not have internal struts for the chassis screws. I have mounted my chassis with x4 rear chassis screws on the internal folded flanges. It does move more than the 50w chassis as there are not the outfolded chassis flanges but it does clear the speakers (not Alnicos tho').
I will probably need to add internal bracing to use the internal chassis braces.

Hope the info regarding the Mojo cab is useful.

[SpentMusic]

The series II BB cabinet is 32 x 23 x 10.5 and it will fit an 18 watt chassis with out any problem - size wise. The issue is the chassis can only be secured to the back panel and almost all of the 18 watt chassis I've seen are to weak and will distort over time w/o proper support as is provided in an 18 watt cabinet. Once the chassis starts to bend it puts stress on components inside and things will go wrong.

Another point is when you put the boomy 18 watt inside a giant cabinet like the BB the low end goes all to @()*#&$. I've built (regardless of my advice not too) 3 = 18 watt versions of a full size BB cabinet. They all sounded for crap and each of the customers over time converted the cabinets to JTM 45 chassis inside and returned to buy a 2 x 12 18 watt combo cabinet. Just my advise and opinion.

[guitarmike2107]

Thanks Jeff that is really insightful, I know a few guys who only attach the 18watt chassis to the rear panel without the built in support, the bending issue makes sense.

[SpentMusic]

The issue for the 18 watt chassis is the open end design. It is not that heavy a chassis but with all the weight centering on the 4 screws to the back panel it is going to distort over time. Give it a few good bumps in the back of the equipment truck/van and it is all done!! Needs the mounting blocks to sandwich it in there.

[trancedental]

I wondered why my 18W chassis has become bent when I opened up my BB style cab recently

I've got mine attached to the back panel with the 4 screws on the chassis, better make a pair of wooden brackets before it gets worse!!!