Newbie chassis questions for 18w combo

[staapa]

Hi,

I'm getting ready to build my first 18w style amp. It will be a LiteIIb w/ VVR. I would like to build it as a 1x12 combo and I'm trying to figure what is the proper chassis, and understand the details of how it should mate to the cabinet. A couple of rambling questions follow:

I've seen a few sites selling "18w chassis" that are 17x6.5x2.5 with wings on either end. But the way these are drilled they I guess they are for heads because the socket holes are on the "top" rather than the edge. What is the correct chassis for a combo? I imagine it should be a bit narrower than a head chassis, but I'm not sure. Also any suggestions on where to get a blank (undrilled) one?

My woodworking experience is quite modest. I've only built one cabinet before (a simple head following plans from the Ax84 site), but it turned out nice. I found the Modulus "1974 Style Combo" drawings and they look pretty detailed. If I follow carefully I think I can built it. However, I'd like to double check my understanding of how the chassis mounts... I gather the chassis is bolts up to cabinet blocks through holes drilled in the same side as the transformer mounts, and then the rear panel is attached with bolts through captive nuts in the chassis lip. Is that correct--that the rear panel is held in place by the chassis, which is in turn bolted to the cabinet innards? That's what I gather from the drawings, but it seems odd. I would think it would be easier to simply bolt the chassis to the rear panel, and then bolt the rear panel to the rest of the cabinet. It doesn't quite add up so probably I'm confused about something. Can I buy a clue?

Thanks, David

[ChrisU]

Chassis should be an open ended U shape 19 x 6.5 x 2.5 but a 17 inch width is ok. It doesn't actually matter what type of chassis is used but the type with the 'wings' at the ends is easier to mark out when fitting to the rear panel. With the modulus drawings you need to allow extra clearance for the cloth and piping round the baffle. Don't bother with the mounting blocks. If you glue them in you can't get to some of the screws that hold the baffle in. The chassis is perfectly ok mounted to the rear panel.

[staapa]

Thanks for the info and the tips.

[staapa]

I'd like to find a speaker to go with my Lite2b project. I'm hoping for a domestic alternative to the G12H30, which I believe are now Chinese-made.

Any opinions on how the Eminence Wizard or Weber 1230 stack up?

Thanks!