Anyone tried closing the back of their combo?

[Jona]

I've just bought a mk. III, which is the first time I've ever bought a combo with the intention of gigging. It's flight cased so I can put the amp on top of the case for good monitoring, definitely loud enough for any stage and my entire rig now fits in the boot of my car- so far so good.

The only concern in terms of sound is loss of bass response and tightness, which I have noticed when comparing the combo to the amp plugged into a closed back 2x12 with V30s (when I plugged in both the EV completely outgunned the V30s for volume!).

So has anyone tried to remedy this by adding an extra panel to the rear of their combo, effectively 'closing' it? It would be a simple job and easily reversible, apart from 4 screw holes in the bracing- in fact the bracing is extended such that it looks as though this is an intentional possibility.

I'll probably try this regardless but very interested to hear your experiences, with any amp but particularly EV loaded mark combos.

Thanks

 

[Rob Lockwood]

My concern would be the cooling of the amp. If you sealed the back off well enough to make it work as a closed cab there would be nowhere for all the heat from the tubes to go except up into the chassis. The fan would not help as it would have no fresh air to circulate. You could try it to see if you get the effect you want on the sound but for longer term use I think you might risk shortening the life of amp components. I couldn't say how much but I guess that Mesa put the fan on those combos for a reason. If closing the back has the effect you want on the bass you could try to get a matching 1x12 EV cab and close that off then sitting the combo on top of it. Also the speaker is then sat direct on the floor which can help bass response.

 

[chipaudette]

As stated above, closing off a combo is a very bad idea. It will overheat badly and the amp could die. Bad bad bad.

If you want the closed-back sound, you'll have to get a closed back cab. If you're gonna get a cab, you might as well replace your combo with a head.

Note that you could actually keep your current amp and put it into an empty head shell instead of going out and buying a head-version of your amp. Mesa sells empty head shells or you can order one from a private builder (there are a couple on this board). You'd then just pull the amp out of your combo and install it into the empty head. You could keep your empty combo, or you could sell it on eBay. Whatever floats your boat.

Chip

 

[RectoStudioGuy]

Why not just use an ext. cab?

 

[Jona]

I'm really keen not to use an extension cab AND the combo- Chip I completely agree that if I do that I might as well just make it a head.

I'm reasonably handy with woodwork so I'm sure I could knock up a decent head cabinet, might have to get it professionally covered though. If I do this, is the empty combo and flightcase worth much on it's own? I can't really see why anyone would want it, other than as an unwieldy cab, unless they want to convert the other way of course- not that likely, especially in the UK.

This does appeal, but it may well be that I'd save money by selling the combo and buying a purpose-built head on its own.