modding a combo into a head?

[Drew]

This is just an idea I've been toying with of late... I'm looking for thoughts on how feasable this would be.

A bunch of you guys around here know how I have a thing for low-wattage guitar amplifiers, and how I'd kill for a three-channel, high gain amp pushing maybe 10 watts. Well, last time I was home, i plugged into a Crate VC-508 (i think) down at my old local guitar store; 5-watt class A EL-84 driven combo with a single channel, and one volume, one gain, and one tone control. I was seriously impressed by the thing- surprisingly good tone, WAY more gain than I'd ever need (we're talking nearly Dual Recto caliber, when cranked up- i was finding my comfortable "lead" range at like 6), and while there was just one tone knob, the mid boost/bass and treble boost thing at either end of the sweep was quite effective. And at $199, I almost pulled the trigger right then- it'd make a killer recording amp.

however, there's a few things that aren't quite perfect, for me. The lack of reverb or three-band EQ would be a slight detriment in a recording amp, but you could work around that on disc. The big one, though, was the 8" speaker- it didn't sound horrible, but the lows were definately cosntrained. Of course, this isn't a huge problem for recording, when I find myself rolling off the extreme low end on my guitar tracks anyway, but still...

So, i got to thinking, this thing would kill if it had a speaker out. There's a line out on the control panel, and I was hoping maybe it would double as a speaker out. Grabbed the manual off their website a few minutes ago, and it doesn't. (However, with a y-cable, you can use it as an effects loop, i guess, which would allow me to patch in a graphic EQ and a reverb; cool!). So, the first thing that sprang to mind would be to disconnect the internal speaker and wire on a femal 1/4" jack so i could hook it up to my cab (the amp's internal speaker and my Recto 2x12 are both 8 ohms)

However, then i started thinking... I could pick up some oak down at the local Home Depot, and peice together a head enclosure to put the innards of the amp in, and hard-wire a true speaker out into the thing. How difficult would this be to do? Assume a mild amount of woodworking experience; I'd hardly expect to be able to do a professional job, but I feel reasonably confident that I could do all the necessary measuring, cutting, assembling, and finishing needed to build an enclosure that would fit the current innards of the Crate. It would't look amazing by any means, most likely, but the result would be a VERY cool small gigging amp (i've always known that changes in tube wattage don't have a massive change on total output, but even through an 8", this thing was LOUD when i accidentally turned up the master before turning down the gain; huge blast of feedback) capable of hanging with a band (possibly with the aid of a mic) while generating some nice poweramp grind, and yet still have a tremendous amount of preamp gain on tap, and doubling as a great recording setup that could still generate some great tones at levels that are sane in an apartment complex.

Has anyone done anything like this before? Any suggestions, or things to keep in mind? I'm seriously tempted; i figure, worst case scenario, I'm out about $200 for the amp and maybe $50 for parts, and even if the results are cosmetically nothing to brag about, i still think it could be a fun project. Anyone? I'll be back in the berkshires this weekend, and I've got enough free cash to go ahead with it; I'm seriously thinking of doing this.

-D

[Jammy]

Its a simple mod, especially with amps like that. The whole of the circuity should be mounted in a metal box at the top of the combo. unscrew this and remove the speaker wires, mount in the new box, re-attach your speaker and your done. Ive got a feeling I could do this with my brothers laney in a day easily, and thats about the same level of amp I would think...
-better shred than dead-ANDY

[Algiman]

I agree entirely with Jammy, this would be a simple change to make. I'd suggest fitting a female jack to the amp chassis rather that hang one off the speaker lead though just to make it a stronger connection - cables have a nasty habbit of getting snagged. There should be room to drill a hole in the chassis to mount it, then reconnect the speaker wires internally.

[Drew]

Jammy, that's kinda what I was thinking. Only complication is that the speaker's hard-wired to the output, meaning I'd have to create and wire on speaker out jack. I don't see this being a huge holdup, though, although I'd probably need to find someone with all the necessary gadgetry to cut metal, to make me a little maybe 2" square peice with a hole the right size to accept a female 1/4" jack for the speaker out. I think a friend of mine's dad has this kind of stuff in his basement, and if not, my old XC skiing coach taught shop on the side up at my old high school... Come to think of it, his son plays a bit of guitar too now, i believe.

-D

[Jammy]

I did a mod on my brothers laney to convert the line out jack to a speaker out, if you dont need the line out, and its got one, that conversion is easy, as the hole and the socket will allready be there. If you do what a seperate output this will not be difficult either, all you need to do is remove the circuitry from the metal case, drill a hole (seriously easy with a power drill) and then fit the jack. When drilling sheet metal its always a good idea to drill a smaller, pilot hole first.
-better shred than dead-ANDY

[Drew]

Good call, I was thinking of just using the existing wiring, shielding it, and running it to a seperate section of the back of the amp, and having an output there.

I was thinking of holding onto the line out to use as an effects loop, per the original post, but that's another option, too...

Of course, this is all pending how this thing sounds with my own RG7620, and not the Jackson Soloist I was demoing it with... But that's on the plans for this weekend.

-D

[Algiman]

If you do choose to take a drill to the chassis then see if you can put a block of wood behind the point you are drilling into - saves damaging the metal or worse yourself.

[Drew]

good idea, algiman. I'll keep that in mind.

Took another look at the chassis on the crate site- the top panel, at least, does't have much open space for an additonal jack. 'll have to check this out in person and see if there's room on the back.

-D

[Algiman]

With most amps when you look inside the chassis there is loads of spare room, I doubt you'll have any problems finding space. Be interested to hear how you get on.

[Drew]

damnit, now I'm really psyched to do this. The weekend is a LONG way away...

-D

[ScottB]

I built a new cabinet to house the amp section of my Carvin XV112 combo. Being top mounted, the profile reminds me of a Fender Dual Showman head. I used Peavey tolex for the covering and aluminum diamond plate for the front panel.

If you decide to wrap yours in tolex, I can help if you'd like.

[Petie]

Originally Posted by Drew

(However, with a y-cable, you can use it as an effects loop, i guess, which would allow me to patch in a graphic EQ and a reverb; cool!).

Crate effects loops are WEIRD. I have a Quadradrive head (4 channels, 2 tube and 2 solid state) which has a mono effects send and a stereo return, but the return is a single, stereo connection so if I want to use stereo effects I need a Y cable going from both outputs of the effect into the single stereo input of the amp, or the effected sound only comes out of one side of the stereo spectrum. Of course this is sometimes useful in faking the sound of using two amps, or using a pitch shifter to fake a bass doubling the guitar an octave down.

I have found that if I set a mono plug very carefully pulled about a 1/4 inch out of the socket I get the effect in mono.

[Drew]

Screamjem- I was thinking of doing a natural wood finish, stained maybe a rich ruby, with a gloss finish over the top. It'd be a bit of work, especially sanding and buffing the gloss, but if the woodwork underneith came out acceptably, it'd look pretty cool.

However, if i slaughter the carpentry, i might need to talk to you about that tolexing.

I was thinking last night, though, and I'm wondering if for the time being it might not be a better idea just to mod it for a speaker out; i mean, we're talking about a 5-watt tube practive amp that weights 18 pounds and could practically be carried around in your average backpack- that, especially if you had the option of running it through a real cab, is pretty cool.

Although, it'd be a LOT of fun to turn the thing into a full-sized head... and even 5 watts is still pretty damned loud. I think if I go ahead with this, eventually I'll want to build a matching 1x12 open back cab (I love the sound of open back cabs, there's something a little "airier" in the highs; not brigher, just more open), sized to fit under a full-width head and a bit taller than my recto 2x12- basically, seriously oversized, but still fairly light, given the single speaker and open back construction. It'd be a pretty cool small gig rig...

Well, this all depends on my impressions on the Crate with my own guitar, this weekend... I'll see how it goes.

-D