Can you convert an amp into a extension cabinet?

[DM3MD]

That’s a really good idea! I suppose the tweeter will be in a different location but that’s nothing. And I would have to remove the rubber feet...big deal. The porting will be on the top now, but again, I think we would be splitting hairs here sound wise. I’m liking this idea, too!

Another poster mentioned the electronic possibility of this, so I really need to see how this would or wouldn’t work based on the ohms and the drivers.

It’s fun to do things differently and think outside the box!

 

[Skillet]

Does the amp have a line out? Wouldn't it be better just to run out of the first amp, into the second amp, stacked, and have twice the wattage and yet still both speakers at your disposal?

 

[ZAR14]

I have an old Berhinger 15" combo that is fried. I was thinking of doing exactly that, bypassing the amp and wiring the speaker directly to an existing input jack...
BWAAAHAAAA (Evil Mad Scientist Laugh)

 

[gepettus]

Go DIY! I made this beauty out of a GK MB212 combo

 

[Cave Puppy]

Short answer - yes. I had a Roland DB500 that I used for years. The head kept crapping out after about 20 solid years and repairs wouldn't work anymore so I pulled the head off (which really lightened the weight) and fashioned a lockable speaker jack on the back. I still use that cab every week.

 

[fig]

chop the top so it’s flat

What I am trying to do is set another Strawberry Blonde amp on top of it, run a cable down from where it says “extension cab” and plug that in to the back of the modified amp...thus creating a micro stack with 2x10’s.

This is the mental impression I keep getting (quick photo frankensteining):

It may be wrong, but it looks good LOL.

 

[DM3MD]

^^^That’s exactly what I’m trying to do!!!

 

[funkinbottom]

It’s fun to do things differently and think outside the box!

Agreed, could be a fun project. Obviously the first step would be remove the amp section (I assume that no longer functions properly?). If you're not comfortable with a circular saw as dowunder suggests, heres an alternative method. Cut the top front to back close to the sides to have access to what will now be the new top (the "shelf" the amp currently sits on). At this point I would try to peel the tolex down the exterior sides to a hair below were I wanted to cut. , you could use a multi-tool, like this one , to cut the sides flush with new top. Run some masking tape down the new top along the sides and you can lay the blade right on top top to make cuts, like this. Once sides are cut, you can apply contact cement to the bare wood and to back of tolex. Let it dry and fold tolex over top, trim waste, and done. If results are not quite as beautiful as hoped, do as chadface mentioned and flip it upsidedown so the cut side is now the bottom.

 

[Lava]

Wouldn't chopping up the cab mess with the integrity of the cab's sound?

 

[DM3MD]

Wouldn't chopping up the cab mess with the integrity of the cab's sound?

I thought of that, but I think I’ll be ok on that one. I wouldn’t be removing that much material. I’m actually wondering how the sound will be affected going from a sort of “active” to “passive” set up. That’s the risk though here!

 

[chadface]

Wouldn't chopping up the cab mess with the integrity of the cab's sound?

Nah, the speaker is in a separate ported enclosure so should be fine.

I'm assuming both speakers are 8 ohm so total impedance will be 4 ohm. Output from the amp will be double so overall it will be plenty loud.

What is the head doing? Have you explored repairing it?

 

[Flamingo21]

Can't you just split the signal from your bass, and feed one to each combo? Simplest solution.

 

[vvvmmm]

I have an old Peavey Classic that fried. I pulled the head and used a black cloth-wrapped board to cover that space, installed a cuppla Celestions and use it under my HD130 when I want a Twin sound. I mean, the concept works ...

 

[R Upsomegrub]

I’m definitely NOT trying to make it look like a hack job. What I am trying to do is set another Strawberry Blonde amp on top of it...

I did this with an SWR Workingman's 12 combo. I pulled the amp and carefully cut the "top" off, saving the carpet and handle to re-use. I installed a jack plate and wired it up. The tweeter wasn't working and I didn't really need it, so I didn't bother to hook it up (although I left it in the cab). I used it with the SWR WM12 I had at the time, but now use it as an extension cab with a Markbass 121P.

 

[Downunderwonder]

The @funkinbottom plan looks good if you have one of those newfangled waggle thingummywhatsits. I would test the peelability of the tolex before committing.

 

[diegom]

I have a guitar-playing friend who plays small shows almost exclusively using a 90s solid-state Marshall combo (2x12), powered by his 80s, hot-rodded Marshall JCM800. If the tube amp gives out, he has the back up at the ready...
Combos make GREAT cabs!

 

[vvvmmm]

I'm assuming the 800 is just a head? Cool idear!

 

[abarson]

I second the idea to build an extension cab to sit under the combo. Same amount of work, and probably better results.

 

[DM3MD]

You guys are great! I’m putting together a plan and I’m going to make this happen. It will be an 8 ohm amp going into an 8 ohm extension cab.

I’m going to play around with the different cutting aspects of the top and how to get the tolex to look decent. Truthfully, with the combo amp on top of it and being this is for light rehearsals, I think that the spiffiness factor won’t be a huge deal. I’ll delve into to this soon, but I continue to welcome your positive feedback and ideas. It’s fun doing things differently!

 

[chadface]

You guys are great! I’m putting together a plan and I’m going to make this happen. It will be an 8 ohm amp going into an 8 ohm extension cab.

I’m going to play around with the different cutting aspects of the top and how to get the tolex to look decent. Truthfully, with the combo amp on top of it and being this is for light rehearsals, I think that the spiffiness factor won’t be a huge deal. I’ll delve into to this soon, but I continue to welcome your positive feedback and ideas. It’s fun doing things differently!

I would use a heat gun and peel the tolex back. Then cut with a circular saw.

I believe it's a 4 ohm head with an 8 ohm speaker, add another speaker and total impedance is 4 ohm.

It might make sense to wire it up before cutting anything to make sure you like the way it sounds. I am pretty sure you'll like it if you already like the combo by itself.

Good luck and have fun with it. Sounds like a neat project