JMD102 Combo - extension cab...yes or no?

[MF2680]

Hi. Newbie here - though I've been plucking information for a few months (thanks guys ). I've had a JMD102 100w combo for a couple of years (been taking really good care of it because of the construction issues , and it seems to be paying off! ).
I've just joined a new band , and feel the need for a bit more 'spread'. Since I used to have a JCM800 2x12 combo, I thought it would be straighforward. However, after checking the manual and poking around a bit on the forum, I'm confused. There was a post on 28 July 2012 which eventually concluded that it wasn't possible to add another 2 x 12 cab to the JMD102 while keeping the internal speakers connected. Is this correct?

[kossofffan]

Welcome to the forum,

Yes you're correct in that you must not run an extension cab along with the internal speakers.

[P A U L]

From what I see, you should be able to, but it's not as straightforward as you think.

I'm guessing that the internal speakers are 16 ohms each. They have them wired in parallel, so that comes to 8 ohms (which is the limit). You will need to create (or purchase) a series splitter box, & run another 2x12 parallel cab. This will make the combo internals & the extension, like a 4x12 series/parallel & the 4 speakers will run at 16 ohm (you will need to use the 16 ohm out, not either of the 8 ohm.

I just made a parallel box, to do the exact opposite:



Just make sure it's wired in series. Might be a good idea to put a good sized label, stating that both sets of speakers are running at 16 ohm (series/parallel).

[MF2680]

Thanks both. With the benefit of hindsight, I'd should have gone for a 100w head & 4 x 12. Would have hopefully avoided the mdf construction giving way as well; always living in fear with the combo, gig after gig....!
I'll look into the splitter - may source some local expertise to sort it out. Do you know anybody who's actually done this? How did it turn out?
Cheers!

[P A U L]

Here's where I got the idea to make mine:


http://procablesnsound.com/items/speake ... detail.htm

They charge $34. I think mine cost about $25 (& I did all the work), so the extra $10 could easily give you piece of mind, especially if you're unsure how to wire it, &/or are not real experienced w/ soldering.

I'd recommend consulting w/ them, to let them know what you're doing, just to be sure.

[MF2680]

Thanks. I'll look into this when I get can. In the meantime, I'm going to try a sturdy stand to raise it up a couple of feet - it might make a difference.

[kossofffan]

Just a thought, if you brought a flight case on wheels, it would protect it in transit and provide a stand at the gig!

[P A U L]

One of the guys @ MF got the guys @ Sourmash (IIRC) to make a new cab, looks badass! Probably about the same as getting a flight case, or less...

(edit) here's the thread:

http://www.marshallforum.com/cabinets-s ... again.html

[kossofffan]

One of the guys @ MF got the guys @ Sourmash (IIRC) to make a new cab, looks badass! Probably about the same as getting a flight case, or less...

(edit) here's the thread:

http://www.marshallforum.com/cabinets-s ... again.html

That white JMD combo build is stunning and just looks so 'right'

Wish I knew of someone in central England that could do that!

[P A U L]

How about these guys?

http://www.zillacabs.com/

[kossofffan]

How about these guys?

http://www.zillacabs.com/

To be honest, I did think of them after I posted but didn't know they would recover combo's. Will give them a call. Cheers.

[P A U L]

I saw someone post one of their 2x2 cab's for sale, which made me think of them.

From their about page:

About Zilla Music and Zilla Cabs

Our only goal at Zilla Music is to make the best musical equipment available. Using nothing but the highest quality hand selected materials and tried and tested construction techniques we make some of the finest gear around... We take great pride in our name and put love and experience into every cabinet we produce.

We provide a number of services including...

Standard sized or custom electric guitar amplifier cabinets
We build a number of standard size amp cabs with a choice of speakers, Tolex, grill cloth, piping and hardware. We also produce custom guitar cabs so if you're looking for something a bit different, oversized, light-weight, easy to carry, a combo extension cabinet or anything your heart desires (snake skin 6x10 anyone?) we can make it for you.

Our cabs are award winning with great reviews in the UK guitar magazines and great feedback from our customers too:

"A very big thank you.... it looks cooler than an awful lot of very cool things and sounds spectacular – bright, clear punchy and even better than I thought it would. The sound that was in my head is now in my hands"
David Rees - Happy customer

Recovering
If you want a different look for your amp and fancy a Red Marshall JCM800 head, a Snakeskin Mesa Dual Rectifier or a bright orange Vox AC30 then speak to us. We can recover your amplifier head or combo or existing speaker cab in a range of Tolex to give really make you stand out in the crowd.

Check out our Recovering page to see what a white, brown and orange Marshall amp looks like, check out our available Tolex coverings and then get in touch to talk about what we can do to make your amp/cab look great.

Conversions
We often get asked to do amplifier conversions from either a head and cab in to a combo amp or vice versa converting a combo amp in to a separate head and cabinet - a great way to reduce the weight of a heavy combo and make it more portable. Check out out Custom sizes section for more info

Ordering a Zilla Cab
There are a few ways to order a brand new Zilla Cab or one of our Ex-Demo models. Either order directly from us by getting in touch, or visit our eBay store.

Looks like they'll do just about any/everything. Just depends on price, I guess...

[dukealexan]

You could convert the combo into a head and then buy you 4x12 or buy 4 new 8ohm speakers get an empty 2x12 cab and wire them both up in series then you could plug them both in.