2 Cabinets in 1 Head...

[Mark 7]

I got a Mesa 2x12 extension cab to go with my Bogner 4x12 - the Mesa is 8 Ohm and the Bogner is 16 Ohm which I think is OK as a safe mismatch. When I first plugged them in I noticed that only one or the other would work - I have a Mesa Road King which can be switched in each channel from speakers A,B or A&B. After fucking around with the jacks a bit I can finally get both working but notice a pretty steep drop in volume in each cab when both are going - is this normal? It would make sense for the power to now be absorbed by 6 speakers instead of 4 (or 2). I realized I've never used more than one cabinet before. Just checking.

 

[LordOVchaoS]

What speaker outs are you using? You shouldn't notice a volume drop. Plug the 8 ohm cabinet into a 4 ohm jack and the 16 ohm cabinet into an 8 ohm jack and all should be well. If you've done that already I'm not quite sure what to tell you.

 

[Chris]

Careful with that axe, Eugene. Make sure you're not overloading your power amp, or you'll cook it.

 

[LordOVchaoS]

Careful with that axe, Eugene. Make sure you're not overloading your power amp, or you'll cook it.

If he hooks it up like I said to it will be ok. The combined cabinets make a 12 ohm load and the way I told him to hook it up should be 100% safe. I'll check the Mesa site though to be sure, be back in a minute...

 

[Mark 7]

Holy shit - I read it wrong in the manual! I have both going into the A&B 8 ohm out. I see where the 8 should be in the 4 and the 16 into the 8 - I only have one shorting plug to plug into B when B is not being used - wouldn't I need another one to satisfy both?

 

[noodles]

Mark, the shorting plug on the Road King is there for one reason: if you're not using B, but one of the speaker selector knobs gets inadvertently/accidently set to B or A/B. A nice little safeguard to prevent output transformer meltdowns.

If you want both cabs on at all times, it is best to hook it up on A like Joe showed you, and leave the shorting plug in any of the inputs on B.

 

[LordOVchaoS]

Holy shit - I read it wrong in the manual! I have both going into the A&B 8 ohm out. I see where the 8 should be in the 4 and the 16 into the 8 - I only have one shorting plug to plug into B when B is not being used - wouldn't I need another one to satisfy both?

Huh? Shorting plug? Just use one speaker cable for each cabinet. I'm not sure what you mean by shorting plug?


EDIT: Did a little reading and I am now enlightened in the world of shorting plugs. Uh... what ^he^ said. Just plug your 8 ohm cab into the 4 ohm jack on A and the 16 ohm cab into the 8 ohm jack on B

 

[noodles]

Huh? Shorting plug? Just use one speaker cable for each cabinet. I'm not sure what you mean by shorting plug?

The Road King has a shorting plug that is plugged into one of the speaker jacks on the B side. This is because the Road King has A/B/A+B speaker selection, and Mesa doesn't want anyone inadvertantly blowing the output transformer when they have only one cab.

EDIT: OK, I see you already figured this out.

 

[Mark 7]

Mark, the shorting plug on the Road King is there for one reason: if you're not using B, but one of the speaker selector knobs gets inadvertently/accidently set to B or A/B. A nice little safeguard to prevent output transformer meltdowns.

If you want both cabs on at all times, it is best to hook it up on A like Joe showed you, and leave the shorting plug in any of the inputs on B.

WOW! that makes a huge difference! Once again, you've bailed my ass out - thanks! So I have it the way it shows (and Joe showed) in the manual and have each channel set to speaker A only. I see now why the shorting plug and have it in the 8 Ohm B just to be safe.

Joe - there's another set of speaker inputs below those shown in the manual so for each channel in the RK you could run a clean channel using one specific cabinet (like an open 2x12) and have both or another in any of the other channels.

Combine this with the G-System and it can be overwhelming but like a bad car wreck, I'm strangely attracted.

BTW Dave - the Amp Gizmo I got shit the bed - Ron was great and immediately shipped me a new one (great guy). Then the GS (which was a demo) took a dump and I got a new one and it is f'in great. Then I get an AKG wireless bug last week - go to play last Saturday and lo & behold - same frequency as my bass player's bug - damn. Returned it and got a new frequency today. This is a lot of shit to put together to use, but the sound is worth it.

So I definitely don't want to be returning the Road King because of user error.

Thanks guys!

Huh? Shorting plug? Just use one speaker cable for each cabinet. I'm not sure what you mean by shorting plug?


EDIT: Did a little reading and I am now enlightened in the world of shorting plugs. Uh... what ^he^ said. Just plug your 8 ohm cab into the 4 ohm jack on A and the 16 ohm cab into the 8 ohm jack on B

Do you mean the 16 into the 8 ohm on "A"?

 

[LordOVchaoS]

Do you mean the 16 into the 8 ohm on "A"?

Now that I see you're using A only, yes... that's what I meant

 

[noodles]

WOW! that makes a huge difference! Once again, you've bailed my ass out - thanks!

Not a problem. It's a complicated amp, and one switch flip can ruin your entire day! Right before we went on at Nevermore, I could get nothing out of channel 3. Turns out the loop switch got bumped from loop 1 to loop 2. Since nothing was in loop 2, no sound. Having a good case is the best way to prevent these things, but they sometimes still happen.

Since the guy I replaced played through the same thing (as a matter of fact, I own his first RK), Mike was a big help my first day setting it up. I can only assume he and Matt spent some time together fiddling with it. This is an amp where the manual really is helpful.

BTW Dave - the Amp Gizmo I got shit the bed - Ron was great and immediately shipped me a new one (great guy). Then the GS (which was a demo) took a dump and I got a new one and it is f'in great. Then I get an AKG wireless bug last week - go to play last Saturday and lo & behold - same frequency as my bass player's bug - damn. Returned it and got a new frequency today. This is a lot of shit to put together to use, but the sound is worth it.

Ron is a very cool dude, and was very helpful in making sure I knew exactly what his product would do for me before pulling the trigger. Things like that happen with everything, so I judge how the company handles it. It's good to hear he stands by his product, no questions asked. :yesyway:

I'd get rid of the bug if I were you. I used to own one, but I really could tell how it screwed up my tone. It just clips off the extreme ends of the frequency spectrum. It's a pretty low quality unit, probably because the transmitter is too small to fit everything you need in it. So, I'm back with transmitter packs.

So I definitely don't want to be returning the Road King because of user error.

It takes alot ot hurt a Mesa product. As long as you make sure both A and B have a load (or ground plug), it is almost impossible to hurt it. I've seen a DualRec take a dive off the top of a 4x12. It shattered the fuse without doing any further damage.