B200s Question?

[RandallRG]

I just got my B200s in today. As I was told this is the way to hook it up with my MP-1 & to also be in "Stereo" with BOTH of my 4x12 8ohm cabs? Output "A"&"B" from my MP-1 to Channel "A&B" "In" of my B200s. Then Channel "A" Out to 1 of my 4x12 Cabs & then Channel "B" Out to my other 4x12 Cab. This way BOTH "A&B" are being used. When I have Channel "A' hooked up (by itself) to 1 cab it works fine. If I unhook or take out Channel "A" & put it in Channel "B" & run it to 1 cab it also works this way. Now if I hook up BOTH "A&B" & run BOTH "A&B" outs of my B200s to BOTH of my cabs ONLY 1 Channel & 1 of my Cabs work? The other channel has NO volume coming out of it.
I checked my MP-1 & BOTH "A&B" Outs work fine on it. Any info would be appreciated...Thanks! Steve   

[rnolan]

Hey Steve,  :whoohoo!: . You are connecting it properly. From what you posted, both channels on the the B200s are working (i.e. A or B to cab "1" with the same speaker lead, both work). So it's either a problem with the other speaker lead (most likely culprit) or an issue with cab "2". Try A (or B) to cab "2" but with the lead that you know works, if this works then it's a speaker lead problem, if not there's an issue with cab 2 (most likely input jack).
Note: I'm assuming you are using good quality "speaker" leads ? and not shielded guitar input leads (these are not designed to take the current). Also it's very unusual to "shield" a speaker lead and speaker leads use much thicker gauge wire (to cope with the current). I find that 20amp or 15amp power cable works well for speaker leads. ADA recommends 12 to 16 gauge speaker cable (see manual attached)
Cheers R

[RandallRG]

Hey Rich how ya doing? I am using 12 gauge cables. I also double checked both outputs (separately) on my MP1 & they are both working properly. When I check each of my cabs (separately) they to are working fine also. The speakers are the original Randall Jags (8ohm) that Eminence made for them back in the day. All 8 speakers are in great shape. I have not had any issues with either of my Randall Cabs since I got them. I took the cover off of my B200s to check out the board etc just to see if I noticed anything "burnt" or maybe a solder joint that was broken or cracked. It looks pretty good to me but since both of my cabs work fine I still think it has something to do with the amp? Hope all is well buddy...

[rnolan]

Hey Steve, well that's a bit more perplexing  :???:
So please confirm:
B200s A to cab 1 works (nothing plugged into B out), B200s B to cab 2 works (nothing plugged into A out), when both A and B outs plugged in (which were both working) no sound ? If this is the case, then it's more MJMP territory, however, if so, you could re-flow the board that connects to the output jacks (can't hurt). It may be the output jacks need replacing ? (it's like when you have both A and B plugged in, the amp thinks both (A & B) have nothing plugged in and it turns the channels off (again see manual for running just one channel). It could just be that your output jacks need a good clean with contact cleaner ? And they tend to be the highest "wear" spot on B200s.

Hey buddy, very cold here this time of year, but all is well  we'll get you sorted out, but it should have just worked !! You may need to replace your output jacks (jump that bridge if we need to) but MikeB did this recently so we can talk you through it if required.

[MarshallJMP]

Seems more to me like an input problem,which input always works,A or B?

[rnolan]

From what Steve said, both A or B work fine as long as only A out or B out is being used (so inputs are ok, as are each output (A & B) individually), but when he has both cabs connected (A & B outs) it cuts out. Well that's my current take on it. So the B200s will detect there is nothing plugged into one of it's outputs (A or B) and shut it down.  What "seems" to be happening in Steve's is when there is a jack in both A & B outs (which both work fine independently, Steve correct me if I'm wrong here !! i.e. all leads are good etc. A to cab 1 (nothing in B)  , B to cab 2 (nothing in A)  both  A & B then connected, no sound  ), it shuts both channels down.

[rnolan]

Hey Steve, when you opened it up, there should be 3 small pcbs (input pots, input jacks, output jacks), do any of these show any signs of being worked on ?? (solder joints look a bit different etc, flux deposits any where ?) ?? Coz this is weird, it should just work fine... unless someone changed something (input or output) to make it run mono ?? B200s are not meant to be bridged in mono, but maybe someone has tried ??

[RandallRG]

FIXED IT!  :whoohoo!: (LOL) Traced it down to one of my "patch" cords (being bad) that I was using from my MP-1 to my B200s. It was bad I plugged another one in & BOOM it works Awesome! Rich your not kidding the Chorus sounds KILLER now! I believe you said the best way to run the volume on these is setting the volume on A&B to around 6-7 or around 3:00 (the headroom is pretty big with these right?) on the B200s & work the volume through my MP1...right? Thanks again for the help/input guys I appreciate it! 

[rnolan]

Cool  :whoohoo!: . Seems MJMP had it nailed  input problem, though from what you posted ( A & B worked fine independently, so I ruled that out). Anyway great your up an running.

I have 2 schools of thought re poweramp settings, in PA context I turn them up full/max (so maximum headroom). With guitar rack rigs I tend to vary power amp from about 12 o'clock (good quietish starting point) to around 2/3/4 o'clock (depends on stage etc.). What is important is to fine tune your tones at very loud (stage) volumes and then turn them down (preamp or poweramp). The audio engineer in me says turn power amp up full and adjust at MP1, though many years of experience says (this is once you've got your sounds tweaked for live stage vols), you can back off the power amp to suit. But hey hey 6 - 7 should sound good (though may upset the neighbors LoL, done a bit of that in my time...)