I had bought the B-450 combo cab a few months ago with a B-600 head inside it and with 2/10 and a horn, it really flaps your pants legs.
This may also be the reason why there is a problem in the B-200 combo Notch Switches staying ON all the time too. Time will tell about that situation however.
It had a problem that took me a while to figure out, no thanks to the fine, concerned people at Acoustic though.
There is no indicator from the factory on what footswitch you should use and it can be quite confusing to try every one in the store trying them to see which will or won't work. All you get is weasel-words and they have no answers at all.
Initially the problem surfaced when I bought a two-switch stomp to turn
ON & OFF the
Standby and the
Notch Filter. I went through several brands, and even my Crate unit didn't work nor did my Fender or any of my Peavey switches.
When plugging in the pedal the Notch Filter automatically defaults to
ON and you won't even know as there is no indicator bulb of anything to tell you so. Your sound will be all goofed up as it creates an plastic-y artificial sound in the speakers that you may not like much.
What I found was that I had to mod a footswitch to get it to work correctly.
The model footswitch I got was a
Live Wire Solutions FSW22 Dual-Latching Footswitch. 
At the moment I cannot find a listing for it on any sites.
The situation however will likely be the same with any generic switch assembly as long as it doesn't have any LEDs or lights to indicate which switch is depressed. That's important!
No LIGHTS! .
If you follow the instructions I guaranty that it will work correctly. There are a few things to know first though.
The plunger-type switches in this (
and likely all the other latching switches of the same purpose) have two sides of operation to them.
1)The Rotary or Sliding contact that gently makes the connection first to avoid a big 'pop' or 'snap' on making the connection. This is the LEAD side of the switch.
2)The final-holding part of the switch is what you need to access since there is no real problem with any pops or clicks when you hit these switches. This is the LAG or HOLDING part of the switch.
There will likely be all sorts of internal jumpers and smaller wires that are used for the 'lead/lag' application of these switches. At this point I cut off all wires (actually unsoldered them and pulled them out of the eyelets on the lugs themselves).
This pix unfortunately show the
AFTER MODS situation. But you should get some idea anyway what happened.
Now – you will need to find an Ohm meter to find the
HOLDING or
LAG part of the assembly.
The test follows:::
Place one lead from the meter on either of the two center lugs of one of the switches. This is a
COMMON wiring position to make the switch truly a
DPDT switch: we don't care about that for this application.
HOWEVER one side will be slower to engage as the plunger is pushed down – we want to isolate that part of the switch.
While pressing the plunger down, watch the meter – you will see a pattern of
ON/OFF and the positions in which they connect in relation to the meter and the depth the plunger is at that moment.
Test all positions and make a small note as to what combinations work right at the same moment the plunger is totally down, or fully depressed. These are the connections we want.
Always test the lugs against the center lug – as the center is the
COMMON connection on the switches no matter if it's a
LEAD or
LAG contact.
I just unsoldered the jumper wires and pulled them out of the eyes on the unused lugs.
The
BLACK wire was the
COMMON – yours should be the same. That's what the Ohm meter is for – to find that common wire! You can always open the 1/4” connector by unscrewing the sleeve and look to see too.
One side of the switch – the unused lugs here – are the
LEAD connections and although they are small amperage capacity, if you mess up these will work OK anyway. It's just best to use the
LAG connections as they are designed to carry the amps – which there aren't much of anyway!
COMMON here is the RED wire.
YELLOW is the NOTCH FILTER wire.
BLACK is the STANDBY wire
Acoustic Gen-II Footswitches Solved. 
