I have a plexi which is switchable between 4 8 and 16 ohms which I was running into a marshall 1922 cab rates at 8 ohms ( 2 x 16ohm speakers in parallel) - no problem.
I then bought another cab and want to change the speakers, but I accidentally bought speakers rated at 8ohms.
So the new cab would be wired in parallel and give me 4ohms.
No prob using the cabs separately - i just switch between 4 and 8 ohms on the amp.
However if I use both cabs together I've got one cab at 4 ohms and one at 8 ohms - running in parallel gives me 6 ohms. Is this ok to mismatch and should I set the amp at 4 or 8 ohms?
Or is there any other solution to this problem?
thanks
Comments
You would probably be better to wire the new cab with the speakers in series to give 16 ohms, which then gives a total impedance of 5.33 ohms when used with the 8-ohm cab, and is safe with the amp at either 4 ohms or 8 ohms, but better at 4 with a Marshall. In this case 2/3 of the power will go to the 8-ohm cab.
What speakers are they? Does the 1922 still have the stock G12T-75s?
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
The first 1922 is running two V30s of 16 ohms each (I changed the g12t-75s)
The 8 ohm speakers are are G1265s. I would rather the bulk of the power went to them really as trying to get away from the harshness of the v30s a bit.
Cheers!
Unless you really crank the amp into power-stage distortion, impedance matching is not that critical anyway - and also contrary to popular belief, it's actually safer for valve amps to run into a too-*low* impedance load than too high, if you can't match it. (Although the opposite is true for solid-state, which is where this probably comes from.)
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Thanks!