Concert lead question

[cantkillanidea]

The speaker outputs on the back of the amp dont specify what impedance the speakers should be. Does that mean I'm ok to use anything? I have a sunn 610L which from what I've read is 6 ohms and a marshall 1960 (i can run at 4 or 16 ohms) Would I be fine using the marshall at 4 with the sunn at 6?

[grimniggzy]

if you ran a cab at 6 ohms along with a cab a 4ohms you'd be running a total load of 2.4 ohms.
which is cutting it close for vintage equipment. your head may be able to take it but i wouldn't suggest it.
i'm sure many people know more than myself on here but that's my opinion.
the math you'd have to do would look something like this.
4 ohms X 6 ohms = 24
4 ohms + 6 ohms = 10
then take you're answers and divide
24 / 10 = 2.4 ohm load total

i would suggest that if you do both cabs run the marshall at 16
if you do the same math with 4ohms and 16 ohms
the total load turns out to be 4.363
which would be much safer

i believe if you have a '79 concert lead (probably black face with red knobs) it's meant to run at 2ohms.
but i wouldn't push a 30 year old piece of equipment that far for such little payoff as well as possible heartbreak.
hope this was helpful.

[cantkillanidea]

Awesome, thanks for the help. I tried the Marshall and both 4 and 16 ohms and there was virtually no difference. I'll definitely run it at 16. Thanks again for the help.

[grimniggzy]

sorry fixed my dumb math.
redoing this math in my head woke me up in the middle of last night. haha

[grimniggzy]

glad to help though.

[EdBass]

Awesome, thanks for the help. I tried the Marshall and both 4 and 16 ohms and there was virtually no difference. I'll definitely run it at 16. Thanks again for the help.

Keep in mind; in this scenario over 70% of your power will be going to the 6X10, so IMO the Marshall will pretty much just add a little "flavor" to your overall tone.