best out of my recto cabs. ohm q?

[wildrat666]

have 2 cabs, one straight and one slanted both 8 ohm:
shold I drive them from 8 ohm to 8 ohm or should I drive them in stereo and which ohm on the head.? it says 4 ohm in stereo.

which one to choose for best performance. please enlighten me!!

 

[wildrat666]

now i engage the first cab(8ohm) to 4 ohm and the other(8 ohm) to 4 ohm. is it right?

 

[Russ]

sounds right to me

 

[jbird]

Running out the two 4ohm outs to each cab won't be stereo! I'm sure you could also daisey chain 'em, but I'm not sure what speaker out you would use from the head? Would it be a single 4ohm out to the 1st cab's 8ohm in, then the 1st cab's out to the 2nd cab's 8ohm in? I'm talking Mesa cabs of course. :wink:

 

[wildrat666]

there are one jack that says" 4 ohm in stereo" but can that be right???

 

[jbird]

there are one jack that says" 4 ohm in stereo" but can that be right???

Absolutely! The cab can be split to stereo! But that would require two amplifier sources!

 

[richey]

Jbird is right. I burned some tubes up this way. I talked to a guy at Mesa when I was ordering replacements and he said that this is how I burned my tubes up. In order to use the 4 ohm stereo jacks on the back of the cab, you have to have two power sections. This is what all those stereo power amps are for (2:90, 2:30, etc.).

 

[wildrat666]

ok. won´t do that then!!!but what happens if I drive the cab 1 to 8 ohm and cab 2 to 8 ohm??

 

[ThunderMonkey]

ok. won´t do that then!!!but what happens if I drive the cab 1 to 8 ohm and cab 2 to 8 ohm??

This is THE correct way to run your rig without blowing your Output Transformer !
amp 4 ohm out --> slant cab, 8 ohm in mono
amp 4 ohm out --> straight cab, 8 ohm in mono

If you run a single cab obviously run 8 to 8. Like jbird
said the stereo splits are for 2 different amp sources.

Ohm's law is tricky but always remember divide by 2 and you'll always be safe. Running it 8 to 8 (on both cabs) gives too much resistance and will heat up and fry your OT or wear your tubes out fast. :roll:

 

[Russ]

If you run a higher mismatch then you are fine but you get darker tone. The ohm match going into a pair of 4 ohm taps with your pair of 8 ohm cabs is correct matching. I wouldn't bother doing the "stereo" thing though. Keep it simple. Most drive their amps as mono even with a pair of speaker cabs. Look at your manual if you have to.

Here's the actual formula for your situation as was posted not long ago:

Matched output R(or less)= (R1*R2) / (R1+R2)

 

[jbird]

So, with Mesa cabs there is an "in" and "out"option! Meaning, I suppose, you have the option of daisey-chaining the cabs: So, one amp speaker tap out, to 1st cab in, then 1st cab out to 2nd cab in! Would the one tap from the head be a 4ohm or 8ohm? And what's the diff?