running dual 4X12 cabs

[heavymetal0061]

I think I have my rig hooked-up correctly,,,but ya never know?
I have a single Rectifier solo Head 50 and running 2 slant 4X12 Rectifier cabs.
currently I have it hooked-up this way:
4 ohm out of my rectifier head, into the 8 ohm input than 8 ohm out of 1st cab to the 8 ohm input of my 2nd cab. are we good?

 

[ryjan]

No!!!!! Two 8 ohm cabs = 4 ohm total. Run them both into the 4 ohm speaker outs lest you blow the tranformer. Please read your manual.

 

[94Tremoverb]

That's exactly what he's doing, he's just daisy-chaining the cabs instead of connecting them both to the head. Two 8-ohm cabs makes 4 ohms no matter if they are both connected to the amp or daisy-chained, the cab outputs are still in parallel with the inputs. There's really no risk to the amp even if you get it wrong anyway, Mesas are very tolerant of impedance mismatches and at worst you'll just shorten the tube life a bit.

I still don't like daisy-chaining though, because if the first cable goes faulty you lose the load on the amp altogether, which *is* risky. Obviously this is true if you're running just one cab no matter what you do, but if you're running two you're safer to connect both directly to the head when possible.

 

[ibanez4life SZ!]

^I could be missing something here, but I believe the above answer is wrong.

Two cabs daisy chained is a SERIES connection, meaning you are running a 16 ohm load. Run the first cab into the 16, and chain the second one off the first.

Two cabs, each into the head, is a parallel connection, and makes 4 ohms. So you run each cab into the 4 ohm connections on the head.

Actually, I'm about 99.9% positive about this.

 

[heavymetal0061]

That's exactly what he's doing, he's just daisy-chaining the cabs instead of connecting them both to the head. Two 8-ohm cabs makes 4 ohms no matter if they are both connected to the amp or daisy-chained, the cab outputs are still in parallel with the inputs. There's really no risk to the amp even if you get it wrong anyway, Mesas are very tolerant of impedance mismatches and at worst you'll just shorten the tube life a bit.

I still don't like daisy-chaining though, because if the first cable goes faulty you lose the load on the amp altogether, which *is* risky. Obviously this is true if you're running just one cab no matter what you do, but if you're running two you're safer to connect both directly to the head when possible.

OK ,yes it is a daisy chain hook-up.my thoughts exactly! 2-8ohm cabs= 4ohms.. why do they have an "in" and a "out" for 8ohms on the back of the cabs? 4ohm is split for bi-amp or stereo. On the back of my Rec. head there are 2-4ohm outputs and 1-8ohm output, does'nt make sense to me to hook each 8ohm cab into each seperate 4ohm output jack on the back of the head,,,mismatched in my eyes,,,I too am not a big fan of daisy chain set-ups???

 

[heavymetal0061]

^I could be missing something here, but I believe the above answer is wrong.

Two cabs daisy chained is a SERIES connection, meaning you are running a 16 ohm load. Run the first cab into the 16, and chain the second one off the first.

Two cabs, each into the head, is a parallel connection, and makes 4 ohms. So you run each cab into the 4 ohm connections on the head.

Actually, I'm about 99.9% positive about this.

OK ,yes it is a daisy chain hook-up.my thoughts exactly! 2-8ohm cabs= 4ohms.. why do they have an "in" and a "out" for 8ohms on the back of the cabs? 4ohm is split for bi-amp or stereo. On the back of my Rec. head there are 2-4ohm outputs and 1-8ohm output, does'nt make sense to me to hook each 8ohm cab into each seperate 4ohm output jack on the back of the head,,,mismatched in my eyes,,,or is that what your telling me to do, Run each 4ohm output from the head into each 8ohm on each cab???

 

[94Tremoverb]

ibanez4life SZ - sorry, you're wrong.

Daisy-chain jacks on speaker cabs are almost always in parallel. Just because one cabinet appears to be connected 'after' the other does not mean they are electrically in series - it's how the jacks are wired that matters. While it would be possible to have them wired for series, I can't think of any cabinet I've ever seen that is like that.

Mesa cabs are definitely wired with the Out jack in parallel. Check the pic of the inside of the panel in this thread: http://forum.grailtone.com/viewtopic.php?f=4&t=43336. You can see that the Out jack (closest to the camera) is a non-switching type, which means it cannot be used for a series connection, which has to make/break the signal path.

Two 8-ohm cabs connected to the same amp is a 4-ohm load whether they are directly connected or daisy-chained.


Why do they fit an Out jack? I don't know. It isn't really necessary since I don't know of any Mesa amp with only one 4-ohm jack - although it could be useful for some amps. Why is the amp labeled as 4 ohms on two jacks when you plug in two 8-ohm cabs there? (Which *is* what you should do.) Because the total load is 4 ohms, so you need to use the 4-ohm tap on the transformer, which is connected to both jacks inside. I agree the labeling should be clearer - really it should be shown as 4 ohms for *both* jacks, not each.

Some Laney amps have a very nice panel graphic like this which shows exactly what you connect to where, with boxes round the correct jacks and a list of speaker combinations. You can just about see it here: http://media.photobucket.com/image/laney%20gh100l%20back%20panel/baz_strikes_back/guitarstuffsale006.jpg

 

[heavymetal0061]

First I want to thank everyone for all your help!!
Second! now I'm confused as hell!! your talking to a simple mind here!
will this be the correct way to run my rig?:
run each 8ohm cab to each 4ohm output jack on the back of the head??
and let's see if I have this clear?
by running each of my 8ohm cabs into each 4ohm output jacks on the back of my head this will create a "SAFE" 4ohm load?

 

[94Tremoverb]

Exactly.

 

[heavymetal0061]

Exactly.

THANK YOU!!!!!