#1
Hey all,

So I found a Marshall 1960A cab for a good price using Craigslist, and ended up picking it up. It currently has the 75-watt model Celesition's (G12T-75) in it, which I don't particularly care for so much (except w/JCM 800 style amps). Each speaker in the cab is 16 ohms.

I also have a 2x12 cabinet. It has a V30 clone, and a 50-watt rated G12H30 clone in it. I love this particular speaker combo, but they are 8 ohm speakers.

My question is, if I wanted to swap out the 75 watters, and pick up more of the V30/G12H clones to replace them, would I be able to wire 8 ohm speakers together in a way that won't screw up the mono/stereo operation switch on the back of the cab? or do I need to buy 4 new 16 ohm speakers for it?

Thanks!
- Gibson Flying V 120 #1 (White)
- Gibson Flying V 120 #2 (Cherry)
- Gibson SG Standard ('61 style)
- Jackson DK2M

- ENGL Fireball 60
- Avatar 4x12

- Many pedals, plus other stuff
#2
what's the output impedance on the amp you're using?

if it's 8 ohms, then yes, you can use series-parallel wiring and have 8 ohms no problem.

if it's 4 ohms, then you can't very well do it with 8 ohm speakers. at least as far as i know.
Quote by Steve46
thanks alot ice condition!! your the breast!


The best bosom in all of UG.
#3
The amp is a Mesa Boogie F-50, and it has 2 4 ohm input jacks, and one 8 ohm one. Though when more funds are available, I will probably sell this amp and upgrade to something else.

The 1960A in it's stock form, can be at 4 or 16 ohms in mono, or 8 ohms per side in stereo. Just not trying to screw up the original functionality of the cab up I guess.
- Gibson Flying V 120 #1 (White)
- Gibson Flying V 120 #2 (Cherry)
- Gibson SG Standard ('61 style)
- Jackson DK2M

- ENGL Fireball 60
- Avatar 4x12

- Many pedals, plus other stuff
#4
is there a switch to switch between 4 and 16 ohms? it'd have to switch between parallel and series-parallel wiring to do that . . .

if you're only going to be using the mesa, you should be fine. if you want to get a new amp, you can always rewire it, if it doesn't have an 8ohm output. it's not like it's hard to do, just twisting wires together.


to have an 8-ohm output, with four 8-ohm speakers, you have to wire them in series-parallel.


basically, what this means, is you take the 4 and put them into 2 groups of two, and wire them in series


8 + 8 = 16

8 + 8 = 16

and then wire those two sets together, in parallel.

16 + 16 = 8


in series, you add the impedance.

ie:

2 + 2 = 4

4 + 4 = 8

8 + 8 = 16


in parallel, you divide by two.

ie:

16 + 16 = 8

8 + 8 = 4

4 + 4 = 2
Quote by Steve46
thanks alot ice condition!! your the breast!


The best bosom in all of UG.
#5
Yeah, there is a switch on the cab to switch it between 4 and 16 ohm operation in mono.

I guess the question then is, which input would I use to run it at 4 ohms if I were to rewire everything differently? The impedance switch is the thing I'm not sure about, which is why I'm wondering if I'm better off just using 16 ohm speakers, and wiring them the same way the ones in it now are.
- Gibson Flying V 120 #1 (White)
- Gibson Flying V 120 #2 (Cherry)
- Gibson SG Standard ('61 style)
- Jackson DK2M

- ENGL Fireball 60
- Avatar 4x12

- Many pedals, plus other stuff
#6
well what are you trying to accomplish then? a 4 ohm load?
Quote by Steve46
thanks alot ice condition!! your the breast!


The best bosom in all of UG.
#7
Yeah, that's the idea. The F-50 can't be run at 16 ohms, and I'm trying to run the cab in mono.
- Gibson Flying V 120 #1 (White)
- Gibson Flying V 120 #2 (Cherry)
- Gibson SG Standard ('61 style)
- Jackson DK2M

- ENGL Fireball 60
- Avatar 4x12

- Many pedals, plus other stuff
#8
well if it has 2 4-ohm jacks, and an 8-ohm jack, you should be all set with 8-ohm speakers.


for two 4-ohms, you'd wire two pairs of speakers in parallel, so that they make a 4-ohm load, and then give each pair a mono jack.

i explained above how to make them into an 8-ohm load
Quote by Steve46
thanks alot ice condition!! your the breast!


The best bosom in all of UG.