1960a with new speakers but 8 and 16ohm

[g0ldr4k3]

Hello, I'm buying a 1960a cab but I really don't like the 12t-75. I have 2 vintage 30 8ohm and 2 greenback 16ohm that I would like to install inside.
Can I wire the 2 greenbacks in parallel and the 2 v30 in serial ? ohm laws are ok? is it worth it? do you have a diagram?
Amp is a 6100lm so I can run it at 4 8 and 16 ohm without problem... but I would like to wire the cab to use a second head sometimes that has 8 ohm output. if the volume is reduced could be an advantage because I don't need it very much at home.

thank you
thank you
thank you!

 

[Gene Ballzz]

Hello, I'm buying a 1960a cab but I really don't like the 12t-75. I have 2 vintage 30 8ohm and 2 greenback 16ohm that I would like to install inside.
Can I wire the 2 greenbacks in parallel and the 2 v30 in serial ? ohm laws are ok? is it worth it? do you have a diagram?
Amp is a 6100lm so I can run it at 4 8 and 16 ohm without problem... but I would like to wire the cab to use a second head sometimes that has 8 ohm output. if the volume is reduced could be an advantage because I don't need it very much at home.

thank you
thank you
thank you!

That will yield 5.33 ohms. All in parallel will yield 2.67 ohms. 2 greenbacks in series wired in parallel with both v30s in parallel will yield 10.67 ohms. None of these scenarios is ideal, and you also need to consider any differences in sensitivity between the different speaker models.
Just Sayin'
Gene

 

[fitz]

Amp is a 6100lm so I can run it at 4 8 and 16 ohm without problem...

Series/parallel at 5.33 ohm on the 4 ohm tap is not too bad of a mismatch.
But keep in mind, that 4 ohm setting on your amp requires an internal amp jack re-wire of the 16 ohm selection of the impedance switch.
You don't have all 3 selections available, the 16/4 is an either/or.

Best option would be to get a pair of 16 ohm V30's and sell the 8 ohm set.
T-75's & V30's is also a common speaker pairing you may want to try.
Might go well with a 6100.

 

[PelliX]

Unless you run two taps into the cab the 8 Ohm speakers will be doing more of the work than the 16 Ohm ones.

Can I wire the 2 greenbacks in parallel and the 2 v30 in serial ?

Nyes.

ohm laws are ok?

Ohm's law is still doing fine. It's just not working in your favor here...

is it worth it?

Probably not. Work out which speakers you like best and get another two. Or just use/install/run two speakers in the 4x12.

 

[g0ldr4k3]

mmmmnew question since I have 2 speaker output that I didn't remember.... can I use a 4x12 with 4 v30 8ohm and a 2x12 with the greenbacks 16ohm together? with the amp with 8ohm setting.

 

[Dogs of Doom]

since you'll have 2 cab's at 8 ohm, you'll use the 4 ohm out...

 

[g0ldr4k3]

I have an headache....... well I could wire the 2 16ohm to be a 8ohm cab? and 4 8ohm v30 remain 8 ohm cab?
so if I have now 2 cab @ 8 ohm why do I have to switch the amp to 4?
ignorance @maximum level here....

 

[JohnH]

I can't think of any ideal scenarios to use the greenbacks with the V30's in general. But here's a few ideas:

1. If you are using the speaker with an amp with a group of 5 separate output jacks. Then you can rewire the two v30's in series to make 16, and wire that to one output iack. Then seperely wire the two greenies in parallel to another jack, as an 8 ohm pair. Then use two leads to the amp, the 8 ohm greenie pair goes to a 4 ohm amp jack and the 16 ohm cab pair goes to an 8 ohm amp jack. It's actually all good in terms of ohms and balance, but you need two speaker leads and its specific to an amp with a full set of 5 jacks.

2. Keep two g12t75's, which are probably 16 ohm, and do series parallel with two 16 ohm greenies for a perfectly fine 16 ohm cab.

3. get two new speakers to match ohms with either the greens or the v30's, wired series parallel

 

[g0ldr4k3]

well.... I think I will change 4 g12T with 4 v30 and stop!! too much headche! I will keep greenbacks in a 2x12 to play them sometimes. I have 4 v30 but 8ohm, can I swap them in my jcm900 lead cabinet 1:1 ? why do you think the g12s are 16ohm? can I test them like I test a pickup with a multimeter?

 

[Chris-in-LA]

I have an headache....... well I could wire the 2 16ohm to be a 8ohm cab? and 4 8ohm v30 remain 8 ohm cab?
so if I have now 2 cab @ 8 ohm why do I have to switch the amp to 4?
ignorance @maximum level here....

Your output jacks are most likely wired in parallel. Two 8ohm loads become one 4ohm load.

 

[JohnH]

well.... I think I will change 4 g12T with 4 v30 and stop!! too much headche! I will keep greenbacks in a 2x12 to play them sometimes. I have 4 v30 but 8ohm, can I swap them in my jcm900 lead cabinet 1:1 ? why do you think the g12s are 16ohm? can I test them like I test a pickup with a multimeter?

Fair enough! That's a good plan

i reckoned that the current G12T75's are most likely all 16 Ohm just because that's what is standard in a 1960.

You can use a multimeter set to ohms, to measure this. A 16 ohm speaker, or a cab wired in series-parallel for 16 Ohms, will measure a bit less than 16, usually about 13 to 14 Ohms on a meter. The difference is because the meter reads using DC, while the speakers rated ohms value is measured at about 400 Hz

 

[g0ldr4k3]

ok thank you!! I will take the v30 from another cab, in origin it has 4 and 16 input and 8ohm in stereo....how can they be 4 8ohm speaker? I am missing something....

 

[JohnH]

That combo of 4 speakers, combined to give 4 or 16 ohm mono , or 8 ohm stereo can only be done with four 16 ohm speakers.