I changed my cab to stereo and..

[IcedEarth112]

im curious how many ohms my cab is now.. it was 8 ohms when it was mono so im pretty sure all the speakers are 8 ohms, but now that its stereo would i have to change my ohms setting or what? im wondering cause my amps hissing has got a bit louder and above the tubes there is a faint smell of rubber or something that i dont think was there before.

 

[HolyDirt]

Re: I changed my cab to stereo and..

im curious how many ohms my cab is now.. it was 8 ohms when it was mono so im pretty sure all the speakers are 8 ohms, but now that its stereo would i have to change my ohms setting or what? im wondering cause my amps hissing has got a bit louder and above the tubes there is a faint smell of rubber or something that i dont think was there before.

How many speakers does the cabinet have? Did you wire each stereo side of the cabinet in series or in Parallel? What is the ohm rating of your amp? No amp should, by design, smell like burning rubber. Either way, you gonna need to fix either your cabinet or your amp.

 

[IcedEarth112]

Re: I changed my cab to stereo and..

the amp is switchable of 4 8 or 16 ohms, the cab has 4 speakers, it was a mono cab at first but i was trying to solve a problem with it(fairly long story) so i snipped the wires connecting two the jacks together in the cab to make it stereo.

 

[devastone]

Re: I changed my cab to stereo and..

You changed something by cutting those wires, but it's hard to tell what. Are 2 speakers wired to each jack now? If so, each jack is probably 16 ohms, but could be 4, hard to tell without more information. A picture of the jacks and the speaker wiring might help.

BTW, if the amp is switchable to 4, 8 or 16, it probably already was stereo. You can get an 8 ohm cab, or you can have a 4/16 ohm switchable cab, but you don't get all 3 unless it is stereo splittable.

 

[ErikH]

Re: I changed my cab to stereo and..

If it was 8 ohms mono then chances are it's 4 ohms per side stereo. The standard way of wiring is with all 4 speakers run as mono, they are wired series/parallel, with a total impedence equal to the speakers' rating (8 ohms in this case). When split in stereo, each side (left and right pair) is wired in parallel (2 x 8 ohms parallel = 4 ohms).

The burning you smell could very well be the output transformer if your amp is set for 8 or 16 ohms and not 4.

Rule #1: never snip wires unless you know what they are for and what you are doing. It sounds like you took a guess rather than really knowing what to do.

Edit: How many amps do you have? You do know you cannot run stereo from one amp. You need to separate amps to get the stereo affect. And before anyone brings them up, the Marshall Dual Monoblocs are/were 2 amps in one chassis.

 

[IcedEarth112]

Re: I changed my cab to stereo and..

my amp has 2 outputs to go into a cab so i have all the speakers working on the cab, it all works fine except i had the wrong ohm settings, how much will it cost to get this output transformer fixed?

 

[ErikH]

Re: I changed my cab to stereo and..

my amp has 2 outputs to go into a cab so i have all the speakers working on the cab, it all works fine except i had the wrong ohm settings, how much will it cost to get this output transformer fixed?

But that is not stereo. Running both outputs to both sides of a stereo cab with *your amp* is the same as using one output to the mono input on the same cab with *your amp*. The signal is still mono. You didn't need to do what you did in the first place.

To get a stereo affect, you need two separate amplifiers with the guitar signal split with either a delay, reverb, chorus or whatever other effect you want to use to get the stereo affect.

If your output tranny is damaged, take it to a tech for a quote. I know the power tranny in my Marshall runs about $140.00, and that doesn't include the labor to have it installed.

Just so ya know, most tube heads or even SS heads have two speaker outs to allow the player to run 2 cabinets, hence a full stack. Even then, running 2 cabinets of the same impedence, the amp must be set to half of one of the cabs (2 x 8 ohm 4x12 cabs = 4 ohms at the amp or 2 x 16 ohm 4x12 cabs = 8 ohms at the amp). This is because the speaker jacks on the back of the amps (including yours) are wired in parallel.

 

[IcedEarth112]

Re: I changed my cab to stereo and..

alright well thanks for the help.. i guess the schecter guitar i want is gonna have to be pushed back even further now..

 

[Reload in 5]

Re: I changed my cab to stereo and..

If all 4 speakers still work, and only 2 work on each jack, it is likely 16 ohms per side.
Are you sure that 2 speakers are on each jack ?
my cab was wired series / parrallel with a jumper to the second jack to make a parrallel out to the next cab. If you cut that, all 4 speakers would still work on 1 jack and none would work on the second.

 

[IcedEarth112]

Re: I changed my cab to stereo and..

effff... this is confusing :smack:

 

[ErikH]

Re: I changed my cab to stereo and..

If all 4 speakers still work, and only 2 work on each jack, it is likely 16 ohms per side.

Nope. That's not how it works. If you have 4 x 8 ohm speakers in a cab wired series/parallel, and then split them in to pairs (left and right), each pair is a 4 ohm load because they are wired in parallel, not series. He just needs to replace the wire he cut and use his amp set to 8 ohms with the mono input jack on the cab. If he doesn't know which one that is, then call Avatar since they put the cab together.

 

[Farkus]

Re: I changed my cab to stereo and..

Sounds like you're pretty uncertain of what to do. I'm not insulting you at all bro, I just want you to realize this can really screw your amp up. I'm going by the equipment you have in your sig as examples; if you're using something else please let us know.

I would go the following route:

If you got the cab straight from Avatar, they may be able to tell you how they wire the 4X12 cab. They may even be able to help you get it back to stock. You're not actually using your cab in 'stereo' anyway if you're using it with one amp (good call ErikH). Another point is this...even if you have the cab wired in stereo correctly, you'd better be sure that the two speakers on each side are rated to handle the amp...Vintage 30's are rated to handle 60 Watts each. If your amp is even close to 120 Watts (which the JSX is) you could fry 2 Vintage 30's by cranking it up (trust me, I've been there).

Another alternative is to go ahead and take the amp and cab to a QUALIFIED tech. He/she should be able to wire the cab back to stock for you. You may not have blown anything up yet inside the amp, but I'd sure as heck get it checked out first or your amp may get fried further.

Hope this helps.

 

[devastone]

Re: I changed my cab to stereo and..

If it was 8 ohms mono then chances are it's 4 ohms per side stereo. The standard way of wiring is with all 4 speakers run as mono, they are wired series/parallel, with a total impedence equal to the speakers' rating (8 ohms in this case). When split in stereo, each side (left and right pair) is wired in parallel (2 x 8 ohms parallel = 4 ohms).

I'm not sure how Avatar wires it's 4-12s, but if it was me, I would run the series connections on each side, then parallel the jacks. That would make it 16 ohms on each side. It's much easier to wire the jacks in parallel than in series. In fact, if it is an Avatar cabinet (judging by my 2-12 Avatars), they probably just have standard 2 conductor jacks, you can't wire them in series, they pretty much have to be parallel (unless I'm thinking really slow right now, it happens).

In other words, I still don't have enough info to make the call.

As Erik said, you're still running in mono so you didn't change anything. Hook the cabinet back up the way it was and use your 8 ohm setting on your amp.

Your amp may be fine, again, hard to tell. If it does smell like it's burning when you get everything hooked up right again, take it to a tech. It's possible you only cut one of 2 wires or something (there should have been 2 wires between the jacks, not just one) and shorted the 2 output jacks together. Again, hard to do any real diagnosis from your description.

 

[IcedEarth112]

Re: I changed my cab to stereo and..

i cut both wires. would it be ok if i just got 2 wire nuts and connected my wires back with those?

 

[muttonchopsrule]

Re: I changed my cab to stereo and..

i cut both wires. would it be ok if i just got 2 wire nuts and connected my wires back with those?

you're best off without any breaks in any of the wires, and i'd recommend you replace the ones that you cut.

refer to this link to be sure that your cabinet is wired properly:
https://forum.seymourduncan.com/showthread.php?t=94933

 

[devastone]

Re: I changed my cab to stereo and..

you're best off without any breaks in any of the wires, and i'd recommend you replace the ones that you cut.

refer to this link to be sure that your cabinet is wired properly:
https://forum.seymourduncan.com/showthread.php?t=94933

I don't think his cab is wired exactly like any of those (at least I'm guessing), similar, but not quite. It may just confuse the issue more. All of your illustrations only have one jack, adding the 2nd jack changes things.

 

[Pink Unicorn Horsey]

Re: I changed my cab to stereo and..

What would help is if you could provide us with some pictures of your amp and, more importantly, your cabinet with the wires.

- Keith

 

[ErikH]

Re: I changed my cab to stereo and..

What would help is if you could provide us with some pictures of your amp and, more importantly, your cabinet with the wires.

- Keith

The cab yes, but the amp, not necessary because it's a JSX and the speaker jacks on it are wired parallel just like any other tube head.

The cab is going to be wired series/parallel for 8 ohms total and 4 ohms each side. That's just how it works when using 4 x 8 ohm speakers in a 8 ohm cab. The second jack is (was) wired to the first in parallel. This is for daisy chaining it to another cab.

The cab was not wired for stereo operation to begin with. See here: http://www.avatarspeakers.com/wiring diagrams.htm

I believe what Avatar does is they wire each side of the cab to each jack and then connect both jacks together. Pics will confirm that but I believe that is how they come.

 

[Pink Unicorn Horsey]

Re: I changed my cab to stereo and..

The cab yes, but the amp, not necessary because it's a JSX and the speaker jacks on it are wired parallel just like any other tube head.

The amp just so that everyone knows we're talking about the same things. We don't want anything deep-fried.

- Keith

 

[ErikH]

Re: I changed my cab to stereo and..

The amp just so that everyone knows we're talking about the same things. We don't want anything deep-fried.

- Keith

His amp is a Peavey JSX, that is known. The pic will show two jacks and it will say above them that they are wired in parallel, 4 ohm minimum. Next to them is the impedence selector switch. Trust me, I looked at Peavey's site yesterday.