Cabinet impedence question.....

[PowerTube]

Okay, I have an old KMD cabinet from the mid-80's, loaded with Celestions. The speakers are 8 ohms each and the cabinet is wired in series/parallel, giving me 8 ohms overall. No problem there.

However, this cabinet has two inputs, which I'll assume is for stereo operation. So my question is.....if I plug into both inputs, am I getting 4 ohms or 16 ohms? I've never used both inputs together so I have no idea. The Vetta combo requires no less than 8 ohms per side in a stereo cabinet and I don't want it shutting down from too small a load.

[jackson1]

I'd say you'd get 2 x 8 ohm.

If puzzled, remember that certain input jacks acts as a switch too, altering the config of the cabinet.

[PowerTube]

I'd say you'd get 2 x 8 ohm.

If puzzled, remember that certain input jacks acts as a switch too, altering the config of the cabinet.

But here's where I'm confused..... two 8-ohm speakers can't make 8 ohms. If they're wired in series, they make 16 ohms. If wired in parallel, they make 4 ohms. Or is there something I'm missing here?

Kaman (KMD) has ZERO support on their website even for current products, let alone old stuff.

But thanks for the info about switching jacks. I didn't know that.

[Bert]

But here's where I'm confused..... two 8-ohm speakers can't make 8 ohms. If they're wired in series, they make 16 ohms. If wired in parallel, they make 4 ohms. Or is there something I'm missing here?

Kaman (KMD) has ZERO support on their website even for current products, let alone old stuff.

But thanks for the info about switching jacks. I didn't know that.

You are correct. You should probably pop it open and take a look to see how they are wired.

My Mesa 4x12 is is 4 ohms in stereo mode, so I'd guess yours is too, but that's only a guess.

[PowerTube]

You are correct. You should probably pop it open and take a look to see how they are wired.

My Mesa 4x12 is is 4 ohms in stereo mode, so I'd guess yours is too, but that's only a guess.

That's a bummer, because the Vetta manual says that the minimum impedence per side on a stereo cabinet must be 8 ohms. I'm thinking that mine goes to 4 ohms when ran in stereo.

[PowerTube]

Also...is there a way to test impedence with a multimeter or doesn't it have to have a current running across the speakers at the time?

[jackson1]

But here's where I'm confused..... two 8-ohm speakers can't make 8 ohms.

I assumed it had 4 speakers. You didn't state so and I jumped to conclusions

[Bert]

That's a bummer, because the Vetta manual says that the minimum impedence per side on a stereo cabinet must be 8 ohms. I'm thinking that mine goes to 4 ohms when ran in stereo.

Yes, actually, you can figure out by measuring the resistance in mono mode. Then if the resistance in stereo mode is cut in half, you know the impedance is cut in half too (4 ohms). If the resistance doubles, then so does the impedance.

[PowerTube]

I assumed it had 4 speakers. You didn't state so and I jumped to conclusions

Ah....you're right. Sorry about that. It's a 4x12.

[jackson1]

What?! Concentrate man! Focus! Is it 2 or 4?

If it's 4x12 my initial answer is valid.

Pass the bong, man

[PowerTube]

If it's 4x12 my initial answer is valid.

I don't follow. It's a 4x12 and each speaker is 8 ohms. It's wired series/parallel for 8 ohms total. So how can it be 8 ohms per side? Two 8's in series equals 16 ohms. Two 8's in parallel equals 4 ohms.