Can I make a 16ohm cab 8 ohms?

[arsmusic]

I have a 2x12 guitar cab. The speakers are greenbacks 8 ohms per speaker. Cab wired in series so it is 16 ohms. I could wire parallel and make it 4 ohms. My question is could I wire it in parallel and then add a 4ohm resistor in series and make the cab 8 ohms total? In theory this will work. But is this a thing that can be done with speakers?

 

[musipol]

You could, but it won't respond like it did previously(load presented to output xfmr won't be quite the same) and cab will be quieter. I have done this in an attempt to reduce volume and didn't care for the results. Reminded me kind of like a completely resistive dummy load. It changes the power tube distortion characteristics, and not to my liking.

 

[john12ax7]

You want a reactive load, not just resistive. Get a 16 ohm reactive load and run that in parallel with 16 ohm cabinet. Result is 8 ohm total and still good tone at half the power.

 

[Bo Deadly]

What exactly are you trying to accomplish? If you're trying to use the can with another amp that has an output transformer, usually the output transformers have multiple taps. Meaning maybe it has a 16 ohm tap?

 

[mjrippe]

As long as the cabinet is higher impedance than the amp output, it is safe to use. In other words, if your amp is 8 ohm out and the cab is 16, you're fine. But if your amp is 16 ohms and your cab is 8, not good.

 

[Brian Roth]

Not TOO high (like an open circuit) with tooooob amps. <g>

Bri

 

[arsmusic]

I have a KHE switcher.

https://www.khe-audioelectronics.com/shop/acs-8x4
I am running 8 heads to 2 cabs. Everything is set at 8 ohms. One amp at a time. To one cab at a time. So 8 to 8 ohms on everything. I know I can run 8 to 16 and be cool. I was just wondering if I could switch it up to 8 to 8 instead of buying 2 new speakers for the cab. But I think I will probably just keep it at 16 ohms and be cool with it.

PS: One cab is 8 ohms (v30s) and one cab (greenbacks) is 16 ohms

 

[mjrippe]

Unless you are not happy with the tone, I think leaving it and being cool will work best

 

[arsmusic]

Unless you are not happy with the tone, I think leaving it and being cool will work best

Yes, I think that is what I am going to do.

Thanks guys

 

[Michael Tibes]

You could also parallel a 16ohm resistor to your cab. Maybe you get lucky and find a cheap 2nd hand loadbox / speaker simulator for that task. Depending on the wattage you could obviously also just use one speaker of the cabinet. Even if it's just to verify if it really sounds better to run the correct impedance.

Michael

 

[arsmusic]

You could also parallel a 16ohm resistor to your cab. Maybe you get lucky and find a cheap 2nd hand loadbox / speaker simulator for that task. Depending on the wattage you could obviously also just use one speaker of the cabinet. Even if it's just to verify if it really sounds better to run the correct impedance.

Michael

I though about running one speaker. Though a lot of my amps are 100 watts or even 120 watts. Running that through one single greenback 25 watt speaker will probably eventually blow it out.

I do have a fryette load box. Maybe I could experiment running that is parallel at 16ohms. Or just leave it the way it is (cab at 16 ohms) and just deal with it.

 

[abbey road d enfer]

I though about running one speaker.

Beware that using just one speaker and disconnecting the other changes the cab tuning. You need to short the unused speaker.

 

[Michael Tibes]

Beware that using just one speaker and disconnecting the other changes the cab tuning. You need to short the unused speaker.

Interesting. Why is that so? Does it kinda put a brake on the membrane?

Though a lot of my amps are 100 watts or even 120 watts. Running that through one single greenback 25 watt speaker will probably eventually blow it out.

You can safely delete 'probably eventually' from that sentence. A few years ago I 'only quickly tried out' my 200W Marshall with a 100W cab, playing it clean, 'should be no problem at that volume' - quoting my stupid self. We didn't even make it halfway through the song once... The smell of the burned voice coil stayed for days though.

Anyway, it's only worth all the effort if the cab sounds better when it's driven with the right impedance. Decades ago in my band I used to intentionally mismatch the impedance because I liked the sound better like that. Not sure if I'd feel the same nowadays, haven't tried it in a long time.

Michael

 

[abbey road d enfer]

Interesting. Why is that so? Does it kinda put a brake on the membrane?

Yes. If it was open, it would flap against the other in opposite sync.

Anyway, it's only worth all the effort if the cab sounds better when it's driven with the right impedance. Decades ago in my band I used to intentionally mismatch the impedance because I liked the sound better like that. Not sure if I'd feel the same nowadays, haven't tried it in a long time.

Indeed. Using a lower Z cab decreases the damping factor, increasing the resonance hump, which many players like. The actual max power is reduced somewhat.
The reverse, unsing a higher Z cab, gives a more controlled, tighter sound; the risk is the amp becoming unstable and starting to eat output tubes.