Silly question of the day...

[JACink]

Just a curiosity here...

If you have a combo amp, with an extension output, this extension output is almost always wired in parallel to the speaker in the cab.

If you then had an extension cab, which also has a "through" connection to daisy chain to another cab, this is also (almost) wired in parallel.

Connecting the extension cab to the combo, whilst powering the cab from the combo, the extension cab also has an output that would connect another cab in parallel to the other two.

If the amp in the combo was to die, would connecting another amplifier to the extension port of the extension cab basically run both cabs, or would having a dead amp (obviously unplugged from power) on the other end cause issues?

 

[Jim C]

The issue is that ganging multiple cabinets together would probably create such a low impedance condition that the amp would be hurt

 

[mmbongo]

Yes you would most likely fry your new amp as well since you'd have another amplifier still connected in the chain.

If you rewire the dead combo so the amp is no longer in the picture you could maybe do what you're saying.

 

[BadExample]

If the amp in the combo was to die, would connecting another amplifier to the extension port of the extension cab basically run both cabs, or would having a dead amp (obviously unplugged from power) on the other end cause issues?

Never connect outputs from two amps together, regardless of status. If I understand your question, you'l have two dead amps

 

[JimChjones]

My minimally informed guess is that I think it would depend on exactly how that dead amp was built and how it had failed. If there was a dead short across the output, for instance, it might make for a rather bad day.

 

[Old Garage-Bander]

My minimally informed guess is that I think it would depend on exactly how that dead amp was built and how it had failed. If there was a dead short across the output, for instance, it might make for a rather bad day.

Even if not a “dead” short the output of the one amp, dead or alive, turned on or not is very low by design and would probably be enough to harm the other amp even without any speakers involved.

 

[Jim C]

Ooops
Missed the second amp issu
You have the opportunity to possibly kill two amps; if the combo amp was disconnected, you would get to kill the working amp.
If you gave us info on amps and the impedance of all cabinets involved we could better advise you.
Ideally a sketch as to the hook up plan too.
I have big money that says if you create less than a 4ohm load, and your amp isn't designed for that low of an impedance, you will let the magic smoke out

 

[agedhorse]

Never connect one amp's output to another's, there is no way to know how the connected circuitry will interact but almost always one or both amps suffer catastrophic failure. If one amp's already failed, then obviously the other working amp would be the most likely amp to suffer.

 

[Downunderwonder]

Everything you connect on any daisy chain is then connected to everything else, all in parallel. Don't do it.

 

[beans-on-toast]

Best that you don’t ask a general question. Be specific about the amp’s make and model.

 

[JACink]

Best that you don’t ask a general question. Be specific about the amp’s make and model.

I asked it as a general question because I was curious. I have no plan on doing this, at all, ever. I learned the "do not connect amp output to amp output" a long time ago (when a friend invented his own way of bridging amps ).

I had just never thought about the result of having a dead amp on the other end or the circuit.

Again, just a curiosity, not a real life situation.

 

[JACink]

Oh, and thank you all for the input!

 

[Jim Carr]

Oh, and thank you all for the input!

I've always been disappointed in combo manufacturers for omitting any way of accessing the ampifier's output alone, and the speaker's input alone.

I realize they assume the vast majority of users would just get themselves in trouble with such features, but Fender mainline guitar combo's have had this feature for at least 65 years, and nobody seems to have been harmed.

Since I nearly always have a spare amp head at a gig, there have been two occasions where guitarist's amps died. One was a Fender 112 (Deluxe?) and the other a 212 Musicman. In each case, I swapped in my spare head by disconnecting the amp out->speaker jack and hooking in my spare amp.

Tears of joy always ensued, as guitarists tend to equate amp death on a gig with something akin to erectile disfunction.

 

[beans-on-toast]

I’ve owned only one amp, a Univox, that had a wire running from the chassis to the speaker. All the others have had jacks.

I prefer the jacks on the back of the chassis. Some combos have the jack on the bottom so you have to contort and look underneath to find it. Reverb pan connections are fine this way but I don’t care for speaker connections like this. They usually do this when there’s no room on the back of the chassis but not always.

The same goes for IEC power connections. They should be on the back of the chassis. Having them on the bottom where they can fall out is an accident waiting to happen. Marshall has done this.

 

[BurningSkies]

Just a curiosity here...

If you have a combo amp, with an extension output, this extension output is almost always wired in parallel to the speaker in the cab.

If you then had an extension cab, which also has a "through" connection to daisy chain to another cab, this is also (almost) wired in parallel.

Connecting the extension cab to the combo, whilst powering the cab from the combo, the extension cab also has an output that would connect another cab in parallel to the other two.

If the amp in the combo was to die, would connecting another amplifier to the extension port of the extension cab basically run both cabs, or would having a dead amp (obviously unplugged from power) on the other end cause issues?

I'd not assume that they're wired in parallel. Many combo amps with extension jacks are actually series...

 

[Coolhandjjl]

No questions are silly. If we all knew everything, we wouldn't need this forum, or anyone else's.

 

[tjh]

No questions are silly. If we all knew everything, we wouldn't need this forum, or anyone else's.

… no wonder my wife doesn't do the forum thing …

 

[yodedude2]

edit: oh hey, I just remembered. I have an old 70s guitar combo that was modified. it has some sort of 'disconnect' jack on the back. when you plug into this jack, it disconnects the combo's amp head from the speaker. i'm not quite sure how it works, but it does work. I've used it before. perhaps it was called an 'interrupt' switching jack?