What would happen if?

I'm with Newbie on this one... just do it. it's temp anyhow.

You must have a completed circuit for electrons to move - conduct.

Connect and disconnect whatever, with the amp dead off. Once amp connections are made put whatever cables onto whatever speakers. Only one leg (one positive or one negative) of the cables not being listened to needs be disconnected to prevent any current flow into those 'off for now' speakers.... not both. Of course, insulating the exposed leg so it won't touch it's proposed binding post is important.

A balloon or tape, or a shoe or phone book... anything preventing conductivity will suffice.

Just 'member, power off the amp prior to making up and unmaking ANY connections to the speakers themselves.

As was said above about A/B ing, I'd shy away from instantaneously attemnpting that event. Given the power up and down safety measures you'll want to take, it's not viable anyhow. Just take notes instead.

I don't see any reason why you can't do that, and get reasonably valid results. Provided of course that, as many have said above, you make absolutely sure to avoid the possibility of a short circuit, and as long as connections are changed only with the power off.

The idea of disconnecting only one leg of one of the cables is not correct. It will invalidate your results because on the other polarity (positive or negative; the opposite polarity from the one that you disconnect the one leg from) you will have that polarity conducted in parallel through the corresponding legs of two cables. The current will take advantage of that and divide itself between both paths on that polarity, in inverse proportion to the resistance of each path.

I don't think that concerns about antenna effects and capacitive loading are likely to be relevant to the power amp/speaker interface, due to the extremely low output impedance that power amps have to have (well under one ohm usually), as well as the fairly low input impedance of the speakers themselves. The low impedances would load down any rf or emi that was picked up from the air (that's why speaker cables are usually not shielded, not to mention that the frequency of the interference would be far too high for the speakers to respond to). The added capacitance is likely to be have essentially zero effect because the resulting capacitive impedance (reactance) would be vastly higher than the output impedance of the power amp. It would be a completely different story with line level interconnects.

Regards,
-- Al

Wouldn't do it. Too many unkowns to say what would happen. You're essentially adding a capacitor across the amp's output. Depending on the capacitance the amp may not like it. However large or small, you're asking the amp to drive an additional needless capacitive load. At the least you're affecting frequency response somewhere. Likely that your evaluation of each cable would be scewed also because of the additional capacitance that wouldn't be there otherwise.

Cheers!

Robert
RSAD

Following up on my previous comments about capacitance, consider the following calculation:

Assume as a very rough ballpark that cable capacitance is 50 picofarads (pf) per foot, a typical number. Assume a 20 foot cable length. That gives a total capacitance of around 1000 pf.

The resulting capacitive reactance at 20,000 Hz (the worst case frequency within the audio band, in terms of the potential effects), based on 1/2piFC (pi = 3.14; F = frequency in Hertz, C = capacitance in farads, to get results in ohms), would be a capacitive reactance of around 8000 ohms.

With the output impedance of the amp likely to be well under 1 ohm, and the speaker input impedance likely to be 8 ohms or less, 8000 ohms of capacitive reactance is, in comparison, essentially infinite, and it would seem to the amp/speaker interface that the capacitance is not there.

Regards,
-- Al

Almarg

The rules for current flow must have changed when I wasn't looking.

At some point long long ago, a completed path for voltage or current, if you would rather, needed to be in place.... or still more simplified, one leg to bring it in on, and one for the return. Things are a bit more involved than that, but in essence that way worked then and now... though perhaps there is some new one conductor circuitry that actually can send and return voltage and current into a component or device without the need for another path to complete the circuitry.

The speakers which has but one leg of the two speaker cables attached to them and to the amp as well have to be there for them to work. For the amp to see an additional load as it were.

Hook one of the two supplied wires in the speaker cables to the speaker, whichever one doesn't really matter. Next, connect the same wire in the second speaker cable to the other speaker. Turn everything on and tell me you can then hear music or even sound. you won't be able to. I assure you.

That could work if a wire was connected to the unlike post on those speakers which were properly connected. That way only one wire would run from the amp to one pair of speakers, and the return path would come via a connection to the playing or properly wired pair.

The load presented to the amp by those speakers that are correctly connected is all the amp will see. The singular existing connection I mentioned still in force on the unused pair can not present any significant load or sufficient resistance, by virtue of having only one lead connected. That circuit is what is called, an 'open' circuit.

There is no completed path for the supplied energy for which to enter the single wire connected speakers, and then return to the amp.

Even if the still attached single leg/lead runs directly into a cap, the effect will be negligible. Unnoticeable. Harmless. No noise.

The note as to having things in parallel doesn't stand up either, as all paralell circuits that in fact operate share both a common or actually a neutral, most likely a ground somewhere, and one hot or feed line, and in EVERY CASE a return path for the signal needs to be in place physically. this can be either the aforementioned common/neutral, or in some instances a common chassis ground or actual ground.

Although you say there is a lets say feed line.... where is the common or return in the speakers which do not have their returns connected, and only one lead afixed to them?

They don't... so coincidentally, they can not be seen as a load by the amp.

it is just like a broken filament in a light buld... break that filament... conduction ceases as the circuit is then, interuppted. A light switch is the same premise.

A return path must be in place always for current flow. AC or DC... it matters not.

If the benighn characters in a speakers xover contributed to some ancillary effect it would be so small as to require a metering device that measured in the thousandths to determine the actual value of it. it would be so infinitesimal as to not be contributary audibly, or mechanically in my proposed premise.

Essentially removing one or both leads at the speakers binding posts will accomplish the same result.

My method is simply easier and quicker, and will not harm either componenet… amp or speaker. If this connecting and disconnecting takes place while the amp is de-energized entirely.

When a person can figure out how to supply energy and return it using a single wire, it will revolutionize the electronic industry, and our world as we know it.

Talk about being 'single ended'! wow.