Unused channels on a multi channel amp

Tripper, this has ZERO to do with having a load connected. The inquiry was about the efficacy of capping unused inputs.
Sean, the only input that will benefit from a shunted input is a phono input. The RFI/EMI interference often posited has as much scientific grounding as a Santaria ritual. The only missing ingredient is the chicken blood.

How much of a difference is either audible or measurable will depend on the design of the amp, how much internal cross-talk it demonstrates from channel to channel ( primarily due to poor circuit layout and / or internal cable routing ), the ability of the circuit to reject extraneous noises ( due to poor shielding and / or microphonics ), etc... These are all real factors that are both audible and measurable. Resistively shunting the input can only help this situation and lessen the potential for them to occur.

IF any of the above were to take place within the amp i.e. signals being induced into the early gain stages of an amp, it is the very nature of the circuit to not only amplify these signals, but to try to output them to a load. If there is no load, the output devices themselves and any loading circuitry inside the amp would have to absorb that energy and dissipate it as a slightly higher level of heat.

The level of heat and / or "abuse" that the output circuitry has to undergo in such cases is typically minimal with most well designed SS gear, but many circuits aren't "well designed" and / or built with quite as much precision as we would like to think. This goes for both inexpensive and quite costly products alike. Having said that, the mass majority of tubed gear should never be run without a load on it.

As such, using the approach that i mentioned above can only help the situation / put one's mind at ease / help the longevity of the gear / potentially improve sonics. NO, it is not "necessary" by any means and NOT following this procedure won't destroy your multi-channel amp beyond usability should you choose to not shunt the inputs and / or the outputs.

Having said that, i've always thought that the goals of most people frequenting this forum were to achieve the highest levels of performance from their gear / installation that they can. As such, i tried to provide some simple and reasonably inexpensive tips that i thought might apply to the subject at hand. Sorry if i offended anyone and / or presented my opinion as being anything other than my opinion. Sean
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Porziob, He asks two ?s; unconnected outputs And capping inputs. Zero plus 1.

Tripper if there`s no input, why does the channel need a load. It`s a little bit like wondering what a dead person will have for dinner.

I tried to explain how signals could enter the unused channel(s) through extraneous and / or internally generated sources. I also tried to explain that most amps do generate "leakage" from their output stage on their own, albeit very small quantities most of the time. This is why i suggested resistively shunting both the inputs and the outputs as it completely isolates and protects the unused channel(s).

As a side note, using a resistive shunt on the input will not have any potential side effects compared to simply shorting the unused inputs. Using this method of resistively shunting unused inputs on a preamp can also be used to varying levels of success. In some cases, directly shunting or "shorting" the unused inputs on a preamp and / or power amp can result in sonic degradation. This has to do with poor isolation of each input i.e. higher than desirable levels of cross-talk, etc... Sean
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