# Gain controls



## NBPk402 (Feb 21, 2012)

I had a strange response from a Tech when I was picking up my Yamaha P7000s from Service today (for a failed Power Supply). The Tech asked me if I am leaving the gain controls up (since they were up when taken to the shop for repair), and I said yes, as it is in an active setup. He told me that i should be turning the gains down before turning on the amps. I told him that they are being used in an active setup, and the gains are set and then left...he said they should be turned down before turn on. I felt this was strange as all of my gain controlled amps are left in the on position, and turned off/on via a remote controlled outlet.


What do you do?


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## AudiocRaver (Jun 6, 2012)

There are two reasons I can think of to possibly want to turn them down.

The reason the tech was probably referring to, to protect drivers from pops and clicks on turn on / turn off. Or the possibility of getting "blasted" with an unusually hot signal by accident somehow. If this is not a problem for you, don't worry about it. My gain controls stay up all the time, except for the AVR gain, which acts as master volume, which I reflexively turn down when changing sources, and sometimes even between tracks. Just a careful habit.
With analog pots, if that applies, if they sit on the same gain setting for years and years, a tiny bit of corrosion can take place and the sound might start to cut in and out. Then you jiggle the pot to get the sound back. You also now have a "noisy" spot on the pot when turning it back and forth. This not a problem with better quality pots, or with electronic volume controls.


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## tonyvdb (Sep 5, 2007)

I would agree with the above, no reason other than to avoid a "pop" sound in the system when powered up. The gain controls are only there to adjust the maximum input level that the amps will receive.


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## AudiocRaver (Jun 6, 2012)

Another way of accomplishing the same is to follow the standard practice of power amps _on last_ and _off first._

With a DSP device, NEVER unplug the power into the device while the subsequent power amps are powered on. I did it once without thinking and got a HUGE *kapow!* Thought I had blown drivers for sure. Luckily the were unscathed.

Turn off power amps / turn down system volume any time you are plugging / unplugging cables, reconfiguring, loading DSP presets, at least the first time until you know how much noise will occur from that event in your system.

miniDSP's devices behave very quietly with config changes and loading of presets, but the first few changes, or any time I am not certain, the volume is turned down first for safety.


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## NBPk402 (Feb 21, 2012)

Thanks for the info! What I usually do is turn on or off the amps with my Insteon outlet... My preamp, and MiniDSP DDR88M boxes are on 24/7 (which i am assuming is ok). :T


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## AudiocRaver (Jun 6, 2012)

Sounds OK to me.

Only reasons to turn precision equipment off:

It uses a lot of power.
It runs unusually hot, where the reliability degradation over time would be more than the reliability degradation from power on/off thermal cycles - you can pretty much only guess at this. With most equipment, thermal cycling is harder on it than just sitting being hot.
Prevent video screen burn-in.
You hate to wait for warm-up.


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