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Concerned about damaging preamp on turnoff

I have a couple of Studio Projects VTB1 mic pre's. They don't have an on/off switch, you plug them in and they're on.

However, when turning them off i.e. turning off the power strip they're plugged into, I notice that the level meter slams into the full/max red zone. It doesn't matter where the input/output gain controls are set, does this every time.

Is there any reason to be concerned about this? They seem to work fine so far, but I cringe every time this happens. Obviously I have to be able to turn them off and the manufacturer hasn't provided any other way to do it.

Is this normal and nothing to be concerned about?

Thanks for all shared wisdom.

Reply to
docsavage20
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No. And if it had a power switch, you'd see the same thing. Put a piece of duct tape over the meters if it bothers you.

Reply to
Mike Rivers

Yes, all equipment with single-ended electronics do this. You're seeing the capacitors discharging unequally. Some give a similar thump on power up. You worry too much.

--scott

--
"C'est un Nagra.  C'est suisse, et tres, tres precis."
Reply to
Scott Dorsey

Slams into the zone, or slams into the peg stop? The former is harmless. The latter is potentially damaging to the meter, if it happens over and over.

Reply to
William Sommerwerck

Feisty, huh Mike? But yes, I notice this happening with all my meters. Mic pre's, mixers, effects processors, you name it. Since I have been observing this happening for several decades, I assume it is probably safe.

Reply to
Dr. Dolittle

The

They're green/amber/red lights.

Reply to
Doc

Should be a simple matter of wiring an on/off switch into them. I use the switches off older computers for the industrial audio gear of mine that comes sans switches.( the switches that are located on the rear case, usually rated at 15a's or higher.) You could just pick up a simple push button switch at you local electronics jobber, then all you have to do is drill a mount hole on the front of the pre-amp case and wire it on into the high side of the incoming power.

Reply to
none

Doesn't even make the top 500 list of things to be concerned about.

Reply to
Richard Crowley

"Richard Crowley" bravely wrote to "All" (17 Dec 05 23:30:25) --- on the heady topic of "Re: Concerned about damaging preamp on turnoff"

RC> From: "Richard Crowley" RC> Xref: core-easynews rec.audio.pro:1060288 RC> sci.electronics.repair:351810

RC> Doesn't even make the top 500 list of things to be concerned RC> about.

Indeed, never mind about the lights and meter needles... The main thing I'd really be concerned about is damaging junctions. The reason is that each time a junction carries a substantial reverse current it might cause some ionization in the semiconductor material. The consequence of this is a permament shift in the characteristics such as lower gain and increased noise. So there is some advantage in protecting junctions likely to encounter such transient spikes.

A*s*i*m*o*v

... All the world's an analog stage & digital circuits play only bit parts

Reply to
Asimov

Or just get a Clapper.

Reply to
Bill Lorentzen

heh heh...

Reply to
Doc

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