Concerned about damaging preamp on turnoff

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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.

 

[Mike Rivers]

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?

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.

 

[Scott Dorsey]

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.

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

 

[William Sommerwerck]

However, when turning them off, I notice the level meter

slams into the full/max red zone.

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.

 

[Dr. Dolittle]

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.

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.

 

[Doc]

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.

They're green/amber/red lights.

 

[none]

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.

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.

 

[Richard Crowley]

They're green/amber/red lights.

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

 

[Asimov]

"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" <[email protected]>
RC> Xref: core-easynews rec.audio.pro:1060288
RC> sci.electronics.repair:351810

They're green/amber/red lights.

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

 

[Bill Lorentzen]

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.

Or just get a Clapper.

 

[Doc]

Or just get a Clapper.

heh heh...