Audio signal "blow" a pedal?

[m_charles]

Hi All!
Is it possible to "blow" a pedal by running an incredibly large audio signal into the input?
Like if you pushed a keyboard signal dimed, into a pedal?
thanks!!

[R.G.]

All pedals are not created equal.

Someone with experience and circuit design skills will design their pedals so that forseeable misuse (like, say, plugging the PA speaker output into the input of the pedal...  ) will not damage the pedal. Someone who really doesn't understand circuits all that well and "designs" in the sense of mixing a little mustard, a little peanut butter, and some oregano and seeing how it tastes  will have no idea how the circuit they "designed" works under this kind of abuse.

That doesn't mean that mustard-oregano peanut butter might not taste good, but it's probably not a good fire retardant, either. 

Depends on the pedal. The devil is in the details.

[m_charles]

Man, I may have just lost an argument then... 
I'm gathering that its not as simple as a buffer being what would protect it?

[aron]

R.G. would know more - but for most "pedals" out there, I wouldn't think a standard keyboard line level out would blow a pedal.
The key being "most" and "line level".
I would take the bet that the pedal would not be "blown" by the output of a keyboard (if it's a standard performing keyboard with line out).

[TheWinterSnow]

R.G. would know more - but for most "pedals" out there, I wouldn't think a standard keyboard line level out would blow a pedal.
The key being "most" and "line level".
I would take the bet that the pedal would not be "blown" by the output of a keyboard (if it's a standard performing keyboard with line out).

The components used in a 9V powered pedal can indeed handle line level. Considering +4dBu is indeed around 1.228Vrms, the total peak power then being 3.4v.  Keeping in mind that some high output guitar pickups can indeed hit an output of +12dBu or 3.1Vrms, most effects pedals that do run on 9v if the semiconductor devices had been biased to allow a quiescent bias of 4.5v would have a headroom of 3.18v.  The result is that most small signal transistors and op amps have a maximum to exceed base(gate) to collector(drain) that is in the 30-40v range.  That is the equivalent of a 100-120 Watt amp.  For the most part as long as the device that you are using ins't distorting all shall be good.  Like R.G. said though, the devil is in the details, result in the spec sheet of the first gain stage or refer to the manual, depending on the situation.

[J0K3RX]

try it!

[Mick Bailey]

Depends what keyboard. My modular will output 20v P-P on the VCA 'direct out' jack and for a stomp box I guess that would be "incredibly large" by the usual standards, but still with the operating voltages of most components.

[Mark Hammer]

Will or can?

[midwayfair]

Will or can?

try it!

I feel like the forum is rapidly approaching a "Challenge Accepted" post in this thread.

[Paul Marossy]

IMO, the only thing that will "blow" a pedal is plugging it into the wrong wall wart (like AC or massive DC overvoltage). I don't see a line level signal or guitar ever doing a thing to a pedal.

[diydave]

I blew up my "ruby" while audioprobing a tube-amp. 
And it wasn't DC that blew it up, because there is a high-voltage cap soldered right after the probe to block any DC.

[GGBB]

IMO, the only thing that will "blow" a pedal is plugging it into the wrong wall wart (like AC or massive DC overvoltage). I don't see a line level signal or guitar ever doing a thing to a pedal.

I don't really know a thing about this, but if there's 20V p-p in some cases as Mick stated, couldn't that potentially "blow" something like a 16V electro cap?  Inquiring minds want to know.

[R.G.]

Will or can?

I thought we'd get a lot of responses like we have.

The OP said "Is it possible...?".
The answer to that is clearly "yes".

A different question, and the one most of the respondents have answered is "Is it likely...?".
And the answer to that is "no".

A better statement of the question would probably be "How likely is it that an audio signal could damage a pedal by being connected to the pedal's input?"
The answer to that is: it's not too likely, as most effects circuits are not terribly fragile. However, there are unusual audio signals of such a size and impedance that they could damage inputs to pedals that are not designed for reliability under conditions of forseeable misuse. Some PA systems can provide 120Vac, 50 or 60Hz when driven by a proper input. You can drive a hair dryer with some PA's. Power supply test equipment includes desk-sized audio power amplifiers which can do much the same thing, for testing power supplies. So - not likely, but possible.

[Paul Marossy]

IMO, the only thing that will "blow" a pedal is plugging it into the wrong wall wart (like AC or massive DC overvoltage). I don't see a line level signal or guitar ever doing a thing to a pedal.

I don't really know a thing about this, but if there's 20V p-p in some cases as Mick stated, couldn't that potentially "blow" something like a 16V electro cap?  Inquiring minds want to know.

Maybe in that case it's possible, but I said "line level". Anything that is built to modern day standards I don't think is cause for any concern. Of course, if some wise guy thinks he can take the output of his tube amp and run it thru a pedal and then to his speakers, well then all bets are off.

[R.G.]

The OP said "incredibly large". That's a pretty big range.   

[duck_arse]

I know a wise guy, put his amp output into one of my fuzz boxes to see if it would **?**, I don't know what. it didn't, and it hasn't since.

[Paul Marossy]

The OP said "incredibly large". That's a pretty big range.   

True dat! 

I know a wise guy, put his amp output into one of my fuzz boxes to see if it would **?**, I don't know what. it didn't, and it hasn't since.

I rest my case then. Ha ha.

[Jdansti]

If you try it, please have the video running and post the results. 

[greaser_au]

I blew up my "ruby" while audioprobing a tube-amp. 
And it wasn't DC that blew it up, because there is a high-voltage cap soldered right after the probe to block any DC.

Hey diydave...

Consider what happens on either side of the probe's blocking capacitor over (say) the first 10ms or so when you apply a the probe to an valve anode at operating potential,  as the cap  (which initially has 0V across it ) charges up...

david