Author Topic: Can you damage your amp from experimenting on a breadboard?  (Read 622 times)

major tonality

Can you damage your amp from experimenting on a breadboard?
« on: January 25, 2021, 07:38:36 PM »
Hi everyone, I am an extreme noob and this is an extreme noob question.

I am wondering if you can just go crazy on a breadboard while it is hooked up to your amp. Can you freely plug in and unplug different components without risking damage to the amp, or are there certain things you shouldn't do? I would think there would be a risk to the amp if you have a breadboarded circuit that increases the voltage a lot, or something to that affect.

Sorry in advance for the basic question.

Thanks everyone!

GibsonGM

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Re: Can you damage your amp from experimenting on a breadboard?
« Reply #1 on: January 25, 2021, 08:35:13 PM »
Depends on the amp, Major.  Welcome to the forum, by the way!  It's a good question.

If you limited the input to the amp to <12V AC or DC or so, I'd say you are safe. [you should NEVER feed an instrument amp DC, but it can happen accidentally...]  Most of our stuff is 9V...sometimes 18V.    If there is an input cap on the amp (should be on solid state, some tube amps have them, some don't)...it may be worth checking its voltage rating if you can.    After that, you may find an opamp or other circuitry that could be somewhat sensitive to what you feed it.    I've never blown an amp this way (burst box ha ha), but I've probably damaged my speakers once or twice by feeding it a signal with WAY too much bass...

Limited to 9V or 12V, I'd say no, you won't hurt anything.  Especially if you ALWAYS make sure you have a nicely rated cap on the output of the breadboard, rated for more than the power supply of what you're working on [to block DC].   Too much bass with a cranked amp caveat aside ;)     I always start out with the amp volume very very low, and adjust accordingly...haven't run into any problems by doing things this way.    I use a small practice amp for BB first, and if the circuit is worth it I move to my larger amp(s) after I know it's working.

Enjoy the forum!
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idy

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #2 on: January 25, 2021, 09:33:19 PM »
"Hot swapping" means taking a component out and replacing it while things are plugged in and turned on. BUMP. To be avoided. Many breadboard set ups will BUMP if you adjust a pot or something... If you plan to do much you will want to make some kind of face plate for pots with wires to the breadboard.

major tonality

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #3 on: January 25, 2021, 10:31:43 PM »
Depends on the amp, Major.  Welcome to the forum, by the way!  It's a good question.

If you limited the input to the amp to <12V AC or DC or so, I'd say you are safe. [you should NEVER feed an instrument amp DC, but it can happen accidentally...]  Most of our stuff is 9V...sometimes 18V.    If there is an input cap on the amp (should be on solid state, some tube amps have them, some don't)...it may be worth checking its voltage rating if you can.    After that, you may find an opamp or other circuitry that could be somewhat sensitive to what you feed it.    I've never blown an amp this way (burst box ha ha), but I've probably damaged my speakers once or twice by feeding it a signal with WAY too much bass...

Limited to 9V or 12V, I'd say no, you won't hurt anything.  Especially if you ALWAYS make sure you have a nicely rated cap on the output of the breadboard, rated for more than the power supply of what you're working on [to block DC].   Too much bass with a cranked amp caveat aside ;)     I always start out with the amp volume very very low, and adjust accordingly...haven't run into any problems by doing things this way.    I use a small practice amp for BB first, and if the circuit is worth it I move to my larger amp(s) after I know it's working.

Enjoy the forum!

Thank you! Very helpful  :) Could you explain what the output capacitor is doing to protect the amp? And how someone could accidentally feed DC into the amp?

major tonality

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #4 on: January 25, 2021, 10:35:50 PM »
"Hot swapping" means taking a component out and replacing it while things are plugged in and turned on. BUMP. To be avoided. Many breadboard set ups will BUMP if you adjust a pot or something... If you plan to do much you will want to make some kind of face plate for pots with wires to the breadboard.

Gotcha, what do you mean by bump?  :icon_question:

idy

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #5 on: January 25, 2021, 10:51:06 PM »
Loud noise.

DIY Bass

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #6 on: January 26, 2021, 12:09:32 AM »
I once built a compressor kit powered by 9V.  I did not read the instructions well enough, and it was set up to also boost microphone level signals to line level.  I plugged an active bass into it.  The preamp in my bass amp was OK, but after a while the graphic EQ board developed enough problems to blow the fuse.  I tell that story as a way of saying that it is potentially possible to damage your amp even without hot swapping components just by what you put in front of it.  I am not sure that is a reason to stop doing it though :-).  I tend to experimentation with a small headphone amp that I built.  If I break it I can probably repair it, and if I break it too badly then it's not the end of the world.

garcho

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #7 on: January 26, 2021, 01:25:57 AM »
Depends on the amp, Major.  Welcome to the forum, by the way!  It's a good question.

If you limited the input to the amp to <12V AC or DC or so, I'd say you are safe. [you should NEVER feed an instrument amp DC, but it can happen accidentally...]  Most of our stuff is 9V...sometimes 18V.    If there is an input cap on the amp (should be on solid state, some tube amps have them, some don't)...it may be worth checking its voltage rating if you can.    After that, you may find an opamp or other circuitry that could be somewhat sensitive to what you feed it.    I've never blown an amp this way (burst box ha ha), but I've probably damaged my speakers once or twice by feeding it a signal with WAY too much bass...

Limited to 9V or 12V, I'd say no, you won't hurt anything.  Especially if you ALWAYS make sure you have a nicely rated cap on the output of the breadboard, rated for more than the power supply of what you're working on [to block DC].   Too much bass with a cranked amp caveat aside ;)     I always start out with the amp volume very very low, and adjust accordingly...haven't run into any problems by doing things this way.    I use a small practice amp for BB first, and if the circuit is worth it I move to my larger amp(s) after I know it's working.

Enjoy the forum!

Thank you! Very helpful  :) Could you explain what the output capacitor is doing to protect the amp? And how someone could accidentally feed DC into the amp?

Thatís a complicated answer, read up on DC, AC and capacitor basics. Short version: capacitors block DC (your power supply) and pass AC (your audio signal).
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GibsonGM

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Re: Can you damage your amp from experimenting on a breadboard?
« Reply #8 on: January 26, 2021, 05:17:01 AM »
Let's say a boost calls for a capacitor on its output.  If you forget to put it in the circuit, you may then send the DC that's running whatever is doing the boosting right out the output jack into the amp.  Or, if you short that cap on your BB, same thing.   Opamps, transistors and the like use bias voltages at THEIR inputs to do their job, so there is DC 'around them'.   That is what those input and output caps do - as well as acting like little tone controls, they block that DC from going where it shouldn't.    That's not usually a big deal, but in theory it COULD be - it's good practice to contain your DC  :)

You can measure for it at an effect's output, just use a patch cord on the output and measure DC volts between the 2 jack conductors while it's on. More than a few millivolts may mean a leaking capacitor. 
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iainpunk

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #9 on: January 26, 2021, 08:00:35 AM »
my old breadboard setup had a 1Uf output cap (non-polarised) and a 50k volume pot to keep the DC off the output.
its wise to have a box or something similar to protect the breadboard and to mount pots, in and outputs as wel as a standard 9v connector, having a fixed output cap and volume control can be handy to have.

cheers, Iain
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Kevin Mitchell

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #10 on: January 26, 2021, 02:37:24 PM »
I once made the mistake of grabbing a reverb tank from inside an amp while it was on  :-[
It got pulled onto the speaker magnet and hit hard. The sound was so foreign that the neighbors probably didn't know who to call to complain. And it was so loud that I'd bet no one was too sure where it came from.

Anyways, it survived that. So I think anything on a stompbox level is no threat  :icon_lol:
It's good to be weary but great when you learn how robust things can be. Even when it's something you should never do.

It is a great questions. And again, welcome!
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aron

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #11 on: January 26, 2021, 07:30:44 PM »
Kind of makes you want to make a small box with capacitor and pot inside. A safety box.

iainpunk

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #12 on: January 27, 2021, 07:35:46 AM »
Kind of makes you want to make a small box with capacitor and pot inside. A safety box.
or you connect this box permanently to the breadboard enclosure!
also, some high forward voltage clipping diodes to protect against big spikes.

cheers, Iain
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deadastronaut

Re: Can you damage your amp from experimenting on a breadboard?
« Reply #13 on: January 27, 2021, 09:35:56 AM »
breadboard with a cab sim pedal after it into your mixer/stereo......then try on your amp later.  8)
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