Breaking speakers by turning off a synth

[madmarkmagee]

Hey I always notice when I read manuals it always says to power off speaker before turning off devices hooked up to them like synths to prevent damage. I accidentally turned the synth off before the speakers on mid volume yesterday and that got me thinking about the chances of damaging speakers. Does everyone here always turn the speakers off first, do people sometimes forget? How hard would it be to damage speakers? My monitors boast a circuit which protects the monitors from excessive volume, would this protect them against accidentally powering off the synth first? Thanks for your help/input.

[Rick N Boogie]

It's always best to turn on amps/speakers/etc last, and off first. Prevents any surges from hitting the spkrs. Doubt any harm was done, but just make it habit to avoid any issues.

[rschnier]

Power off the speakers/amplifier first and wait 15-30 seconds before powering off things upstream. The power supply capacitors in the amp typically take that long to discharge, and until they are discharged you can still propagate "thumps" through to your speakers. Generally if you don't hear a thump you're OK; the problem is that when do you hear a loud thump the damage may already be done.

[pflosi]

It's handy to keep a monitor volume controller such as the Mackie Big Knob to turn down the volume when powering stuff on / off / patching things in the patchbay / inserting fx / etc.

[Miles Powerhouse]

I just turn down the volume on either my monitors (M-Audio AV30s) or turn it down on my Audio Interface (Roland Tri-Capture). I have seen someone blow their Line6 amp because he was switching guitars and cables. It made a big -POP!- and a little bit of fuzz, then quit working. He was so mad he almost threw his guitar on the ground, and I just stood there saying, "I tried to warn you...". Because I did.

[Don T]

Turn-on/turn-off thumps are more likely to destroy an amp rather than speakers!

At any rate, any synth that generates enough of a DC spike to damage any associated audio gear needs to be checked/calibrated for DC offset, or "VCA balance". It is also possible that a spark-suppressor cap added to the power switch (Assuming there is not one fitted) can help soften the impact of a spike.

[silikon]

the problem is that when do you hear a loud thump the damage may already be done.

That would have to be some pretty high energy thumps going on... I've had all manner of electric music device in the studio at one time or another, and turn-on thump is the last thing I would expect to damage speakers. Have you ever sat in a studio when a guitar player yanks a cable out of his guitar, and then back in, with the amp still energized?

That sound alone has made me almost defecate myself on several occasions.

h**l, one time one of my friends' children decided that it was cool to fiddle with my valve amp, messing with all the knobs willy-nilly, just pretending he's a f**k telly switchboard operator or something, and ended up essentially plugging the same cable at different ends into the HI and LOW inputs and then firing up the amp. BOTH power switches. The sound was deafening; 60cycle hum at 130dB. At least that's what it felt like to my innards across the house. Amazingly, none of the circuits on the amp were toasted. I expected the amp to take the business before speakers...

Echoing others in the thread about powering up end devices before amps and speakers (or speakers if self-powered) is usually a decent idea. I can't imagine this sort of thing being a prevalent occurrence however -- on/off thumps causing speaker damage in normal situations -- I would expect there to have to be quite an inrush to cause that sort of damage...

[rschnier]

the problem is that when do you hear a loud thump the damage may already be done.

That would have to be some pretty high energy thumps going on... I've had all manner of electric music device in the studio at one time or another, and turn-on thump is the last thing I would expect to damage speakers. Have you ever sat in a studio when a guitar player yanks a cable out of his guitar, and then back in, with the amp still energized?

I had a woofer cone bottom out and get crunched enough that it rubbed against its magnet from that point forward. It was from a single transient that was generated somewhere upstream of the amp, 2 or 3 seconds after the power was turned off to everything at once. The amp still had plenty of juice in its PSU capacitors (it could continue playing audio for a good 10-15 seconds after its power was switched off). Since that episode, I power off the amp, wait upwards of a minute, then power off the upstream stuff. YMMV.

[cornutt]

At any rate, any synth that generates enough of a DC spike to damage any associated audio gear needs to be checked/calibrated for DC offset, or "VCA balance".

There are some digital synths that generate pretty nasty pops when they initialize the DACs at power up. My V-synth does that... I have to wait until it is booted up before I turn the amp up.

[Don T]

At any rate, any synth that generates enough of a DC spike to damage any associated audio gear needs to be checked/calibrated for DC offset, or "VCA balance".

There are some digital synths that generate pretty nasty pops when they initialize the DACs at power up. My V-synth does that... I have to wait until it is booted up before I turn the amp up.

Oh yeah, no doubt. Digital amps are even worse, even some of them have anti-thump circuitry. Some of them, right at start-up, are basically a dead-short across the power supply until the clock chip/resonator gets going. Not a lot of fun if they drive big MOSFET output transistors.

If anyone is reading this, and you have/are thinking about getting a digital amp, don't you DARE plug any kind of input in when the amp is powered up, volume down or not. It's damaging enough to "normal" transistor amps, but it can positively (and literally) smoke a digital amp!