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RCA jacks are constructed such that the inner pin of the plug cannot contact the outer ground ring at the same time that it is contacting the jack's inner pin contact. Disconnecting the plug could short the signal line of the cable to ground, but only after disconnecting from the DSP - the device that would see the short would actually be the amp on the other end of the cable.

Also - I'm not seeing it listed as a feature on the data sheet, but most op-amps are protected against short circuits on their output; a brief short wouldn't cause it to blow like that. If that particular op-amp is sensitive; then there should be current-limiting resistors in series with it's output to prevent just such an occurrence.

I suspect that you just got unlucky and the op-amp chip just happened to blow co-incidentally.
 

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I would be very suspicious and check the rails etc. It should be pretty hard to kill an OPA1678 with some R on input and output. ESD is a possibility but I’d be surprised if there’s no protection diodes in these DSPs.
 

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Thats the one, literally less than a couple weeks with it
Hey if that's the one then you should be good to go.. squaretrade should pay out, I have used it before. Just read ALL of the terms and conditions before even contacting them.. i do not know if the warranty is transferable, so check that in the terms or ask them before making a claim. if it is not transferable have the guy you bought it from make a claim.. i can almost assure you that the square trade route will be cheaper than sending it back to ATF since square trade normally pays for shipping.. and in most cases like this where they don't have the capability to repair it they will normally just pay out cash for it granted you do not violate the terms and conditions of the contract... if its just a regular warranty and not accidental coverage i would shy away from saying anything about plugging or unplugging the RCAS..

you or the original purchaser should contact square trade (after reading the terms very thoroughly)

they will send you a shipping label and have you send it back to one of their "repair centers" to evaluate it

what this really means is they are probably sending it to their facility where an insurance adjuster glances at it to see if they can fix it for cheaper than the payout amount is.. in this case they will not have the capability of fixing it if I had to guess.

they will probably ask you a bunch of questions, and should cut you a check for the amount of the original purchase price.

what they will definitely ask you is if there is a manufacturers warranty.. because the square trade warranty is only good if the manufacturers warranty will not cover it.. in this case it will not because helix only gives a warranty if you buy from an authorized dealer in the united states.. So you might be able to send it back to the guy in Europe that sells them on eBay.. but I doubt square trade would be ok with sending it to anybody other than the OEM manufacturer unless its one of their "authorized repair centers" .. so if you get an email from audiotech fischer or MSC (american dealer for helix) saying "no there is no manufacturers warranty because you bought it of ebay" then you should be able to use the square trade warranty.. but once again, I would probably leave that part out unless asked about it... i would simply tell square trade there is "no manufacturers warranty because the manufacturer is in germany" and they can check that themselves if they really want to. worst case audiotec fischer will accept it and make you pay for repair since it does not have a manufacturers warranty in which case square trade is supposed to pay for shipping and the repair (good news for you since international shipping is insanely expensive)

square trade advertises their warranty on eBay when you buy an item listed as "brand new" so they should honor that warranty since that warranty was bought in conjunction with that product as an add on with the sole purpose of being used for that item purchased on ebay. so there is no way they can say "oh its not valid because there is no manufacturers warranty." They can only burn you if you violate the terms somehow and that's why you want to read them very well.. but like i said, i would leave that on a "need to know basis" (regarding ebay not being an authorized dealer)

anyways.. this is just based off my experience which was also something i bought on ebay and used square trade.... but yours may vary.. but i suspect after a few questions and back and forth they should cut you a check.. (just leave out the part about you plugging or unplugging the RCA. adjusters look for reasons to not pay claims and that could be one. you don't want to mention anything about anything being an accident or possibly your fault,.. that's game over for your claim. keep it to the bare minimum of what they require and get your check)

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Discussion Starter · #26 ·
Hey if that's the one then you should be good to go.. squaretrade should pay out, I have used it before. Just read ALL of the terms and conditions before even contacting them.. i do not know if the warranty is transferable, so check that in the terms or ask them before making a claim. if it is not transferable have the guy you bought it from make a claim.. i can almost assure you that the square trade route will be cheaper than sending it back to ATF since square trade normally pays for shipping.. and in most cases like this where they don't have the capability to repair it they will normally just pay out cash for it granted you do not violate the terms and conditions of the contract... if its just a regular warranty and not accidental coverage i would shy away from saying anything about plugging or unplugging the RCAS..

you or the original purchaser should contact square trade (after reading the terms very thoroughly)

they will send you a shipping label and have you send it back to one of their "repair centers" to evaluate it

what this really means is they are probably sending it to their facility where an insurance adjuster glances at it to see if they can fix it for cheaper than the payout amount is.. in this case they will not have the capability of fixing it if I had to guess.

they will probably ask you a bunch of questions, and should cut you a check for the amount of the original purchase price.

what they will definitely ask you is if there is a manufacturers warranty.. because the square trade warranty is only good if the manufacturers warranty will not cover it.. in this case it will not because helix only gives a warranty if you buy from an authorized dealer in the united states.. So you might be able to send it back to the guy in Europe that sells them on eBay.. but I doubt square trade would be ok with sending it to anybody other than the OEM manufacturer unless its one of their "authorized repair centers" .. so if you get an email from audiotech fischer or MSC (american dealer for helix) saying "no there is no manufacturers warranty because you bought it of ebay" then you should be able to use the square trade warranty.. but once again, I would probably leave that part out unless asked about it... i would simply tell square trade there is "no manufacturers warranty because the manufacturer is in germany" and they can check that themselves if they really want to. worst case audiotec fischer will accept it and make you pay for repair since it does not have a manufacturers warranty in which case square trade is supposed to pay for shipping and the repair (good news for you since international shipping is insanely expensive)

square trade advertises their warranty on eBay when you buy an item listed as "brand new" so they should honor that warranty since that warranty was bought in conjunction with that product as an add on with the sole purpose of being used for that item purchased on ebay. so there is no way they can say "oh its not valid because there is no manufacturers warranty." They can only burn you if you violate the terms somehow and that's why you want to read them very well.. but like i said, i would leave that on a "need to know basis" (regarding ebay not being an authorized dealer)

anyways.. this is just based off my experience which was also something i bought on ebay and used square trade.... but yours may vary.. but i suspect after a few questions and back and forth they should cut you a check.. (just leave out the part about you plugging or unplugging the RCA. adjusters look for reasons to not pay claims and that could be one. you don't want to mention anything about anything being an accident or possibly your fault,.. that's game over for your claim. keep it to the bare minimum of what they require and get your check)

View attachment 337482
Really appreciate this run down, I'll be contacting square trade tomorrow and seeing what I can get done
 

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It's your own fault from very bad practice.
NEVER EVER hot plug RCA leads , that would be the quickest way to blow your speakers if there isn't a good connection straight away (floating input) , friend of mine blew some expensive pro pa tweeters setting up for a big function doing exactly as you did , whenever you disconnect or connect anything electrical ALWAYS ALWAYS disconnect the power first or at least make sure it's powered off , you are just asking for trouble and have just been lucky so far.

If you were in Australia I could have fixed that for you , very easy to replace the ic with a hot air rework station like I have at work and I deal with surface mount components ( 0402 and smaller ) all the time as I'm an electronics tech.
 

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Discussion Starter · #28 ·
It's your own fault from very bad practice.
NEVER EVER hot plug RCA leads , that would be the quickest way to blow your speakers if there isn't a good connection straight away (floating input) , friend of mine blew some expensive pro pa tweeters setting up for a big function doing exactly as you did , whenever you disconnect or connect anything electrical ALWAYS ALWAYS disconnect the power first or at least make sure it's powered off , you are just asking for trouble and have just been lucky so far.

If you were in Australia I could have fixed that for you , very easy to replace the ic with a hot air rework station like I have at work and I deal with surface mount components ( 0402 and smaller ) all the time as I'm an electronics tech.
Thanks for the heads up, I've honestly never heard of this advice and wish I saw it sooner, I very often use to do that without consequence, guess it's a lesson learned
 

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It's your own fault from very bad practice.
NEVER EVER hot plug RCA leads , that would be the quickest way to blow your speakers if there isn't a good connection straight away (floating input) , friend of mine blew some expensive pro pa tweeters setting up for a big function doing exactly as you did , whenever you disconnect or connect anything electrical ALWAYS ALWAYS disconnect the power first or at least make sure it's powered off , you are just asking for trouble and have just been lucky so far.

If you were in Australia I could have fixed that for you , very easy to replace the ic with a hot air rework station like I have at work and I deal with surface mount components ( 0402 and smaller ) all the time as I'm an electronics tech.
Quality gear, especially designed for automotive, should have protection/clamping and/or AC coupling.

Thanks for the heads up, I've honestly never heard of this advice and wish I saw it sooner, I very often use to do that without consequence, guess it's a lesson learned
It really shouldn't be a problem.
 

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I've literally been hot plugging/unplugging rca's for years to troubleshoot various issues and have never once had a problem, using these very processors. Highly doubt that's what caused this.
 

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Sorry that's just wrong and bad practise and bad advice , like I said NEVER EVER hot plug anything doesn't matter if it's the most expensive piece of equipment in the world you should NEVER EVER do it , again it's very bad practise and just asking for trouble.
I'm an EE with 20 years of experience. If hot-plugging line level connections kills something, it was designed by morons.
 

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I'm not an EE, but I do design stuff as a hobby (professionally I'm a software guy).

I mostly agree with yobbo7 - if hot-plugging a RCA causes a device to fail (especially in the manner that this one did, where an IC lets out the "magic blue smoke") then it was indeed designed by morons.

However - the speaker damage thing is a real possibility; as you can end up sending a nasty high-power transient into a tweeter that just can't handle it. Functionally, it's the same thing as driving the amp into clipping, hard.

Based on the apparent damage; it looks like that op-amp chip developed a short across the power rails. A transient across the output pin usually won't do that - you could very well destroy the ability of the op-amp to produce an undistorted output signal - but making a continuous short between the positive and negative rails is unlikely.

I think you just got unlucky.

BTW - some connections are specifically designed to accommodate hot-plugging: MIDI ports, Ethernet ports; most RS232, RS422, and RS485 ports, USB ports, many (but not all!) VGA ports, headphone jacks, and some PCI slots (typically found in server-grade machines where you want to avoid having to restart the system to replace a failed card) all come to mind. You probably wouldn't find it in serious use today, but the LocalTalk networking system used by classic Macs was also hot-pluggable; but the ADB keyboard & mouse ports weren't - you could fry your ADB chip on the motherboard by plugging in a keyboard or mouse while the Mac was on (fortunately ADB hasn't been a thing since the late '90s - it's all USB or Bluetooth instead).
 

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Signal level connections should be fine with hot plugging as long as its a standard connection and nothing too unusual -- however some stuff like one random headphone amp I have specifically states to never hot plug it because there is no current limiting. It is good practice to mute the input connection when doing any such hot plugging at least for your own personal auditory comfort. When an audio connection is made or broken, one of the conductors will generally be made or broken first, and this is where some really bad things could happen(Ever touched a bad connection and accidentally turned it into an FM receiver as long as you were touching the correct conductor?).

I'm not an EE, but I do design stuff as a hobby (professionally I'm a software guy).

I mostly agree with yobbo7 - if hot-plugging a RCA causes a device to fail (especially in the manner that this one did, where an IC lets out the "magic blue smoke") then it was indeed designed by morons.

However - the speaker damage thing is a real possibility; as you can end up sending a nasty high-power transient into a tweeter that just can't handle it. Functionally, it's the same thing as driving the amp into clipping, hard.

Based on the apparent damage; it looks like that op-amp chip developed a short across the power rails. A transient across the output pin usually won't do that - you could very well destroy the ability of the op-amp to produce an undistorted output signal - but making a continuous short between the positive and negative rails is unlikely.

I think you just got unlucky.

BTW - some connections are specifically designed to accommodate hot-plugging: MIDI ports, Ethernet ports; most RS232, RS422, and RS485 ports, USB ports, many (but not all!) VGA ports, headphone jacks, and some PCI slots (typically found in server-grade machines where you want to avoid having to restart the system to replace a failed card) all come to mind. You probably wouldn't find it in serious use today, but the LocalTalk networking system used by classic Macs was also hot-pluggable; but the ADB keyboard & mouse ports weren't - you could fry your ADB chip on the motherboard by plugging in a keyboard or mouse while the Mac was on (fortunately ADB hasn't been a thing since the late '90s - it's all USB or Bluetooth instead).
It's so unusual to blow up an op amp used for line level audio when doing normal 'safe' things that are expected. And connecting a line level output to a line level input while both are on shouldn't cause any issues -- never heard of it happening with correct cables and signals. Two dead devices with one car?

Funny thing-- ADB in some cases IS hot-pluggable in hardware, but MAC OS itself didn't natively support that. There was a 'mouse jolt' application that helped with hot plugging mice. And since you can daisy chain ADB ports, you can physically connect computer>keyboard>computer, which is probably pretty disastrous if they're both on. But, some G3 tower I can't remember which had enough power output on the adb port to backfeed a different g3 power supply(this one being beige) through the motherboard and get the fans spinning when said beige g3 wasn't connected to mains. An old computer with fans that just start spinning when it's dissassembled and supposedly disconnected is quite freaky.
 

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Discussion Starter · #38 ·
I'm not an EE, but I do design stuff as a hobby (professionally I'm a software guy).

I mostly agree with yobbo7 - if hot-plugging a RCA causes a device to fail (especially in the manner that this one did, where an IC lets out the "magic blue smoke") then it was indeed designed by morons.

However - the speaker damage thing is a real possibility; as you can end up sending a nasty high-power transient into a tweeter that just can't handle it. Functionally, it's the same thing as driving the amp into clipping, hard.

Based on the apparent damage; it looks like that op-amp chip developed a short across the power rails. A transient across the output pin usually won't do that - you could very well destroy the ability of the op-amp to produce an undistorted output signal - but making a continuous short between the positive and negative rails is unlikely.

I think you just got unlucky.

BTW - some connections are specifically designed to accommodate hot-plugging: MIDI ports, Ethernet ports; most RS232, RS422, and RS485 ports, USB ports, many (but not all!) VGA ports, headphone jacks, and some PCI slots (typically found in server-grade machines where you want to avoid having to restart the system to replace a failed card) all come to mind. You probably wouldn't find it in serious use today, but the LocalTalk networking system used by classic Macs was also hot-pluggable; but the ADB keyboard & mouse ports weren't - you could fry your ADB chip on the motherboard by plugging in a keyboard or mouse while the Mac was on (fortunately ADB hasn't been a thing since the late '90s - it's all USB or Bluetooth instead).
Here's something I just thought about

Sometimes when I would be doing stuff I would get a little shock if I touched the amp (that was being unplugged when DSP started smoking)

It wasn't always, I attributed it to maybe the clothes I was wearing building up a charge along with cloth seats in the car

If its a problem with the amp not grounded well, the static charge on the amp casing could have traveled into the DSP via the RCA

The op amp that's burnt is a 2ch, looking at the dsp channel A and B look to be run by this chip, and the same rcas were the ones being unplugged when it started smoking...
 

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Discussion Starter · #40 ·
Do you remember if you had a similar situation with the RF dsp? I was also wondering if it could be a problem with the amp?
When the RF gave up it wasn't being handled at all, I had just completed a little EQ session and while cleaning up I heard a pop when I put up the rear seat (where it's mounted)

It still worked after the pop as music continued playing, but it did not turn back on the next day
 
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