Did I damage my active speakers by connecting them to a headphone dac/amp (Hifiman EF499)

[Metala]

Long story short - I bought a Hifiman EF499 dac amp while testing some more demanding headphones. It's already connected to my PC. At the same time I had a sound blaster g6 connected to my activev speakers - a 10 year old edifier R1700BT. So, to avoid having 2 different dacs on my desk I decided to use the superior EF499 for the active speakers as well and connected them using the RCA OUT (not balanced) to the RCA IN on the speakers. They sounded actually great, but a week later the speakers died.

Did I cause it, or was it just time for the R1700BT to go after 10 years of loyal service? A short google returned that I can actually kill active speakers if I connect them to a headphone amp which confused me.

As far as I researched, the EF499, a relatively powerful headphone amp, outputs full power on its RCA OUT. Could this have overwhelmed the old speakers expecting much less input power?

Sorry if stupid question, I plan to buy new active monitors and I don't want to ruin them too.

 

[amirm]

Certainly possible especially if you blew both speakers.

 

[DVDdoug]

CA OUT (not balanced) to the RCA IN on the speakers.

RCA-out to RCA-in (line-level out to line-level in) is correct.

And since headphone-voltage is about the same voltage as line-level, a headphone out usually works for either one. I use the "headphone" output on my laptop for line-in frequently.

The main difference is that headphone outputs are capable of driving the lower impedance of headphones, and the headphone output will always be volume-controlled whereas line-outputs aren't always adjustable.

You should NOT connect a speaker output to a line input! (Although you can often get-away with it if the amp only puts-out a couple of Watts.)

Certainly possible especially if you blew both speakers.

Some quick research says that only one is active and they are wired together.

 

[kemmler3D]

How did the speakers stop working? Were you playing them very loud? Are you sure the speakers are dead and not just the internal amp on the speakers?

 

[Metala]

How did the speakers stop working? Were you playing them very loud? Are you sure the speakers are dead and not just the internal amp on the speakers?

This is a good point.

I was out as it happened. They were left on as usual, because the power button is on the back and quite inconvenient, so most of the time I don't bother turning them off.

As I came back this evening, I noticed I had no sound and saw that the power indicator on them was off even though they were supposed to be on. Of course I tried to turn them off and on again a few times, with no signs of life.

So it makes sense that the electronics are dead and not specifically the speakers. That being said, as it happened a week after I connected them to the 4w amp, could it be related? Google said it can, but I don't understand much of electronics and I want to avoid ruining the next pair.

 

[Metala]

RCA-out to RCA-in (line-level out to line-level in) is correct.

And since headphone-voltage is about the same voltage as line-level, a headphone out usually works for either one. I use the "headphone" output on my laptop for line-in frequently.

The main difference is that headphone outputs are capable of driving the lower impedance of headphones, and the headphone output will always be volume-controlled whereas line-outputs aren't always adjustable.

You should NOT connect a speaker output to a line input! (Although you can often get-away with it if the amp only puts-out a couple of Watts.)


Some quick research says that only one is active and they are wired together.

I used the "single ended" RCA OUTs on the back of the amp. The specs say "THD+N (Line out): : 0.008% (0dB)", I have no idea what this means, but some reviews mentioned it outputs full power on the back that is not volume adjustable.

The active speakers had a RCA to 3mm cable which was previously connected to the G6 3mm line out, so I changed the cable to RCA to RCA so I can connect them to the new dac that only has RCA out and no 3mm jack.

I start to think maybe the electronics gave up after 10 years of service, because the power indicator lamp does not light at all now.

UPDATE: I just checked on the back of the speakers it seems I connected the RCAs to the "PC IN" and not in the "AUX IN". I have no idea what this means, could this be the problem? As I said, the speakers worked fine for more than a week.

 

[kemmler3D]

This is a good point.

I was out as it happened. They were left on as usual, because the power button is on the back and quite inconvenient, so most of the time I don't bother turning them off.

As I came back this evening, I noticed I had no sound and saw that the power indicator on them was off even though they were supposed to be on. Of course I tried to turn them off and on again a few times, with no signs of life.

So it makes sense that the electronics are dead and not specifically the speakers. That being said, as it happened a week after I connected them to the 4w amp, could it be related? Google said it can, but I don't understand much of electronics and I want to avoid ruining the next pair.

It could be related, it's also possible that the power supply in the speakers simply overheated and died, a random capacitor gave up, etc. In this scenario I personally think PSU trouble is more likely than the speakers having been blown up by the headphone amp.

To my knowledge it's hard to use an amp to damage something if it's not even outputting anything...

 

[pablolie]

Don't active speakers have the ability to implement way more protection for drivers? If the drivers don't react to any music at all, something else is going on in the amplification and protection circuitry...
In my limited experience with damaged speakers, they still try to produce some sound...

 

[wwenze]

Things that do damage to all electronics:

- Moving them around (e.g. a dry joint breaks)
- Changing the things you connect them to (maybe worse common-mode noise / spikes)

 

[Metala]

Thanks for the replies.

From what I read, connecting the active speaker via line-in to the line out of a headphone amp should not be the cause for the apparent electrical failure that killed it.
This means it should be generally safe to connect the new speakers to the line-out of the headphone amp.

Correct?

 

[pablolie]

Thanks for the replies.

From what I read, connecting the active speaker via line-in to the line out of a headphone amp should not be the cause for the apparent electrical failure that killed it.
This means it should be generally safe to connect the new speakers to the line-out of the headphone amp.

Correct?

A mismatch in levels could still cause damage. If your preamp (headphone amd *and* preamp via RCA) is pumping out maximum voltage and your active speakers are at max volume, obliteration might still happen. Many moons ago, I had to temporarily move for work, and I set up a simple system with AudioEngine A5 (active speakers) and a Squeezebox Classic acting as preamp. One day, during a thunderstorm, the Squeezebox went crazy and pumped out max volume. I was *just* in time to prevent major damage, and luckily the speaker volume wasn't turned too high.

 

[Metala]

A mismatch in levels could still cause damage. If your preamp (headphone) is pumping out maximum voltage and your active speakers are at max volume, obliteration might still happen. Many moons ago, I had to temporarily move for work, and I set up a simple system with AudioEngine A5 (active speakers) and a Squeezebox Classic acting as preamp. One day, during a thunderstorm, the Squeezebox went crazy and pumped out max volume. I was *just* in time to prevent major damage, and luckily the speaker volume wasn't turned too high.

I am not connecting it to the headphone out but to the line out on the back of the amp.
The line-out of the EF499 is fixed volume and can't be adjusted.

 

[Metala]

I feel a bit stupid now, but the problem got suddenly resolved by itself.

I disconnected the RCAs from the edifiers so I can remove them from my desktop but got distracted and left them as is while not connected to the amp.
30 minutes later I saw the power led was suddenly on again. I connected the RCA to the LINE IN and they work again...

As I mentioned in a previous comment, it turned out I connected them initially to the PC IN ports and not in the LINE IN on the edifier (both RCA inputs next to each other) and even though they worked for a week, maybe in time in triggered some protection.

Removing the RCA cables for some minutes resurrected them...