[ablaze]

recently I had one driver of my Sony CD3Ks die on me. distorted and very much reduced in volume. and these cans are barely 2 months old only. so I'm trying to figure out what went wrong.

I've had suggestions that my amp: X-can V2 (also very new, approx a month old) could be the culprit? Could it be? I'm don't play my music loud, and my cans are plugged in to the amp all the time. even when I'm turning the amp off and on (does that make a difference?) I AM using a custom power supply for it (5A max, 11v output measured with a multimeter. for comparison the stock psu is 12v AC, I think 1A max) could that have somehow caused a voltage surge or something, frying the cans? (but from what I read, the X-can regulates the voltage fed into it)

Honestly, I've no idea what went wrong. The X-can and the CD3Ks were fine all this while, no distortion, no strange "symptoms" nothing, then suddenly one of the driver fails. I'd love to hear any thoughts and suggestions you guys may have. thanks in advance.

 

[antness]

If you have a multimeter, you should check the DC voltage from the left and right outputs to ground. It should be only a few millivolts.

 

[ablaze]

how should I do this? I'll need a male-to-male 1/4" TRS adapter and plug it into the headphone out of the X-cans to measure, is that right?

 

[antness]

That should work.

 

[ablaze]

thanks antness.

if its not the amp, what else might it be?

 

[ablaze]

antness, did you mean AC voltage there instead of DC voltage? isn't music an AC waveform?

 

[Northern Oak]

He is asking you to measure the DC offset voltage, I guess and I think he's talking about the amp, right?

 

[Hirsch]

Do you have any other source that can handle headphones? Even the output of a pcdp would do (preferable not the same source you're using with the X-Can).

First step: Try the headphones with another amp, or headphone jack. If the sound is attenuated still, then you need to look at a headphone repair. If the sound of the headphones is normal, then you take a look at the amp, and maybe the source.

Then hook up the X-Can again, but from your source hook right channel to left and vice versa. Is the problem on the same side or does it change? This will let you localize the problem to the amp or source.

In my X-Can, when I had it, the stock tubes measured poorly, and it wouldn't shock me if one died a premature death. So, if the headphone is OK, the next step would be to change the tubes, and see if the attenuation is in the same channel. If changing the tubes changes the affected channel, you need a new tube(s).

 

[ablaze]

Hi Hirsch, thanks for the advice, but the problem has been found to be with the cans ie. they're currently being repaired at the Sony service centre.

My question is, what might have caused them to fail? tested the amp, there's no DC leakage. what else could it be?

 

[shard]

I am also using a custom PSU with my X-Can V2, what I found with my PSU is that when I turn it on, my headphones pop very loudly. I never noticed it before until I put on my headphones before I turned on my PSU. Lets just say that my listening hobby could have ended right there. This cannot be good for the headphones and if I had not caught it early I am sure my headphones would have blown eventually.

I have spoken to the person who built my PSU and he admits that he should probably have added a capacitor somewhere so that the initial power up does not cause such an effect. Bringing my PSU back to get that fixed.

Do you have the same problem with your custom PSU? If so, that could be the problem.

 

[ablaze]

Yes, it pops, but I never thought too much about it cos I believe others have reported it, even with the stock psu I think. BUT you make a good point, I think I'll be unplugging my headphones before turning it off or on from now on.

 

[TravelLite]

Quote:

Originally posted by ablaze ...I think I'll be unplugging my headphones before turning it off or on from now on.

Good idea. Or perhaps turn the volume down.

Personally, I happen to think it's generally a good practice to turn the volume pot to zero, i.e., completely counter-clockwise, even before power-up and power-down.

As a side note, all HeadRoom's amps from the AirHead to the Max carry the following generic advisory:


Quote:

We recommend turning the amp OFF or ALL THE WAY DOWN before plugging in or unplugging your headphones to avoid short-circuiting the amp.

TravelLite

 

[PinkFloyd]

Hi Ablaze,

Never power up or power down with the headphones connected as the X-Can sure does make some funny noises during both stages.

On power up mine makes a kinda "thump" sound and on power down it makes a type of sucking mouth organ sound. These noises are not enough to blow a driver unless you maybe power up with the headphones connected and the volume control turned up?

If I am turning any amplifier on or off I always turn the volume control down first... it's standard practice. I remember when I had been working on my little B-Tech amp and was refitting the volume knob, I had turned the pot to the maximum position to align the knob but forgot to turn it back to the minimum position. I switched the amp on, connected the headphones and then hit "play" on the CD player and was almost deafened! The headphones survived though.

There is every possibility that you got a faulty pair of headphones (these things happen) and it wasn't the amp that caused it but to be absolutely certain I would recommend that you always turn down the volume and remove the phones before switching off and always turn the amp on before connecting the headphones. You'll soon get used to the procedure and it will become second nature.

Hope this has helped.

Pinkie.

 

[ablaze]

thanks guys (and thanks pinkie for responding so quickly

). all points noted. *mental note taken*

ok, just one question, tube amps are supposed to have a load all the time right (why, I'm not sure). so which is worse: leaving the amp unloaded whilst powering up/down, or leaving the headphones in, and potentially damaging the cans?

 

[PinkFloyd]

Quote:

Originally posted by ablaze thanks guys (and thanks pinkie for responding so quickly ). all points noted. *mental note taken* ok, just one question, tube amps are supposed to have a load all the time right (why, I'm not sure). so which is worse: leaving the amp unloaded whilst powering up/down, or leaving the headphones in, and potentially damaging the cans?

Best solution would be to leave the amp on all the time.

The X-Can V2 is "not" a tube amp so don't worry about load as it doesn't apply the X-Can V2 which is a hybrid design and strictly not a "valve" amplifier.

If you have to switch it off then remove the phones first.

Mike.