[Oya?]

Hi DIYers (this seems to be the most appropriate section for my problem),

I've been using an HDAM module in my DAC, and it gets very warm during use, enough so to be felt through the chassis lid. There's these hot spots in the back of the PCBs that's hot enough to burn to the touch. It's hotter on one side of the module than the other. I'm wondering if one of the components in it have shorted, but it looks difficult to test without dismantling. Sound-wise I can't hear anything wrong with it when I compare it to my OPA627s.

From my reading I understand that the HDAM should only be somewhat warm. Is this something to be worried about? Any advice would be greatly appreciated.

I've also removed the coverings that came soldered onto the module. It's now bare like you'd see on pics online. I noticed they were copper; could they have acted as heatsinks?

Thanks very much for your time.

 

[Pars]

Pics would help, but yes if they were copper or metal, they could have been providing some heatsinking.

 

[Oya?]

This is how it looked originally:



The black panels around the side came painted but are bare copper on the inverse, and they were soldered onto the PCB.



This is what it looks like now. Thinking about it now, the HDAM ran quite warm even with the panels but I only became concerned about the heat after I took them off. Maybe they did help to control the heat.

I've crudely alleviated the heat issue by repositioning the module under the chassis vents, but it still runs hot and I'd like to get a better solution. Could you think of how I could go about heatsinking it?

 

[error401]

I don't think they should be getting very hot. It's only supposed to be drawing 25mA per module (per the specsheet), at I assume +/-12V. P=IV, so P = 600mW per module. That's really not that much, I can see it feeling warm, but not burning you. I suspect something is wrong with the module.

 

[Oya?]

Quote:

Originally Posted by error401 /img/forum/go_quote.gif I don't think they should be getting very hot. It's only supposed to be drawing 25mA per module (per the specsheet), at I assume +/-12V. P=IV, so P = 600mW per module. That's really not that much, I can see it feeling warm, but not burning you. I suspect something is wrong with the module.

It's certainly warm enough that I can feel the heat rising through the chassis vents. After an hour or two of use the chassis becomes very hot. While it's admittedly quite pleasant (it's winter here at the moment), something's just bound to go up in flames so I'm gonna use a regular op-amp in the meantime.

Do you think it possible that the HDAM's components might fail here and there and still function normally sound-wise? I'm not sure how the nature of its construction holds up; IC op-amps seem a lot more obvious when they fail.

 

[error401]

Quote:

Originally Posted by Oya? /img/forum/go_quote.gif It's certainly warm enough that I can feel the heat rising through the chassis vents. After an hour or two of use the chassis becomes very hot. While it's admittedly quite pleasant (it's winter here at the moment), something's just bound to go up in flames so I'm gonna use a regular op-amp in the meantime. Do you think it possible that the HDAM's components might fail here and there and still function normally sound-wise? I'm not sure how the nature of its construction holds up; IC op-amps seem a lot more obvious when they fail.

I'm really not too sure. If the chassis is vented, I don't think 600mW, or even 1W would be enough to cause a significant long-term temperature increase. If it's working fine, perhaps some sort of bias adjustment has gotten out of whack? I'm not sure how the circuit is set up...

Burson seem to offer a lifetime warranty on them, I would really recommend contacting them, they will be able to tell you with a fair degree of certainty whether there is something wrong, and they're the ones you'll need to contact if there's a problem anyway.

 

[persivore]

Its possible the module could be oscillating due to the long length of wire between the main PCB and the opamp.
Is it possible to plug the module directly into the PCB, or is there not enough room for it to fit?

 

[Pars]

That's a good thought regarding the possibility of oscillation. If possible, you might try measuring the current draw of the HDAM and see if it is above spec.

Also, you mentioned that the panels you removed were soldered to the PCB? Probably soldered to a ground plane for shielding.

 

[Oya?]

Thank you for the replies; regarding oscillation, I'm a bit DIY-challenged but I'll look into measuring the values. I can plug it straight into the socket standing upright if I remove the chassis but IIRC it runs quite hot as well; I will give it another run.

The module isn't Burson branded, but a Chinese OEM.