Time to consult the hive mind again.
I have an Eltax Atomic A-10 sub which works fine.
For the last year I have been using it with the AMP power switch set to the AUTO setting (OFF/AUTO/ON) and this has worked ok until I recently noticed it now stays on permanently, not automatically going into standby after a period of no bass input.
I have completely isolated it to test, other than mains input and found the following:
The AMP power switch works ok in the OFF/ON setting but in AUTO it powers up in a second (LED goes from red to green and faint hum audible).
With the switch in the OFF position I can isolate the mains by pulling the power lead or switching the transformer power switch to OFF and there will be a while before the capacitors discharge and the LED dies. Now in that time if I switch the power switch to AUTO it still switches on (red LED turns green before fading out).
I would say then, that without audio input and mains connected to eliminate noise, this would indicate a circuit failure of some kind.
Better on than off I suppose, however if I could fix it I would.
I have the schematics... somewhere, just needing a little point in the right direction to look.
Any help would be appreciated.
I have an Eltax Atomic A-10 sub which works fine.
For the last year I have been using it with the AMP power switch set to the AUTO setting (OFF/AUTO/ON) and this has worked ok until I recently noticed it now stays on permanently, not automatically going into standby after a period of no bass input.
I have completely isolated it to test, other than mains input and found the following:
The AMP power switch works ok in the OFF/ON setting but in AUTO it powers up in a second (LED goes from red to green and faint hum audible).
With the switch in the OFF position I can isolate the mains by pulling the power lead or switching the transformer power switch to OFF and there will be a while before the capacitors discharge and the LED dies. Now in that time if I switch the power switch to AUTO it still switches on (red LED turns green before fading out).
I would say then, that without audio input and mains connected to eliminate noise, this would indicate a circuit failure of some kind.
Better on than off I suppose, however if I could fix it I would.
I have the schematics... somewhere, just needing a little point in the right direction to look.
Any help would be appreciated.
You r right, looks like something is dead inside of your sub. If you'll post the schematics, I can take a look for a reason of the failure.
PS: Actually, to manage auto On/Off function properly ( 100% stealthy, no noticeable delay for tuning On, no permanent On, no On/Off cycling etc), a sub system need something more than just a comparator with fixed threshold. Just by reading your post, I got an idea, how to improve On/Off detector! System may perform a calibration of silence and set up the threshold according to particular room EM noise environment. Probably not bad idea would add a notch filter (-6db is enough) before the comparator, 50Hz or 60Hz for Europe or USA 😉
PS: Actually, to manage auto On/Off function properly ( 100% stealthy, no noticeable delay for tuning On, no permanent On, no On/Off cycling etc), a sub system need something more than just a comparator with fixed threshold. Just by reading your post, I got an idea, how to improve On/Off detector! System may perform a calibration of silence and set up the threshold according to particular room EM noise environment. Probably not bad idea would add a notch filter (-6db is enough) before the comparator, 50Hz or 60Hz for Europe or USA 😉
Thanks, the service manual can be downloaded here:
https://elektrotanya.com/eltax_atomic_a-10_subwoofer.pdf/download.html
I'm fine checking and replacing components, just need assistance on where to look for issues.
https://elektrotanya.com/eltax_atomic_a-10_subwoofer.pdf/download.html
I'm fine checking and replacing components, just need assistance on where to look for issues.
MicMac2, no problem. All are on the 1st page, and I see no reason to be dead for the parts related to auto On/Off function. However, I see that function is poorly designed yet. The problem is the full DC pass there, hence opamps DC ofsets are affecting the final threshold - it is very unreliable. Quite possible if all parts are ok but DC drift slightly up for some reason, and function is stopped working for now. I did some simulation for you with tl072ac, please take a look for all [V] nodes, and compare with your sub. As well check the +/-12V rails symmetry.
Attachments
Thanks for the effort.
With schematic downloaded, screwdriver and DMM on standby I noticed that the power led was showing red in the AUTO position. Something I hadn't seen for a while.
I'm going to leave it be for now and watch it carefully over time.
Could some RF interference have caused it to activate?
Bear in mind it even did this completely disconnected and only using the power stored in its capacitors.
If so it's source is external to my house.
With schematic downloaded, screwdriver and DMM on standby I noticed that the power led was showing red in the AUTO position. Something I hadn't seen for a while.
I'm going to leave it be for now and watch it carefully over time.
Could some RF interference have caused it to activate?
Bear in mind it even did this completely disconnected and only using the power stored in its capacitors.
If so it's source is external to my house.
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