Axiom Home Page Forums General Discussion Technical Questions ADA1250-3 : Right Chanel Drops Out

I have a 7.2.4 setup (Yami 3070 + ADA1250-3 on 12-volt trigger for the front 3 Channels) to an all Axiom Speaker setup. My main Front Right Speaker started to drop in and out during playback, almost like there was a loose wire. Anyway, after duly wobbling connections (which did not help), I powered the ADA1250-3 off/on (at the back switch) and the issue disappeared (at least for now).

Anyone come across this before? I've (in the past) had similar issues with the Subs but that was a long time ago.

Thanks
Nathan

Are you sure the self-protection wasn't engaging? We're you listening "loud"?

Nope - not loud and only FR was impacted, not FL or C

The self-protection works on a per channel basis. So if there's a loud drum that exceeds "spec" on one channel but not others, the protection for that channel will activate.

Now you say it wasn't loud but you may have been listening to a dynamic piece that took the signal say 22dB above nominal that activated the protection.

That protection by the way is very transient. If it was stuck off and you could only clear it via the power switch, there's something else going on. FWIW, when the protection kicks in on my Pioneer, I have to cycle the power. Maybe there are certain conditions that activate that same kind of behavior on the ADA. Or maybe you have an older ADA and the protection on the new ones behaves differently than yours.

I'm about to watch another set of GOT with the setup (trying to get through it all again before the next instalment drops). It is was only the FR, not the C, not the FL. It would drop in and out all movie. Sometimes it would be fine for some time but then it would cut in and out consistently. Lets see how it goes tonight.

OK - so no issue tonight.

Hi Nathan,

Any number of things could be causing the dropout. The most obvious one would be a small short in the speaker connections for that channel, but I'm assuming you have checked them carefully at both ends. There are two protection mechanisms in our amplifiers, one is over-current and is provided internally in the Class-D audio controller IC and the second, external mechanism handles high/low input voltages, DC offset, and thermal. In some conditions the external protection can latch and requires powering the amplifier off and on again to reset. I'm not sure how long you've had your ADA1250, but if it has been for a number of years I would suggest purchasing a can of compressed air (available at most electronics or computer stores), removing the top of your amplifier after it has been unplugged for at least 30 minutes, and spraying the tops of the amplifier modules closest to the rear panel to clear off any dust or debris. Believe it or not, we have had a few circumstances where a thick layer of dust or dead bug has caused an intermittent short, and at high switching frequencies it does not take much.

Thanks,

Andrew

Nathan, do you not have a bug screen installed over the ADA vent slots? Axiom should include that as an option for warmer climates.

On top of Andrews great advice, coming from a recent PC build, you can always use a hair dryer on cold, as it will create more volume and last much longer than compressed air.

I use a small tooth brush and lightly scrub as i use the compressed air or hair dryer.

Be careful with a hair dryer. The air right at the nozzle can still be quite hot. I'd also be concerned about static as those air molecules are hot and dry and brush up against the plastic nozzle. It could work but it's risky.

Thanks for all the advice. My current plan is to see if it reoccurs after the power cycle. If it does I'll them try the above suggestions as the ADA is hard to get to as it is shelf mounted a couple of meters above the floor and awkward to get to. The ADA has been in use for about 18months and continually powered (minus any power offs of the circuit when electrical work has been done).

I wonder if a low voltage condition can latch the protection.

I wonder if a low voltage condition can latch the protection.

Another thought would be to ensure your preamp is not the issue. If you notice this again, you could swap left and right channels from the preamp to amp and continue to listen.

If it is the amp it will continue to occur on the right. If it moves to the left it would be something in the preamp/connection.

Granted this is a long shot....but could help you isolate.

FYI - Still going strong without issue. I'll call it case closed (for now)

Nope - happened again & power cycling it fixed it. Will have to find time to drag it out and open it up ....

Unplug it and let it stand for an hour before you put your mitts in it and fry yourself on the beefy caps!

Chicken! My plan was to open it up and test it like a 9-Volt battery with my tongue.

Stick your wedding tackle in there mate, and have a bit of a party, eh?

I really need to pull my thumb out and see what is up. Still just unplugging it when the issue occurs. Sorry for the delay but it's normally on "Movie Night" and I just power cycle it and then it is all good (for a bit). If it is a bug I had hoped it was a crispy dried critter by now!

The three ADAs I have are all rock solid. Sure I've driven them all hard to the point where the protection has kicked in but that's to be expected. I've never had to "re-boot" them though.

BTW, I couldn't activate the protection on the 1500 by normal means. It wasn't until I connected two M5s in parallel per channel that the impedance dipped down to 2 Ohms and kicked on the protection. By that time, I was experiencing 112dB peaks at 13 feet away so I'd say that's pretty darned good.

I finally got the ladder, removed the 1 billion screws on the top of the ADA, Spayed Canned Air all over it then reversed the process. There was a layer of fine dust but that was all. Everything else looked brand new.

As before the unit then played fine but after some time the RHC would start dropping out again. These are brief drop outs....

Edit - I swap around a few items (speakers, cables etc) and see if the issue moves or disappears. I hate intermittent things like this.

Swapping speakers did not make a difference.

But I did notice when not playing anything (and increasing the Vol to 0DB), there was a faint and constant background hiss if you put your ear near the speakers... but on the Right Speaker this hiss would be interrupted by a faint Tick Tick Tick ... then silence (drop out) then would return to the hiss and after some time the cycle would repeat.

Listening to it longer, it is mostly Hiss --> Tick --> Silence --> Hiss (but on a variable time interval between Ticks and how long the Silence is).

Also - I can rule out the source (into the AVR) as it happens across all sources.

The ticking sound is the protection kicking in. The root cause of that is unknown.

The hiss is normal. It's a combination of noise in your environment and noise induced by the circuits within the ADA. To know how much of that noise is ADA-induced, you'd have to connect each ADA input to a noise-free ground with a short, shielded cable.

OK - I get the "Hiss --> Tick --> Silence --> Hiss" on the RH channel even when everything is OFF with the exception of the Amp.

The hiss is still normal even when everything is off (except the amp). It appears the tick is due to a fault inside the amp. I'm assuming you've checked the speaker wires and don't have a strand shorting somewhere. Try removing the speaker cables at the amp to see if the ticking stops.

I'm fine with and understand the Hiss. It is well below the soundfloor at normal seating distance.

It's the drops outs.

I'm not sure I get your suggestion. If I remove the speaker cables I will have no idea if it is still dropping out ... as at that point I will not hear anything at all as the speaker will not be connected! I'll check the speaker connections again to double check (they are hard to see, so you never know).

But, I'm now worried I've got a cap going bad in the ADA.

No change after fiddling with cables. Still get the issue. If anything it is become more frequent over time.

Well - that's about it for the next week (travelling).

Dude, send it to Axiom for an exorcism and take a Fukitol pill to chill.

Agree your best bet is send it back to Axiom. They'll know what to do.

I've had my ADA1250 3 channel for 2 years with no issues.

Have you tried another RCA/XLR or swapped the ones your using currently. Could be the cable to connector short {bent cable}.

Yeah thanks - I've sent an e-mail to Axiom for any other suggestions as well before I RMA.... it as it is a long way from Oz to Canada for a big heavy box Whats the bet it is just a 10cent cap on one of the boards?

10 cent caps vaporize when you play that Aussie devil-worship music.

I have one of the newer computer speakers that have the amp built inside the M3 speakers. It had a problem that it would intermittently cut out. I thought it was a bad power supply but sent it back to Axiom. They rebuilt the whole amp inside the unit and now it just rocks.

They don't mess about at Axiom with the repairs. Likely an intermittent fault like that will cost more to spend source diagnosing rather than just rebuild the amp board.

So - I pulled the amp out, took photos and sent them to Andrew (all looked fine), shook out some crap (bits of what looked like thin bits of solder), jiggled all the cables, swapped my input/output cables when putting it back..... and so far it has been perfect. Only been playing the radio so far and not drop outs. Next test is Aussie devil-worship music (ABBA) so cross fingers it is all good!