Breathe Audio Elevate BA-2430 whole house amp problem

[bluto]

I got this to work on from a friend. It is a 4 zone, 2 source whole house amp with keypads in each zone. The problem description was static on all sources in all zones. I surmised that the problem was a bad audio filtering cap. Upon cracking the cover I found over 50 10uf 50v caps. No other values which is weird. I checked them with my cap analyzer and found on really dodgy one that was a different brand then all the rest. I replaced it and 4 others near the input stage.

Now I go to test it. Well there is no static but a new problem. A hum on all zones/channels. It sounds sort of like a 60hz hum. So I double check all my work, even pulled the caps I did one at a time to try to get it to stop. No luck, so I look next to the power supply. It is linear with a large center tapped transformer. I shotgunned the 4 small caps on there just for the hell of it. No change. So now I try to use my thinking cap and attempt to determine if there is some sort of hum originating at the power supply. I pull out my scope meter which I am good at turning on and not much else.

So eventually I figure out the right button to press and I am off probing voltages. The supply puts out +25v, -25v and +12v. See the pictures, but I think the -25v has a 120hz ripple on it which could be the source of the hum. Its a little strange because the voltage was lower (-18v) probing just the power supply with the connection to the amp removed (pic 2&3). With everything in place for the amp to work I got the proper -25v (pic 4&5). Both however show a 120hz ripple. The +25 and +12 rails were normal. What causes this? One of the filter caps going bad maybe? They look like high quality items (Topcon!).


TLDR: I have a 120hz hum on a whole house audio amp. I have isolated it to the -25v rail. Any suggestions on how to fix this are most welcome.

[mariushm]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

One of the large capacitors filters the +25v and another filters the -25v ... the one for -25v is probably going bad.
Try swapping the main capacitors around... if the problem moves to the other 25v ... you have the solution.

[kc8adu]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

just replace both.
i see you have an esr meter.
compare the 2.
the scopemeter just told you the one on the - supply is shot.

[bluto]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

I have a capanalyzer which I don't yet fully comprehend. I pulled both caps. Tested the first one and it fails with the DCR (DC resistance) low alarm. The second one doesn't react at all on the capanalyzer. I am not sure what to make of those results. Both read in excess of 10,000uf capacitance on my DVM (Out of range - 10,000 is its limit). But I know not trust that measurement as proof that they still work. So now I am off to order 2 new caps from DigiKey! I'll report back with my results.

edit: I will add that the one that didn't react seems a little bulged on top as compared to the other one.

[budm]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

If you have good Fluke True RMS meter, you can check the AC ripple voltage on those two filter caps, it should not be more than 5% of the DC reading.

[Th3_uN1Qu3]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

Well, the scope already showed him what he needs to know - the cap on the -25v rail is bad.

[kc8adu]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

yep open.that scopmeter is a damm handy tool.
i use mine a lot.

Well, the scope already showed him what he needs to know - the cap on the -25v rail is bad.

[retiredcaps]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

One retiredcaps' bonus point to bluto for a picture of your Fluke scope.

I now totally regret not acting faster when a Fluke handheld scope showed up on my local kijiji ad for $100 (MSRP was $1000). I decided to do some research first before buying!

I could have easily resold it for much more.

[bluto]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

Success! Another one saved from the dumpster. The two new filter caps did the trick. So if anyone else has hum or static on your amp on all sources and in all zones, just order yourself up 2 ea of the filter caps (P/N P6917-ND) from digikey.com and you will be back rocking out in no time at all. Thanks for all the helpful replies too!

[kaboom]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

Its a little strange because the voltage was lower (-18v) probing just the power supply with the connection to the amp removed (pic 2&3).

No capacitance! You were reading pulsating DC.

With everything in place for the amp to work I got the proper -25v (pic 4&5)

Not really. The voltage appeared to come up, since there are some smaller caps on the amp board that were vainly trying to hold the voltage up. But still no filtering, hence ripple and buzz. Just a 'gotcha' to beware of- as you've seen, it can mislead you. The scopemeter sure didn't, though!


Glad to hear you fixed it! I'll bet it "thumps" its cover when you hit the power switch- there's a nice transformer in there!

[bluto]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

That makes a lot of sense. Thanks for the insight. I guess this one goes against the caveat of 'leave the big filter cap alone' that we have when working on switch mode power supplies.

[Longbow]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

I got this to work on from a friend. It is a 4 zone, 2 source whole house amp with keypads in each zone. The problem description was static on all sources in all zones.

The interesting part of this repair is getting an accurate problem description. Was the hissing reported by the owner, or actually heard by the OP? It sounded like there was a new problem once the hissing noise was fixed. But I'm sure that the original symptom was hissing AND hum.

[rroach]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

The interesting part of this repair is getting an accurate problem description. Was the hissing reported by the owner, or actually heard by the OP? It sounded like there was a new problem once the hissing noise was fixed. But I'm sure that the original symptom was hissing AND hum.

You guys appear to be pretty good on the Breathe Audio equip...I'm not very technical but have a problem. I have 3 2430s running in my home covering 3 zones...nicely wired.

Anyway...lightening strike and I have nothing functioning...all lights are on but nobody is home. I borrowed a friends unit, plugged it in and it works...

Where should I look to solve this problem or should I replace them?

Ray in Brantford Ontario
ray@cwxedi.com

[bluto]

Re: Breathe Audio Elevate BA-2430 whole house amp problem

So you are saying that the zone lights on the front all come on, but no response at the keypads? I would start by taking it apart and posting pictures. Someone here may be able to spot something amiss. I would start by probing all the voltages and maybe pull the data sheet on the control ICs at the back of the bottom board. No response to the keypads could indicate one of those is toast. They could be proprietary parts though.