2. amps-preamps
  3. 130040-84541

Oh man, I broke my class D amp. Make fun of me. Then help.

So... I made a new pair of super fancy interconnects this evening. Of course I was on auto pilot on the second one, especially the last connector. And, of course I always test my DIY cable projects before install..

Except tonight. Installed the ICs and all I hear is clicking. Not loud, and independent of the volume on the pre. Independent of source. Weird. I shut everything down and figure maybe, for the first time ever, I miswired a cable, so I pulled the new ICs and tested. Sure enough, I crossed my signal and ground. I repaired my mistake, reinstalled and now the amp the crossed IC went to is jacked.

The volume is much lower than the other channel, there is distortion during strong high frequency signals and the sound drops out during strong low frequencies signals. The other amp is fine. I swapped channels coming from the pre and the problem stayed with the amp. I doubt it is the speaker, as there were no sudden loud noises. Just the innocuous clicking...

So, what did I fry? Some kind of capacitor? Or everything? The amp is a Ghent audio monoblock, which is class D and uses ICEpower a/s modules. It is a GA-M500. Here’s its webpage: https://www.ghentaudio.com/amp/ga-m500p.html

I’m fine sending it in for repair, but if anyone has either knowledge of amp design or the unfortunate luck to have done this, I’d love to just fix it myself and save a lot of sending it around the world. Also, feel free to make fun of me. I deserve it. Such are the consequences of hubris.

If you’re wondering, I used KLEI pure harmony connectors, which have two identical looking tabs, one on each side, to solder the signal and ground to. If you look even remotely closely you can easily tell which is the ground.. but it’s not at bad as if I had done this with a more traditional RCA connector. That would have been really pathetic. 

Also. Recommendations for repair shops please.

Ugh.

128x128toddverrone

Showing 9 responses by toddverrone

toddverrone's avatar
toddverrone OP
838 posts
 
Thanks guys! I'm going to see if I can get a replacement board first. If not I'll just order a new pair.  They're going for $1100 for a pair. I could buy one for $600, but they changed the design, so they wouldn't be exactly the same. I'm far too OCD for that.
 Tim, those boards look nice.. how plug and play are they?
toddverrone's avatar
toddverrone OP
838 posts
 
Wow, thanks everyone. Good to know I’m not alone! Yesterday I did the best thing one can do after screwing up royally: I took my kids and their friends to a beautiful Ozark swimming hole and we spent 9 hours basking in beauty and playing in a waterfall.. ahhh.

@atmasphere I did try different Interconnects ​and had the same problem. I’m sure the one I built is good now. I fixed the switched connection and TESTED THE DAMNED THING FOR CONTINUITY!

@spatialking I don’t see why a weak voltage like a signal would screw anything up, but it has. Like I said above, I tried other sources and different cables, moved the amp.. it’s the amp for sure. And man, yeah, shorting an amp in that fashion seems much more exciting and dramatic!

@asvjerry those poor fish...

Greg - the clicking was only there when I had the faulty IC connected. Then it just sounded like garbage and eventually stopped working most of the time. The problem I have is that the B&O module used in my amps isn’t made anymore. The only one I’ve seen is on eBay for $900!

On a positive note, my wife, the breadwinner, just said "buy some new ones". Also, a friend who works with class D amps in an industrial setting told me that he and his electronics guy could fix it. I was dubious, but he’s insistent, so we’ll see.

And, to and a big fat twist, I came home from the climbing gym last night to find my wife still awake, looking through my eldest son’s phone. She found all kinds of interactions with racist, white supremacist scum on social media and some porn. It’s going to be a long summer.. and it definitely put a broken amp into perspective, in terms of the crap I’m going to have to fix.. teenagers. Jeez.



toddverrone's avatar
toddverrone OP
838 posts
 
That was great, Jerry. I actually chuckled out loud!
toddverrone's avatar
toddverrone OP
838 posts
 
Jerry - that's good to hear. Your wife sounds like a good one too. Patience and understanding in a marriage are rare, one thing I love about the people on here is they recognize that. I've been on far too many forums where there's plenty of denigration of spouses who get in the way of the hobby. That's the wrong perspective.

As for the porn, I'm not worried about that, but we did talk about the difference between 'healthy' porn, where it looks like everyone is enjoying themselves, are not drugged and have real bodies, vs the rest. The racist stuff comes from us living in a bubble here in NW Arkansas, where he doesn't see its consequences. So he thinks it's absurd and funny. Now I've got him reading Roots. That should help bring some perspective..

@atmasphere I think I tried different sources, but now I can't remember. I'll try again after I put the amp back together. Thanks for the insights!
toddverrone's avatar
toddverrone OP
838 posts
 
Also profound, on second reading..

A miraculous thing has happened. After unplugging and reseating all the connectors to the board then taking out the fuse, checking it for continuity and reinstalling it, I hooked up the amp to double check I didn’t have a brain fart when I was trouble shooting the first time. Lo and behold! It works!

Sounds as good as the day I got it. No more sound cutting out, no more distortion. What the dickens?

@atmasphere thanks for questioning my trouble shooting! I went back and re-read what I wrote. I did swap RCAs, it stayed with the amp, not the signal. But, just to be sure after reading your post, I thought I’d double check. Vielen dank!

Final result is a resurrection! Hallelujah!
The new, repaired and double tested ICs sound great as well. A pretty solid Wednesday night!

Thank you for all the input and stories of fellow stupidity. Shared suffering...
toddverrone's avatar
toddverrone OP
838 posts
 
Happy to have provided some comic relief. Especially with the outcome!

Happy Friday everyone.
toddverrone's avatar
toddverrone OP
838 posts
 
Bonzo Dog Dooda Band. What a name. The music, despite a silly edge, is actually quite amazing!
toddverrone's avatar
toddverrone OP
838 posts
 
I love how your posts read like screen plays.
toddverrone's avatar
toddverrone OP
838 posts
 
@boneman73 it's funny you should mention openDNS. I just finished setting it up on our network today. As far as phones, I'm trying a nanny app that I still need to dial in..

As for power, I built a power box that I also installed TMOVs in for surge suppression. Next one will have cascade diodes. The storms we've had this spring had so much lightning. It was enough of an impetus to get me to install the whole house surge suppressor I'd been meaning to for at least a year. Next I need to install a service entrance suppressor and I should be as safe as possible. I also have filters plugged into the outlets my washing machine and fridge are on.

And I also unplug during storms. Unless I'm listening. It is fun to watch...
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