2. amps-preamps
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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
kdude66
1,200 posts
 
Todd,

Very nice muck up.

Class d amps don't have protection circuits like other amps,usually only have 1 fuse in the pwr supply.You might look at that other wise you probably will have to replace the module or send it in.

If I remember Ghent audio is in China,you might be able to get a replacement module sent to you.

Good luck to you,

Kenny.
timlub
2,040 posts
 
Todd,   I believe those Ghent amps are fairly expensive these days.  If you find that it is truly shot,  I might recommend these... Very nice sounding modules,  I believe that they'll fit in the Ghent cases... 150 to 8 and 300 to 4.  Good luck,  Tim 

http://www.ebay.com/itm/Abletec-Anaview-ALC-0300-1300-B-330W-Mono-Amplifier-DIY-/172703831462?hash=i...

toddverrone's avatar
toddverrone OP
840 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?
kdude66
1,200 posts
 
Todd,

You might look into the Ncore nc400 modules and pwr supply.

I have a pair in nice black Ghent audio cases that I would probably sale,don't really use them other than comparison to other class d amps.


Kenny.
timlub
2,040 posts
 
Hi Todd,  I bought these from an Abletec distributor in the UK.  I paid more than this. I believe someone bought up the last of the inventory.  I have built with these and oddly enough, just reinserted them back into my system a couple of days ago.  I immediately smiled,  there is a rightness about these.  Patrick Bostrom did these after the original Ice Modules.  I do find these better.  I built them side by side and put them in a stereo case.  I have them wired for single ended or balanced and have run them in both configurations without issue. As long as the boards fit into your case,  you should knock these out in an hour or so. 
Good luck, either way. Tim
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