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I think I just smoked my Amp

Ummm… yeah… what the title says…

Just received a new pair of speakers, Thiel MCS1. I got them hooked up, powered up my pre and my amp, started playing a test track (a progressive house song), I immediately noticed a slight crackle in the right channel, and as soon as the song got to the part where the bass beat dropped, the amp went into protect mode. It stayed in protect for about five seconds, then the “operate” light came back on, but the audio did not return. I powered the amp down, tried powering back up, but the protect light immediately returned, but it was extremely dim. Now, the power switch does nothing; nothing lights up. I smelled the vents in the top, and nothing smelled burnt or out of the ordinary.

My uneducated guess is that the lower impedance (4ohm nominal, 3ohm minimum), strained an aging cap which then gave up the ghost, but really I have no idea. My previous speakers were a much easier load (10ohm) and the amp handled them just fine.

 

I really don’t know what to do now, but I’m bloody devastated.

My system: 

ARC LS25 MKII

ARC D400

SMSL M400

Auralic Aries

rfnoise
rfnoise OP
153 posts
 

Thanks to everyone who took the time to respond. The status of my D400 remains unchanged. Visual inspection didn’t reveal any possibility of shorted speaker cables.

I spent most of the day driving to retrieve my CODA amplifier from storage; maybe I should store my things closer to where I actually live 😐

I’m going to figure out how to open the case, and run down those fuses.

@bigkidz I appreciate the offer, but am located in Oregon, and trying to avoid shipping this amp if at all possible (no original packing materials). Coincidentally, my speakers were shipped from NJ.

 

 

 

 

curiousjim's avatar
curiousjim
4,678 posts
 

New, the D400’s came with two extra 8amp slo blow fuses.  Maybe there was a reason for that.

Hopefully that’s all it is.

gs5556
1,234 posts
 

Crackling sound, DC protection engaged, plus blown fuse is very likely a shorted output transistor. Replacing a fuse is not going to help in that situation. Also, to make matters worse, those Sanken output transistors are no longer manufactured. A substitute may work or it could cause stability or distortion issues. SS amps are  finicky.

rfnoise OP
153 posts
 

Well I managed to locate two fuses

the first, in the obvious place next to the power cable was one of these:

Due to the opaque nature of the cylinder, I can’t see whether the filament is intact or not.

The second fuse was on the main board. It was in a really awkward spot, but I managed to get it prised loose with a long wooden skewer. It’s one of these:

It looks to be intact, but I’ve had fuses on my bike that looked good, but actually needed replaced.

 

I’m going to go ahead and order both, and cross my fingers.

If it was the fuses, I’m curious to know what would cause that. Could there be something wrong with the new speakers that could cause that? Or just bad luck?

 

@gs5556 

I’m guessing those are the metal devices lining the sides of the case against the heat sink. If it is a failed transistor, I’m guessing that’s game over for my amp?

rfnoise OP
153 posts
 

Well, nothing amiss with these speakers. My CODA amp is driving them fine. Too bad it’s such a lousy match for my pre.

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