2. amps-preamps
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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
juanmanuelfangioii
958 posts
 

This may help.

https://www.arcdb.ws/Database/D400/ARC_D400MKII_schematic_and_parts_list.pdf

juanmanuelfangioii
958 posts
 

Here is a pdf of the OM.

https://www.arcdb.ws/Database/D400/ARC_D400_manual.pdf

bigkidz
3,381 posts
 

I'm in New Jersey and I can take a look at it if this helps.

gdnrbob
4,444 posts
 

The schematic shows two fuses. Most likely, one is at the power cord, the second is probably a rail fuse- which is located inside the amp.

I am with Ralph on this,  one or both fuses may have blown. Just try replacing them. (Of course, you can look at them and see if they are blown, too).

If a capacitor blew, you would see a darkened spot on the board or a distorted piece. 

I unintentionally shorted my McCormack amp once, and Pat and Steve guided me through the diagnosis. Yup, I blew out the rail fuse/s.

When my Ayre amp suddenly died, Ariel asked me to look inside- When I showed him the blackened spot in the amp, he said ship it back to repair the capacitor.

Have you checked you speaker connections/interconnects? Anything that might have grounded the signal?

Bob

itsjustme
681 posts
 

if you blew a fuse -- or anything else that quickly either you have a coincidence, ro, i suspect, you shorted something liek a speaker wire, and that short likely is still there.  Check carefully.  In fact begin withe the speakers disconnected. if you hapen to own a VOM, with everything off, and ideally, but not reqyired, with the wires disconnected form the amp (its off, right?  and has been for a long time, right?) measure the resistance across the speaker terminals.

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