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Break-in of a Class D amp?

I'll spare everyone the "brand tribe" debate, and keep my question/details generic.

I recently had to have my 2ch ClassD amp "serviced" by the manufacturer.  Yes, it's an ICEPower derived unit.  I'd been SUPER happy with it for well over 18 months, until one morning when I heard a buzzing coming from inside the amp itself.  I took a video, poked the manufacturer, and they voluntarily opted to fix it for me.

Fast forward a week, and the amp is back in my stack.  But something is amiss. 

I can tell they wholesale replaced the entire ICE module, as the "power up" delay from standby is "different" than before, and it seems to exhibit less overall "gain" than prior to repair.

But the most disturbing thing, and one that literally smacked me in the face... was the lack of high frequency authority.  While there is a soundstage, and lows are not an issue... it's missing all the "presence" and "life" in the top end.  I have tracks that I can play that elicit EMOTION when I queue them.  All the detail and fidelity is like, muted.

The previous board had hundreds of hours of time to burn in, and boy I exercised it.  Is this what I'm now encountering?  Or has anyone out there experienced this situation?  

I would normally just knuckle down and "grind out" hours of "work" for the amp... and not come here asking for advice... but the fidelity difference is so striking... that I can't get over it.

Thoughts?
rabbottmke
oldhvymec
5,101 posts
 
The first thing I would do is contact the repair person and ask if they replaces the module with the same type? With a different startup delay and sound, I'd be asking a question or two.. You have nothing to loose and maybe a discount on a second module.  If they don't sound or work the same way, that's really not in the best interest of ANY stereo system.

It's not fixed... BUT it will work.. I've had to FIX a lot of those repairs in my life. We have a different term for it though.. It's called 1/2 A$$ed.
BUT you have a working system making sound. Certainly better off than you were AND maybe the guy didn't know there would be a difference.

I don't think there was anything malicious, just uninformed.. AND he sure can't fix what he doesn't know about, AY?

Those Blue meters can be spendy. I've owned the MC601s and 1.2s.

My back is hurting thinking about them.. I have vintage Mac gear.. Valve gear.. They are heavy too.. Not Class Ds, where you have to ADD weight.. LOL
rabbottmke OP
23 posts
 
So indeed it is the same board.  ICEPower 1200AS2.  Comparing pictures, the only REAL difference, is the AC transformer has more "vibration isolation goo" packed between the windings and the core/cage.

I'm positive this was just a "board swap".  No harm, no foul.

And yeah... MC601's yada... Maybe an MC302 cause I don't need TONS of power/reserve for my particular speakers.  But indeed.  Heavy.  :)
tmcclintock
35 posts
 
To answer your original question, my ICEPower class D amps took quite a few hours to break in.  I wouldn't say they gained detail but more like the highs smoothed and got clearer, so detail was more distinct. 
rabbottmke OP
23 posts
 
@tmcclintock Yeah, I'm guessing something is different here.  After 24 hours of burn in (yes I know, a very short period of time), I'm starting to pick up new details.  

While the high's are still not as pronounced, the bass is significantly more pronounced.  I have GoldenEar Triton 2+'s and had to dial the subwoofer gain down to almost nothing.  While I like some "pronounced lows"... this is obscene.

I had to turn off the system after only 3 partial tracks.  It's not enjoyable.  Time to dig around in the couch cushions for some extra change.

Thanks for all the advice folks.
georgehifi's avatar
georgehifi
10,312 posts
 
So indeed it is the same board. ICEPower 1200AS2. Comparing pictures, the only REAL difference, is the AC transformer has more "vibration isolation goo" packed between the windings and the core/cage.
While the high's are still not as pronounced, the bass is significantly more pronounced.


Strange all should be the same with just a mains trany change, unless some small damage was done to both channels of the Class-D board which limits the HF and gives the impression the bass is up.

By any chance did you listen to one of your other amps while this was getting repaired?

Cheers George


 
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