Building the Audio Note Kit 1 SET amp...

I wonder if Brian at A-Note could send you an amp that he knows is working properly to see if it does work with the Decapos. If it does work, then you know you'll still need to troubleshoot, if it doesn't, then you could save everyone a lot of time and trouble trying to diagnose a problem that may not exist.

Like most of us here, I'm pulling for you to get this sorted out to the point where when it's all over, you are absolutely thrilled with the outcome.

Best of luck and thanks for keeping us all in the loop.

Reb, does Brian agree at this point that the test you did with the problem tracks at Sebrof's with yours versus his amps confirms a problem? They are two different amp/designs for example. Frequency response differences in teh lower octaves alone for example might account for that if teh AN is attempting to put out more power at lower frequencies for example.

Seikosha's idea comparing apples and apples amps sounds like a good one to me. I'm not sure that output power ratings alone tell the whole story in regards to what to expect necessarily.

Also I would guess someone familiar with the amp like the AN tech or Brian could identify if the sonic effects of the amps clipping, which is undoubtedly bound to occur at some point, is as expected. For example, assuming soft clipping, teh volume might stop going up well before audible clipping occurs.

Just some more food for thought FWIW. Sounds like the best thing is for an expert in your particular amp to give it a once over in person, which is where you are heading.

REb, one other question I am curious about. Did your amp go louder at Sebrofs before clipping than at home with the Ref 3as? I would expect at least that assuming use with the more efficient speakers. Whether or not one amp rated a few watts higher than another would actually go as loud or louder in any particular case is a little greyer for me.

Seikosha and Mapman,
Everybody agrees that this amp isn't working properly. The tech actually sent Brian video of his scope readings and they confirmed a problem. I played some bass heavy music for Brian and even over Skype he could hear the distortion when the volume went up. I think the experiment at Sebrof's confirmed that this isn't a speaker mismatch problem - we heard the same effects there. We're just not yet sure what's causing the amp to misbehave in this way and not put out its rated power. But I'm confident we'll figure it out one way or another.

If the 86db efficiency number that you posted about earlier is accurate (that would explain some of my failed attempts at De Capo/SET pairings) a healthy version of your amp may still, unfortunately, turn out to be a mismatch.