Brrgrr, I have heard the jr's multiple times in the past including recently at the 2005 HE show with the DK hybrid integrated and found the dynamics and staging/imaging one of the best at the show. However, there was "grunge", as you put it, to the high frequences that tired me after about 1/2 hour. I originally thought it was due to the DK but now I think it's due to the jr's. I have heard similar problem before. But it can be due to many things such as poor AC or your DAC. The Gamut amp is unlikely the culprit. First try turning off the ambience tweeter if possible - you can fine tune later. If this doesn't work, try balanced interconnects - I believe the Benchmark and Gamut are balanced designs. If this doesn't work, try a passive line conditioner - some manufacturers or dealers such as audioadvisor.com and amusicdirect.com offer free in-home trial. Or lastly your DAC may be the problem in which case you may need to get another digital source or mod it hoping it will get rid of the problem.