I received my ACA 2b earlier this week and have been listening to it as much as possible since then. As Michael mentioned I'm having problems with the mains of one channel but have been able to work around this for the time being. My system now sounds more dynamic, transparent, and has more punch. Some context: Norh 6.1 Prisms, IRD mb100s, and a fully modded Music HAll CDP all held together with Bolder m80 interconnects and speaker cable. My previous preamp was an NAD T750 receiver. The sound of the ACA is easy to recommend for the price. I love my speakers and amps and thought a Norh component would be a good match. Sonically it is but I'm disappointed with the faceplate and controls, I don't feel they do this little guy justice. I would prefer something akin to the construction of the mb100/Le Amp.
Back to the sound. With my setup it is very vibrant, a little too forward for my taste on some recordings. I listen to a good deal of jazz and so far this is where the STOCK ACA has exhibited some real strengths as well as shortcomings. I love the bass. Pat Metheny & Charlie Haden's BEYOND THE MISSOURI SKY sounds like I've never heard it before. Patricia Barber's VERSE sounds so much more dynamic and nuanced through the ACA. However, I gave some of my Miles Davis quintet recordings a quick listen the other night and they sounded harse and glaring.
Fortunately there are other tube choices and I plan to try some other 6922s. Have been doing some research and Upscale Audio has quite a few tubes to choose from. Also a power cord upgrade to a Bolder Nitro. I listen to music all of the time and prefer it warm, slightly laidback. I have no doubt I can tweak the ACA a bit more to my taste.
It's getting late and I'm going to have to cut this short. This is a start anyway. I posted on Harmonic Discord for the first time earlier this evening thinking it was time to put in my 2 sense. It was suggested I come over here. I'll follow up and hope to hear what some other folks think.
