My sense in general of the ACA is that midrange, 'girl and guitar', is it's forte. It's warm there, even a bit soft and fuzzy. It doesn't have the bass extension or control of a MoFo built with IRFP240's, or the broad spectrum even-ness and detail of an F3 clone, which is my current favorite. But if you have a 'bright' source like some DACs I think it can do wonders to warm up and mellow things out, and I would much prefer it to a Class D amp. As many others have said, it works well with sensitive speakers, and I do think it can help with bright speakers like some Klipsch. It's really important to keep in mind the speakers you're working with though. I don't think the ACA is the right choice for any 2- or 3-way with a big coned woofer, it lacks the control to do the mid-bass justice. That said, I'm hearing things from the ACA mini that makes me hopeful for mid-bass in my main system, which has Seas A26 kit speakers.
Please keep in mind this is all very subjective.
Ok. The ACA mini doesn't have quite the mid-bass response in my system I was hoping for, but oh god the treble and vocal detail is otherworldly. Detailed but not bright or harsh. Does wonders to smooth out two digital sources, both of which are somewhat problematic even after running through a B1 buffer. It's really a stark contrast to the original ACA imo. Listened first to Cannonball Adderly's Somethin' Else off of CD, then moved on to some singer-songwriter stuff off a RPi DAC.
Yeah I could use an active preamp in my armamentarium. I almost certainly would have gotten more out of the MoFos with one.
Idk if it's the morning or what, but playing Gish, one of the 'forbidden albums' while my partner is out (she doesn't like The Smashing Pumpkins), and I must say there is really nothing wrong with the thrumming electric bass put out by this little amp. If you want to build just one Class A PASS amp, this may be the one.
Idk if it's the morning or what, but playing Gish, one of the 'forbidden albums' while my partner is out (she doesn't like The Smashing Pumpkins), and I must say there is really nothing wrong with the thrumming electric bass put out by this little amp. If you want to build just one Class A PASS amp, this may be the one.
Agreed. Any of the line stage kits and/or boards in the diyAudio store would give you an improvement in the areas you're looking for.
I honestly haven't listened to either amp in a while, and my impressions are stale. I am getting curious to try the ACA in balanced mode, driving two-ways with a series crossover, but I have to convert one of my preamps to do that first. That won't help for comparison to the ACA mini.
The ACA (classic, not ACAmini) doesn’t need to be driven by balanced to get bridged output… the self-inverting trick with the 39K resistor takes care of that.
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Hi Ranshdow. FWIW I did my own ACA Mini board layout and added a selectable line inverter stage to the input of one channel. I ran the Mini in bridged mode using this and it sounded pretty good. But briefly. I have done no extensive listening yet. I need to build another amp so I can do that in stereo. I might get that done this weekend.