CWelsh

You make an excellent point. My enjoyment of the amp is subjective. Others may find it less pleasing than I do. And, I will admit that the cost and the fact that I assembled the kit contribute to my evaluation. Still, for less than $750, I don't know that you can beat it. I've tried some Class D amps and agree that they sound great, especially for the price, but the ACA has something I really like, and that makes me happy.

I did read the ASR review, but it has been a couple of years or so. My memory is, he didn't like it because of the high distortion ratings using his measurement tool. Even Nelson Pass acknowledges that it has second order harmonic distortion numbers that look high. Apparently, the same is true of virtually every tube amp in existence. Whatever the case, I can tell you the thing sounds pretty freaking amazing through high efficiency speakers. I watched another reviewer on YouTube absolutely trash the ACA. However, what he was really testing was a Chinese clone he picked up on Ebay for cheep and playing it thorough not terribly efficient speakers. Crazy people!

That's a good question. I spent a fair amount of time doing an A B comparison to make sure there were no glowing differences, but that isn't the same as taking measurements. Maybe someone with more technical know how that I have will chime in with a suggestion. Do you suppose measuring voltage at the speaker terminals might do it? At some point, I intend to build and try the DIY Audio active bi-amp crossover, which I believe should offer the same capabilities for individual channel gain adjustments. In the amp itself, I think minor tweaks to the bias pots might do it. I'm guessing, here.

The new ACA is up and running! In each of the available options (bi-amp, bridged mono and parallel mono) there is an improvement over the single ACA. The essence of the sound doesn't change, but there is more detail, the sound stage seems to have greater depth, and the bass is tighter. What I found with the parallel mono mode, is how all the improvements are very noticeable at lower volumes. This is a pretty big change from the single amp. These things seem to be made for Klipsch speakers. For less than $750, I have 15 wpc of single ended pure class A amplification. Not too shabby, if you ask me.

I just ordered my second ACA. Going to see just how far I can go with them.

Also note that there is a parts list in one of the posts near the top of this page.

Hi have, but the price increase is substantial to get the SP14 with a remote and I haven't gotten beyond my bang-for-the-buck tendencies. Especially since I plan to buy a second ACA.

Two guys grow up together, but after college one moves to Georgia and the other to Texas. They agree to meet every ten years in Florida to play golf. At age 32 they meet, finish their round of golf, and head for lunch. "Where do you wanna go?" "Hooters." "Why Hooters?" "They have those servers with big boobs, tight shorts, and gorgeous legs." "You're on." At age 42, they meet and play golf again. "Where you wanna go for lunch?" "Hooters." "Again? Why?" "They have a cold beer, big screen TVs, and side action on the games." "OK." At age 52 they meet and play again. "So where do you wanna go for lunch?" "Hooters. "Why?" "The food is pretty good and there's plenty of parking." "OK." At age 62 they meet again. After a round of golf, one says, "Where do you wanna go?" "Hooters." "Why?" "Wings are half price and the food isn't too spicy." "Good choice" At age 72 they meet again. Once again, after a round of golf, one says, "Where shall we go for lunch?" "Hooters." "Why?" "They have six handicapped parking spaces right by the door and they have senior discounts." "Great choice." At age 82 they meet and play again. "Where should we go for lunch?" "Hooters." "Why?" "Because we've never been there before." "Okay, let’s give it a try."

@The Dude Have you finished your preamp project? I've been looking pretty seriously at the Tubes4HiFi SP13 kit. It doesn't have a phono section, but I don't listen to that much vinyl and I can always play that through my Marantz. I also have a Rotel phono amp that I can haul out of storage if necessary.

Changing the subject just a little... not much... I'm sitting here listening to Steely Dan's aja streaming in ultra hi-def. I'm in bliss and I'm not even a huge Dan fan. I've been playing with speaker placement over the last couple of weeks. Klipsch recommends keeping the Forte IIIs within about 10 inches from the back wall for best bass performance. I tried that and found the bass pretty subdued. Plus, the sound stage was just flat. I pulled the speakers out to 16" with a very slight toe-in and it is a world of difference. I don't have the tools to measure the actual performance of the speakers, and maybe I would find everything completely out of whack if I could, but it really sounds great!

I have no complaints at all about my Forte IIIs, either. I was just saying it seems many others think so.

Yeah...what about that? Man, we need some audio engineers who can speak plain English to chime in. I feel like I'm reasonably intelligent and I think I understand some of this stuff, but I have to admit that I've never had that AHA moment where it all clicks into place and I can say, "if I do X I will get Y result". But, maybe that kind of clarity is just beyond me. Heck, I still think it radio is absolute magic, let alone television across the airwaves. 🤫

I don't think you're missing anything. My question was never really about loudness, but about whether the extra watts add something to the overall sound other than that ability to play it louder.

You are correct...I should have said SPL increase rather than loudness.