Just want to thank the community on here as new amp has been working well and sounding amazing espythanks to @ItsAllInMyHead @chermann. Have included a pic and vid. Super happy onto the next project.
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I have built 2 ACAs but without the switch shown in the pic above. Sorry for a dumb question but how would I wire them both for Mono bridged output?
^ Not a dumb question at all. You'd wire them exactly as in that diagram. Just follow the "blue" line that runs from the output of Side A through the resistor and back to the input of Side B. You just won't have a switch and you can ignore the connections to the XLR etc. You don't even need two RCA jacks.
I know that's a pretty quick answer... and there must be something more that you need re: the "how", but I'm not sure what's unclear. Maybe sketch up what you're thinking or take a pic.
I know that's a pretty quick answer... and there must be something more that you need re: the "how", but I'm not sure what's unclear. Maybe sketch up what you're thinking or take a pic.
So in all honesty I started my journey with this addiction with a few tube amps, last one I built was the kegger/skunkie kt120 monoblocks, and the matt/ skunkie color preamp, not 100% sure if i love it more than my modified 300b..
Issue is with tubes, i couldn't get past it when the mrs had them on all day... while not actually home !! Doh!
So, i toss in the amp camp amp i built 4 years ago but didn't have a passive volume control or a preamp and am surprised with how enjoyable it is. 2 weeks ago i do a "more is better!" and what do you know, a delivery with my 2nd amp camp amp!
So, as of just a few short minutes ago, i am absolutely gob smacked with how amazing 2 aca's in parallel mono sounds!!
At least for my system, bridged mono sounded good but was not nearly as earth shattering as parallel..
Dunno if anyone reading this has Elsinore's for speakers, if there is im curious if your as thrilled as I am!!
Thank you Nelson and Thank you Joe!
Issue is with tubes, i couldn't get past it when the mrs had them on all day... while not actually home !! Doh!
So, i toss in the amp camp amp i built 4 years ago but didn't have a passive volume control or a preamp and am surprised with how enjoyable it is. 2 weeks ago i do a "more is better!" and what do you know, a delivery with my 2nd amp camp amp!
So, as of just a few short minutes ago, i am absolutely gob smacked with how amazing 2 aca's in parallel mono sounds!!
At least for my system, bridged mono sounded good but was not nearly as earth shattering as parallel..
Dunno if anyone reading this has Elsinore's for speakers, if there is im curious if your as thrilled as I am!!
Thank you Nelson and Thank you Joe!
@AudioFanMan Thanks for your post. I've been on the fence for awhile about next steps and I appreciate hearing about your experience with dual ACAs.
I currently have one ACA powering my Klipsch Forte IIIs and I think it is great. I use the preamp-out mode of my Marantz 1060 ahead of the ACA. I've been thinking about either adding a second ACA along with a tube preamp from Tubes4HiFi, or taking the leap to an Aleph model, but I don't feel like I can do both. An additional ACA gives me the flexibility to try not only two different dual mono modes, but also straight bi-amping. Additionally, with the Active Crossover Bi-Amp kit and a Class D amp that I already have, I have even more options. I hear really great things about the Aleph, but I'm also really curious how far I can go with a pair of ACAs and would love to hear your thoughts. Of course, I will appreciate the thoughts of anyone else, as well.
I currently have one ACA powering my Klipsch Forte IIIs and I think it is great. I use the preamp-out mode of my Marantz 1060 ahead of the ACA. I've been thinking about either adding a second ACA along with a tube preamp from Tubes4HiFi, or taking the leap to an Aleph model, but I don't feel like I can do both. An additional ACA gives me the flexibility to try not only two different dual mono modes, but also straight bi-amping. Additionally, with the Active Crossover Bi-Amp kit and a Class D amp that I already have, I have even more options. I hear really great things about the Aleph, but I'm also really curious how far I can go with a pair of ACAs and would love to hear your thoughts. Of course, I will appreciate the thoughts of anyone else, as well.
I don’t have those speakers but do have a set of Emotiva T2 that get driven with parallel ACA amps. By far, our favorite amp!
Yup, a pair of ACAs in parallel mono -
What we call a gateway drug 😉
What we call a gateway drug 😉
@CWelsh52,
I dont know abot Klipsch Forte IIIs, but have a feeling that they are efficient, and would only guess that if they are, try the ACA's bridged and parrallel for yourself. That said, my speakers sure like the parallel ALOT more, night and day different for me and they are some where near 96% i believe..
I cant really say anything other than I am 100% in love with my setup. I think the Color tube preamp from matt and modified by Skunkie is so worth building. Price, ease, and adjustable.
The kt120 monoblocks are in a league of there own but as Stephe mentioned "bright", not harsh or tiring but certainly not muddled! That said being able to dial in the right amount of 2nd order harmonics or color is why I jumped at the opportunity.
That preamp is whats driving my aca's and im so shocked at how good they sound.. im worried that they may replace my "main" tube amp addiction!
I dont know abot Klipsch Forte IIIs, but have a feeling that they are efficient, and would only guess that if they are, try the ACA's bridged and parrallel for yourself. That said, my speakers sure like the parallel ALOT more, night and day different for me and they are some where near 96% i believe..
I cant really say anything other than I am 100% in love with my setup. I think the Color tube preamp from matt and modified by Skunkie is so worth building. Price, ease, and adjustable.
The kt120 monoblocks are in a league of there own but as Stephe mentioned "bright", not harsh or tiring but certainly not muddled! That said being able to dial in the right amount of 2nd order harmonics or color is why I jumped at the opportunity.
That preamp is whats driving my aca's and im so shocked at how good they sound.. im worried that they may replace my "main" tube amp addiction!
The Fortes are 98-99 db efficient, so the single ACA can drive them to pretty painful levels. I also have an old Fisher X-101-B tube integrated that puts out 28 wpc. At my normal listening levels of 65-75 db, I find the Fisher has a touch more bass presence. I'm guessing dual mono ACAs might erase the difference.
I will take a look at the Color/Skunkie preamp. Thanks for the suggestion.
I will take a look at the Color/Skunkie preamp. Thanks for the suggestion.
We seldom get past a watt, have had a much larger amp (class A) and have amp that churns out 85 (A/B). Not sure what the magic of the ACA is with these speakers but they like each other! The larger class A produced more pressure that we just didn’t need. If it sounded any better we couldn’t hear it. The A/B driven to the same pressure is not even close in fidelity.
I hear what you're saying about the ACA magic with high efficiency speakers. Not being an engineer, I also scratch my head wondering what is the benefit of having an amplifier with more output power (sometimes significantly more) than is needed to drive a given speaker to a given output SPL. I understand that more is needed for dynamic spikes, etc., but just how much more?
I raised this question on a Klipsch forum and got some interesting discussion going, but can't say I came away with any extra understanding. I still wonder what it is about the ACA. It seems like 8 wpc shouldn't sound that good. Is it the fact that it is Class A? Or, is it that it is single ended? Both? Whatever it is, I like it. However, when you move past the ACA to other Pass Labs and First Watt products, 25 wpc seems to be pretty common.
Personally, it isn't my goal to reach audio nirvana. I don't have an unlimited budget, and probably wouldn't enjoy owning a top-shelf commercially made system nearly as much as knowing I built some of the pieces that enable my economy system to get me 95% of the way there. I suspect most of us here feel the same way.
I raised this question on a Klipsch forum and got some interesting discussion going, but can't say I came away with any extra understanding. I still wonder what it is about the ACA. It seems like 8 wpc shouldn't sound that good. Is it the fact that it is Class A? Or, is it that it is single ended? Both? Whatever it is, I like it. However, when you move past the ACA to other Pass Labs and First Watt products, 25 wpc seems to be pretty common.
Personally, it isn't my goal to reach audio nirvana. I don't have an unlimited budget, and probably wouldn't enjoy owning a top-shelf commercially made system nearly as much as knowing I built some of the pieces that enable my economy system to get me 95% of the way there. I suspect most of us here feel the same way.
It is a Nelson Pass single-ended Class A amp. One of a few amp designs of similar nature which include the Aleph J and now the Aleph Jzm. These have a distinctive sound compared to various push-pull amps such as the F5 family, F6 and M2.
Build several and enjoy the best and most reasonably affordable expressions of Audio Nirvana.
Well, I have stepped through the gate, so I anticipate building others in the future. However, for now the budget only allows so much and I think I'm going to scratch that itch of seeing what I can attain with the ACAs.
Steppenwolf drew a distinction between dealers and pushers in their song, The Pusher. I hear versions of, "Hey, man, try some of this...it will blow your mind" every time I come here, and it is great. I really wish I had started this journey a long time ago, but I'm here now and having fun.
Steppenwolf drew a distinction between dealers and pushers in their song, The Pusher. I hear versions of, "Hey, man, try some of this...it will blow your mind" every time I come here, and it is great. I really wish I had started this journey a long time ago, but I'm here now and having fun.
We at Linear Systems have something a bit unusual to share. For years, we’ve collaborated with our friends at DIYaudio to support their educational projects, including the Amp Camp Amp by the legendary designer Nelson Pass. We’ve now captured the Amp Camp Amp schematic (with Nelson’s blessing) into the fantastic new circuit simulation software developed for Qorvo by our old friend Mike Engelhardt, the author of LTspice. Mike has included the schematic capture in the QSPICE demo schematic library (File/Open Demo Schematic/Nelson Pass Amp). QSPICE is free, allowing you to modify the JFET bias and run simulations. Check it out here: https://lnkd.in/eq5EVv46
Thank you Tim! That's very thoughtful of you.
I would like to feebly request one little change: please consider eliminating "four way connection dots" from your circuit schematic. The dots (which indicate "We Are All Connected Together") are small and difficult to see on a high resolution monitor; worse, they're impossible to see after printing, especially when printed at home using an old printer whose ink is also old and whose paper is cheap.
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I would like to feebly request one little change: please consider eliminating "four way connection dots" from your circuit schematic. The dots (which indicate "We Are All Connected Together") are small and difficult to see on a high resolution monitor; worse, they're impossible to see after printing, especially when printed at home using an old printer whose ink is also old and whose paper is cheap.
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Hi Mark, I'll try to do that, still very much learning the art of schematic capture. Best, Tim
Sorry for the super noob question, I’m just starting my diy journey. I too have the forte III’s. How would one wire a pair in parallel vs using them in bridged mode?