The ACA idles at 1A and 19VDC per channel. The F2 idles at 3A and 24VDC per channel (about 75W per channel).
The ACA is mu follower single ended whereas the F2 is CCS loaded single ended. The mu follower provides a bit of extra power output.
The higher current of the F2 gives it the advantage of higher power output into lower impedance (e.g. 4 Ohm) speakers.
The ACA is mu follower single ended whereas the F2 is CCS loaded single ended. The mu follower provides a bit of extra power output.
The higher current of the F2 gives it the advantage of higher power output into lower impedance (e.g. 4 Ohm) speakers.
Way back in the day I had a Harmon Kardon receiver that put out 35 wpc. It drove a pair of Genesis 210 speakers nicely. Seems we have gotten away from efficient speakers since then. The ACA I think is at it's best with an efficient speaker. I'm lucky to have a nice pair of Hestia OB's that are 91 SPL iirc and they really sound fine with my newly completed ACA. But today, efficient speakers are rare. What speakers are you all using with a single stereo ACA? I've done some looking but there is not much out there. You can find the original Hestias here; https://www.audiocircle.com/index.php?topic=108003.0
I built the top 2/3 leaving the woof off in leu of a planned powered sub. ( that is still my plan).
I built the top 2/3 leaving the woof off in leu of a planned powered sub. ( that is still my plan).
thanks, ben/6l6 for your replies.
i don't need high power; i'm using my f2 clone (and an almarro a205a mkii to drive speakers ~100db-efficient, and ~95db-efficient; both 8 ohms. i'm just looking to reduce wattage at idle when the amps are on, but not doing much. seems the aca amps will reduce power consumption, but not a lot...
doug s.
i don't need high power; i'm using my f2 clone (and an almarro a205a mkii to drive speakers ~100db-efficient, and ~95db-efficient; both 8 ohms. i'm just looking to reduce wattage at idle when the amps are on, but not doing much. seems the aca amps will reduce power consumption, but not a lot...
doug s.
i was interested in the amp camp, because there was a pair f/s for a ridiculously low price. (i think they're gone; i emailed the seller early, but i bet the 1st person who saw the ad bought them.)
i'd already bought a pair of aiyima a07 max amps with 48v/5a (6.3a max) power supplies for $166 shipped; they just showed up yesterday & they're breaking in today. tomorrow nite, i will swap out their op amps for some highly rated akliam lc2 discrete op amps, for an additional $61 shipped. 12w total idle current is a bit better than 80w total idle current for a pair of the aca's. if they don't work out, i can still go back to the ~250-300w idle current of what i have; they sound great in my quad-amped system; the f2 clone driving full range drivers in oris horns from 175hz to 7khz, and the almarro driving beryllium ribbon tweeters >7khz.
from what i've read about these 3255 chip amps, they're very nice. (as are the lc2 op amps i bought- positively compared to sparkos and muses02.) here's an interesting vid from a speaker designer, whose company is responsible for the highly reviewed cube audio and qualio speakers. he likes these amps better than his ~$5k naim integrated, to drive his qualio iq's :
i decided on the aiyimas, based on the fact that i prefer its layout/features to the fosi he reviewed, and he also spoke highly of aiyima's lesser predecessor, the a07. and he said one of his buds used the model i got to replace some €10k amp in his system, as it was better.
doug s.
I have a Fosi Za3 enroute. I ordered it before the ACA caught my eye. Was thinking I would use it to drive a sub now. Going to put the ACA through it's paces today. Some Lou Reed from his NY cd and Joni Mitchell from Miles of Isles. I expect it to do very well based on what I've heard from it thus far.
@doug s. - Unless I missed something re: the context -
Typical ACA power consumption ~20W per channel => 40W
Typical F2 power consumption => ~75W per channel => 150W
As a percentage ... of course the difference is the same regardless of the number of channels. In terms of absolute power draw, it's a larger gap. Just depends how you want to frame it and what your goals might be.
Edited to add - if your F2 idles at 200W, then the gap is even larger.
Edited to add again - Dang! The new First Watt site looks great!!!! Little bit of wonkiness on the articles page... everything is a SIT-4. The reviews seem to be correct.
Typical ACA power consumption ~20W per channel => 40W
Typical F2 power consumption => ~75W per channel => 150W
As a percentage ... of course the difference is the same regardless of the number of channels. In terms of absolute power draw, it's a larger gap. Just depends how you want to frame it and what your goals might be.
Edited to add - if your F2 idles at 200W, then the gap is even larger.
Edited to add again - Dang! The new First Watt site looks great!!!! Little bit of wonkiness on the articles page... everything is a SIT-4. The reviews seem to be correct.
Last edited:
The ACA with the 24v supply dissipates around 40w per channel (1.6 amp quiescent current per channel) The 19v original ACA was nearer 20 watt per channel dissipation.
keep us updated about your reaction to the fosi. my aiyimas are breaking in (w/stock op amps); so far so good.
sorry to side-track; when i saw a pair of aca's advertised for $125; i was very interested. but it seems someone else beat me to it. i checked the ad, and they're still not marked sold, so i may yet hear from the seller. for that price, it's worth trying, certainly. kind of how i felt about the aiyimas, hah!
doug s.
Hi Folks,
Have finally started assembling my ACA boards, I have 2 questions :
I saved my old IBM laptop supplies for a pair of amps, they are 20V 3.5A . Will these work ok ? (I'm assembling according to the 1.6 build guide)
I'm struggling to find a chassis mount DC connector rated above 1A for the power socket (UK suppliers) Do I just buy a 1A connector and assume it will be ok ?
Thanks,
Rob.
Have finally started assembling my ACA boards, I have 2 questions :
I saved my old IBM laptop supplies for a pair of amps, they are 20V 3.5A . Will these work ok ? (I'm assembling according to the 1.6 build guide)
I'm struggling to find a chassis mount DC connector rated above 1A for the power socket (UK suppliers) Do I just buy a 1A connector and assume it will be ok ?
Thanks,
Rob.
Attachments
As long as you balance the channels for a 20V supply it should work. ( but I know little) Do the voltage checks outlined in step #56 in the V1.6 bill guide
https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.6+Build+Guide/5?lang=en. Look at the V1.8 build guide long enough to familiarize yourself with the minor changes from the V1.6 but follow the 1.6 build guide for the most part. Read both those guides end to end before you start. Good luck and have fun.
https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.6+Build+Guide/5?lang=en. Look at the V1.8 build guide long enough to familiarize yourself with the minor changes from the V1.6 but follow the 1.6 build guide for the most part. Read both those guides end to end before you start. Good luck and have fun.
Thanks,
I'm sure I remember reading that the 20V supply would be ok, it's just I bought the boards so long ago that when I came back to this thread it all seemed to be 24V.
I've decided to do without the chassis power connector, I will use a cable gland and solder the power supply wires direct. Better solution than using an underspec connector.
Rob.
I'm sure I remember reading that the 20V supply would be ok, it's just I bought the boards so long ago that when I came back to this thread it all seemed to be 24V.
I've decided to do without the chassis power connector, I will use a cable gland and solder the power supply wires direct. Better solution than using an underspec connector.
Rob.
Have a look at (these panel mount barrel jack products on mouser.com) and see whether any of them are usable. They are rated 5 amperes and 7.5 amperes. I checked exactly one of them, chosen at random, and found it on mouser.uk
Started a Za3 thread in the solid state forum; https://www.diyaudio.com/community/...mited-impressions-vs-aca.408857/#post-7592059