ACA is an amazing amplifier. There are a few little things that can be done to make it even easier to be driven. The local 24V DC rail decoupling capacitor can also be changed to tune the sound to blend with the rest of the system. The output sound-coupling cap can also influence the sound. I have 20K/90K combo at the input to allow my DAC with resistor I/V to drive it better at all frequencies. The local decoupling cap is 0.1uF 50V non-polar NX Black Gate. The SMPS is mounted inside the ACA, wiring is a combination of pure copper and pure annealed silver ribbons that provides for a nice blend that is both very fast and very natural. All this with an SMPS supplied with a kit.
The end result is simply amazing. The bass drive, extension and purity is unbelievable (with Dynaudio Contour 1.3's with 4-ohm nominal impedance and 86dB/W efficiency). The natural flow of the sound and the natural presentation is stunning. I can now clearly see the depth of the sound stage. I can not stop listening to it.
It took me a while to arrive at the sound that I really like (my kids and wife also love the latest incarnation, which means it is indeed really good - they are taught crowd to please). The trick is to do one mod at the time, be persistent, have a reference amplifier to compare the ACA with it, and have someone else with whom you can confirm your opinion. And give it time...
I do not believe nor I expect that the Aleph J, that I will start to build soon, will improve on these little ACA's. These ACA's are simply beautiful to listen to. But, one can hope.... (especially after I gained some experience on how to get the ACA's to sound to my liking).
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"All this with an SMPS supplied with a kit."
Any one tried it with a low noise linear supply. I'm asking because I've now got wall warts and SMPS powering lots of stuff and it's going to get worse as I'll need a supply for a Pearl 2 once I build that.
I'm thinking of getting two sets of DIY Audio power supply boards and building one box with four 24 VDC outputs for Two ACA, Pearl and Nutube. Maybe two or four Toroidy Transformers exposed on the top of the box.
Any one tried it with a low noise linear supply. I'm asking because I've now got wall warts and SMPS powering lots of stuff and it's going to get worse as I'll need a supply for a Pearl 2 once I build that.
I'm thinking of getting two sets of DIY Audio power supply boards and building one box with four 24 VDC outputs for Two ACA, Pearl and Nutube. Maybe two or four Toroidy Transformers exposed on the top of the box.
12V/50Ah + 12V/50Ah = 24V/50Ah........so 50Ah:6,5A = 7,6h theoretically,
in practice could be less........
The ACA are absolutely wonderful little amps, no argument from me!!
Build the AJ.
You'll love it.
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The ACA are absolutely wonderful little amps, no argument from me!!
Build the AJ.
You'll love it.
Well, you may hate it before you love it. I've built a pair of ACAs, an F6, an M2, and the Aleph J. The Aleph J took many hours of playing before it smoothed out. It was strident and harsh for the first month. Now it sounds amazing. I don't know why it took so much longer than the other amps to settle in. Make sure you give it some time.
I find myself in a pickle. I love the balanced operation of the monoblocks, I love the distortion cancellation, extra power, etc. I also love my older NAD 1240 preamp. The preamp only has single ended outputs.
I need some opinions, search for a balanced preamp and hope i like it as much as the NAD... or get a DI solution like an ART box and use it with the NAD? What are the thoughts on something like a direct box? Does it alter the signal too much, add anything, etc? If not, any recommendations?
Thanks.
I need some opinions, search for a balanced preamp and hope i like it as much as the NAD... or get a DI solution like an ART box and use it with the NAD? What are the thoughts on something like a direct box? Does it alter the signal too much, add anything, etc? If not, any recommendations?
Thanks.
If the DI box is passive and uses transformers you are depending on the box using good quality, transparent transformers. You could also DIY your own balanced to unbalanced converter using Jensen or Cinemag transformers which are known to be transparent. Jensen also makes DI boxes using their transformers but they are quite pricey. The active type DI boxes use op amps, so that is likely not where you want to go with a system having an ACA.
see in build thread and I believe - it must be covered somewhere - ACA is having built in SE to Bridge operation mode ..... thus you need just SE input
see small toggle switch on back of amp
no need for semi-solutions , when existing one is superlative to that
only premium solution (proper balanced preamp or high quality xformer with all impedance issues covered) is better
edit : it will be certainly wiser to toss NAD on curve (making happy some Kido) and build Iron Pumpkin ....... but look at price of that move ......... and it demands proper balanced sources , for full Trip to Heaven
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I have the ACA 1.6 version and am considering trying a pair of linear power supplies-- possibly the Chinese Zerozone 24V/5A on ebay @$165. I've had good results with the Zerozone in other applications. Just need to confirm the ACA DC input plug size. Is it 2.5mm/ID 5.5mm/OD?
Anyone else compare the Meanwell SMPS to a LPS?
Anyone else compare the Meanwell SMPS to a LPS?
There is a significant THD penalty for using the switch vs balanced drive. See graph below or refer to post 7038 and 7040 in this thread.
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therefore pairing with 8 ohm speaker is still better in overall ? compared to 4 ohm