Well I hooked up one of my ACAs to my lab supply. No noticeable noise. So it appears that my power bricks are toast. My ACAs came with the 19V Power bricks. So to change to a 24V supply all I would need to do is adjust the bias. Might try a linear supply (probably later) or just work on finishing another set of amps. My M2X and F6 mono blocks just need some chassis components to be operational.
Quite possibly the SMPS is the culprit but you should check the total current draw is within the max limit of the PSU. In other words make sure the ACA's are not drawing a bit more quiescent current than they should,
I decíded to upgrade my original First Edition monoblock ACA’s back panel connectors. After all these years the RCA’s were looking a bit corroded, and we’ve also upgraded the PSU connector and the speaker posts. It’s feels great to get them looking more current. I had already added the resistor required to upgrade the 1.0 PCB a few years ago, and now I figured I’d adjust them for a new Meanwell 24v supply, since the 19v supplies weren’t the quality of the current Meanwells.
Because they are monoblocks, I figured I’d stick with one PSU per channel, which meant they could be a bit smaller. I got 2 of the Meanwell GST90A24-P1M that can output 3.75A ea. Which is more than plenty, and it wasn’t much more expensive for a pair.
So that’s another great thing about the ACA’s -they can be upgraded to the current spec, and since you built them the upgrade is easy!
Because they are monoblocks, I figured I’d stick with one PSU per channel, which meant they could be a bit smaller. I got 2 of the Meanwell GST90A24-P1M that can output 3.75A ea. Which is more than plenty, and it wasn’t much more expensive for a pair.
So that’s another great thing about the ACA’s -they can be upgraded to the current spec, and since you built them the upgrade is easy!
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Hey, guys. Was hoping I could ask a couple questions to the experts here because I'm a little lost.
My friend gifted me his ACA because he could never get it working. I've since gotten both boards operational, but the wiring on the back panel is having me scratch my head a bit. There are so many revisions to this kit I am not sure what I am supposed to be looking at. I am unsure what version board I have, it says "Nelson Pass 2018) on the boards. Here's some pics of back panel wiring:
Originally the resistor off of the bridged-stereo switch was soldered to one of the negative speaker terminals. I have since moved it to the Red RCA input per the current directions, but now I am not so sure this is correct as I've seen a couple older kits wired the same way that my friend wired it. Also why are the top contacts on the switch bridged? Why is the bridged-stereo switch wired to RCA inputs when current revision is not? Does everything look safe to you guys? There's just so much going on with the wiring in this design I can't wrap my head around it all with my limited DIY knowledge.
Any insights would be greatly appreciated. Thanks for looking guys.
My friend gifted me his ACA because he could never get it working. I've since gotten both boards operational, but the wiring on the back panel is having me scratch my head a bit. There are so many revisions to this kit I am not sure what I am supposed to be looking at. I am unsure what version board I have, it says "Nelson Pass 2018) on the boards. Here's some pics of back panel wiring:
Originally the resistor off of the bridged-stereo switch was soldered to one of the negative speaker terminals. I have since moved it to the Red RCA input per the current directions, but now I am not so sure this is correct as I've seen a couple older kits wired the same way that my friend wired it. Also why are the top contacts on the switch bridged? Why is the bridged-stereo switch wired to RCA inputs when current revision is not? Does everything look safe to you guys? There's just so much going on with the wiring in this design I can't wrap my head around it all with my limited DIY knowledge.
Any insights would be greatly appreciated. Thanks for looking guys.
Is the switch 3-position? Does it have a click at up, middle, and down?
If yes, it’s a 1.8 and it’s currently wired incorrectly in your photos above.
Proper wiring here:
From 1.8 change guide - https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.8+Change+Information/10?lang=en
If yes, it’s a 1.8 and it’s currently wired incorrectly in your photos above.
Proper wiring here:
From 1.8 change guide - https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.8+Change+Information/10?lang=en
There will be no difference. The transistor is used only as a simple shunt to set the bias current. Any small differences in Vbe will give differences in bias current but that difference will be tiny and unless you yourself name a figure to work to, you would be none the wiser.
Hi guys,
My current ACA setup consists of two ACAs in balanced XLR mono mode connected to a Sabaj A20D 2022 edition DAC.
I purchased a new turntable (Pro Ject Debut Pro) and was wondering how I can go about connecting both my ACAs in mono mode to the turntable so I still get the 15w maximum output.
I do have an iFi Zen Phono Amp. Also, my DAC has an option to use preamp mode.
Thanks!
My current ACA setup consists of two ACAs in balanced XLR mono mode connected to a Sabaj A20D 2022 edition DAC.
I purchased a new turntable (Pro Ject Debut Pro) and was wondering how I can go about connecting both my ACAs in mono mode to the turntable so I still get the 15w maximum output.
I do have an iFi Zen Phono Amp. Also, my DAC has an option to use preamp mode.
Thanks!
^ I don't see any analog inputs on that DAC/Headamp. I only did a quick search, and I may have pulled up the incorrect unit.
Looks like that Zen phono has a 4.4mm balanced output... I can't find any specs etc for that, but someone may know more than I. There is no attenuation on that product.
tl;dr - I believe you need an actual pre-amp, but can't be 100% certain.
Looks like that Zen phono has a 4.4mm balanced output... I can't find any specs etc for that, but someone may know more than I. There is no attenuation on that product.
tl;dr - I believe you need an actual pre-amp, but can't be 100% certain.
