Guys, I have a "problem" - or not(?) 🤔 .
I am using one ACA Mini to power the mids (500 - 1200Hz) of active horn system. I am not sure if it was the case from the beginning, but the amp is kind of "noisy". The is a constant "buzz" building up when I flip the swith to the "on-position" which is audible in the listening position without music playing.
Is this just the normal noise to be expected in a 100db+ rig or is the anything I can try?
Your feedback will be greatly appreciated - thx. in advance.
I am using one ACA Mini to power the mids (500 - 1200Hz) of active horn system. I am not sure if it was the case from the beginning, but the amp is kind of "noisy". The is a constant "buzz" building up when I flip the swith to the "on-position" which is audible in the listening position without music playing.
Is this just the normal noise to be expected in a 100db+ rig or is the anything I can try?
Your feedback will be greatly appreciated - thx. in advance.
Amps 'hiss' to some degree or other and that is unavoidable but they don't of themselves buzz...
100db sensitivity on the speaker front is going to be very revealing of problems however the first questions have to be:
1/ Is the ACA Mini running off the recommended Meanwell PSU?
2/ Can you hear the buzz if you disconnect the amp input and apply a shorting plug?
100db sensitivity on the speaker front is going to be very revealing of problems however the first questions have to be:
1/ Is the ACA Mini running off the recommended Meanwell PSU?
2/ Can you hear the buzz if you disconnect the amp input and apply a shorting plug?
This might suggest that the buzz is more related to ripple on the supply and that if the bias current of the amp increases from cold then that in turn then increases the ripple on the supply which can then make its way into the amp. That would be expected with a simple linear supply more than switching type though.
Thank for the response. Hiss is probably a more fitting description. Yes, PSU is the recommended Meanwell. I haven't tried shortening the input yet.
Hiss as in white noise? If that is what you mean then it may be normal.
You would have to try with the ACA input shorted to prove it though. Any noise (hiss and or hum/buzz) from anything connected to the input (like a preamp) may well be noticeable with such sensitive speakers.
You would have to try with the ACA input shorted to prove it though. Any noise (hiss and or hum/buzz) from anything connected to the input (like a preamp) may well be noticeable with such sensitive speakers.
I tried to record the sound on my mobile but somehow I cannot post it here - yes, it might indeed be the natural behaviour of the amp on this particular speaker....
That remark helped tremendously 👍. Indeed the culprit was NOT the ACA Mini - but my DSP. Lowering the input gain there solved the problem.
OK, I followed the instructions in the original Pass article and the build guide and no joy. I think it's a power issue. I get continuity across the + and - tabs of the power input jack -- plus a little puff of smoke -- oops. When it was plugged in, the diode faded in and out a bit. Perhaps it is the jack itself. In any event, is there a basic troubleshooting thread in this forum, so I can try to go through things in an orderly way? I've done some searching and don't see that here. Thanks and happy new year!
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How much ESD precaution do you all take with these FETs? From reading the thread, I hear these are pretty hearty devices, but I don't have a sense of how careful I need to be with them out of the bag.
@Nelson Pass -- Thank you for this design. I just saw your BAF '21 talk on it a few weeks ago and it does indeed bring new people into DIY audio. I got one for myself and one for each of my kids. After I teach them how to make a clean solder joint, your ACA Mini will be their first electronics projects.
"@channel" -- Kudos to you all. What an awesome corner of the internet. I've never read through 2568 back posts on a forum thread before, but this one is totally worth it.
@Nelson Pass -- Thank you for this design. I just saw your BAF '21 talk on it a few weeks ago and it does indeed bring new people into DIY audio. I got one for myself and one for each of my kids. After I teach them how to make a clean solder joint, your ACA Mini will be their first electronics projects.
"@channel" -- Kudos to you all. What an awesome corner of the internet. I've never read through 2568 back posts on a forum thread before, but this one is totally worth it.
As long as your not playing with your Van der Graaf generator while handling them, you should be okay.
Hi
You seem to have a few short circuits with some of your solders. I took a few pics where I’m wondering what’s the extra solder for ? Please check these out.
@e_fortier I read much earlier in this thread and my friend who built one of these previously said that pot pins 2 and 3 needed to be shorted because of a missing trace on the boards from the last couple of months. So I soldered them together (with wire). If this is simply wrong info, I'd be grateful to learn that.
For example, this post and a few following: https://www.diyaudio.com/community/threads/diy-aca-mini.379037/post-7361916
Is this series of posts a misunderstanding?
For example, this post and a few following: https://www.diyaudio.com/community/threads/diy-aca-mini.379037/post-7361916
Is this series of posts a misunderstanding?
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@royewest see https://www.diyaudio.com/community/threads/diy-aca-mini.379037/post-7362227. Those pins are connected by a top trace (red in the original documentation).
Deleted a post... if anyone read it... ignore... I looked at the wrong schematic... and of course noticed that 30s after posting. 