Thank you. yes it has large holes for air circulation. Working on this frame was a pita..custom made to suit the board.
Built this little gem over Christmas. First tried it with 4 ohm AR3a speakers and it really pushes them quite well. Sound quality is fantastic! Have plans to try the Mini with Heresy's but can't stop listening to the AR/Mini combo. I am in the process of building some cabinets for Altec 604's and was wondering what the Mini's output power would be into a 16 ohm load?
I have used my bridged ACA (first gen boards) into Altec 605Bs in open baffles. With yet more sensitive 604s, I'm sure your Mini will work well, and that a pair of bridged Minis would be great.
audiosteve did it. Search his name and the word Mini. You should be able to track down some of those posts.
I use a preamp that takes single ended inputs and outputs balanced signal (based on a Neurochrome THAT Driver card). One preamp balanced output out to one ACA Mini channel input hot, the antiphase balanced preamp hot to the the other Mini channel hot. You need to make sure the two input grounds are tied to each other and the two output grounds are tied to each other as well. The PCB may well do this (you can check this with your DVM). I have never used the passive SE to BAL connection method, where you make up a preamp/source to power amp cable. You do need two ACA Minis to do this either way, and end up with monoblocs if you have seperate power supplies for each side.
I will say that trying the natural (as is) SE connection first may be a wild success, so buying/building the pieces you need to have the balanced monobloc setup could be much more than you need. And, it will sound somewhat different.
I will say that trying the natural (as is) SE connection first may be a wild success, so buying/building the pieces you need to have the balanced monobloc setup could be much more than you need. And, it will sound somewhat different.
I did my own board layout making two mono boards with space for a unity gain op-amp inverter on one so it could be used as part of a bridged pair. I figured the op-amp up front (TL071 low noise FET input) was no big deal at all. The power amps are still all the same and the signal being amplified already went through more op-amps than you can count between the recorded instrument and the CD or record being listening to. BTW, ACA Mini bridged sounds very good to my old ears. Here is a picture attached of Rev 2. I Tested and listened to Rev 1 but bridged have not hooked these up yet. I have a par of ACA chassis to put them in. Been too busy lately to get it done. The boards you see here have a more usable layout than Rev 1. Also no FETs or 'Jumper in' circuit populated here yet and the connectors are more mainstream. I'm listening to my Rev 1 stereo amp as I write this,
Finally had schedules line up and was able to host my friend Matt over and have him build his first DIY project, the elusive and rare “EXPERIMENTAL” ACAmini. (M. Johnson PCB)
I’m happy to say there’s another DIYer in our ranks, welcome Matt!
I’m happy to say there’s another DIYer in our ranks, welcome Matt!
So....I saw a KiCAD video on YT and ended up making an ACA mini mono board with @Mark Johnson 's SMPS filter. Can you guys tell me if I've effed up anything pls? This is the first time I've used KiCAD and I'm not a circuit designer or an EE so feel free to be as brutal with your comments as needed
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That looks pretty good to me. 👍 But then, I'm only a lapsed EE. I'll leave layout analysis to someone even remotely qualified.
Do the mounting holes conform to UMS?
Kind regards,
Drew
Negative. I just threw them where there's space. Not sure what I'll do for enclosure yet - will figure it out later.
If you're willing to change the I/O around you can probably make the whole layout more efficient. And an easy one; move the line from Q4 to P2 to the bottom layer and you can get rid of the vias in the power line that crosses it.So....I saw a KiCAD video on YT and ended up making an ACA mini mono board with @Mark Johnson 's SMPS filter. Can you guys tell me if I've effed up anything pls? This is the first time I've used KiCAD and I'm not a circuit designer or an EE so feel free to be as brutal with your comments as needed
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