Finished!!!
Thank you everyone for their help! Especially @birdbox and @Nelson Pass
This little thing sounds incredible! It’s pushing my DIY coaxial cabinets with ease. The bass is much fuller than the class D amp I was using while waiting for this to finish. I am super satisfied!
Turns out the wiring was opposite of what we thought. Push in to turn it on. Looks fine to me though 🙂
Thank you everyone for their help! Especially @birdbox and @Nelson Pass
This little thing sounds incredible! It’s pushing my DIY coaxial cabinets with ease. The bass is much fuller than the class D amp I was using while waiting for this to finish. I am super satisfied!
Turns out the wiring was opposite of what we thought. Push in to turn it on. Looks fine to me though 🙂
Beautiful looking. But this is simpler.... Radio Shack APM-200
https://www.ebay.com/itm/3756014168...MI77nh7IKFiwMVCxqtBh1eqQDNEAQYAiABEgLjRPD_BwE
https://www.ebay.com/itm/3756014168...MI77nh7IKFiwMVCxqtBh1eqQDNEAQYAiABEgLjRPD_BwE
Yeah...there a new ones that look even better imo: MC2100
I just like the looks of them built into an amp.
It says "Please select AC12V/500mA AC power input". I'm guessing this means you would need to power this separately from the amp.
A couple of weeks ago, I finally put together an ACA Mini from the DIYaudio store kit. It was super easy—no more than an hour to assemble and another hour to get the bias stable. The trickiest part was adjusting the potmeters, as even the smallest change had a big effect. Next time, I’ll definitely go with 10-turn potmeters for more precision. But overall, it’s been running smoothly for weeks now, so that’s really just a one-time thing.
I’m using the ACA Mini as a tweeter amp for a pair of compression drivers, after reading a lot about its treble clarity. I knew it had low gain, but I wasn’t expecting to need to turn up the gain on my crossover to +5dB to match the midrange. Normally, I’d set the gain to around -10 to -12dB with my other amps, so that’s a 15-17dB difference. This suggests the ACA Mini only has around 10dB of gain, which is lower than I anticipated. I thought the gain was closer to 15dB, but I must have misread that somewhere.
I believe the low gain is contributing to the lack of dynamics. I’ve experienced this with other low-gain amps before, and adding a gain stage really helps bring out the "drive," which seems a bit lacking here when compared to my Hiraga amp. Out of the box, the Hiraga just sounds better—not just because it’s louder or more powerful (since 1 watt would be plenty for my 110dB/w drivers). I’m not using a preamp—just a DEQX crossover with a max 2V output. That’s enough to drive the ACA Mini to clipping, but a little extra gain would give it a bit more authority.
Does anyone know of a simple Class A gain stage that could run off the same power supply? I think an extra 6 to 12 dB would really bring the ACA Mini to life. It sounds great—sweet and clear—but it could use a bit more punch!
I’m using the ACA Mini as a tweeter amp for a pair of compression drivers, after reading a lot about its treble clarity. I knew it had low gain, but I wasn’t expecting to need to turn up the gain on my crossover to +5dB to match the midrange. Normally, I’d set the gain to around -10 to -12dB with my other amps, so that’s a 15-17dB difference. This suggests the ACA Mini only has around 10dB of gain, which is lower than I anticipated. I thought the gain was closer to 15dB, but I must have misread that somewhere.
I believe the low gain is contributing to the lack of dynamics. I’ve experienced this with other low-gain amps before, and adding a gain stage really helps bring out the "drive," which seems a bit lacking here when compared to my Hiraga amp. Out of the box, the Hiraga just sounds better—not just because it’s louder or more powerful (since 1 watt would be plenty for my 110dB/w drivers). I’m not using a preamp—just a DEQX crossover with a max 2V output. That’s enough to drive the ACA Mini to clipping, but a little extra gain would give it a bit more authority.
Does anyone know of a simple Class A gain stage that could run off the same power supply? I think an extra 6 to 12 dB would really bring the ACA Mini to life. It sounds great—sweet and clear—but it could use a bit more punch!
Thanks. That looks simple enough I'll give it a look. I might omit the output cap since the ACA mini allready has an inputcap.
Gain is indeed 14dB to 15dB.
I could be mistaken but what you report seems to me more DF related. Have you checked impedance and phase curves of your LS?
I could be mistaken but what you report seems to me more DF related. Have you checked impedance and phase curves of your LS?
It is a 16ohm compression driver used from 3500Hz on up in an active system. Well actually what sells as a 16ohm driver. Minimum impedance is around 9ohm, rising to about 12ohm. phase reponse is prety flat as well, haven't got the numbers at hand. Effiency is 110dB/watt so around 107dB/2.83V in this case. Should be an easy load for this amp.
Indeed!
Jumpers IN offers to my ears a slightly bit more "drive" as you say (perception I get is as a slightly faster rising front), as do the mods BTW, but TBH it won't change the "enjoyable Mini sound signature" by miles...
Don't know if more gain in the chain can really change that, but an additional "fast sounding pre" as you want it could perhaps... so good luck to you!
Claude
Jumpers IN offers to my ears a slightly bit more "drive" as you say (perception I get is as a slightly faster rising front), as do the mods BTW, but TBH it won't change the "enjoyable Mini sound signature" by miles...
Don't know if more gain in the chain can really change that, but an additional "fast sounding pre" as you want it could perhaps... so good luck to you!
Claude
Given the low price of the board and basic kit if really wanting a mono Mini I would simply take the stereo board and basic kit and complete then only one half of the Mini.
The Mini is already double Mono so to say from the PS cap on, and savings on a dedicated Mono Mini regarding board + JFETs + SMPS would be negligeable IMHO vs simply not populating one half / one channel of the existing stereo Mini board...
Just my quick POV
Claude
The Mini is already double Mono so to say from the PS cap on, and savings on a dedicated Mono Mini regarding board + JFETs + SMPS would be negligeable IMHO vs simply not populating one half / one channel of the existing stereo Mini board...
Just my quick POV
Claude
^ Are you asking if you can use an existing ACA Mini and run it bridged or parallel?
Hi all !
Here is the latest build by Claude, with his mods underneath.
In preparation for an upcoming V biamp 'integrated' assembly...
Thanks to Mr. Pass, diyaudio community, and Claude 🙂
Gilles.
Here is the latest build by Claude, with his mods underneath.
In preparation for an upcoming V biamp 'integrated' assembly...
Thanks to Mr. Pass, diyaudio community, and Claude 🙂
Gilles.
