Skylar88 -
What does the enclosure have to do with it?
You're right. The enclosure has nothing to do with it. Newbie mistake, sorry.
Ground is ground, but my underlying argument stands - I think... Both amps should share a common ground for successful bridging. Or am I committing another audio sin? 😀
Bridged channels are usually in the same chassis, but it is not an absolute
requirement. It's just nice to have a single good common ground.
requirement. It's just nice to have a single good common ground.
Thanks so much for this. I’m in the middle of giving it a try and swear I couldn’t find R13 anywhere on that schematic!
As a side note, I think I need new glasses - soldering is much more difficult than it used to be.
As a side note, I think I need new glasses - soldering is much more difficult than it used to be.
awesome, thanks! i also made this table, maybe it will also be helpful:
R1 .47 3W
R2 .47 3W
R3 .68 3W
R4 .68 3W
R5 100
R6 100
R7 10k
R8 1K
R9 1K
R10 332K
R11 10K
R12 39.2K
R13 10k
R14 1K
R15 2.21k
C1 3300
C2 1000
C3 10
C4 10
Q1 IRFP240
Q2 IRFP240
Q3 ZTX450
Q4 2SK170
P1 5K
Everybody - Please feel free to post photo in the thread!
Soundhappy - The ACA's CCS is most accurately called a Mu-Follower.
The output node between the power resistors and the CCS on top of those resistors allows the CCS to vary into the load
to help the output device drive it. (More power, more damping)
ACA is a Single-Ended common source amplifier with his CCS special Mu-Follower variant. I get it 😀
Thanks 6L6 for all amazing good DIY work Bravo!
Attachments
I couldn’t find R13 anywhere on that schematic!
R13 = 10K is connected to the LED diode 🙂
Attachments
R13 = 10K is connected to the LED diode 🙂
Thanks! I have no idea why I couldn’t find it.
Thanks! I have no idea why I couldn’t find it.
Happens to me frequently.
I focus attention strongly and search all around, but the thing is easy straight in front of me

Funny phenomena ! Good luck to Your Diy amp build
I like this photo! 🙂
That's Linear System's Paul Norton in the background. Super nice guy!
ACA evenement DIY
Linear System's made first ACA Camp video

Hello, I just finished the aca amp, in the schematic there is not volume pot. does this mean that the volume is not adjustable? please any help ia appreciated.
bye,
sjariev
bye,
sjariev
Hello, I just finished the aca amp, in the schematic there is not volume pot. does this mean that the volume is not adjustable? please any help ia appreciated.
bye,
sjariev
No volume pot in the default kit.
6L6 mentioned a 25k pot between RCA input and amplifier a couple of posts ago, you should find it going back in the thread.
Edit: Maybes it was in the ACA 1.0 thread / build guide.
Last edited:
Some pictures of a finished George 🙂 :
Finishing up build
Playing some magic (Keith don't go live by Nils Lofgren) through my Dynaudio's Special 25. as pre-amp I use the (here invisible) NAD Masters M12 with BluOS streamingmodule
Astonishing my colleagues at work putting the NAD Masters M22 (Hypex nCore based) to shame when it comes to soundstage and holographic presentation. The M22 literally costs 10 times as much😀
A brilliant amp designed by a brilliant man! Thanks Nelson! Next step... ditch my own NAD M22 for a Pass XA25?
Later guys, cheers Dan.
Finishing up build
An externally hosted image should be here but it was not working when we last tested it.
Playing some magic (Keith don't go live by Nils Lofgren) through my Dynaudio's Special 25. as pre-amp I use the (here invisible) NAD Masters M12 with BluOS streamingmodule
An externally hosted image should be here but it was not working when we last tested it.
Astonishing my colleagues at work putting the NAD Masters M22 (Hypex nCore based) to shame when it comes to soundstage and holographic presentation. The M22 literally costs 10 times as much😀
An externally hosted image should be here but it was not working when we last tested it.
A brilliant amp designed by a brilliant man! Thanks Nelson! Next step... ditch my own NAD M22 for a Pass XA25?
Later guys, cheers Dan.
.......Next step... ditch my own NAD M22 for a Pass XA25?
........
oh, yes!
btw , it's Fugly!
give us some closer picture of front ......
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Couldn't leave my trusted esotar2 Dynaudio 's out of the pictures, or the M12 for that matter, love that pre-amp
Dan.
I love Dynaudios ..... small ones .... but I hate one thing with small speakers - when listening on low volume , everything is just ........ smaller.
that's why I generally prefer big spks
that's why I generally prefer big spks
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