Quoted
If you are sure the Black terminals are connected to the GND / 0 volt line then they will all be connected together through the power supply leads, so no output...
So the 'Parallel v2' scheme cannot work.
V3 is what you would need to do. I have left a wire between 2 of the black terminals to bond the 0 v / GND of both ACAs together.
If you are using two power supplies, then it will be much better to go 'horizontal' (however you want to configure your caps...) then each monoblock will have its own power supply rather than 'share' half and half with the other block.
If you are sure the Black terminals are connected to the GND / 0 volt line then they will all be connected together through the power supply leads, so no output...
So the 'Parallel v2' scheme cannot work.
V3 is what you would need to do. I have left a wire between 2 of the black terminals to bond the 0 v / GND of both ACAs together.
If you are using two power supplies, then it will be much better to go 'horizontal' (however you want to configure your caps...) then each monoblock will have its own power supply rather than 'share' half and half with the other block.
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Reply
Looking into this a bit more I see something I hadn't appreciated before the ACA now sold and referred in the build guides using the diyaudio chassis has one power supply which is used to power both channels. got my act's from the diyaudio shop with the heatsinks and all parts and at that time those parts included power switches and power sockets to run with one power supply per channel so from day one the two channels have been completely isolated from each other with no common ground. which also accounts for the annoying fact that my input and output does not match that's shown in the build guide!
I don't want to resolver the caps or other option in and out terminals/sockets wiring vertically to avoid this is exactly the same as horizontal I realise now as I have in effect four completely independent amplifiers there are no grounds or power supply shared between them at the moment.
if running parallel is a matter of linking all inputs and outputs, is that's right? then I am thinking that v2 of the layout will work? and also the v2 brides should work as is.
Im going away now to think it through again. thanks for all the insight so far
If you are sure the Black terminals are connected to the GND / 0 volt line then they will all be connected together through the power supply leads, so no output...
So the 'Parallel v2' scheme cannot work.
V3 is what you would need to do. I have left a wire between 2 of the black terminals to bond the 0 v / GND of both ACAs together.
If you are using two power supplies, then it will be much better to go 'horizontal' (however you want to configure your caps...) then each monoblock will have its own power supply rather than 'share' half and half with the other block.
If you are sure the Black terminals are connected to the GND / 0 volt line then they will all be connected together through the power supply leads, so no output...
So the 'Parallel v2' scheme cannot work.
V3 is what you would need to do. I have left a wire between 2 of the black terminals to bond the 0 v / GND of both ACAs together.
If you are using two power supplies, then it will be much better to go 'horizontal' (however you want to configure your caps...) then each monoblock will have its own power supply rather than 'share' half and half with the other block.
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Reply
Looking into this a bit more I see something I hadn't appreciated before the ACA now sold and referred in the build guides using the diyaudio chassis has one power supply which is used to power both channels. got my act's from the diyaudio shop with the heatsinks and all parts and at that time those parts included power switches and power sockets to run with one power supply per channel so from day one the two channels have been completely isolated from each other with no common ground. which also accounts for the annoying fact that my input and output does not match that's shown in the build guide!
I don't want to resolver the caps or other option in and out terminals/sockets wiring vertically to avoid this is exactly the same as horizontal I realise now as I have in effect four completely independent amplifiers there are no grounds or power supply shared between them at the moment.
if running parallel is a matter of linking all inputs and outputs, is that's right? then I am thinking that v2 of the layout will work? and also the v2 brides should work as is.
Im going away now to think it through again. thanks for all the insight so far
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Now I understand where you are!
Yes the first kit (which you have) does have different instructions too, no wonder we had (literally) crossed wires!
The parallel picture v2 you posted is correct.
The bridged picture now needs a little clarification to be sure.
If you do a simple continuity test (use the 2k range) from the outer ring of the RCA connector (which is GND) to the Black output terminal and the reading is 800 - 1000 ohms then your picture is correct. If it is zero ohms then move everything to the Red terminals.
Either way you will have to common the GND lines of the pair you make into monoblocks. Easiest is to link the terminals, that measure zero ohms in the above test, together.
Hope that makes sense???
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Have you guys seen this review of the ACA? It's awful. I've never heard of this guy or site?
Pass ACA Class A Power Amplifier Review | Audio Science Review (ASR) Forum
Pass ACA Class A Power Amplifier Review | Audio Science Review (ASR) Forum
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It’s not awful it was comedy
For those of us who strive to listen to the best music we can over the last 20, 30 or 40 years and we’ve owned many amplifiers many receivers many pairs of speakers to that never ending wallet draining drive for beautiful music.
If we’re in this form then we probably already finished building the ACA. And if we have good music source and a good set of speakers we were probably blown away by this little jewel that only puts out 8 WATTS.
We also know if you have your speaker placement correctly positioned in the right room every person you bring through that door when they’re standing in front of the speakers with the right music on you watch their jaw drop or you see their eyes gaze over and their body standstill and they just listen as you wait for them to comment on how incredible that sound of music is that they’ve never heard in that same piece of music on their system at home.
“!But oh my god that horrible distortion!”. LOL Give a technician tools and let him run some numbers it tells you a lot about the technician.
I had to comment on that form I did not defend and I definitely did not copy and paste and put up some numbers from test with equipment. Just a response of my experience building this little amplifier and all the students in my electronics class that I turned on to the little ACA amplifier and even my instructor in electronics class who is a avid audiophile Who is blown away by this little amplifier In its category as a excellent training tool to get somebody into this hobby. Below is my listed response.
(“ I just came across this form and this review very interesting reading from a very uninformed perspective. Several years ago I came across this amp camp amp version 1.1 that only used a 19Vault power supply and only produced 4W or 5 W of power. Because it was advertised as class A is what caught my attention because I used to own a Tandberg amplifier that I bought used on a recommendation of a neighbor who is a high-end audio sales person I was only 22 not a lot of money and he told me it was only 10 W of class A and it was switchable to class AB at 40 W. I was used to class D amplifiers Sony Panasonic Kenwood Fisher Onkyo Denon Marantz that had 80 W or 150 W So I was not interested in a puny little amp that only was capable of 10 W of power or 40 W of power but I was ignorant and did not know what class A amplifiers can do and how they sounded.
Flash forward some 30 years and when reading forms I came across ACA (Amp Camp Amp) I was in college in electronics class EET 101 at the time And we were told to pick a graduation project. So at first I only purchased the transistors the PCB boards were out of stock so I built it on a breadboard. The resistors and diode’s and other little project parts were all free provided by the class I was in build a class a power supply from leftover scrap products I had from torn down scavenging.
I did read the details on this amplifier indicating they recommend higher 90s db efficient speakers 8 ohms to be exact. So I downloaded the Gerber files to build the Fostex BK-20 folded horn kit cabinet. To come over to the wood shop on the CNC machines used a few sheets of Baltic Birch plywood and constructed my speakers from scratch. Using the Fostex FE206EN drivers Rated at 98db Because I actually read the instructions and recommendations about this little amplifier I was about to build it’s called “Following Instructions!”. After listening to this working on the breadboard and it was absolutely outstanding I scavenged old aluminum computer case some heat sinks that I scavenged from a dead inverter board off an air conditioning unit part of my job I get for free. The PCB version 1.1 B became available and I bought them up assembled it Brought it to class with the speakers that weighed 80 pounds apiece and blew away the students and the teacher with both loudness and unbelievable sound they could not believe that was coming from 4 W. I got my A in class on this project. Sound source was a Microsoft Surface pro 4 laptop, Fed into a IFI BLACK LABEL, to the ACA.
Sony Panasonic Kenwood Fisher Onkyo Denon Marantz Are all gone in storage or used for reference testing as comparison. The Marantz was from 1972 I completely tore all the boards apart and restored it it resides at my mothers house. all the speakers that were with those different stereo systems I kept for testing reference in comparison.
The sound that comes from the Amp Camp Amp is definitely class A. Last year I purchased the expensive Italian aluminum cases and built the 15 W class A amp camp amp mono blocks. I’m now currently building Nelsons BA3 Front end preamp stage for my ACA For my Electronics class 102A project.
Next class project Nelson’s alpha J Amplifier.
It’s amazing how the stats and the numbers adding up to the best baseball team are supposed to be the winner but they don’t always win.
The NASCAR race car with the highest horsepower in the best driver who wins the best pole position and has the best statistics loses the race but he had the best numbers.
$3 billion in 500 years of combined knowledge of engineers send a satellite and with all the best equipment in the best math with numbers and it crashes.
And look at here again reading this form about the fancy equipment and the math and the readouts and Plotted charts. That come to a result put in black-and-white on paper. You could put the best tools and equipment into the hands of a person. And their results can show all the bells and whistle‘s and smoking glitter.
Well you can see where I’m going with this and I guess you know with all those numbers and readings mean.
Still to this day a quarter million dollars in equipment and not having the right person driving it cannot compare to what your ears hear. Numbers, math, fancy paper LOL “).
For those of us who strive to listen to the best music we can over the last 20, 30 or 40 years and we’ve owned many amplifiers many receivers many pairs of speakers to that never ending wallet draining drive for beautiful music.
If we’re in this form then we probably already finished building the ACA. And if we have good music source and a good set of speakers we were probably blown away by this little jewel that only puts out 8 WATTS.
We also know if you have your speaker placement correctly positioned in the right room every person you bring through that door when they’re standing in front of the speakers with the right music on you watch their jaw drop or you see their eyes gaze over and their body standstill and they just listen as you wait for them to comment on how incredible that sound of music is that they’ve never heard in that same piece of music on their system at home.
“!But oh my god that horrible distortion!”. LOL Give a technician tools and let him run some numbers it tells you a lot about the technician.
I had to comment on that form I did not defend and I definitely did not copy and paste and put up some numbers from test with equipment. Just a response of my experience building this little amplifier and all the students in my electronics class that I turned on to the little ACA amplifier and even my instructor in electronics class who is a avid audiophile Who is blown away by this little amplifier In its category as a excellent training tool to get somebody into this hobby. Below is my listed response.
(“ I just came across this form and this review very interesting reading from a very uninformed perspective. Several years ago I came across this amp camp amp version 1.1 that only used a 19Vault power supply and only produced 4W or 5 W of power. Because it was advertised as class A is what caught my attention because I used to own a Tandberg amplifier that I bought used on a recommendation of a neighbor who is a high-end audio sales person I was only 22 not a lot of money and he told me it was only 10 W of class A and it was switchable to class AB at 40 W. I was used to class D amplifiers Sony Panasonic Kenwood Fisher Onkyo Denon Marantz that had 80 W or 150 W So I was not interested in a puny little amp that only was capable of 10 W of power or 40 W of power but I was ignorant and did not know what class A amplifiers can do and how they sounded.
Flash forward some 30 years and when reading forms I came across ACA (Amp Camp Amp) I was in college in electronics class EET 101 at the time And we were told to pick a graduation project. So at first I only purchased the transistors the PCB boards were out of stock so I built it on a breadboard. The resistors and diode’s and other little project parts were all free provided by the class I was in build a class a power supply from leftover scrap products I had from torn down scavenging.
I did read the details on this amplifier indicating they recommend higher 90s db efficient speakers 8 ohms to be exact. So I downloaded the Gerber files to build the Fostex BK-20 folded horn kit cabinet. To come over to the wood shop on the CNC machines used a few sheets of Baltic Birch plywood and constructed my speakers from scratch. Using the Fostex FE206EN drivers Rated at 98db Because I actually read the instructions and recommendations about this little amplifier I was about to build it’s called “Following Instructions!”. After listening to this working on the breadboard and it was absolutely outstanding I scavenged old aluminum computer case some heat sinks that I scavenged from a dead inverter board off an air conditioning unit part of my job I get for free. The PCB version 1.1 B became available and I bought them up assembled it Brought it to class with the speakers that weighed 80 pounds apiece and blew away the students and the teacher with both loudness and unbelievable sound they could not believe that was coming from 4 W. I got my A in class on this project. Sound source was a Microsoft Surface pro 4 laptop, Fed into a IFI BLACK LABEL, to the ACA.
Sony Panasonic Kenwood Fisher Onkyo Denon Marantz Are all gone in storage or used for reference testing as comparison. The Marantz was from 1972 I completely tore all the boards apart and restored it it resides at my mothers house. all the speakers that were with those different stereo systems I kept for testing reference in comparison.
The sound that comes from the Amp Camp Amp is definitely class A. Last year I purchased the expensive Italian aluminum cases and built the 15 W class A amp camp amp mono blocks. I’m now currently building Nelsons BA3 Front end preamp stage for my ACA For my Electronics class 102A project.
Next class project Nelson’s alpha J Amplifier.
It’s amazing how the stats and the numbers adding up to the best baseball team are supposed to be the winner but they don’t always win.
The NASCAR race car with the highest horsepower in the best driver who wins the best pole position and has the best statistics loses the race but he had the best numbers.
$3 billion in 500 years of combined knowledge of engineers send a satellite and with all the best equipment in the best math with numbers and it crashes.
And look at here again reading this form about the fancy equipment and the math and the readouts and Plotted charts. That come to a result put in black-and-white on paper. You could put the best tools and equipment into the hands of a person. And their results can show all the bells and whistle‘s and smoking glitter.
Well you can see where I’m going with this and I guess you know with all those numbers and readings mean.
Still to this day a quarter million dollars in equipment and not having the right person driving it cannot compare to what your ears hear. Numbers, math, fancy paper LOL “).
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Technician? I am an electrical engineer. Electronics was my hobby well before I got my degree. I built my first audio amplifier in 1970s when I was in middle school.
I answered the rest of your post on ASR Forum.
I bought an ACA because I needed a modestly priced very low watt Amp that would keep my system going over Xmas while my valve amp was being repaired. Attenuating the 12watt per channel valve amps output enough to make the volume knob useable for more than a 1/4 turn had been a challenge.
I built the single ACA carefully over a day and hooked it up to 105db/watt single driver speakers with plate amp driven subs. The result was spectacularly good at any price let alone for something I'd soldered up my self. When the Valve amp came back the ACA was replaced but some qualities I'd heard where lacking. So a few months later and itching to know what a bridged pair would sound like and thinking most people would need the extra watts if I wanted to sell, I bought a second one.
The bridged pair now have a permanent home and it's the valve amp that's been put back in it's box.
If great sounding hi-fi came down to just how things measured in a lab there wouldn't be an amplifier in production that cost more than $10 and for $10 you'd have perfection. Not surprising that the perfect amp doesn't exist yet given how little is known about the workings of the signal processor - the human brain.
I'm happy to recommend the ACA to any one with sensitive speakers as being a great sounding AMP that's pleasing to the ear with a massive sound stage that will keep your toes tapping and give you the emotional engagement with the musical performance you'd expect but that's sadly often lacking from equipment costing 10 times the price.
A lot of comments on the other forum about lack of power remind me of the same idiot comments posted under articles about electric cars - The it's no good I can't tow my boat with it brigade. ACA works very well when used as intended if it won't drive your speakers tough it's not for you.
I built the single ACA carefully over a day and hooked it up to 105db/watt single driver speakers with plate amp driven subs. The result was spectacularly good at any price let alone for something I'd soldered up my self. When the Valve amp came back the ACA was replaced but some qualities I'd heard where lacking. So a few months later and itching to know what a bridged pair would sound like and thinking most people would need the extra watts if I wanted to sell, I bought a second one.
The bridged pair now have a permanent home and it's the valve amp that's been put back in it's box.
If great sounding hi-fi came down to just how things measured in a lab there wouldn't be an amplifier in production that cost more than $10 and for $10 you'd have perfection. Not surprising that the perfect amp doesn't exist yet given how little is known about the workings of the signal processor - the human brain.
I'm happy to recommend the ACA to any one with sensitive speakers as being a great sounding AMP that's pleasing to the ear with a massive sound stage that will keep your toes tapping and give you the emotional engagement with the musical performance you'd expect but that's sadly often lacking from equipment costing 10 times the price.
A lot of comments on the other forum about lack of power remind me of the same idiot comments posted under articles about electric cars - The it's no good I can't tow my boat with it brigade. ACA works very well when used as intended if it won't drive your speakers tough it's not for you.
I have a feeling that commercial speakers shows dB figures that is a bit optimistic. I am surprised that with my 93-94 dB OBL-15 speakers I almost never reach 1W in power unless I play louder than I need or want or I have guests which like heavy metal played at concert levels. My ACAs can play "painful" loud if pushed with OBL-15 speakers. ACA is a perfect amp used with speakers which you could also use a 7W 300B SE amp. With this kind of amps you need speakers where a normal listening level is reached with output power below 1W in average.
Since the Naim Nait2 (class AB) appearance, it is my main amp. When it came out, the whole hifi world appraised it, it was one of the first, low powered amp with big transfo !
Nad used the same philosophy years later and got its reputation through it.
The FW approach being in some ways identical, I built the ACA. You see I don't listen to music with graphics, I am not an electronician, I use my ears ! And this little ACA is singing very much as well or better than the Nait2 which I guess do not give much to recent productions.
Keep your graph, open your ears.
Nad used the same philosophy years later and got its reputation through it.
The FW approach being in some ways identical, I built the ACA. You see I don't listen to music with graphics, I am not an electronician, I use my ears ! And this little ACA is singing very much as well or better than the Nait2 which I guess do not give much to recent productions.
Keep your graph, open your ears.
"Amplifiers need to have a lot more power" (from that "review")
well... the above tells it all
what I do not understand is... why someone spends his time "testing" something that is right the opposite of how **he** **believes** things should be?
/rant
back to listening at my 3W 2A3 amplifier now
well... the above tells it all
what I do not understand is... why someone spends his time "testing" something that is right the opposite of how **he** **believes** things should be?
/rant
back to listening at my 3W 2A3 amplifier now
So what.
I know quite a few electrical / electronic engineers who have no clue whatsoever about Audio stuff or good sound for that matter. Ohm's law is great and very helpful but it tells you fcuk all about how a certain topology or design decision will influence sound.
At the end of the day we listen to the devices and compare them to the imaginary or memorized "live" sound.
Not sure if you know but the "sound" with its timbre, depth, spaciousness, accuracy, richness, subtlety, brings emotions that cannot be described based of the input from a CRO (cathode ray oscilloscope) or a SpecAn.
And if you want to compare the distortion of Amp X to Amp Y that's fine.
1% vs 0.001% has to be considered in the context of class of operation, efficiency, load and many other factors.
But at the end we listen with our ears.
Anyone can write a review about a subject they don't understand, are not willing to understand and are ignorant in their approach.
Being an electrical/electronic engineer means nothing in the context of Audio if one cannot listen and most importantly hear the magic of sound.
I am an electronics engineer too but that is really irrelevant.
I am a listener and a music lover first.
My current amps are a ACA, a MoFo, a ZenLite Headamp and a E88CC SRPP headamp.
According to your school of thought they are all distortion generators.
To me they are glorious music machines.
I listen to them daily.
Got rid of all Rotel, NAD, Pioneer gear that I had before.
A final piece of advice - in this digital age one should be wary of posting rubbish about things they don't know or understand. It will always come back to bite you.
Hasta la vista.
I like to test my builds and make measurements to test if they are up to spec. or maybe better with some slights modifications
I try to compensate for the psychological effect. The only way is to listen for a very long period of time. It is easy to be too excited about something you just have built that seems to work. Also the opposite if you test an amp where the mind is negative the sound probably will sound bad.
ACA is not so good with a passive pre as it will interact with the NFB loop. Also gain is not as high as with other Pass power amps. For my speakers the relative low gain in ACA gave me a very silent (noise) setup.
I try to compensate for the psychological effect. The only way is to listen for a very long period of time. It is easy to be too excited about something you just have built that seems to work. Also the opposite if you test an amp where the mind is negative the sound probably will sound bad.
ACA is not so good with a passive pre as it will interact with the NFB loop. Also gain is not as high as with other Pass power amps. For my speakers the relative low gain in ACA gave me a very silent (noise) setup.
Not if you care about how a good Class A sounds. People consider Class A to have less distortion than other amplifier configurations. Such is not the case here.
What do you mean so what? He called me a technician and I explained I was not.
My background is linked to in every review and post on ASR.
If you are going to take shots at me, at least spend a bit researching who I am before making arguments that can be shown to be false so easily.
You are confusing the art and recorded music with sound reproduction. Regardless, if you have results of double blind tests of this amp showing those attributes versus another amp, I would love to read it. Until then, I listened to it and it has none of the things you mention over other amplifiers.
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I am too. The difference between us is that I had to have proper listening skills as part of my job and you do not. Maybe you post some evidence of how good you are in detecting distortions. Then we have something to chew on. As it is, what you say goes against the fact that you are defending an amplifier which distorts the artist's intent and call it great. If that kind of distortion is great, why didn't the artist put it in the music?
Again, vast majority of audiophiles are not critical listeners. That is there reason they don't hear these artifacts that we can prove 100% reliably with measurements. Without this fact, all this non-performant gear would not exist in the market. So that is not in dispute.
What is in dispute is why you would want to buy a low-power amplifier with tons of distortion when you get could one with much more transparent sound so that you could hear artist's intent.
Well, we will see.