Hi,
I am new to this forum and I write from Spain.
I just bought two units of ACA v1.8 (I am eager to build it when I receive it) and I am reading a lot in this forum, but ACA v1.6 threads are very long and dense.
I have a question that may have already been answered. I hope you forgive me.
From what I see, the best operation is in two monoblocks in parallel input since the specifications are from 16w to 4ohm, 8w to 8 ohm and a damping factor of 20. Is this correct?
My question is how the speakers are connected to the amplifier, since I am looking at the connection diagram on the rear panel and I did not quite understand it very well. Could someone clarify for me?
On the other hand, I understand that in this mode of operation it is not necessary to connect the two RCA (L / R) since the connection is internal. Right?
Greetings from Spain
PS: sorry for my English ...
I am new to this forum and I write from Spain.
I just bought two units of ACA v1.8 (I am eager to build it when I receive it) and I am reading a lot in this forum, but ACA v1.6 threads are very long and dense.
I have a question that may have already been answered. I hope you forgive me.
From what I see, the best operation is in two monoblocks in parallel input since the specifications are from 16w to 4ohm, 8w to 8 ohm and a damping factor of 20. Is this correct?
My question is how the speakers are connected to the amplifier, since I am looking at the connection diagram on the rear panel and I did not quite understand it very well. Could someone clarify for me?
On the other hand, I understand that in this mode of operation it is not necessary to connect the two RCA (L / R) since the connection is internal. Right?
Greetings from Spain
PS: sorry for my English ...
Welcome opm
I'm happy to see more spanish/spaniards? in the forum. Don't worry about your english, sure mine is worst than yours.
ACA is a wonderful little amp, you`ll be very happy. I've make 3 pairs and every one works first time. All of them stereo, sorry I can't help you.
Good luck with your ACAs.
I'm happy to see more spanish/spaniards? in the forum. Don't worry about your english, sure mine is worst than yours.
ACA is a wonderful little amp, you`ll be very happy. I've make 3 pairs and every one works first time. All of them stereo, sorry I can't help you.
Good luck with your ACAs.
To get an idea, I'd suggest you take a look at the v1.6 Build Guide, especially steps 53 - 55 that looks at the various ways to hook up the amp. Obviously v1.8 is a little different but until a guide comes along, that's the best I can think of to get you moving along.
The store page has a table of configuration and power details.
I ran my ACA v1.6 as a pair of balanced XLR monoblocks for living room use. I moved on and now I've got one of the amps driving some speakers at my desk where I work from at home. In that mode, there's more than enough drive to sort me out. That said, I've got reasonably sensitive speakers (North of 90 dB/W/m), so there will always be an "it depends" aspect to your setup.
Again, the store page has details on this.
I would suggest that you absorb as much guidance as you can without boiling your brain. So, keep reading. There's always a little bit of detail that you'll be glad that you knew by taking the time.
Not sure when the new v1.8 guide will go up, if you can wait, that will probably be the most direct path if you want to minimise juggling information.
I understand that the only thing that changes in v1.8 is the silkscreen of the rear panel and the wiring connections.
In this link https://cdn.shopify.com/s/files/1/1006/5046/files/ACA_V1.8_Rear_Panel.jpg?v=1593489546
you can see the connection to the speakers in parallel mode and it is very strange.
OUTPUT CONNECTION: (PARALLEL MONO)
A+ TO SPEAKER +
A- TO SPEAKER -
B- TO SPEAKER -
Are 3 cables used for one speaker?
In this link https://cdn.shopify.com/s/files/1/1006/5046/files/ACA_V1.8_Rear_Panel.jpg?v=1593489546
you can see the connection to the speakers in parallel mode and it is very strange.
OUTPUT CONNECTION: (PARALLEL MONO)
A+ TO SPEAKER +
A- TO SPEAKER -
B- TO SPEAKER -
Are 3 cables used for one speaker?
If you put a wire between A- and B- on the amp, you only have only 2 wires to the speaker.
A+ to speaker + , and A- to speaker -
(So you have 2 wires on connector A- )
A+ to speaker + , and A- to speaker -
(So you have 2 wires on connector A- )
Thanks for answering.
It's what I was planning to do, wire between the negative channels. The only thing that seemed strange to me.
Is there a way to update or improve the ACA?
It's what I was planning to do, wire between the negative channels. The only thing that seemed strange to me.
Is there a way to update or improve the ACA?
ACA modifications
This is still what I like to suggest as an initial set of ACA modifications. Both R16 and C101 are extra components that need some jury rigging to install on the PCBs from the store. And most have found them to be worthwhile.
I also recommend building a linear PSU that will provide 28V to 32V on the board, and using IRFP140 Mosfets for Q1 and Q2. This will require larger heatsinks than the standard chassis that comes with the full kit. Fortunately the store carries the Mini Dissipante 3U, 250mm. This is just the right size for an enhanced ACA. If you are willing to go this route, you will probably find that a single stereo amplifier performs as well (and better) than a pair of bridged ACA monoblocks. A little extra effort in building a good PSU really pays for itself.
There is some really great work in the last few pages of the "ACA with premium parts" thread from some newer contributors. We're building a nice community with lots of ideas to explore.
Enjoy the music 😎
This is still what I like to suggest as an initial set of ACA modifications. Both R16 and C101 are extra components that need some jury rigging to install on the PCBs from the store. And most have found them to be worthwhile.
I also recommend building a linear PSU that will provide 28V to 32V on the board, and using IRFP140 Mosfets for Q1 and Q2. This will require larger heatsinks than the standard chassis that comes with the full kit. Fortunately the store carries the Mini Dissipante 3U, 250mm. This is just the right size for an enhanced ACA. If you are willing to go this route, you will probably find that a single stereo amplifier performs as well (and better) than a pair of bridged ACA monoblocks. A little extra effort in building a good PSU really pays for itself.
There is some really great work in the last few pages of the "ACA with premium parts" thread from some newer contributors. We're building a nice community with lots of ideas to explore.
Enjoy the music 😎
Last edited:
Hello TungstenAudio, I really appreciate your intervention.
I have not yet received my two ACA v1.8 units and at the moment I have no intention of purchasing a new chassis.
What interests me is the linear PSU. I have been reading the ACA thread with premium parts, but there comes a time that I cannot follow the thread since many people who are knowledgeable in electronics intervene and I get lost.
Is there a linear PSU ready or to build in an "easy" and concise way for two monoblocks? Is there a turorial?
Regards
I hope my English is not very confusing
I have not yet received my two ACA v1.8 units and at the moment I have no intention of purchasing a new chassis.
What interests me is the linear PSU. I have been reading the ACA thread with premium parts, but there comes a time that I cannot follow the thread since many people who are knowledgeable in electronics intervene and I get lost.
Is there a linear PSU ready or to build in an "easy" and concise way for two monoblocks? Is there a turorial?
Regards
I hope my English is not very confusing
1) The ACA mods work well with the 24V brick PSU that comes with the full kit. You can skip R16.
2) A linear PSU for this amp is custom built to fit into the available space, and does need a larger chassis. No kits or tutorials are available. Too many different options.
2) A linear PSU for this amp is custom built to fit into the available space, and does need a larger chassis. No kits or tutorials are available. Too many different options.
Search generic Firstwatt power supply (all model uses the same) and build just the +24 rail. It's easy, but be careful with 220v. If you want monoblocks, build 2 psu.
Easier: buy some board and fill with good components. I get mine from Tea-Bag group buy, very very good boards (Thanks you Tea-Bag!!)
You can also buy Universal Power Supply from Diyaudio Store. 6L6 wrote a build guide:
diyAudio Power Supply Circuit Board v3 illustrated build guide
A single board can provide 2 x +24v using one or two transformers.
diyAudio Power Supply Circuit Board v3 illustrated build guide
A single board can provide 2 x +24v using one or two transformers.
vitorio is correct. Care is required if you go that route though.
You'd need to make sure that you get capacitor polarity and connection to your rectifier bridge in the correct orientation for the negative rail because in that use case, the -ve rail is being repurposed as a positive rail.
Another option is to consider a single rail PSU such as that worked up by xrk971, AKSA and jhofland:
Post #145 - Single Rail SLB PSU
That way you're less likely to get confused and you'll have an easier life. But hey, living life on the edge has an exciting quality. Popping a cap is just one of the bumps in the road - avoidable with care. Just don't rush..
You'd need to make sure that you get capacitor polarity and connection to your rectifier bridge in the correct orientation for the negative rail because in that use case, the -ve rail is being repurposed as a positive rail.
Another option is to consider a single rail PSU such as that worked up by xrk971, AKSA and jhofland:
Post #145 - Single Rail SLB PSU
That way you're less likely to get confused and you'll have an easier life. But hey, living life on the edge has an exciting quality. Popping a cap is just one of the bumps in the road - avoidable with care. Just don't rush..
Hey guys, what is the power rating for the small metal film resistors with color codes in the ACA 1.8 kit? They look they might be 600mw?
Would this linear power supply be suitable for ACA v1.8?
LPSU100 Alimentation stabilisee lineaire 24V 4A 100W pour Amplificateur FDA - Audiophonics
LPSU100 Alimentation stabilisee lineaire 24V 4A 100W pour Amplificateur FDA - Audiophonics
Difficult to say without internal pictures/schematic. Yes, IF published power rating is ok for constant use. One power suply/2 ACA boards.
Better ask Audiophonics. Saludos
Better ask Audiophonics. Saludos
That is a nice looking power supply. Maybe a bit expensive.
So far, I prefer linear PSU for my ACA builds. These make it possible to use plenty of bulk capacitance, which improve the sound of the amps. It would be nice to see a linear PSU such as this which could be adjusted to 28V or 30V, which is how I like to run the IRFP140 and other power Mosfets.