I have a subwoofer under each speaker and run the speaker cables to the subwoofer plate amps and then another short length up vertically to a single full range driver. At the moment I’m driving the ACA unbalanced bridged but don’t see that running from balanced ACA would make any difference. My plate amps are designed to take left and right channel and combine both and have no output terminals. So if I was using just one I’d have to cable to the back of each speaker and then on to the sub. A lot of plate amps have four inputs and four outputs keeping the channels seperate if you wish. Plate amps are only taking a look at the signal from the speaker cable. Your main decision will be ether to go ACA to speaker to sub or ACA to sub to speaker dependent on position of you equipment. You could end up with long lengths of cable all over the shop.
Oh boy, two contradicting answers a minute apart from each other 
well, I had a feeling the 2 hots was an issue with a bridged amp. Currently I run speaker wire from a NAD amp to my speaker, then a short run of wire from the speaker terminals for a little device that lowers the speaker level to line level... then a short RCA to the sub input
Russound ADP-1.2 Speaker-level to Line-level Adapter at Crutchfield
It works really well, so just trying to figure the safest way to mimic this with a bridged amp. What would be the best way to get a ground from this?
well, I had a feeling the 2 hots was an issue with a bridged amp. Currently I run speaker wire from a NAD amp to my speaker, then a short run of wire from the speaker terminals for a little device that lowers the speaker level to line level... then a short RCA to the sub input
Russound ADP-1.2 Speaker-level to Line-level Adapter at Crutchfield
It works really well, so just trying to figure the safest way to mimic this with a bridged amp. What would be the best way to get a ground from this?
if there is no critical connection of amps (origin one and plate amp) through safety GND, you can even end without hum and buzz , and use balanced amp as feed for SE input of plate amp
but, if there is safety GND involved, it could end in tears
simple as that
point is having a clue what is happening
I've shed more than few tears, so sorta had some experience in avoiding same all, all the time ........
not once was said - GND is state of mind ........ it can be real, it can be virtual, it can be floating ....... but one thing it always must be - it must be deliberately organized
but, if there is safety GND involved, it could end in tears
simple as that
point is having a clue what is happening
I've shed more than few tears, so sorta had some experience in avoiding same all, all the time ........
not once was said - GND is state of mind ........ it can be real, it can be virtual, it can be floating ....... but one thing it always must be - it must be deliberately organized
Is the assumption that you are using 2 ACAs in dual mono configuration?
that's another set of questions
not complicated to answer, but need to be specific - in which way i can do this and that
I believe there is (maybe in Jim's build tutorial?) explanation of two ways of ACA balanced operation - classical feed with XLR, and second - feed with RCA while ACA connected in (lets call it) self- bridging arrangement
in any case, that really calls for proper manual, something on par with F4, with plenty of funny sketches
who's gonna make that ........
not complicated to answer, but need to be specific - in which way i can do this and that
I believe there is (maybe in Jim's build tutorial?) explanation of two ways of ACA balanced operation - classical feed with XLR, and second - feed with RCA while ACA connected in (lets call it) self- bridging arrangement
in any case, that really calls for proper manual, something on par with F4, with plenty of funny sketches
who's gonna make that ........
I’m using 1 RCA cable to each ACA operating in bridged mode. ACA are not earthed. But if I understand correctly XLR cables to a new pre-amp that will be earth connected may create a link not previously present. That might cause problems because of the way my powered subs are currently wired.
If both sides were "hot" than you'd hear nothing when you feed the speaker, either.
One side of a balanced output from a source, is phase inverted with respect to the other. And it comes out of the speaker outputs the same way. It gets inverted in the amplifier circuit as well so each side comes out opposite of what it was fed.
So as long as one side of the sub high level input is not at ground - it is ok to drive the sub input with the two - posts.
Hi,
I just finished my first ACA V1.8 it was a real fun build.
However, now I try to set the DC balance and I notice some strange behaviour. After turning on the DC goes up to about 12-13V but it begins to decrease immediately. It is the case with both channels.
Do you have a good advice for me? Or should I just wait for a while after turning on?
Thank you in advance!
I just finished my first ACA V1.8
it was a real fun build.However, now I try to set the DC balance and I notice some strange behaviour. After turning on the DC goes up to about 12-13V but it begins to decrease immediately. It is the case with both channels.
Do you have a good advice for me? Or should I just wait for a while after turning on?
Thank you in advance!
Attachments
Yep just leave it on away from drafts but with room for air to get around it. The pots are very sensitive just the the tiniest pressure with barely visible movement will see the meter start moving. If you’ve got more than one meter it helps to have both sides hooked up at the same time. It’s a game of patience very tiny movements with a bit of waiting and watching each time will get you on target faster. It might take you an hour and you might not get to 12volt- if you can get to 11.8 or 12.1 both sides then turn everything off and wire it up for some tunes.and enjoy.
Nice work! Steve covered it, but don't be in a hurry. It will be all over the place when you power on...then settle down (voltage stops changing) - that is when you want to start to adjust. It is really hard to get it to 12.00 volts...but if you get it really close (I think I got to 11.95 on both channels) fine.
Hi,
I just finished my first ACA V1.8
However, now I try to set the DC balance and I notice some strange behaviour. After turning on the DC goes up to about 12-13V but it begins to decrease immediately. It is the case with both channels.
Do you have a good advice for me? Or should I just wait for a while after turning on?
Thank you in advance!
give that time to warm up, i mean the heatsinks, then you can start adjusting, 1/2 b+ is the goal....
imo, adjustments using the scope is best, looking for the most symmetrical and maximum peak to peak sine wave...this is around 1/2 of b+...
are you sure you did not solder that in backwards, i takes a long time for that cap to pop if you get it wrong, that cap should not get real warmer than ambient....
@ Tony that’s way beyond the scope understanding and equipment levels of most of the kit builders. It would need some detailed instructions and advice on signal generators and scopes that are adequate for the job adding a lot of cost to getting the kit built. In the meantime ACA sounds pretty awesome setup with simple multimeter. I’m sure your correct but doesn’t help me or any other builders understand how to do what your suggesting. Would love a good explanation and photos of waveforms etc.