Have a read at this. Figure #4 is the optimal method but remember this leaves the signal inverted and so you may need to correct that (hint... swapping the speaker lead around is the simplest way).
For what you want you might get away with passive mixing... figure #1.
Audio Signal Mixing.
do you not just use either a second pre out to the subwoofer or use the high level inputs on the subwoofer from the speakers themselves? I have two ACA's running balanced off a Schiit freya and take the subwoofer off the RCA pre out. Am I missing something? obv. the subs have a plate amp and their own filters.
So that was my confusion. As far as I can tell there is just one output on the ACP+ which is the preamp I was considering. I had read that speaker output could go into the sub amp if it has speaker level inputs. Thanks for the help.
You can use a "Y" adapter coming out of the preamps outputs:
AudioQuest Hard RCA Splitter 1-male-to-2-female audio splitter at Crutchfield
Monoprice RCA Plug to 2x RCA Jack Splitter Adapter, Gold Plated - Monoprice.com
https://www.amazon.com/Mediabridge-ULTRA-RCA-Y-Adapter-Inches/dp/B005DL2OVE
There are several different types. These will, (in theory) add some extra capacitance, impedance and resistance to the signal, but IMHO, it's not usually audible.
AudioQuest Hard RCA Splitter 1-male-to-2-female audio splitter at Crutchfield
Monoprice RCA Plug to 2x RCA Jack Splitter Adapter, Gold Plated - Monoprice.com
https://www.amazon.com/Mediabridge-ULTRA-RCA-Y-Adapter-Inches/dp/B005DL2OVE
There are several different types. These will, (in theory) add some extra capacitance, impedance and resistance to the signal, but IMHO, it's not usually audible.
You may also want to try mosfet input if you happen to have LND150 on hand. No gate leakage.
Hi all, First post from a long time lurker. I have a couple of questions for those based in the UK. I'm hoping to build one or possibly 2 ACA's. I have been advised by the DIYAudio store to purchase my enclosures directly from Hifi2000 in Italy. I'm very happy to do this but just uncertain about how VAT and import duties will be charged since brexit. I know how it's supposed to work (supplier supposed to collect UK VAT for purchases under £135) but wanted to get some clarification. I've emailed Hifi2000 but have not received a response. I'm just wondering if anyone from the uk has ordered anything from them since brexit and what your experience was? Also I presume that the rest of the kit should be ordered on the DIYAudio store and shipped from the US. Thanks Paul
few more details could help, pics too
you tried another PSU, counting it's power brick?
Please include the input to the ACAs (i.e.: preamp or direct from a
DAC, etc....).
--Tom
I suspect a power brick. I keep had a couple get noisy over the years.
Probably you are using one per channel, so is the hum on just one channel? If so, swap bricks. To see if the noise switches sides.
The current power supply bricks are much higher quality but more expensive. They are also 24v instead of 18v so give more power. The amp circuit hasn’t changed really so it’s worth upgrading.
One will run both channels with the power cable to the amps being paralled outside the chassis.
Obviously this is easier if the amps are next to each other.
Probably you are using one per channel, so is the hum on just one channel? If so, swap bricks. To see if the noise switches sides.
The current power supply bricks are much higher quality but more expensive. They are also 24v instead of 18v so give more power. The amp circuit hasn’t changed really so it’s worth upgrading.
One will run both channels with the power cable to the amps being paralled outside the chassis.
Obviously this is easier if the amps are next to each other.
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