Couldn’t find a pre-diamond impedance, this 803D might be indicative.
As well as the low impedance parts you have a big spike and a tough phase angle to deal with 2-6k, parallel operation of monobloks migh be suggested.
But as always try them out, it could be surprising.
dave
I've been running a couple v1.6 ACA's as balanced monoblocks for several months now. Recently I've noticed that the left channel volume is sometimes lower than the right after powering up and letting them warm for 10 or so minutes. I have an RME ADI-2 FS DAC connected directly to them. When I raise the DAC volume high enough the left channel volume returns to normal levels. Any ideas on what might be causing this? As usual thanks for any help. This community is great.
So you are using the option to feed the output of one channel into the input of the other channel via the switch on the back panel.
Any change if you give the toggle switch a waggle? Maybe link it out as a test
The symptom of it correcting as you raise level is similar to the classic 'dirty relay' scenario in many amps. Don't overlook all connections to the speakers. Make sure all are good.
Also be sure to prove the problem really is with the ACA and not elsewhere in chain by swapping the two ACA's around.
Any change if you give the toggle switch a waggle? Maybe link it out as a test
The symptom of it correcting as you raise level is similar to the classic 'dirty relay' scenario in many amps. Don't overlook all connections to the speakers. Make sure all are good.
Also be sure to prove the problem really is with the ACA and not elsewhere in chain by swapping the two ACA's around.
The harder you push the ACA in terms of output current the cooler it will actually run, the opposite of more usual Class AB amps. The downside of 4 ohm loading vs 8 ohm is that the available output swing is limited (less power in the load) and the distortion will be higher as well.
The voltage and current output available at the speaker terminals is insufficient to start a fire in the normal sense, that privilege is more the realm of 100 watt plus amps that have significant voltage and current delivery available.
The voltage and current output available at the speaker terminals is insufficient to start a fire in the normal sense, that privilege is more the realm of 100 watt plus amps that have significant voltage and current delivery available.
I use a pair of ACAs with KEF 205 speakers - similar size to the D803, with an impedance minimum around 3.7R. I tried both the bridged mode with XLR input and the parallel mode with RCA input. Both work perfectly well and sound good.
The amp is pretty bulletproof so i am not surprised. But how well? My concerens are always with the modifications to FR from an ugly impedance.
I encourage everyone to throw everything at the ACAs, get back with their findings, and we will get a cross-section of what people find works and what doesn’t.
dave
As mentioned, class A amps will actually run full current at idle... so the hotter amp will be a silent one. So 'fires' are not a concern!
In my experience, it worked nicely with 4ohm Totem Rainmakers. A little less volume, luckily my PRE has a HI option that outputs 4v into RCA outputs, which was just the "punch" the ACA needed.
Of course, clipping occurs earlier, so depending on your speaker's efficiency, you may not be able to host an electronic concert in a hall with 2000 people, but for normal listening in a reasonably sized room, it worked nicely!
In my experience, it worked nicely with 4ohm Totem Rainmakers. A little less volume, luckily my PRE has a HI option that outputs 4v into RCA outputs, which was just the "punch" the ACA needed.
Of course, clipping occurs earlier, so depending on your speaker's efficiency, you may not be able to host an electronic concert in a hall with 2000 people, but for normal listening in a reasonably sized room, it worked nicely!
Pair of ACAs driving a pair of Halcyons. They won't get the cops called but provide a satisfying immersion.
Parallel mono provides good bass control with a very lively sound.
Balanced mono is a bit boomier but the speakers do a better disappearing act.
-tom
Parallel mono provides good bass control with a very lively sound.
Balanced mono is a bit boomier but the speakers do a better disappearing act.
-tom
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Hi
As requested by planet10 i will give you the information that my NADA (Scan speak_closed) are working well with 1x ACA. gain is about 12dB and the power is for my room 26m2 enough for powerful listening session. i stream over tidal master mostly and the volume is nearly 3/4 to get a good loudness in the room. playing 1 title and try to push more. near the end of the setting 100 is not needed because you hear about volume setting 92 that the juice is over.
my plan is to finalize my ACA premium and then compare.
After this i want to have 2x ACA mono's over RCA and compare to my brothers F5 1 lateral clone
chris
As requested by planet10 i will give you the information that my NADA (Scan speak_closed) are working well with 1x ACA. gain is about 12dB and the power is for my room 26m2 enough for powerful listening session. i stream over tidal master mostly and the volume is nearly 3/4 to get a good loudness in the room. playing 1 title and try to push more. near the end of the setting 100 is not needed because you hear about volume setting 92 that the juice is over.
my plan is to finalize my ACA premium and then compare.
After this i want to have 2x ACA mono's over RCA and compare to my brothers F5 1 lateral clone
chris
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Hi ACA-people.
I have 2 ACAs running in bridged mono rca mode here and discovered today that I cannot hear any difference in sound quality or max volume compared to one ACA in stereo mode. Driving a pair of Studio 100 clones (which are a bit overkill for the poor ACA I fear). Signal coming from a RaspberryPi and Dragonfly Red. Is it possible that the difference is hardly noticable or did I do something wrong here?
I have 2 ACAs running in bridged mono rca mode here and discovered today that I cannot hear any difference in sound quality or max volume compared to one ACA in stereo mode. Driving a pair of Studio 100 clones (which are a bit overkill for the poor ACA I fear). Signal coming from a RaspberryPi and Dragonfly Red. Is it possible that the difference is hardly noticable or did I do something wrong here?
You should check that both amplifier channels of the bridged amp are producing signal. If the 'second' amp was working correctly but for some reason not receiving its input signal then it would just provide a 'no signal' low impedance return point for the speaker... in other words you would effectively hear just a normal single channel output and not a bridged output.
An easy way to check is to hook up two speakers like in normal stereo configuration, but then flip the rear switch to RCA bridged mode and connect only input A. Both speakers should play at the same volume - but out of phase (which will be difficult to detect).
Thumbnail calculation suggests 7.5 watts would produce 100.5 db at around 3 feet away and 103 db for 15 watts if your clones are 88db: like the real deal spec says. Since your observation was hardly noticeable, guess is you did everything right! In our case, we noticed a pretty big difference in fidelity when we changed to the parallel mode. We listen around 45 - 50 db so max level is really not an issue here. The amp may reach a watt but not often.