jaapatina,
Getting back to your question ;-)
It appears to me that when you build the ACA in a bridged monoblock version and use the XLR inputs with a balanced source and a +24V supply, the max power at 16 ohms, 8 ohms and 4 ohms assuming 1% max distortion is a conservative ~ 18 watts, 10 watts and likely 5 watts respectively. This I believe is because the output stage of the ACA is an SE design.
Somebody please correct me if I am wrong!
In any case, building this design as monoblocks and using the XLR inputs should be sonically advantageous because of the distortion cancellation afforded by the balanced input itself.
Best,
Anand.
Thanks,
Anand.
I have an 'implementation' question:
If you place the ON/OFF switch up front, you only need to take the +V cables to the front. The ground cable needs not 'travel' all the way up to the front and back. Yet, on the ACA 1.5 build guide, those two cables are twisted together.
I have read here (there, somewhere else?) that twisting some cables (not sure if V+ and GND, or if In+ and G, or Out + and Out -) may help reduce HUM.
So, first, which pair or pairs are better served by twisting them?
If the +V and GND, should I run a GND cable all the way up to the front for it to be twisted with the interrupted V+? Does it not matter at all?
Thanks for any feedback, best regards,
Rafa.
edit: Also, why should I double the cable width (twist two red cables) from the PSU to the Switch? Is this just to keep double cable impedance before the interruption and then single-cables interrupted V+? Hard to explain, hope it makes sense.
If you place the ON/OFF switch up front, you only need to take the +V cables to the front. The ground cable needs not 'travel' all the way up to the front and back. Yet, on the ACA 1.5 build guide, those two cables are twisted together.
I have read here (there, somewhere else?) that twisting some cables (not sure if V+ and GND, or if In+ and G, or Out + and Out -) may help reduce HUM.
So, first, which pair or pairs are better served by twisting them?
If the +V and GND, should I run a GND cable all the way up to the front for it to be twisted with the interrupted V+? Does it not matter at all?
Thanks for any feedback, best regards,
Rafa.
edit: Also, why should I double the cable width (twist two red cables) from the PSU to the Switch? Is this just to keep double cable impedance before the interruption and then single-cables interrupted V+? Hard to explain, hope it makes sense.
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It is most critical to twist wires if you have AC but you will never have a perfect DC so it will always be the better solution to twist DC cables also. The double wires is if you feed both channels then you have same mm2 cables all the way. If you optimize for sound quality you don't implement such a switch. Then you just have your main power switch at the 230VAC side and make wiring inside the amp as simple as possible. I am very satisfied with my result. So something to look forward to......if you make a good implementation……
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I was to put together a dual rail LPS for two bridged monos ACAs... a 300VA transformer would do?
and... thinking about it: might even build these as *plain* monos, right?
(just *one* board/channel per "box": don't need 15W, 8 are already more than twice the 2a3 SET i'm happily using)
any contraindication?
I did something like that. I needed the extra space in the box for some large audio grade output caps.
300VA should do it. I have 300VA pr channel…...but that is just me. Don't think you can be sure to pull 8 watt in 8 ohm out of it. It is rated as 5W. It seems to be more than enough for 94 dB speakers with "easy" impedance curve.
Not yet. I'm working on it. The current guide will get you through 75% of the way, and look at post #5075 of the ACA thread for photos showing the biggest differences. The back panel wiring is a bit different is you use the front mounted power switch.
http://www.diyaudio.com/forums/pass-labs/215392-amp-camp-amp-aca-508.html#post5509597
The current guide will get you through 75% of the way, and look at post #5075 of the ACA thread for photos showing the biggest differences. The back panel wiring is a bit different is you use the front mounted power switch. http://www.diyaudio.com/forums/pass-labs/215392-amp-camp-amp-aca-508.html#post5509597
and while waiting for my ACA kits to be delivered... finished assembling(*) a dual rail 24v LPS
my very first "build" *ever*
(*) using ready-made parts: an Audiophonics' LPS board and an ATL DC blocker. Transformer is a Toroidy 300VA 230 -> x2 18v: Galaxy case by Hi-Fi 2000
my very first "build" *ever*
(*) using ready-made parts: an Audiophonics' LPS board and an ATL DC blocker. Transformer is a Toroidy 300VA 230 -> x2 18v: Galaxy case by Hi-Fi 2000
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hardest part was figuring out why, first time I turned it on, it wasn't working 
found out, half an hour later, they sold me two dead fuses
oh... and... while checking voltage at outputs... neg probe slipped and shorted on the + one: feckin' n00bs
all still working fine, though. just must buy new probes
found out, half an hour later, they sold me two dead fuses
oh... and... while checking voltage at outputs... neg probe slipped and shorted on the + one: feckin' n00bs
all still working fine, though. just must buy new probes
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