I just finished my aca and after upping the input from 0.9v to 2v it's come alive. Only my second project, first was elekit with upgrades, and for being such a simple circuit, defies logic that it sounds so good. Gets surprisingly warm though, which I assume is normal. Have it on the bench now rather on a shelf as a result.
The biggest reason for Waxx suggesting building something myself is that I can make a single PCB with more features, as Waxx may want some things integrated to reduce clutter. And because I just very much enjoy making things - 't is the reason I make kits for other people!
Carsten and I may be able to come to some mutual thing, where he can maybe offload some things on to me. Because of my occupation, I literally have whole days where electronics is the only thing I do
If you biased it properly then the heat should be fine.
At 2v input your ACA is outputting a lot of distortion; the typical class A kind. Funny to see how people feel about that.
Carsten and I may be able to come to some mutual thing, where he can maybe offload some things on to me. Because of my occupation, I literally have whole days where electronics is the only thing I do
If you biased it properly then the heat should be fine.
At 2v input your ACA is outputting a lot of distortion; the typical class A kind. Funny to see how people feel about that.
Thankyou HumbleDeer. I was careful to set the 12v on the pot's and allow time for the voltage to settle. I was of the understanding that this amp needed a higher input voltage, what is the best input voltage to obtain (in your mind) the best sound? I can alter the gain? into the amp from my source and have a listen. (Early days for me and learning as I go) James
The guides and amp are currently designed for 19-24v, by far preferrably 24v. You can change the gain by changing the amount of negative feedback, but that does change the sound a smol bit. Another solution is getting a H2.
When adjusting the bias, the voltage can swing up and down on your measurement device for up to a minute or two depending on your meter resolution. Get the voltage near 12v when it starts to move around less - both channels. Leave it on for a couple minutes and go back to adjust the bias. That ensures you're setting the bias correctly for when the amp is warmed up. That's going to be the majority of the time you use it.
When adjusting the bias, the voltage can swing up and down on your measurement device for up to a minute or two depending on your meter resolution. Get the voltage near 12v when it starts to move around less - both channels. Leave it on for a couple minutes and go back to adjust the bias. That ensures you're setting the bias correctly for when the amp is warmed up. That's going to be the majority of the time you use it.
That's exactly what I did, I adjusted closer to 12v straight away, then left it to sit for 10 minutes before re-visiting the adjustment and ended up with the multi-meter showing something like 11.98>12.04V, wouldn't sit dead still on a figure and the adjustment was so fine to get that close.
On the 'distortion' at 2v, is that like a second harmonic I have read about, or is it bad, if so, what's is the best voltage to input into this amp, in you opinion. Cheers and thankyou
On the 'distortion' at 2v, is that like a second harmonic I have read about, or is it bad, if so, what's is the best voltage to input into this amp, in you opinion. Cheers and thankyou
2v is the standard output of a cd player/dac etc.. and most components. As the gain on the ACA is relatively low I find that it comes alive with a good preamp/source. I use the Adcom GFP-750 which is based on a Pass design. It works great. I think a solid active preamp is super important.
I use an elekit tube pre amp I built, into mini dsp, then onto the elekit amp I built and the aca amp I built, split using the DSP as a cross over, with the tube amp providing the lower range and the aca amp driving the upper, ATM. Early audio days for me, learning about cross overs and the effects of such, picking a single item at a time to reduce confusion as to what affects what and will swap the amp duties and test the outcome, etc...
Can the DSP be considered active since I can adjust the gain on all the channels? (Previous maximum was 0.9v, but I opened it up and switched it to a maximum of 2v, whether or not I'm using the full 2v into the amps should depend on where the channel gains are set?)
Can the DSP be considered active since I can adjust the gain on all the channels? (Previous maximum was 0.9v, but I opened it up and switched it to a maximum of 2v, whether or not I'm using the full 2v into the amps should depend on where the channel gains are set?)
That is why i want to use a active preamp again, but before i had the ACA i was using a tube amp with enough gain to compensate. The tube amp is still there (powering my other speakers), but i will get a preamp because the ACA need it. Especially as my phono stage is rather low on voltage output and is build to have a line stage behind it. My DAC can drive the ACA without issue (but it got 2V output) trough the Tishbury passive preamp i have. A H2 is ordered, just waiting on when it's availeble (they are working on it).
It depends on the sensitivity of the speakers. I'm using a DAC + H2 + B1 buffer into 6Wpc ACA with 94dB speakers and the volume is fine for all kinds of music for home listening. That's not from phono, though.Originally Posted by mraudioguru
+1 Whether solid state or tube, but active is the way to go...
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I'm cycling through the different modes. I just switched from balanced monoblocks to single in stereo. There's something special about this amp running in stereo mode, I can't exactly put my finger on it yet, but I could hear it in the first couple grooves. I've never been much good at putting what I hear into words anyway.
Yes, and noise too. But subjectively it sounds more defined in staging, more textural with instruments and vocals, and subtle nuances come to the surface. It’s not just a matter of distortion, you can’t “make” a FW PP amp behave like this…believe me I’ve tried (adjusting P3). Makes me wonder what an Aleph J or J2 might sound like (essential parts happen to be in my drawer). Some how this amp sounds less “distorted” in stereo mode than in balanced.
"Well yes, but actually no."
Don't worry - you shall not need to explain; distortion is a complicated thing and clearly enough people like it that a person like Nelson can make their entire business out of selling distortion boxes.
You can't make an amp X sound like amp Y and there is no need to insist that is because of anything else than the fact they are two different amps. It has nothing to do with bias knobs or anything but simply the fact they are not the same devices.
It is just a matter of distortion though; Noise is distortion, harmonics is distortion, bandwidth limiting is distortion, non linearities of any kind are distortion. And it is no longer a secret some people like some kinds of distortion. Again, looking at Passlabs and PrimaLuna. Two brands that make a living for their respective businessmen.
I, too, do not happen to be able to make Peugot Petit Filou sound like a Ford V8 engine.
Don't worry - you shall not need to explain; distortion is a complicated thing and clearly enough people like it that a person like Nelson can make their entire business out of selling distortion boxes.
You can't make an amp X sound like amp Y and there is no need to insist that is because of anything else than the fact they are two different amps. It has nothing to do with bias knobs or anything but simply the fact they are not the same devices.
It is just a matter of distortion though; Noise is distortion, harmonics is distortion, bandwidth limiting is distortion, non linearities of any kind are distortion. And it is no longer a secret some people like some kinds of distortion. Again, looking at Passlabs and PrimaLuna. Two brands that make a living for their respective businessmen.
I, too, do not happen to be able to make Peugot Petit Filou sound like a Ford V8 engine.