Today many run their DACs directly connected to their class-d amps. I do. Amps with several 100 watts output and over 10A amps out.
I would guess that the signal ground in these amps are not the cleanest one could see. And here comes my culprit... the delicate ground in DACs where both clock ground and Vref grounds are tied up to the dirty class-d ground. Probably not ideal.
Why not make the PWM signal interface (red marking) after the "C" optical and let the input part float compared to the output stage. The only harmful part left sharing ground would be the triangle generator.
I bet such a combo of DAC and amp would be quite better sounding... what do You think?
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I would guess that the signal ground in these amps are not the cleanest one could see. And here comes my culprit... the delicate ground in DACs where both clock ground and Vref grounds are tied up to the dirty class-d ground. Probably not ideal.
Why not make the PWM signal interface (red marking) after the "C" optical and let the input part float compared to the output stage. The only harmful part left sharing ground would be the triangle generator.
I bet such a combo of DAC and amp would be quite better sounding... what do You think?
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Yes. When I have done this, I got slight hum and was in the end required to hook up the ground between them to have it quiet - don't know what the problem was. This was between a Soerkris DAC run as differential / balanced, a Lundahl line trafo and a Hypex Nc400...
Lets check with this guy as hes amp is claimed to use no global FB... so paging @flmhhh to see what he says - would this concept work in the SGD 801-M with retained measured distortion figures?
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Lets check with this guy as hes amp is claimed to use no global FB... so paging @flmhhh to see what he says - would this concept work in the SGD 801-M with retained measured distortion figures?
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Balanced inputs (when implemented right) combined with internal volume control in the power amplifier normally help a good deal. Input transformers also may be of good use too but may result in side effects. In only a few cases with very cheap and unbalanced stuff I noticed such issues, in general it is not an issue to worry about with well designed devices. Leakage of internal SMPS, RF stray in and stray out (!) and correct grounding are issues today.
"Open" power amplifiers so amplifiers without internal volume control connected directly to sources are way more sensitive to this. Besides that there are more good reasons to use internal volume control. It is a simple test too, taking not much time.
"Open" power amplifiers so amplifiers without internal volume control connected directly to sources are way more sensitive to this. Besides that there are more good reasons to use internal volume control. It is a simple test too, taking not much time.
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Maybe you could try to be more friendly and make stuff clear in the first post describing the issue (as common).
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Did you measure the ground in the DAC wrt to a well know stable reference, like a an earth rod etc, while playing 50 watt bass transients in the speakers? Or how do you know it is not an "issue"?
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Haha - coming from U 😉 ... I misinterpreted your answer to comment on my trials with Nc400 - I didn't see it was a general answer to the topic.
On the other hand, my experience was actually that a trafo didn't do it in my case... but I'm sure it can.
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Two wrongs don't make a right. I also think I reacted to the point but was met with a hostile approach straight away. If it makes you feel good that is OK 🙂
On topic: I am pretty sure you will conclude connecting a high power class D amplifier without internal volume control directly to a source is pretty close to a system/user error.
The point maybe is that recent electronic developments solve some issues like high cost/reducing weight but also result in side effects and challenges to get stuff 100 % silent. Issues both hardly avoidable and solvable by the average DIYer.
On topic: I am pretty sure you will conclude connecting a high power class D amplifier without internal volume control directly to a source is pretty close to a system/user error.
The point maybe is that recent electronic developments solve some issues like high cost/reducing weight but also result in side effects and challenges to get stuff 100 % silent. Issues both hardly avoidable and solvable by the average DIYer.
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