Rather than trying to modify each and every equipment's PS, Mark used this filter on his DAC --->
View attachment TAA 4-15.pdf
Attenuation starts at 548Hz (-6dB) and the scale is 10dB/div. The atten far exceeds -100db (10KHz) range of instrument. Out to 10MHz the atten is still -60dB.
Since this is passive filter, the unwanted freqs/noise on the ac line is blocked from the DAC and anything from the DAC is prevented from getting onto the ac line.
This was going to be an article in Linear Audio. but that pub is no more... too late. Oh, well.
THx-RNMarsh
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Hi Richard,
Okay, colour me impressed.
I would need to use two since the signal stuff is on one circuit and the amp is on a direct feed to the breaker panel. You're right in that it's easier to run all my signal level stuff off a line conditioner. The amp I'm not so sure as you really want a low impedance mains feed for those. The other benefit is that I can change out signal stuff without working over each new one's power supply.
What are those filters worth Richard? Do they isolate each device from the other? Right now all my units use real power transformers and linear regulators.
-Chris
Okay, colour me impressed.
I would need to use two since the signal stuff is on one circuit and the amp is on a direct feed to the breaker panel. You're right in that it's easier to run all my signal level stuff off a line conditioner. The amp I'm not so sure as you really want a low impedance mains feed for those. The other benefit is that I can change out signal stuff without working over each new one's power supply.
What are those filters worth Richard? Do they isolate each device from the other? Right now all my units use real power transformers and linear regulators.
-Chris
I dont know where you get that crazy idea. It's certainly my way and works very well. What is your way?..... put up your work here with your data.
Mark has heard an improvement in accuracy from his system when using it --- he isnt alone. This was done 18 years ago and hundreds if not thousands have heard the improvement as well from a commercial version distributed by Monster Products. So, yes the cat needs skinning. My way works. Yours??
THx-RNMarsh
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You can get similar results from the Monster -7000 unit available now on e-Bay. Best deal of the century and backed by real science and engineering.
Yes they ground isolate and to -100db from port to port.
Enjoy
THx-Richard
It's a great relief to know this negativity can still exist without my input.
Yeah, that was probably a little more aggressive than needed, IMHO. With a nice looking graph one can afford a little magnanimity.
Why don’t you try it Mark?
Without/with the power conditioner, measure their SMPS DC out for noise with no signal at the input and FFTing while playing 1kHz tone would be a start.
Also by probing their audio out in the same way.
Use your soundcard for that. A loopback test will tell you how low your expectations should be.
For more elaborate tests under dynamic conditions, send them to Chris
George
Just wait.... I have seen them all over the map. 250 sometimes. >1000 sometimes. I recently bought one and I paid $450. "free" shipping. Works fine. Looks like new. I am going thru my storage... I might find one there
If it helps to know.... the 2 transformers cost me 100 $ each - mfr cost. From China. very special. Not an off-the-shelf item. Similar to a Topaz Ultra-Isolation transformer. Several mfr tried to make them for me to my spec. Only one mfr could do it well enough.
This is prototype isolation…. dont remember - think final version is much better.
You also get significant, sag, surge and transient line protection. D.Martin had primary responsibility for that portion of the design.
All power conditioners passed thorough UL testing.
THx-Richard
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One thing he could do, too, is to disconnect the out analog plug from his hifi system and to measure the voltage between this gear output ground and the hifi system grounds.
In case an earth is used in the AC plug, it has to be isolated, of course.
And it is interesting to try with both phases (normal and inverted) of the AC plug. One thing I do before connecting them together with any gear I plug in my system, choosing the sens that minimize this voltage.
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Why don't I try it? Try what, to find the defect? First off, I don't have schematics. Secondly, the test I would probably most need to do is to introduce HF CM and or DM disturbances on the AC line input and look for feed-through or modulation at the output. If the problem I have is anything PS related it would probably be something like that, not load regulation or something of that nature. I am not equipped for such testing.
And, no matter what I might find I am not going to redesign the SMPS inside them while they are under warranty. Probably I would rig up something to block the problem from happening without actually altering the devices. Actually, that's what I am going to do anyway. Why not cut to the chase then and just block the problem?
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Tryphon’s suggestions are valuable.
Mark, simple things for start. Use your soundcard to probe the DC out of the SMPS and the audio out of the DAC and the amplifier.
I have mentioned no fault, you don’t have to raise any philosophical question, no detailed schematics needed.
Of course, if you expect to get access to the most appropriate test equipment and cover all bases, you’ll remain on the safe side of a good diyaudio.com post contributor.
George
Mark, simple things for start. Use your soundcard to probe the DC out of the SMPS and the audio out of the DAC and the amplifier.
I have mentioned no fault, you don’t have to raise any philosophical question, no detailed schematics needed.
Of course, if you expect to get access to the most appropriate test equipment and cover all bases, you’ll remain on the safe side of a good diyaudio.com post contributor.
George
George, I don't think I want to spend time investigating the problem at this point. I have my hands full with other projects. More than full. Maybe someday out of curiosity I will poke around into that when I am not busy with other things. However, I have a list of other things I probably will want to do first. Besides still working on Chinese DACs, there is a tube guitar amp in pieces I want to redesign. Those things interest me more at the moment, and since I am retired I can pick and choose the things I want to work on to suit myself.
In addition, I don't think I mentioned here but I think I did over in the DAC thread, that I am located on top of a hill where off to the west I can sometimes see all the way across Sacramento valley to the Coastal Mountains, about 100 miles. Just over another hill here to the South of me is a small local airport. Out to the west there is an international airport and an Air Force base. I am awash in radar signals, the highest frequency ones I can see on the scope appear to be around 150MHz. On the AC line there is CM and DM 20kHz that could be radar demodulated by whatever nonlinearities in the AC lines, or some other source altogether, but it's also pulsed. Most likely there are also some much higher frequency RF noise signals I can't measure.
One of the problems I am working on is how to shield or otherwise mitigate the EMI/RFI noise environment here. Whatever I find on that may be applicable to the hi-fi system. Whatever I find using the power conditioner may be useful. Poking around with a sound card is one idea but at this point its hard to say how useful that might be. I can already see noise everywhere at audio and RF frequencies.
Also, I do know that a well shielded steel chassis can essentially block direct ingress of the local radiated EMI/RFI. Star-Quad balanced cable seems to be useful, although haven't tried it yet between DAC and amp.
The big problem is when I open a box up to probe it or measure it. I need maybe an EMI tent somewhere if I need to open a box and measure low level signals, since I have to break open the steel box shielding and keep my test probe interconnections shielded at the same time. For example, hooking a scope probe to the scope calibrator ground and turning up the vertical sensitivity picks up radar. That makes the scope full of artifacts for millivolt level measurements. Also, the effect happens everywhere inside the house and in the garage. Right in the middle of the kitchen dishwasher door is the best null spot for radiated EMI/RFI interference as seen on the scope with the probe grounded to the scope chassis. That may be because it is steel and blocking RF from the west.
In addition, I don't think I mentioned here but I think I did over in the DAC thread, that I am located on top of a hill where off to the west I can sometimes see all the way across Sacramento valley to the Coastal Mountains, about 100 miles. Just over another hill here to the South of me is a small local airport. Out to the west there is an international airport and an Air Force base. I am awash in radar signals, the highest frequency ones I can see on the scope appear to be around 150MHz. On the AC line there is CM and DM 20kHz that could be radar demodulated by whatever nonlinearities in the AC lines, or some other source altogether, but it's also pulsed. Most likely there are also some much higher frequency RF noise signals I can't measure.
One of the problems I am working on is how to shield or otherwise mitigate the EMI/RFI noise environment here. Whatever I find on that may be applicable to the hi-fi system. Whatever I find using the power conditioner may be useful. Poking around with a sound card is one idea but at this point its hard to say how useful that might be. I can already see noise everywhere at audio and RF frequencies.
Also, I do know that a well shielded steel chassis can essentially block direct ingress of the local radiated EMI/RFI. Star-Quad balanced cable seems to be useful, although haven't tried it yet between DAC and amp.
The big problem is when I open a box up to probe it or measure it. I need maybe an EMI tent somewhere if I need to open a box and measure low level signals, since I have to break open the steel box shielding and keep my test probe interconnections shielded at the same time. For example, hooking a scope probe to the scope calibrator ground and turning up the vertical sensitivity picks up radar. That makes the scope full of artifacts for millivolt level measurements. Also, the effect happens everywhere inside the house and in the garage. Right in the middle of the kitchen dishwasher door is the best null spot for radiated EMI/RFI interference as seen on the scope with the probe grounded to the scope chassis. That may be because it is steel and blocking RF from the west.
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