Easy for you RNMarsh to vawe big green bills as you have a credit card... 😉
200$ I would say as it is only a hobby and I'm ready to sweat to keep the price down 🙂
Regards
200$ I would say as it is only a hobby and I'm ready to sweat to keep the price down 🙂
Regards
I'm starting a new thread...
Just because the issue is greater than the need off one - http://www.diyaudio.com/forums/equi...-audio-analyzer-scope-beyond.html#post4476972
Just because the issue is greater than the need off one - http://www.diyaudio.com/forums/equi...-audio-analyzer-scope-beyond.html#post4476972
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Not that I distrust the goals of JensH but a modular community system with the ability to jack in commercial parts or new, newer heard of technologies thru api's would make it most versatile.
Just because the issue is greater than the need off one - http://www.diyaudio.com/forums/equipment-tools/280790-community-audio-analyzer-scope-beyond.html#post4476972
So Jens et al, create the best hw allowing programming beyond 386kzh sampling and atleast 64 bits but keep the addressing open for 128. No supporting chips today? They will be available in a couple of years when demand is back. Remember, we are building for the next 10 years if not longer. I see that ordinary soundcards will move towards scientific measurements but the transition will need pressure from the audiophile community as the quest is about the same...
The software - yes the software to support what hw is achieving - next maybe post in the thread as time is running out.... It did run out...
Just because the issue is greater than the need off one - http://www.diyaudio.com/forums/equipment-tools/280790-community-audio-analyzer-scope-beyond.html#post4476972
So Jens et al, create the best hw allowing programming beyond 386kzh sampling and atleast 64 bits but keep the addressing open for 128. No supporting chips today? They will be available in a couple of years when demand is back. Remember, we are building for the next 10 years if not longer. I see that ordinary soundcards will move towards scientific measurements but the transition will need pressure from the audiophile community as the quest is about the same...
The software - yes the software to support what hw is achieving - next maybe post in the thread as time is running out.... It did run out...
You can't make anything worth it for $200. If you only want to spend $200 you might as well just buy a QA400.
@RNMarsh
You didn't kill the project 🙂
But I have been busy with other things lately. So the progress has been a bit slow.
Having a good ADC (even very good) does not solve all the problems. I think that a large part of the added value of my design is the input stage with very low noise, low distortion amplifiers, attenuators and overvoltage protection.
@Turbon
I am thinking of making it modular, to some degree. Perhaps the ADC and drivers will be moved to a separate board. And the DAC + post-DAC filters to another board.
This will make it possible to replace the converters if something better turns up. Although there is always a risk that the available master clock does not have the right frequency or something similar.
Going to a higher sample rate may be interesting. But using 64 or 128 bit words does not bring any advantages.
I agree with chris719 that if 200$ is what you want to spend then the QA400 is probably a good candidate. If my design ever makes it into production I am sure that it will be well above that price.
You didn't kill the project 🙂
But I have been busy with other things lately. So the progress has been a bit slow.
Having a good ADC (even very good) does not solve all the problems. I think that a large part of the added value of my design is the input stage with very low noise, low distortion amplifiers, attenuators and overvoltage protection.
@Turbon
I am thinking of making it modular, to some degree. Perhaps the ADC and drivers will be moved to a separate board. And the DAC + post-DAC filters to another board.
This will make it possible to replace the converters if something better turns up. Although there is always a risk that the available master clock does not have the right frequency or something similar.
Going to a higher sample rate may be interesting. But using 64 or 128 bit words does not bring any advantages.
I agree with chris719 that if 200$ is what you want to spend then the QA400 is probably a good candidate. If my design ever makes it into production I am sure that it will be well above that price.
Well, if convinced about this being a community effort not dying with the interest of one individual then I would consider investing more. As the URL of this thread and site tells us - DIY- it has never been clarifyed if it equals diymoney...
I may of course be naive and the whole site is about connect startups with potential customers...
IF that would be the case then I better rush for a QA400...
Regards
I may of course be naive and the whole site is about connect startups with potential customers...
IF that would be the case then I better rush for a QA400...
Regards
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I am not running a startup. I am doing this as a hobby project. If the performance turns out to be really good it could make sense to put in into production. With a possibility to make a good analyzer available at a reasonable cost, for the benefit of other members of this forum.
But I have not decided if I even want to bother with that. Especially if some here think that I am just doing this to make money.
But I have not decided if I even want to bother with that. Especially if some here think that I am just doing this to make money.
I think everyone here appreciates your efforts Jens. I don't think Turbon knows what he's talking about to be honest.
I agree. What I might think or believe shouldn't worry you. I'll followcthis with interest but will leave you in peace.
Regards
Regards
Hi JensH,
Didn't posted in this thread before, and I'm one of those who're quietly waiting for the outcome of your project. I already have a QA400 and cannot afford an AP, so your project perfectly fits what I want, and if it has to cost several times that of a QA400 to reach 120dB, personally I find it very much worth it.
Thanks and regards.
Didn't posted in this thread before, and I'm one of those who're quietly waiting for the outcome of your project. I already have a QA400 and cannot afford an AP, so your project perfectly fits what I want, and if it has to cost several times that of a QA400 to reach 120dB, personally I find it very much worth it.
Thanks and regards.
JensH, you doing very good, and important job. Think abut upcoming great instrument that will help to diy guys to reaserch and to create. Do not waste you time on those, dreaming about fine quality analyser, cheaper than good DMM. They are will be with their dreams, and built-in motherboard soundcards forever.
My best wishes to you and you project!
My best wishes to you and you project!
I have been playing with A/D and D/A interfaces to improve on what the likes of QA400 provide for a while now. In so small part inspired by this thread and the work of Jens, and in equal part by a desire to get a measurement system that "takes that step onward" from the QA400 performance I have upped my efforts of late.
From my experience there are a couple of significant "boundaries" that exist.
- The integrated and simple systems such as the QA400 and sound card based systems "hit a wall" in the -100dBc region. Causal factors here being codec driven, interface architectures that are selected and cost
- If you rethink the ADC interface and architecture, I have shown myself that pushing out toward -110dBc is "harder but doable". You need to learn, and pay attention to the detail of each component - and particularly ADC driver interfaces! (watch that RF crud coming out of the ADC!)
- To get significantly better than this is an exercise in fine tuning, and possibly device selection. I have run into issues of inter-channel isolation and the outright inability to generate test signals pure enough to test the ADC's.
What is the relevance here?
The work Jens is doing I think can lead to a couple of outcomes:
- A measurement system that is tangibly better than the typical "off the shelf" device, and takes a step onward from the QA400 pack. This itself need not be massively expensive, more it needs to be "well thought out".
and as a second option - with more work and expense
- A system that goes yet another step - which I suspect will be a hard won battle and possibly a much more expensive one. That extra 10dB will probably be 10dB harder and possibly 10dB more expensive.
The concept of an isolated ADC / DAC subsystem with GOOD quality ADC and DAC components "talking" to a PC using standard drivers delivers a powerful audio test tool. This has not been present in the marketplace for a sensible price from what I have seen to date.
I think the first step above is a laudable and valuable place to start. The trick is differentiation GOOD from "perfection".
From my experience there are a couple of significant "boundaries" that exist.
- The integrated and simple systems such as the QA400 and sound card based systems "hit a wall" in the -100dBc region. Causal factors here being codec driven, interface architectures that are selected and cost
- If you rethink the ADC interface and architecture, I have shown myself that pushing out toward -110dBc is "harder but doable". You need to learn, and pay attention to the detail of each component - and particularly ADC driver interfaces! (watch that RF crud coming out of the ADC!)
- To get significantly better than this is an exercise in fine tuning, and possibly device selection. I have run into issues of inter-channel isolation and the outright inability to generate test signals pure enough to test the ADC's.
What is the relevance here?
The work Jens is doing I think can lead to a couple of outcomes:
- A measurement system that is tangibly better than the typical "off the shelf" device, and takes a step onward from the QA400 pack. This itself need not be massively expensive, more it needs to be "well thought out".
and as a second option - with more work and expense
- A system that goes yet another step - which I suspect will be a hard won battle and possibly a much more expensive one. That extra 10dB will probably be 10dB harder and possibly 10dB more expensive.
The concept of an isolated ADC / DAC subsystem with GOOD quality ADC and DAC components "talking" to a PC using standard drivers delivers a powerful audio test tool. This has not been present in the marketplace for a sensible price from what I have seen to date.
I think the first step above is a laudable and valuable place to start. The trick is differentiation GOOD from "perfection".
Jens, please accept my appologies! I have gone thru the posts and it was my ignorance that showed itself... The appologies are also directed towards all in this thread! I behaved overly blunt and without manners. The work is outstanding - please continue!
Regards
Regards
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Look at PCM4222EVM, - it close to 110dB THD+N, while costs $149 from TI. Even if JensH analyser will cost $600-800, it still to be a small fraction of Prism dScope or AP products.
Tolik,
There are quite a few ADC's out there with typical 108 odd dB THD+N.
I am yet to bump into one that has guaranteed -120dB THD...
As noted earlier, if you pay attention to the interfacing and drivers you can get down at and below -110dB. I remain unconvinced that -120dB will be consistently achievable with "conventional" products.
- Some units are better than others
- If you start driving both channels you can see some interesting effects. If you have the gear, drive both channels with two phase locked 1KHz generators, and then slowly change the phase difference between the L and R channel inputs. On the CS chips the effect is quite interesting.
- To get a buffer / attenuator that does not degrade this is non trivial. Especially across a reasonable dynamic range.
- If you have a separate ADC and DAC, you need to be very - very careful of grounding, else you could end up measuring artefacts of the test system itself.
There are quite a few ADC's out there with typical 108 odd dB THD+N.
I am yet to bump into one that has guaranteed -120dB THD...
As noted earlier, if you pay attention to the interfacing and drivers you can get down at and below -110dB. I remain unconvinced that -120dB will be consistently achievable with "conventional" products.
- Some units are better than others
- If you start driving both channels you can see some interesting effects. If you have the gear, drive both channels with two phase locked 1KHz generators, and then slowly change the phase difference between the L and R channel inputs. On the CS chips the effect is quite interesting.
- To get a buffer / attenuator that does not degrade this is non trivial. Especially across a reasonable dynamic range.
- If you have a separate ADC and DAC, you need to be very - very careful of grounding, else you could end up measuring artefacts of the test system itself.
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