Clearly you haven't worked with Pete's interface or similar circuits. But hey, speculation is far better than data.
so other than the OP, who has turned into the thread troll, everyone seems to be in violent agreement.
Ref the Pete Millet card, sound like you know how to design a better one. Are you offering?
Ref the Pete Millet card, sound like you know how to design a better one. Are you offering?
I am ready to try this.
So, what used 16 bit audio analyser(s) have you found satisfactory?
At what reasonable price?
Best wishes
David
You guys are killing my sleep...
Have you? Then please show some data instead of speculations about my work. Gain/attenuation vs. frequency. Distortion vs. frequency. I'll show mine as soon as I'll get to my bench, perhaps tomorrow, a friend of mine built one from the ebay kit and he's begging for some time for measurements. Told him I don't need to measure how much will drop the signal 1M with 3pF of parasitic cap at 20kHz and how much distortions will add a mediocre (for instrumentation) op amp like the OPA2604, but hey, he's my friend and has less ego than a renowned DIY Audio moderator.
HP 3562A can be acquired for less than the price of a new L22 card. For sure on the American side of the pond?
Hewlett Packard HP 3562A Dynamic Signal Analyzer | eBay
One, located in France, doesn't sell for $700 for quite some time; I'll bet you could get it for $600, just make him an offer:
HP 3562A | eBay
If you are ready for some work, you can get one with a weak display for $120:
Hewlett Packard HP Dynamic Signal Analyzer Model 3562A | eBay
I'm dead...
2 Waly
If I want reliable measure real distortion performance of preamp and power amp, it is simply unusable..not enough resolution and informations.
And do not swap THD+N (16ppm) with THD alone (0.69ppm). To make isolated bal/unbal conversion is easy , use quality signal line trafo (e.g. Jensen, Lundahl) with active distortion compensation, frequency response is flat to more than 80kHz, distortion in audio band about 1ppm.
And yes, card performance is level dependent , for L22 is best distortion performance obtained with levels about 0dBV, both input/output. It is not so complicated to make some dividers at impedance about 1kohm and lower, for audio band no need for compensation. It is not UHF band..
I own Neutrik A2 analyzer, new bought.. It is convenient to use, safe, but THD limit is about 0,001%, no information about harmonics content and about 10times more expensive as Lynx22.
If I want reliable measure real distortion performance of preamp and power amp, it is simply unusable..not enough resolution and informations.
And do not swap THD+N (16ppm) with THD alone (0.69ppm). To make isolated bal/unbal conversion is easy , use quality signal line trafo (e.g. Jensen, Lundahl) with active distortion compensation, frequency response is flat to more than 80kHz, distortion in audio band about 1ppm.
And yes, card performance is level dependent , for L22 is best distortion performance obtained with levels about 0dBV, both input/output. It is not so complicated to make some dividers at impedance about 1kohm and lower, for audio band no need for compensation. It is not UHF band..
2 Waly
Try to show us real performance of Your solution , something like in attached pictures..
Try to show us real performance of Your solution , something like in attached pictures..
Attachments
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An externally hosted image should be here but it was not working when we last tested it.
This was done about 10 years ago with a M-Audio Delta-something or other PCI soundcard inside a desktop PC. It was running in 16 bit mode as the software I had at the time didn't support anything more. I think FFT windows have improved considerably since then. 🙂
Just do me a favour and quote correctly, for the rest I won't argue further, it's useless:
I did..
This is simply not true, show us some measurements using such (used, 16bit) analyzer (and you need quality generator, too..) with dynamic range and resolution as quality soundcard with 24bit resolution.
As an indisputable fact, developers of commercial amps , engineers of audio magazines , and you name it, have all sold their respective analyzers and turned to soundcard. 🙄 The reported data got much better since 🙂
Now, irony off. What is far more interesting is sort of batch mode. It may not be common knowledge , anyway , pro designers of commercial hi end amps give much on "psychoacoustics" , in plain words, what sounds good sells good, how it measures is a different pair of shoes. As a result of compiled insights from experiments in "psychoacoutics", advanced audio magazines report the harmonics spectrum versus frequency and power. A commercial analyzer can perform such measurements, it is a necessity in quality control and quality engineering. Even more advanced magazines go a step further, they report this for "critical" and "less critical" passive speakers as a reactive ( and hence, in practice "real" load). of course these measurements require support of "burst mode" otherwise ...good bye 10,000 bucks a pair speakers.
It has so far turned out, that per thd perfect amps sound nevertheless poor, if the harmonics spectrum has nasty spikes just at these power and frequencies which are in terms of amplitude and frequency spectrum the most frequently appearing in classical music. That becomes worse when driving "critical speakers". It turns out that many amps show this kind of irregularity.
Only some no feedback single ended triode amps appear to be free from this effect.
Now, irony off. What is far more interesting is sort of batch mode. It may not be common knowledge , anyway , pro designers of commercial hi end amps give much on "psychoacoustics" , in plain words, what sounds good sells good, how it measures is a different pair of shoes. As a result of compiled insights from experiments in "psychoacoutics", advanced audio magazines report the harmonics spectrum versus frequency and power. A commercial analyzer can perform such measurements, it is a necessity in quality control and quality engineering. Even more advanced magazines go a step further, they report this for "critical" and "less critical" passive speakers as a reactive ( and hence, in practice "real" load). of course these measurements require support of "burst mode" otherwise ...good bye 10,000 bucks a pair speakers.
It has so far turned out, that per thd perfect amps sound nevertheless poor, if the harmonics spectrum has nasty spikes just at these power and frequencies which are in terms of amplitude and frequency spectrum the most frequently appearing in classical music. That becomes worse when driving "critical speakers". It turns out that many amps show this kind of irregularity.
Only some no feedback single ended triode amps appear to be free from this effect.
Clearly oxymoron,THD perfect and nasty spectrum spikes...THD perfect amp will produce near zero spectrum spikes..
Quite opposite, try to drive difficult complex load with such amp with output impedance about 1ohm. You are too much influenced by some advertising papers..😉
Well...thd is not continuously measured, preferrably for 1 khz and - 3db , or 20 kHz ... here i am talking continous, that is , power and frequency are continuous variables. Here we can tell the amateur from...well.
And of course all those who are able to measure reactive distortion are just wrong as they do not use sound cards. 😀 And i said reactive loads not complex loads
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I have two, and I have used them for 35yr but when I needed ppm thd I used a passive LC ladder on a Sound Tech 1700 and twin T. The 3562 (at least my old one) BTW has issues with noise aliasing.
So what would you recommend these days as cost effective for that level?
Best wishes
David
I call bull on that. In fact I dispute it. Stereophile use AP, Pass labs use AP. So that is 2 that have not sold their analysers. Now name 2 who have and I might see you as less than a troll. But then again, you were arguing about accuracy of sine waves a page or 2 ago and then claim "all" have sold their equipment.
I think this is some sort of German irony. 🙄 Nobody is selling AP analysers except to upgrade to a newer model. Also, earlier I wrote about how I got tired of the limitations of soundcards and bought an actual THD analyser. The measurement floor I get is a little worse than the Lynx, but the greater measurement bandwidth (30, 80 or ~200kHz, with a 4-pole Butterworth rolloff, IIRC) means that in practice it is more sensitive to the high-order distortion products of solid-state power amps than a soundcard whose bandwidth drops off a cliff at the Nyquist frequency. And I got it for less than $200 second hand.
One of these. The military version of the AA501, it comes with no oscillator hence the low price. The SG505 oscillator that is supposed to go with it seems to be unobtanium. I ended up building the oscillator section of Bob Cordell's old THD analyser project from Audio magazine.
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