Exactly.
Frequency stability. Quartz oscillator which clocked the DAC has much better stability then RC in "Victor".
I did not compare. 4x9V alkaline batteries is just so easy and keeps everything off the grid.
The ADC and the DAC of the RTX are commonly clocked. So the "relative" stability is near perfect.
It had completely slipped my mind that the RTX6001 can be used as a USB
dac. Just curious if member has tried using it in that capacity?
Thanks,
Dennis
Demian Martin (1audio) has tried it: DIY Audio Analyzer with AK5397/AK5394A and AK4490
I have of course also, but actually not much. Not enough time.
I have of course also, but actually not much. Not enough time.
See if you can borrow one for this purpose.
Where is JensH. Other side of the pond from me. Closer to you. It's both your interest.
Cheers,
@David,
There are already a bunch of audio analyzers out there, so I'm not sure whether "It's both your interest", unless I can convince Jens et al, that DiAna has some unique features, that any other analyzer can't offer. Besides, till now, I didn't get any response from Jens.
/ off-topic:
BTW, Interested in the latest version of DiAna? Error handling of fake and phantom drivers as well as the DSD transcoder, is now treated in the same way.
Cheers, E.
There are already a bunch of audio analyzers out there, so I'm not sure whether "It's both your interest", unless I can convince Jens et al, that DiAna has some unique features, that any other analyzer can't offer. Besides, till now, I didn't get any response from Jens.
/ off-topic:
BTW, Interested in the latest version of DiAna? Error handling of fake and phantom drivers as well as the DSD transcoder, is now treated in the same way.
Cheers, E.
Edmond -
Can you please summarize the specific measurement capabilities of DiAna that other analysis software cannot offer? Irrespective of the underlying methods, what measurements or conveniences does DiAna provide that are not available in applications like Arta, REW or AudioTester?
Hi Jim,
First of all, DiAna is a distortion analyzer targeted at the development or fine tuning of audio amplifiers, in particular audio power amplifiers. So it is not a universal tool for acoustical measurements.
It measure THD+/-N, IMD and frequency response. Although it also can be used as an ordinary spectrum analyzer, it's not its main feature. Just added, as some people are used to it. As it is a distortion analyzer, it has been optimized to calculate the harmonics of the fundamental.
A special features is extracting and displaying the residual, which, for example, clearly shows cross-over distortion and helps to settle the quiescent current of a class AB output stage. A single THD figure or even a spectrum would be less informative.
Another feature is its ability subtract the distortion from the sound card itself, from an overall measurement including a DUT, thus leaving the distortion of the DUT alone. In this way, the distortion measurement floor can be lowered. Not that much, about 15 dB (due to drift), but together with a dedicated interface, by as much as 60 dB.
Due to the "underlying methods" it is quite robust against noise and RFI, an important property in case of on-board sound cards. It also makes coherent averaging quite easy, as no external trigger is needed. Another consequence of the "underlying methods" is that DiAna can measure harmonics above the Nyquist frequency, provided, of course, that they are not cut-off by the ADC (only possible with a SAR ADC and suitable front-end).
Regarding "Irrespective of the underlying methods", if you mean things like an FFT versus FHT, indeed, irrelevant. But the philosophy behind the underlying methods does matter, as it make DiAna unique. For example, and AFAIK, no other software analyzer is able to calculate with high accuracy variables like frequency, phase and amplitude, from a stream of a sampled sine wave. For DiAna these variables are indispensable and must be as accurate as possible determined. DiAna does it while approaching the accuracy of the FPU itself (provided that the sine wave itself is not distorted, of course. And if it is distorted, then you don't need such a high accuracy anyhow).
Whether all other analyzer don't have any of the features as sketched above, I don't know (too time consuming to figure that all out). Also, above list of feature is just a random selection of all of them. DiAna has also a monitor or oscilloscope function, but I'm pretty sure other analyzers have that too, so let's leave out this kind of things. There is one thing that DiAna does not support: WDM, MME or WASAPI. It only supports ASIO, as all decent sound cards do have ASIO a driver.
Cheers, E.
I tried configuring my software based on the voltage levels indicated on the front panel of the RTX6001, but it seemed I got the conversion coefficients wrong. So I hooked up a signal generator to the input of the RTX6001, set the input level at the RTX to 1 V, and turned the signal amplitude at the generator up until the overflow LED at the RTX started flickering. Then I checked the voltage level on my scope:
I would have expected the overflow LED is a clipping indicator that turns on if the input voltage is such that the ADC output reaches 100% FS. If so, the LED should (a) always turn on at the same voltage level independent of the signal shape and (b) it should turn on if the input voltage exceeds the voltage level set at the input (+/-1 V in this case, or 2 V peak-to-peak).
I am confused. Can someone explain what's going on?
- With a square wave, I got 2.6 V (peak-to-peak) when the overflow LED started flickering.
- With a sine wave I got 3.0 V (peak-to-peak) when the overflow LED started flickering.
- With a triangle wave I got 3.1 V (peak-to-peak) when the overflow LED started flickering.
I would have expected the overflow LED is a clipping indicator that turns on if the input voltage is such that the ADC output reaches 100% FS. If so, the LED should (a) always turn on at the same voltage level independent of the signal shape and (b) it should turn on if the input voltage exceeds the voltage level set at the input (+/-1 V in this case, or 2 V peak-to-peak).
I am confused. Can someone explain what's going on?
If I get you right, you are saying that the voltage levels given on the front plate refer to RMS values? That would be awkward, because the RMS value depends on the signal form. I expected the labels on the front plate to indicate the voltage that is equivalent 100% FS of the ADC output (i.e., ADC output clips if signal exceeds 1V with 1V input selected).