No, osciloscope is on battery. Dut is ok, confirmed working in earlier posts, sound wonderfull. Problem here is levls displayed under software. See picture from post #97, osciloscope widow shows that ddpd (direct digital power dac | dut) is working, Problem here is measurement setup. Wrong levels displayed under booth Rew and Multisim. See also post #89 , levels is corectly measured after auxFilter+attenuator but levels wrongly displays in software, something is wrong, pc drivers, sound card settings, asio drivers, Cosmos, or software, right now I have no idea how to debug.
What Peak to Peak voltage does the scope show at the ddpd output? What full scale voltage range is Cosmos set to? Can you display the Cosmos digital output on a soundcard oscilloscope app on your PC?
https://www.zeitnitz.eu/scope_en
https://listoffreeware.com/best-free-oscilloscope-software-windows/
https://www.zeitnitz.eu/scope_en
https://listoffreeware.com/best-free-oscilloscope-software-windows/
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I am suggesting how to debug. First verify you can use you PC as a soundcard (Cosmos) oscilloscope and that it matches your physical oscilloscope. See the apps I linked to.
If that works, then Cosmos works and the drivers must be working well enough to show the correct signal levels.
IOW, divide a big problem into smaller sections to narrow down where the problem must be.
Not an easy task for me : ) Hardware levels is well known, ddpd out have 1.49Vrms measured on input of the aux+attenuator (contain also 8ohm dummy load). Value measured on OUT of the aux+attenuator+dummyload is 1.49Vrms / 22.71 = 65.6mVrms , those 64mVrms value Cosmoss see as a ?? Somebody told me that DC value inside Multitone mean an input level which looks like is not a try because please see post #97, DC level on pictures have vicewersa efect, looks like DC is something else, what? I'm using Multitone for the first time, have no idea where input levels is displayed, looks like it is missing? Sound card IN is Amanero and sound card OUT is Cosmos. Booth is working as you can see on my osciloscope measured sinewave. Something else is wrong. 64mVrms (in my real case measured value after aux, dummy and attenuator is 65.6mVrms) need to be seen inside Multitone as 23.88dbFS in case 64mVrms! Cosmos is set to 1.7Vrms resolution, and Cosmos see 65.6mVrms, but value displayed under software looks wrong. Even Rew shows wrong value. Rew is a bit complicated because lack of dsd so I will stay with Multitone until frontend for ddpd get finished than I will be able to setup Rew correctly.
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Cosmos ADC has low input impedance (640ohm at 1.7Vrms, 30% less unbalanced) but that should not be a problem for you amp but it may be a problem for your attenuator. If you measure 1.49Vrms at the input of Cosmos ADC set to 1.7Vrms REW or Multitone should have the fundamental at about -1dBFS. If that is not the case then the issue could be in the Cosmos ADC driver or Cosmos ADC itself. With ASIO or WASAPI Exclusive drivers REW does not care about Windows sound settings. For some reason Multitone uses Windows sound settings even with WASAPI exclusive but not with ASIO. Anyhow it is good practice to set default Windows sound devices to something else than what is used in REW/Multitone.
Is the sinewave amplitude shown correctly on the software scope (can you verify the amplitude calibration)?
If its a sine wave and you don't have a hardware scope, can you verify the hardware voltage with a DVM (set sine wave frequency to within the DVM's frequency range)?
If Multitone uses Windows default sample rates, then set it in Windows Control panel to the sample rate you want to use:
The green circle on the left with the white checkmark is not good. That indicates Windows has assigned the device to serve as a Windows default device. As Bohrok2610 said, better to assign some unused sound device as the Windows Defaults. Then Windows is less likely to mess with the sample rate. However, if you plug the sound device into a different USB port then Windows may assign it as default again. So you have to keep an eye on that.
If its a sine wave and you don't have a hardware scope, can you verify the hardware voltage with a DVM (set sine wave frequency to within the DVM's frequency range)?
If Multitone uses Windows default sample rates, then set it in Windows Control panel to the sample rate you want to use:
The green circle on the left with the white checkmark is not good. That indicates Windows has assigned the device to serve as a Windows default device. As Bohrok2610 said, better to assign some unused sound device as the Windows Defaults. Then Windows is less likely to mess with the sample rate. However, if you plug the sound device into a different USB port then Windows may assign it as default again. So you have to keep an eye on that.
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But where is level displayed under Multitone? I do not think it was DC value, please see post #97! DC levels have wiceversa efect when ddpd work on 1.25V DC is displayed -22db but when ddpd is 5V DC value is diplayed -40.1db, it might be that DC value under Multitone have nothing in relation to input level db?
Markw there is no clipping on DDPD. Volume level on DDPD is controled by variable power supply. minimum volume is 1.25V and maximum is 5V. Full bridge voltage is used as a volume level. DDPD work on PDM modulation so input signal must be PDM. I'm using dsd64 and also dsd128. PCM can't work here! My hw setup is folowed by: Amanero is used as an input device for our DDPD (dsd power dac), ddpd can't work with PCM, DSD must be suplied in order to make ddpd work, and itcomplicate things here (if I want Rew). Cosmos adc here is used for measring DDPD. I curently have no idea how to measure Cosmos by an HW scope as you say since Cosmos is an ADC device! All the other things you say in relation to sound settings is setup correctly. All is set to 44100Hz since ddpd will use dsd64 (64 x 44100). All volume levels is 100%. Default sound device is set to anything else other than Cosmos/Amanero. The only thing I not tried is virtual osciloscope! Hardware osiloscope results I have shown you, 1.49Vrms (when ddped volume level is set to 5V) is measured on INPUT dummyload8ohm+aux+attenuator (that input is connected to DDPD out), also I have measured by hw scope after attenuator, getting 65.6mVrms there. So Cosmos input must see 65.6mVrms. Cosmos is connected to Multitone but I do not see right level in db in Multitone, DC db value looks like not an value for signal input level, looks like something else. I have no idea what Multitone see, I do not see where input level db is shown, Multitone missing it?
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Actually DC may be your problem. Have you checked if there is DC in the ADC input signal?
H1 is input level? Ok. So post #97 pictures... while ddpd is on 5V volume level after attenuator we have 65.6mVrms (the one which Cosmos see), pictures shows H1= - 41.2db which is wrong, 64mVrms is 23.88dbFS !
Edit: didn't checked. Hmm, my connection to cosmos is diferential, there should be no DC, ddpd is also fully diferential, maybe some small DC values might be possible, see my osciloscope pictures, dutty is around 50% +- 0.3 , there should be no problem. If I remember I didn't see anything while osciloscope was dc coupled, but I will check again!
Edit: didn't checked. Hmm, my connection to cosmos is diferential, there should be no DC, ddpd is also fully diferential, maybe some small DC values might be possible, see my osciloscope pictures, dutty is around 50% +- 0.3 , there should be no problem. If I remember I didn't see anything while osciloscope was dc coupled, but I will check again!
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You don't necessarily need to use DPDD as a test signal source to calibrate the system, although you could. Besides, don't you know how to make a clipper circuit? You don't clip the dac. You clip the ADC input (with appropriate current limiting of course; how do you think mastering engineers clip recordings to make them sound loud?), or use a clipper circuit. A resistor and a couple of diodes can do it. The point is that you need to find a way to figure out where your measurement system problem is.
Measuring DDPD is the next problem after you get the measurement system figured out.
DSD is main problem here for levels setup. If I supply DSD to my sound cards how can I do calibration without DDPD? Ddpd here is used as a digital to analog converter, Cosmos converts from analog to digital. Digital values from Cosmos is then shown on Multitone. I will check what bohrok2610 say, DC level on DDP out first, maybe there is realy an DC voltage which cause Cosmos to not work correctly. What is meaning of DC inside multitone window?
My suggestion is that you first measure without attenuator with amp's 1.49Vrms output. And check that DC level is low. AFAIK Multitone DC is the actual DC level so you have quite high DC.
Sorry I didn't saw your post. Yes 65mVrms is read while Cosmos is NOT connected. Thank you so much! Thats it, : ) So measurement is correct?
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I will check all the things tommorow, dc level, also output Vrms after attenuator & connected Cosmos, it must show booth osciloscope & Multitone level corectly in case all is right, thank You all so much! I have tried allready withoutattenuator, problem is ground loop since I don't have usb isolation between Amanero and my pc and seccond one ground trought Cosmos usb to my pc, measurement was very bad, my osciloscope show very high noise, few mV, even when there is no sound supplied, I am afraid I will be not able to measure ddpd.
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