Yes, those worked. Sounds like some sort of clipping to me.
Do the nc400's work OK with a normal analog source?
thank Julf.
The amps seem to work fine with two other DACs i have, Focusrite and Motu.
Any other test i can do to check for clipping?
Any thoughts on what could be causing the clipping? as i just measured i see around 178mv DC on each signal wire of the balanced pair, but no common mode DC offset.
The amps seem to work fine with two other DACs i have, Focusrite and Motu.
Any other test i can do to check for clipping?
Any thoughts on what could be causing the clipping? as i just measured i see around 178mv DC on each signal wire of the balanced pair, but no common mode DC offset.
What should i be looking for with the scope? How about feeding a 100Hz sine through the DAC and amplifier and observe the sinewave on the amps speaker outputs?
What would the distortions from the samples above potentially look like?
I put the balanced output of the DAC to my soundcard input and looked at results on the spectrum analyzer for various test tones and also pink noise in the 60-300Hz range. I havent noticed any smoking guns yet.
This almost certainly is a combination of this DACs balanced IV and the Hypex amps.
What would the distortions from the samples above potentially look like?
I put the balanced output of the DAC to my soundcard input and looked at results on the spectrum analyzer for various test tones and also pink noise in the 60-300Hz range. I havent noticed any smoking guns yet.
This almost certainly is a combination of this DACs balanced IV and the Hypex amps.
I did some debugging with an oscilloscope (Gnd probe to chassis and signal probe to +ve speaker out)
I mostly only seem to locate what appears to be switching frequency of the module around 400KHz. The test tone freq i am playing does appear as an envelope. I couldnt figure out a way to trigger to stably display just the test tone freq at the amp output. However, the waves dont appear to be clipping.
Not sure what any stability related oscillations would look like.
Also observed the DAC output (one signal out of the balanced pair) on the osclloscope and it appears fine.
But looking at the signal levels on the oscilloscope i have a theory. Please advice if this is a possibility.
I seem to be playing very close to the base noise level of the DAC during nominal listening. This is because the speaker is 94dB sensitive and are driven by high power UCD400.
At these low levels the noise output of the DAC seems to modulate with the music playing.
At higher output levels, things get too loud for comfort but the distortion isnt noticeable.
Is this just an issue with my gain stages?
If i can reduce the gain of the amp modules, or add a clean balanced passive attenuation to the XLR cable from DAC to amp, maybe i can play the DAC at a level where it performs the best.
I am new to this oscilloscope, so still figuring things out. Over the weekend if i can get back on this i will try and post some pics.
Please comment.
thanks
I mostly only seem to locate what appears to be switching frequency of the module around 400KHz. The test tone freq i am playing does appear as an envelope. I couldnt figure out a way to trigger to stably display just the test tone freq at the amp output. However, the waves dont appear to be clipping.
Not sure what any stability related oscillations would look like.
Also observed the DAC output (one signal out of the balanced pair) on the osclloscope and it appears fine.
But looking at the signal levels on the oscilloscope i have a theory. Please advice if this is a possibility.
I seem to be playing very close to the base noise level of the DAC during nominal listening. This is because the speaker is 94dB sensitive and are driven by high power UCD400.
At these low levels the noise output of the DAC seems to modulate with the music playing.
At higher output levels, things get too loud for comfort but the distortion isnt noticeable.
Is this just an issue with my gain stages?
If i can reduce the gain of the amp modules, or add a clean balanced passive attenuation to the XLR cable from DAC to amp, maybe i can play the DAC at a level where it performs the best.
I am new to this oscilloscope, so still figuring things out. Over the weekend if i can get back on this i will try and post some pics.
Please comment.
thanks
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Good!
Worth testing - just make a passive attenuator out of a couple of resistors. If it turns out to solve the problem, you can then change the feedback resistor of the ncore.
Thanks Guys.
Changing the DAC output stage gain is harder as i dont have the schematic or much help.
I will try a passive attenuator on the XLR interconnect from DAC to the amp.
If things improve i will remove the gain adjustment resistor in ncore and ucd400
Maybe talk to your supplier? The nc500OEM is (as the name implies) an OEM product, not sold directly to customers.
Your naming of this thread just set it up for the good ol discussion that was closed. Thats why I suggested "Hypex NC400 build thread".
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