maty
Major Contributor
I can not hear nothing at 20 kHz now but it is a important paramenter to me, the phase curve. With Class A and A/B it is never a problem (< 6º at 20 kHz, usually).
Below -120db
-thoughtful-
Noise shown in FFT measurements will be false regardless of whether you calibrate the software or not. That's the nature of FFT gain.Paul @pkane , could you make your measurements calibrated?? It is so easy with REW, and comparisons are easier then, especially noise. Please take into account that not everyone here can make it in his head.
Pavel, it was calibrated, I just posted the plot in dBFS. I plan to do more testing and will post the results then.Paul @pkane , could you make your measurements calibrated?? It is so easy with REW, and comparisons are easier then, especially noise. Please take into account that not everyone here can make it in his head.
Paul @pkane , could you make your measurements calibrated?? It is so easy with REW, and comparisons are easier then, especially noise. Please take into account that not everyone here can make it in his head.
Sure, thank you! Noise itself is best to measure in V and then switch scale to dBV. The result in V will remain in top right corner
Quickly reconnected everything to remeasure. This is with ADC in stereo mode, so no 3dB noise floor reduction
View attachment 175599View attachment 175600View attachment 175601View attachment 175602
Interesting, I measure 36uV noise (20Hz-22kHz unw.) at the output of my NC252MP amp, with input terminated by 100 ohm.
If your noise measurement is not influenced by the ADC noise, then the PA5 has higher noise than expected.
Here are reliable noise measurements for the PA5: https://www.l7audiolab.com/f/topping-pa5-poweramp/Interesting, I measure 36uV noise (20Hz-22kHz unw.) at the output of my NC252MP amp, with input terminated by 100 ohm.
If your noise measurement is not influenced by the ADC noise, then the PA5 has higher noise than expected.
Hi @pkane, thank you for your measurements. Is it possible for you to measure the PA5 when reducing the level by -10db using the volume knob of the PA5?
You can see above that 0.55W it's nearly the same as 5W, so seems pretty consistent. I'll run some sweeps later.@pkane if you measure at 1W wich is my normal volume what do you get?
I mean same 5w power output but lower volume knob by 10db. I know, that only possible if you have 4ohm load. If not, you could measure at any meaningful lower power output. Thank youKeep the same power out (5W), but lower volume knob by 10dB, is that what you're looking for? Or lower output by 10dB?
I mean same 5w power output but lower volume knob by 10db. I know, that only possible if you have 4ohm load. If not, you could measure at any meaningful lower power output. Thank you
Oops, thank you, I thought, that you only lowered the output level of your preamp, but the volume knob of the PA5 was fixed at max. level by that measurement.Already measured. Please see above.
I can not hear nothing at 20 kHz now but it is a important paramenter to me, the phase curve. With Class A and A/B it is never a problem (< 6º at 20 kHz, usually).