What brought this on is I recently bought the Topping PA3s, and am disappointed with its performance.
Some people say all amps sound the same - this thread is not about that.
Supposedly the difference between the top THD+n figure (1kHz 5W / 4 ohm), and the THD+n in multi frequencty/power graph, is from test bandwidth
- the THD+n measurement at the very top is done @ 22kHz, multi tone: 45.
The two images below show a 13dB diference
*The edit is bolding and making larger the text above to make more obvious the reason for this thread
If there wasn't a measurement error in the PA3s review, it seems it would be best to do both measurements 22kHz bandwidth, so that the figure representsrepresents the most relevant distortion: distortion in the audible range
* The edit is underlined as it's the proposed solution.
...for clarity.
For further clarity, this thread is not about the PA3s at all - it's just the example which brought this issue to my attention
(The top number is into 4 ohms, the 6.3V p-p proves it. Often the 8 ohm measurement is ~3dB better, but not in the PA3s's case - there's a (very odd) 10dB increase in distortion between ~6 and ~8 watts into 4 ohms, and at 10 watts 4 ohms (= 5w 8), distortion seems to be 7 or 8dB worse)
Some people say all amps sound the same - this thread is not about that.
Supposedly the difference between the top THD+n figure (1kHz 5W / 4 ohm), and the THD+n in multi frequencty/power graph, is from test bandwidth
- the THD+n measurement at the very top is done @ 22kHz, multi tone: 45.
The two images below show a 13dB diference
*The edit is bolding and making larger the text above to make more obvious the reason for this thread
If there wasn't a measurement error in the PA3s review, it seems it would be best to do both measurements 22kHz bandwidth, so that the figure representsrepresents the most relevant distortion: distortion in the audible range
* The edit is underlined as it's the proposed solution.
...for clarity.
For further clarity, this thread is not about the PA3s at all - it's just the example which brought this issue to my attention
(The top number is into 4 ohms, the 6.3V p-p proves it. Often the 8 ohm measurement is ~3dB better, but not in the PA3s's case - there's a (very odd) 10dB increase in distortion between ~6 and ~8 watts into 4 ohms, and at 10 watts 4 ohms (= 5w 8), distortion seems to be 7 or 8dB worse)
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