Pdxwayne
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I have the following on hand to compare:
Topping L30
Sabaj A10h
SMSL HO200
Before I did any measurements, I did listening comparisons first. With my AKG371, my impression was that, often L30 sounded slightly "thin" in bass (like low bass guitar tones in music) as compared to the other amps. But, sometimes it sounded strong and not thin. It just confused me. What happened to my hearing?
The song I used for comparison is this:
Bass guitar starts at 46 seconds of the song.
So I decided to do voltage match and do listening test again. Initially I found channel imbalance issue when using "mid" volume setting. I then decided to switched to "low" volume setting and that helped with channel imbalance issue.
With all amps in LOW volume setting, I first played 250hz tones at a good volume level (as determined by listening to music via k371) to matched all left channel to same voltage. Then I check right channel.
Left and right channel voltage measured for 250hz tone:
L30 0.092 0.093
A10H 0.092 0.092
HO200 0.092 0.093
All three voltages are stable playing the 250hz tone for a minute.
I listened again and it seems L30 again sometime sounded a little thin in bass, sometimes sounded just fine.
I decided to check with 60hz tone next, using the same volume knob level as 250hz.
Left channel voltage measured when playing 60hz tone:
L30 keep moving around between 0.088 to 0.096 V
A10H move a bit between 0.092 to 0.093, mostly stable to 0.092
HO200 move a bit between 0.092 to 0.093, mostly stable to 0.092.
So, A10H and HO200 voltages are stable for both 250hz and 60hz tones.
L30 is not stable at 60hz tone.
Every few seconds it would move by 0.001 V, stop at one extreme for 10+ seconds, then move 0.001 V every few second to another extreme. It would repeat that up and down voltage swing.
Using the first calculator in http://www.sengpielaudio.com/calculatorVoltagePower.htm,
I estimate that the dB difference between 0.088 to 0.096 is about 0.75db. So it would seem for every half a minute or so, I would hear 0.75db louder or softer in 60hz tone, when using my AKG371.
Is this voltage swing of 0.75db at 60hz acceptable behavior?
Thanks!
Topping L30
Sabaj A10h
SMSL HO200
Before I did any measurements, I did listening comparisons first. With my AKG371, my impression was that, often L30 sounded slightly "thin" in bass (like low bass guitar tones in music) as compared to the other amps. But, sometimes it sounded strong and not thin. It just confused me. What happened to my hearing?
The song I used for comparison is this:
So I decided to do voltage match and do listening test again. Initially I found channel imbalance issue when using "mid" volume setting. I then decided to switched to "low" volume setting and that helped with channel imbalance issue.
With all amps in LOW volume setting, I first played 250hz tones at a good volume level (as determined by listening to music via k371) to matched all left channel to same voltage. Then I check right channel.
Left and right channel voltage measured for 250hz tone:
L30 0.092 0.093
A10H 0.092 0.092
HO200 0.092 0.093
All three voltages are stable playing the 250hz tone for a minute.
I listened again and it seems L30 again sometime sounded a little thin in bass, sometimes sounded just fine.
I decided to check with 60hz tone next, using the same volume knob level as 250hz.
Left channel voltage measured when playing 60hz tone:
L30 keep moving around between 0.088 to 0.096 V
A10H move a bit between 0.092 to 0.093, mostly stable to 0.092
HO200 move a bit between 0.092 to 0.093, mostly stable to 0.092.
So, A10H and HO200 voltages are stable for both 250hz and 60hz tones.
L30 is not stable at 60hz tone.
Every few seconds it would move by 0.001 V, stop at one extreme for 10+ seconds, then move 0.001 V every few second to another extreme. It would repeat that up and down voltage swing.
Using the first calculator in http://www.sengpielaudio.com/calculatorVoltagePower.htm,
I estimate that the dB difference between 0.088 to 0.096 is about 0.75db. So it would seem for every half a minute or so, I would hear 0.75db louder or softer in 60hz tone, when using my AKG371.
Is this voltage swing of 0.75db at 60hz acceptable behavior?
Thanks!
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