I reviewed the Gustard H20 which is a high-end headphone amplifier yesterday. Its owner kindly sent me some high-end op-amps to "roll" in there to see what difference it makes.
The task was pretty easy. The top screws come out of the H20 and if you tilt the unit, the lid falls out exposing its pretty guts:
Everything is surface-mounted so not replaceable other than the pair that are socketed. You can see that I swapped one of the channels to Sparko's Lab SS3602 from TI/National LME 49720:
There is massive price difference with the LME retailing for just $2.68 and the Sparko's for whopping $79.80. There better be good bit of improvement for it to be worth putting two of those in there for nearly USD $160.
Op-amp Rolling Audio Measurements
Since the Gustard H20 performance is poor in unbalanced mode, I decided to run the dashboard using my balanced load of 50 ohm:
This is at max volume using 4 volt input which should stress the op-amps. But we see no difference to speak of. SINAD is the same for both (the difference goes either way in every snapshot so not material).
How about at other input/power levels? Let's see:
Don't mind the spikes here and there. The level of distortion is so low that the power supply noise gets in the way and causes variations from time to time. There is no difference really across the full spectrum of input/output levels.
Let's run a high-resolution FFT to see what differences there might be at very small levels:
As noted, the distortion profile is different but not an audible thing since mains noise is higher than it. And we are talking about distortions that well below 120 dB each.
FYI, I ran this test to 1 Mhz and the Gustard H20 was very stable with no signs of oscillation in either channel with either op-amp.
That does not mean the Sparko's lab is a good choice here. I left my test run at full output level for a few minutes and the Sparko's channel started to produce a lot more distortion (down to 90 dB SINAD). I suspected thermal stress and I was right. Touching the Sparko's told me it was running quite hot. IR imaging shows that:
As you see, the Sparko's op-amp is the hottest component despite a number of power transistors in the H20! Maybe this is within its spec and at any rate, you would not be using the H20 at full volume. Still, more power is being used here and there may be longer term consequences.
Conclusions
A while ago I rolled the op-amps in the Topping D10 DAC with no resulting difference. The story repeats here with the much more expensive op-amp from Sparko's Lab showing no improvement whatsoever in the performance of Gustard H20. The H20 has excellent performance in balanced output and so it makes sense that this is all she can produce even if the Sparko's lab is better. We are actually limited by the mains noise here (which the Sparko's may have less immunity to).
So the message remains the same: don't waste your money on such "upgrades" unless they come with tangible, measurable performance improvement. Don't "trust your ears" because you don't know what they are hearing. All you know is what you are perceiving and after spending $160, you may talk yourself into these upgrades sounding better. They do not and cannot.
------------
As always, questions, comments, recommendations, etc. are welcome.
So I got no money donated for me to buy a good sized boat for the upcoming season. So I decided to dial down my expectations and ask for money to buy a paddle board. No idea if I can ride one but one way to find out: get one! So please donate generously using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
The task was pretty easy. The top screws come out of the H20 and if you tilt the unit, the lid falls out exposing its pretty guts:
Everything is surface-mounted so not replaceable other than the pair that are socketed. You can see that I swapped one of the channels to Sparko's Lab SS3602 from TI/National LME 49720:
There is massive price difference with the LME retailing for just $2.68 and the Sparko's for whopping $79.80. There better be good bit of improvement for it to be worth putting two of those in there for nearly USD $160.
Op-amp Rolling Audio Measurements
Since the Gustard H20 performance is poor in unbalanced mode, I decided to run the dashboard using my balanced load of 50 ohm:
This is at max volume using 4 volt input which should stress the op-amps. But we see no difference to speak of. SINAD is the same for both (the difference goes either way in every snapshot so not material).
How about at other input/power levels? Let's see:
Don't mind the spikes here and there. The level of distortion is so low that the power supply noise gets in the way and causes variations from time to time. There is no difference really across the full spectrum of input/output levels.
Let's run a high-resolution FFT to see what differences there might be at very small levels:
As noted, the distortion profile is different but not an audible thing since mains noise is higher than it. And we are talking about distortions that well below 120 dB each.
FYI, I ran this test to 1 Mhz and the Gustard H20 was very stable with no signs of oscillation in either channel with either op-amp.
That does not mean the Sparko's lab is a good choice here. I left my test run at full output level for a few minutes and the Sparko's channel started to produce a lot more distortion (down to 90 dB SINAD). I suspected thermal stress and I was right. Touching the Sparko's told me it was running quite hot. IR imaging shows that:
As you see, the Sparko's op-amp is the hottest component despite a number of power transistors in the H20! Maybe this is within its spec and at any rate, you would not be using the H20 at full volume. Still, more power is being used here and there may be longer term consequences.
Conclusions
A while ago I rolled the op-amps in the Topping D10 DAC with no resulting difference. The story repeats here with the much more expensive op-amp from Sparko's Lab showing no improvement whatsoever in the performance of Gustard H20. The H20 has excellent performance in balanced output and so it makes sense that this is all she can produce even if the Sparko's lab is better. We are actually limited by the mains noise here (which the Sparko's may have less immunity to).
So the message remains the same: don't waste your money on such "upgrades" unless they come with tangible, measurable performance improvement. Don't "trust your ears" because you don't know what they are hearing. All you know is what you are perceiving and after spending $160, you may talk yourself into these upgrades sounding better. They do not and cannot.
------------
As always, questions, comments, recommendations, etc. are welcome.
So I got no money donated for me to buy a good sized boat for the upcoming season. So I decided to dial down my expectations and ask for money to buy a paddle board. No idea if I can ride one but one way to find out: get one! So please donate generously using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
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