Hopefully someone will send Amir the Eversolo F10 class AB amp to review. Stereophile just reviewed that amp and John Atkinson said, 'I was concerned by the higher levels of distortion in the treble compared with those in the midrange and bass.' Would like to see what Amir would have to say after measuring it .
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Eversolo AMP F2 Amplifier Review
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lordhumungous
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The 299 dollar Wiim Vibelink is a superior amp.
OP
- Thread Starter
- #43
As noted in the review, they did not design or build this amp. It is an OEM design by Starke. Their mistake was to not understand intricacies of class D design, and as such, accepting this product to put under their name. I found a year old youtube review which while typical of subjectivist type, also beat them up over this aspect (he tested in room and showed elevated treble response).
OP
- Thread Starter
- #44
Only if you don't understand the simple math behind it.
Nothing is "representative" when it is a single simulated speaker response among tens of thousands.
The differential between 4 and 8 ohm tells you the output impedance of the amp vs frequency. You can see this easily and if you wanted, compute that impedance. With a wiggly response of a complex load, you have no prayer of doing the same.
That simulated load by the way has a bug in it with rising treble phase (or was it level?) post 20 kHz. I know, I built one and ran a test against a class D amp and we discussed it. It showed little useful information.
BTW, take caution in your tone. The only thing worse than not understanding a technical topic is to be insulting as well.
My tone is just fine, thank you. Nor was it insulting.
In this case, the only thing a simple 4/8 ohm "load dependency" test shows is the characteristic of the output filter. And whether it's inside the feedback loop, or not.
In this case, the output filter is optimized for 4 ohms. Obviously.
A dummy, real-world speaker load, of whatever type, is much better at displaying audible "load dependency" issues with amplifiers.
Testing with such on amplifiers with high-ish output impedance can yield a nice deviation curve that might be beneficial to some users.
I probably wouldn't purchase this amplifier. But it wouldn't be because there's a problem with "load dependency." There clearly isn't.
In this case, the only thing a simple 4/8 ohm "load dependency" test shows is the characteristic of the output filter. And whether it's inside the feedback loop, or not.
In this case, the output filter is optimized for 4 ohms. Obviously.
A dummy, real-world speaker load, of whatever type, is much better at displaying audible "load dependency" issues with amplifiers.
Testing with such on amplifiers with high-ish output impedance can yield a nice deviation curve that might be beneficial to some users.
I probably wouldn't purchase this amplifier. But it wouldn't be because there's a problem with "load dependency." There clearly isn't.
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bargainguy
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Quote from the recent Stereophile review of the Eversolo AMP-F10 amplifier:
www.stereophile.com
Eversolo is a group of very low-key, humble, hardworking people. Most of them are in their 20s and 30s, except senior management, [who are] in their 40s. They are not audiophiles but love and enjoy music and movies." She added, "Even though their products are very popular, they have admitted that they are still very green in audio and are making mistakes. But they are eager to learn and improve. With that attitude, they can only do better and better.
They just came out with the F10 class A/B amp - rated 200w/1kHz/8ohms, 320w into 4ohms and 450w into 2ohms - and supposedly it's a good one of their own design from early reports.
Rebadging a Starke design could be a temporary affiliation, a test of the waters so to speak.
If they're young and flexible enough, it'll come back to the design team that the Starke design has the above noted issues, and they'll take action for future builds.
Eversolo AMP-F10 power amplifier | Stereophile.com
A century ago, pioneering psychiatrist Carl Jung had a wild encounter with the power of sound. "In a village on the way from Lake Albert to Rejaf in the Sudan we had a very exciting experience," Jung wrote in his book Memories, Dreams, Reflections. He goes on to describe his participation in a...
Eversolo is a group of very low-key, humble, hardworking people. Most of them are in their 20s and 30s, except senior management, [who are] in their 40s. They are not audiophiles but love and enjoy music and movies." She added, "Even though their products are very popular, they have admitted that they are still very green in audio and are making mistakes. But they are eager to learn and improve. With that attitude, they can only do better and better.
They just came out with the F10 class A/B amp - rated 200w/1kHz/8ohms, 320w into 4ohms and 450w into 2ohms - and supposedly it's a good one of their own design from early reports.
Rebadging a Starke design could be a temporary affiliation, a test of the waters so to speak.
If they're young and flexible enough, it'll come back to the design team that the Starke design has the above noted issues, and they'll take action for future builds.
Class A/B... Considering the performance of cheapo class D stuff built around a Tpa3255 chip or similar, i find funny to see the efforts some have to make reinventing the old class A/B wheel to catch the attention of picky audiophiles ready to spend some more money on presumably more sophisticated gear...
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The 20kHz distortion response versus power level was certainly a concerning feature of the test measurements. The Pioneer SX-1980 amplifier, released almost 50 years ago, had specifications that showed the following distortion characteristcs for 20Hz and 20kHz input signals. These results seem quite reasonable, so we might have hoped to get at least a similar level of performance from a modern amplifier.
HoweSound
Active Member
Thanks Amir for your analysis. I expected better from Eversolo. I am still delighted with my Eversolo A6, purchased based on ASR's review, a perfect pairing with my other ASR recommended purchases, a Hypex Nilai amp and Schiit Freya S pre.
Really somewhat OT, but I would like to see a two ratings system. One vote for engineering excellence and a separate rating for value for money. It feels like there is a valid reason to have two ratings and really shouldn't take us much longer.
ICIETDIYEUR
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With the 'spectacular' raised in the treble under a load of 8 Ohms, I can't even imagine if someone had to use this device with Rogers LS3/5A speakers (15 ohms)...
With a good input diagram, good components and also a correctly implemented PFFB (as for the TOPPING PA5, its diagram is known), the problem would not arise.
Here is an example of a single end schematic (only one channel shown) which can be easily modified using an NJW1195A chip to allow selection between single-end or balanced inputs ->
So do a test based on my remarks and this diagram, take measurements but above all listen and appreciate
NB: FOSI could take inspiration from this and make a new 'V3 PRO' model but comes with a 52V and 12A power supply (the TPA 3255 would be configured in PBTL)
But above all with a level display to please Amirm
With the 'spectacular' raised in the treble under a load of 8 Ohms, I can't even imagine if someone had to use this device with Rogers LS3/5A speakers (15 ohms)...
With a good input diagram, good components and also a correctly implemented PFFB (as for the TOPPING PA5, its diagram is known), the problem would not arise.
Here is an example of a single end schematic (only one channel shown) which can be easily modified using an NJW1195A chip to allow selection between single-end or balanced inputs ->
So do a test based on my remarks and this diagram, take measurements but above all listen and appreciate
NB: FOSI could take inspiration from this and make a new 'V3 PRO' model but comes with a 52V and 12A power supply (the TPA 3255 would be configured in PBTL)
But above all with a level display to please Amirm
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Sokel
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Engineering-wise it's not the worst idea if someone wants to feel that has low THD+N all over, only comparable with new Purifi perhaps.Class A/B... Considering the performance of cheapo class D stuff built around a Tpa3255 chip or similar, i find funny to see the efforts some have to make reinventing the old class A/B wheel to catch the attention of picky audiophiles ready to spend some more money on presumably more sophisticated gear...
(link)
Way inaudible of course, as anything even orders worst, but...
That's what about nice AB's are for, distortion+noise-wise.
Waxx
Major Contributor
This should be a lot better, especially for this price and in the actual market where you get much better amps for less money...
Talisman
Major Contributor
For me, it's a headless panther, without a doubt.
We no longer have any reason to tolerate load-dependent amplifiers at €150, let alone €750. There are several Hypex offerings that revolve around this power amplifier and cost even less.
We no longer have any reason to tolerate load-dependent amplifiers at €150, let alone €750. There are several Hypex offerings that revolve around this power amplifier and cost even less.
I guess by "revolve around" you mean "run circles around"? Because that's what they do. The usual NC252 builds are exactly that price or a bit less, and do indeed run circles around this outdated and underperforming TPA implementation.
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This is a really weird position to take. Clearly there is an issue with load dependency, as in the frequency response depends on the load's impedance at high frequencies. I honestly can't figure out why you're arguing with Amir about this. A simulated complex load can be helpful as an example of how frequency response can vary, but as Amir said it doesn't tell anyone how the amp will actually interact with their speaker's load.
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