[Strale]

Thanks @tibook for this brief review!
It seems a bit unfair for HC4 to be immediately compared to the best of the best (SP3000) .
Anyhow, you mentioned that there is more energy in treble region (6-8 kHz as you described and zippy top end) and some space is lost in HC4 compared to SP3000...but I am wondering:
1. Is HC4 generally prone to fatiguing and shouty sound signature (not compared to SP3000, but generally)? Or is it easy on ears?
2. Does HC4 have that ''black background'' which A&K devices are usually known for?
3. How does it resolve busy passages - can you clearly distinguish between individual instruments and vocals?

Please shed some more light

 

[HifiFrog]

Unfortunately, the Astell&Kern AK HC4 has no independent volume control.
This means that only 16 different steps are available on iOS:
For IEMs, even the first step is already too loud and all further steps are not fine enough.

I would not have expected this design decision from such a premium product.
I will have to look for another product with AKM AK4493S DAC chip.

 

[gmalik]

Unfortunately, the Astell&Kern AK HC4 has no independent volume control.
This means that only 16 different steps are available on iOS:
For IEMs, even the first step is already too loud and all further steps are not fine enough.

I would not have expected this design decision from such a premium product.
I will have to look for another product with AKM AK4493S DAC chip.

The iphone devices volume level is not 16 steps, it is true if you use with the volume button!
If you adjust the volume manually, there are many more more steps!

 

[HifiFrog]

Thanks for the clarification, I didn't know you could fine tune the volume on iOS by using the control center GUI slider (e.g. on Lock Screen).

I would still like to have independent hardware volume or a high/low mode, as there are no setting options for the step size on iOS and the buttons on the DAC are therefore of less use to me.

Unfortunately, I still can't use the device with my IEMs because the minimum volume (step 1) is too loud

 

[Andricop]

Unfortunately, the Astell&Kern AK HC4 has no independent volume control.

What do you mean by independent volume control?

There are volume buttons on the device as you can see on this picture and also in the user manual

 

[HifiFrog]

@Andricop By independent volume control I mean the behavior of FiiO KA5 or Shanling UA4 on iOS.

There you can set the volume independently on source and DAC (e.g. 20% iOS + 40% DAC = 30% total volume). This option has the advantage that I can set the DAC to 1% (still too loud) and adjust it further down on iOS - e.g. to 90% to get a comfortable overall volume.

Another advantage: The DAC can have a finer step size than the iPhone buttons (e.g. 60 or 120 steps as with the FiiO KA5) This avoids the problem of the large step width on iOS.
Since both volume controls are enabled and independent, I can still decide where I want to control it (the other control just needs to be set loud enough to give enough headroom).

If the DAC (like AK HC4) only serves as a "remote control" for the source device, it automatically inherits the too large step width from iOS buttons.
(Yes as I learned earlier, you can use the GUI screen on iOS to fine tune the Volume - but it's cumbersome to use the screen and the buttons on the phone and DAC still have little use)

I've already written more about the different types of volume control DACs can have on iOS here: https://www.head-fi.org/threads/the-ibasso-dongle-dac-thread-–-dc03-pro-dc04-pro-dc06-pro-dc-elite.967987/post-17865068

There I also describe other options that would improve the situation (like with the iBasso DC04 Pro): Disable volume buttons on iOS and only allow adjustments on the DAC (Of course, only more than 100 steps make sense so that the steps are fine enough)

I think that the problem is underestimated by many manufacturers (IEMs are a quickly growing market, and the race is not just maximum power for the big cans). I have already asked Lotoo if they can release a firmware update for the PAW S2 to enable volume control (the PAW S2 is also too loud for me with IEMs). Also I had to send the iBasso DC Elite back for the same reason.

 

[HifiFrog]

1. Is HC4 generally prone to fatiguing and shouty sound signature (not compared to SP3000, but generally)? Or is it easy on ears?
2. Does HC4 have that ''black background'' which A&K devices are usually known for?

1) I did not listen very much with it, and I am no expert for sound signatures, but the DAC is in my opinion on the relaxed/smoother side.
You can also enable oversampling with the switch for even smoother sound.

2) Testet with my IEMs: 3.5mm no noise at all. On 4.5mm very little noise.

 

[Strale]

1) I did not listen very much with it, and I am no expert for sound signatures, but the DAC is in my opinion on the relaxed/smoother side.
You can also enable oversampling with the switch for even smoother sound.

2) Testet with my IEMs: 3.5mm no noise at all. On 4.5mm very little noise.

Thanks @HifiFrog,

I suppose that is what could be expected from AKM AK4493S DAC chip: relaxed and smooth. I was just a bit confused with @tibook comment about zippy top end with HC4, but I guess it was just a comparison with SP3000...?

Regarding the ''black background'', it seems to me it has more than just a noise level. Together with noise, might be that such impression is born out of fast transients and high clarity/definition...not sure. Anyhow, @tibook said:

I will say, that "dark background" thing I've heard the SP3k described as, I get.

I liken the SP3k to an OLED display. Everything looks (sounds) better when its presented against total black.

which is a bit confusing, does this mean that HC4 also has it...or it is just present on the SP3000...?

 

[Andricop]

There you can set the volume independently on source and DAC (e.g. 20% iOS + 40% DAC = 30% total volume). This option has the advantage that I can set the DAC to 1% (still too loud) and adjust it further down on iOS - e.g. to 90% to get a comfortable overall volume.

That's what you should also be able to do with the HC4 from my understanding.

 

[HifiFrog]

@Strale I continued listening to music with the DAC today and would like to reiterate my statement that the DAC is relaxed and smooth. It is more on the hi-fi side than on the analog side.

As I wrote, I had only listened to a few songs that were quiet enough, and these were rather soft in nature.
Especially the highs are rather sharp, fast and energetic (e.g. Hi-Hats).
If you are after something similar to the Lotoo PAW S2 or Cayin RU6 for example, this device is not what you are looking for.

As I have already written, I am not an expert in this field.
I can only recommend everyone to wait for the first reviews from the professionals to see what they say about the sound signature. Sorry again, I shouldn't have commented on this at all.

 

[HifiFrog]

That's what you should also be able to do with the HC4 from my understanding.

The image describes the behavior on Android and Tidal etc.
I use iOS with Apple Music or Qobuz.

Unfortunately, the behavior on iOS is not optimal: The buttons on the HC4 behave like the volume buttons on the side of the iPhone: They always change the volume by 6.25% = 16 Steps. This is an Apple limitation and cannot be changed. The Control Center (the volume control on the screen/lock screen) allows more precise control.
6.25% is too imprecise and it is impractical to use the screen for precise control.

The two other options for how DACs can control volume that I described above would avoid this problem (control volume on DAC only, or control volume on device and DAC independently).

Being able to control the volume only on the DAC would also possibly solve the dangerous problem described in the picture.

I hope I was able to explain why I was so surprised to find this type of volume control on this DAC.

In my opinion it would make sense to change/improve the behavior via firmware update. FiiO did exactly the same with the release of the KA13: The control was reprogrammed from "remote control" to independent control via firmware update.

 

[Strale]

@Strale I continued listening to music with the DAC today and would like to reiterate my statement that the DAC is relaxed and smooth. It is more on the hi-fi side than on the analog side.

As I wrote, I had only listened to a few songs that were quiet enough, and these were rather soft in nature.
Especially the highs are rather sharp, fast and energetic (e.g. Hi-Hats).
If you are after something similar to the Lotoo PAW S2 or Cayin RU6 for example, this device is not what you are looking for.

As I have already written, I am not an expert in this field.
I can only recommend everyone to wait for the first reviews from the professionals to see what they say about the sound signature. Sorry again, I shouldn't have commented on this at all.

Thank again @HifiFrog!
As the matter of fact, I am usually more interested in 'customer' reviews rather than 'professional' ones
So no worries at all.
Also, it is usually needed (for me at least) to spend more time with new audio before I could form some stable statement about it, so I completely understand the change in opinion
Finally, according to your last impression on HC4, it seems it is getting quite similar with what @tibook said about it.

 

[LukeW]

Thank you all so much for your commentary. I'm looking for a dongle to use with Apple Lossless downloads from iPhone 15 and and Audio 64 18t customs. The only other one I've read about is the Cayin RU7. Would you recommend the HC4 over the RU7 or is there another dongle (small size please) that I might use for portable situations that is worthy of this match. Otherwise, I am thrilled beyond words with my SP3000 when at home. Thanks so much for your guidance.

 

[Robster1958]

i just order the HK4 from Moon. will post when received.

 

[JasonNYC]

We would like to wish everyone a very happy and healthy New Year. All the best for 2024.