[ext23]

So I was on a tight budget of around $100 for an amp to drive my new HE-400i. Really wanted to get the Magni 2, but including shipping to Japan it was gonna be about $150, and I found the K5 for $85 on Aliexpress.
 
Its specs are as follows:
 

 
This was by far the most powerful amp I could find in this price range, and since I already owned the X3ii my decision was easy.
 
However I still don't feel like it's going loud enough for the HE-400i. With Spotify, Windows, and the X3 all at max volume, I still need to put the K5 on high gain and about 12 o'clock before I feel like the headphones are 'loud.' FWIW I don't hear any distortion or clipping, but something just feels like it's missing. And as for my mp3s with Replay Gain...just forget about it. Too quiet. I tried turning up the pre-gain in Foobar, but this kind of feels like cheating.
 
Does anybody else have experience with this amp? Are the specs lying to me? Is it a problem that I have to have the amp turned up so loud? Is there anything else I can do to boost the volume along the way? Should I just say **** it and get the Magni 2?

 

[Dulalala]

Is it plugged via the headphone jack on your device or a dedicated line out?

 

[ext23]

  Is it plugged via the headphone jack on your device or a dedicated line out?

 
If you're talking about the X3, it's docked in the top of the amp and acting as a DAC.

 

[pbui44]

Well, the good news is that the FiiO K5 has balanced outputs, which means a more micro-audible sound. The bad news is that the balanced outputs will work only on the X5II and X7 DAPs, as your chart mentions with measurements for the outputs from each DAP.

You can upgrade your DAP and get a Matrix HPA-3B:

http://www.matrix-digi.com/en/products/77/index.html#page1

but that would mean a close-or-higher-than-$1k total purchase. So for now, let's look at what you can fix first, without spending anymore cash. Try upgrading the X3II firmware, and backup all of your stuff before flashing:

http://fiio.me/forum.php?mod=viewthread&tid=39932&extra=page%3D1

 

[ext23]

Try upgrading the X3II firmware

Thanks for your reply, I'm already on the latest firmware. I don't have the player with me right now but could tinkering with any of the following help in getting more volume?
 

Spoiler: X3ii Firmware 2.0 Revisions

The following changes and improvements have been made to FW2.0 compared to FW1.6:

1. 

 Added library search function: activate by holding Shortcuts button in any category or folder browsing screen; use previous / next buttons to switch between numbers and alphabet);

2.  

Added option to manually clear media library database file (via System Settings);

3.

  Added option to delete a track (outside of Now Playing);

4. 

 Added play mode: play single track and stop;

5.

  Added Line Output level options (fixed or variable level);

6.

  Added DoP and D2P options to S/PDIF output;

7.

  Added DAC output reconstruction lowpass filter options (steep and gentle slope);

8. 

 Added Recently Played playlist (via Play by Category);

9.  

Added support for ReplayGain;

10. 

Added docking support to use with FiiO K5 or DK1;

11.

 Optimized UI operation and speed;

12. 

Amended the EQ setting to be dynamic, so as to avoid a sudden low voice when turning on the EQ or a sudden loud voice when turning off the EQ

13.

 Fixed issue with hidden files stored by a Mac OS computer accessing the cards on the X3 2nd gen;

14.

 Miscellaneous bug fixes; 

 

[pbui44]

The following can help out with the output:

5. Added Line Output level options (fixed or variable level);
6. Added DoP and D2P options to S/PDIF output;
7. Added DAC output reconstruction lowpass filter options (steep and gentle slope);
9. Added support for ReplayGain;
10. Added docking support to use with FiiO K5 or DK1;
12. Amended the EQ setting to be dynamic, so as to avoid a sudden low voice when turning on the EQ or a sudden loud voice when turning off the EQ

Check each individual addition and all the settings associated with each addition, then change as necessary.

 

[pbui44]

Since you have a X3II, take a look at this article and its links:

http://www.head-fi.org/a/fiio-x3ii-dap-firmwares-with-custom-themes

 

[ProtegeManiac]

 
This was by far the most powerful amp I could find in this price range, and since I already owned the X3ii my decision was easy.
 
However I still don't feel like it's going loud enough for the HE-400i. With Spotify, Windows, and the X3 all at max volume, I still need to put the K5 on high gain and about 12 o'clock before I feel like the headphones are 'loud.' FWIW I don't hear any distortion or clipping, but something just feels like it's missing. And as for my mp3s with Replay Gain...just forget about it. Too quiet. I tried turning up the pre-gain in Foobar, but this kind of feels like cheating.
 
Does anybody else have experience with this amp? Are the specs lying to me? Is it a problem that I have to have the amp turned up so loud? Is there anything else I can do to boost the volume along the way? Should I just say **** it and get the Magni 2?

 

Your primarily problems in this set-up are the relatively lower sensitivity/efficiency of the HE400i vs, say, the HD6xx cans, and the low voltage of the line output signal from the X3II, which is at 1.36v compared to the more usual 2v for desktop DACs.

 

You can change the HE400i for something else with higher sensitivity, but if you already like the HE400i, then that can be a problem. One option though is just save up and get the LCD-2F later on.

 

If you change the amp you'd have to get the DK1 dock to keep using the player, but even then you'd need to find one with significantly higher gain, not just output power.

 

If you upgrade to the X7 it will be somewhat louder but doing this on its own without either of the previous options wouldn't necessarily give you what you're looking for.

Personally out of all those options I'd be more inclined to just save up and get the LCD-2F (or at least the EL-8) in the future.

 

Alternately, maybe it's not simply loudness that you're looking for, but a different response curve. Less of a neutral response and more of one that presents the music to be more, for lack of a better term, "exciting." So instead of the lower sensitivity HE400i with a near ruler-flat response from 1000hz down to 10hz, you might need to try something more along the lines of the Grado RS1. The sensitivity isn't just much higher, making it far easier to drive (not just to loud levels but also not being hungry for current much less voltage), but you get a response with boosts in the mids.

 

[ext23]

Quote:

 

 

Your primarily problems in this set-up are the relatively lower sensitivity/efficiency of the HE400i vs, say, the HD6xx cans, and the low voltage of the line output signal from the X3II, which is at 1.36v compared to the more usual 2v for desktop DACs.
 

 
Thanks for this detailed comment! I didn't know that line out voltage was even a thing to be honest. The ever-helpful Brooko replied to my comment on his review saying that changing the line out from variable volume to fixed volume in the settings would fix the problem. Honestly, since it's connected by USB and not a 3.5mm->RCA cable, I assumed that setting wouldn't have any effect on the sound. I'm at work now so can't check whether it actually works or not.
 
 

 

just save up and get the LCD-2F (or at least the EL-8) in the future.

 
Easier said than done! The LCD-2 have been my grail headphone for years.

 

[Me x3]

  So I was on a tight budget of around $100 for an amp to drive my new HE-400i. Really wanted to get the Magni 2, but including shipping to Japan it was gonna be about $150, and I found the K5 for $85 on Aliexpress.
 
Its specs are as follows: (...)
 
This was by far the most powerful amp I could find in this price range, and since I already owned the X3ii my decision was easy.
 
However I still don't feel like it's going loud enough for the HE-400i. With Spotify, Windows, and the X3 all at max volume, I still need to put the K5 on high gain and about 12 o'clock before I feel like the headphones are 'loud.' FWIW I don't hear any distortion or clipping, but something just feels like it's missing. And as for my mp3s with Replay Gain...just forget about it. Too quiet. I tried turning up the pre-gain in Foobar, but this kind of feels like cheating.
 
Does anybody else have experience with this amp? Are the specs lying to me? Is it a problem that I have to have the amp turned up so loud? Is there anything else I can do to boost the volume along the way? Should I just say **** it and get the Magni 2?

FiiO K5 should be VERY powerful for HE400i on high gain.
HE400i is an easy load.
 
Not sure why you say your X3II is setted at max volume.
As far as I recall, you can not change the volume of the line out on the X3II.
Are you using the line out?

 

[ext23]

 
Are you using the line out?

 
It's docked into the K5 via the USB port on the bottom of the unit. The X3 has a variable line out, which I had set to max. Gonna try setting it to fixed when I get home tonight. But I assumed the USB connection was independent of the line out...

 

[Me x3]

   
It's docked into the K5 via the USB port on the bottom of the unit. The X3 has a variable line out, which I had set to max. Gonna try setting it to fixed when I get home tonight. But I assumed the USB connection was independent of the line out...

You're right, with the latest firmware you can set the Line Out (fixed or variable).
If you try fixed and nothing happens when docked, you can try using the 3.5mm line out instead, and feed the K5 with it.
(In the same way you would do with a Magni 2)
 
A 3.5mm to 2 RCA cable is needed.
 
Be sure of setting the K5 in the right mode in each case (Line / Dock)

 

[ProtegeManiac]

  The ever-helpful Brooko replied to my comment on his review saying that changing the line out from variable volume to fixed volume in the settings would fix the problem. Honestly, since it's connected by USB and not a 3.5mm->RCA cable, I assumed that setting wouldn't have any effect on the sound. I'm at work now so can't check whether it actually works or not.

 
I didn't know that either, I just thought the Fiio X-players would automatically revert to fixed voltage output when docked, and that only the Ibasso players had line output that was still affected by the digital pot.
 

 
Easier said than done! The LCD-2 have been my grail headphone for years.

 
Plus a high back chair, like the ones you see in Victorian libraries (ex Sherlock Holmes'). You need your head on a back/headrest with these one because of the weight.

 

[ext23]

 

the low voltage of the line output signal from the X3II, which is at 1.36v compared to the more usual 2v for desktop DACs.

 
So I have been looking into this a bit (beware: I am still very much a noob) and this does seem comparatively on the low side of things.
 
However, the consistently-lauded Modi 2 also only runs at 1.5v.
 
In real-world listening terms, what is the volume difference between 1.36v and 1.5v? I realise it probably scales depending on the amplification going on in the next step, but is that 0.14v (or 0.54v) difference enough to make my headphones feel significantly under-powered?

 

[ProtegeManiac]

 
However, the consistently-lauded Modi 2 also only runs at 1.5v.
 
In real-world listening terms, what is the volume difference between 1.36v and 1.5v? I realise it probably scales depending on the amplification going on in the next step, but is that 0.14v (or 0.54v) difference enough to make my headphones feel significantly under-powered?

 
Not a lot of difference but the input specs of the Magni2, which the Modi is often used with, might make 1.5v a lot less of a problem than it looks.
 
Again though what may "seem underpowered" to you could only be partly a problem with sensitivity, power, and gain, and partially if not mostly because you expect a totally different sound. Instead of the flat 10hz to 1000hz of the HE400i, what you need is one with boosts from the upper bass to the midrange, like the Grado RS1.