[Bobblybook]

Quote:

So, aside from being a dock for the E7, the E9 sounds better as well?  If I don't plan to use the 598 portably, I could just go with an E9 and be fine?
 
My listening setup right now is:
 
iPod/Droid X -> 598
 
or at the desk:
 
Creative X-fi Fatal1ty -> Logitech G51 -> 598

This is my issue too. I have a Creative X-fi xtremegamer card, would like to amp my hd598. Not sure how much you've read but when docked, the E7 is only used as a DAC. Not sure what DAC the Fatal1ty has but assuming it's decent, you probably wouldn't need the E7 since you can use the Fatal1ty one. The amping will still be done in the E9.
It seems quite hard to find reviews, etc. of people using just the E9 though since the e7+e9 combo always seems to pop up in searches.
 
I found this thread an hour or so ago and was getting really excited that it would answer my exact problem, but the replies end right here!!
If anyone knowledgeable is reading, BUMP for curiosity!
 

 

[LizardKing1]

Quote:

This is my issue too. I have a Creative X-fi xtremegamer card, would like to amp my hd598. Not sure how much you've read but when docked, the E7 is only used as a DAC. Not sure what DAC the Fatal1ty has but assuming it's decent, you probably wouldn't need the E7 since you can use the Fatal1ty one. The amping will still be done in the E9.
It seems quite hard to find reviews, etc. of people using just the E9 though since the e7+e9 combo always seems to pop up in searches.
 
I found this thread an hour or so ago and was getting really excited that it would answer my exact problem, but the replies end right here!!
If anyone knowledgeable is reading, BUMP for curiosity!

The only place I know with a very good review of the E9 alone is kind of un-postable on Head-Fi, it's a blog by a banned member. I don't know if you're into objective reviews, but if you want someone to tell you how it sounds it has almost none of that, instead you have facts. Google "nwavguy e9", it's the first result. Basically it has very low distortion, output impedance could be lower, but it's fine, so the frequency response shouldn't be changed much by the amp (except on the mini jack, which has a much bigger output impedance for some reason). Great power output, so it will power most hard-to-drive headphones (although maybe some might argue it doesn't "bring them to their true potential", but I'm guessing that is coloration), I've seen users saying they use them with their K701 with no problems. Some channel imbalance, 1.8dB which I find to be a bit, but it's probably inaudible.

 

[stv014]

Quote:

Some channel imbalance, 1.8dB which I find to be a bit, but it's probably inaudible.

1.8 dB is not exactly inaudible, but it is only that much with low volume settings (as it tends to be the case with low quality stereo potentiometers). In theory, this amplifier works best with high impedance headphones, as those are an advantage in all three main problem areas of the E9: channel imbalance at low volume, high noise floor, and high output impedance.
 

 

[catherine]

Quote:

So, aside from being a dock for the E7, the E9 sounds better as well?  If I don't plan to use the 598 portably, I could just go with an E9 and be fine?
 
My listening setup right now is:
 
iPod/Droid X -> 598
 
or at the desk:
 
Creative X-fi Fatal1ty -> Logitech G51 -> 598

I am far from an expert on it, but yes you can use the e9 alone and it should boost the SQ. I actually got the e7 first and used it alone for several months. The difference was remarkable to using the pc soundcard alone. I thought the PC soundcard was great before I tried the e7. I was amazed at the difference. I also do use it as a portable amp with my iPod sometimes, so that was a cool bonus IMO.
 
I just got the e9 this week and haven't tried it alone, but I probably should now that you mention it, just to see. I mainly added the e9 because I ordered some HD650's and figured the e7 wouldn't be enough for them to shine.
 

 

[gohanssjn]

I am really excited to see how the E17 works in the real world.  I might forgo the E9 all together (headphonia reviewer said he didn't like the coloration the E9 added to the E17).  Here's hoping!

 

[nesf]

Quote:

The only place I know with a very good review of the E9 alone is kind of un-postable on Head-Fi, it's a blog by a banned member. I don't know if you're into objective reviews, but if you want someone to tell you how it sounds it has almost none of that, instead you have facts. Google "nwavguy e9", it's the first result. Basically it has very low distortion, output impedance could be lower, but it's fine, so the frequency response shouldn't be changed much by the amp (except on the mini jack, which has a much bigger output impedance for some reason). Great power output, so it will power most hard-to-drive headphones (although maybe some might argue it doesn't "bring them to their true potential", but I'm guessing that is coloration), I've seen users saying they use them with their K701 with no problems. Some channel imbalance, 1.8dB which I find to be a bit, but it's probably inaudible.

10 Ohms should be enough output impedance to colour the sound of the HD598s though, no? 

 

[stv014]

Quote:

 
10 Ohms should be enough output impedance to colour the sound of the HD598s though, no? 

It adds about 1-1.1 dB of bass boost.
 

 

[LizardKing1]

It's not that much, but it might be slightly audible. Honestly, it's not a dealbreaker in any way.
 
If you want another suggestion, the blogger I mentioned built his own amp design, it's available both as a DIY project and through some commercial builders, such as JDS labs. As before, I can't put links to his blog, but if you google "O2 headphone amp" you'll find the link. There's a lot to read one, but you might like it if you're into objective measurements (by the way, O2 comes from Objective 2). It's built entirely around measurements, has no crosstalk, no channel imbalance (by "none" I mean none that is even closer to matter), under 0.1ohm output impedance, powers stuff like the LCD-2, DT880 600ohm and K701 and no background noise. Also there are several threads about it on Head-Fi.
 
I imagine you're pretty set on the E9, but if you really want something made with an objective approach, nothing beats the O2

 

[nesf]

Quote:

It adds about 1-1.1 dB of bass boost.
 

Thanks for putting a number on it for me. 
 
 
 
 

It's not that much, but it might be slightly audible. Honestly, it's not a dealbreaker in any way.

Comes down to how sensitive your hearing is no? I mean I'm pretty sure I wouldn't really notice 1db of bass boost given my hearing but some people might have far more sensitive ears. 
 
Edit: Actually scratch that, I can blind test 10/10 for a 1db drop or rise with my not so good hearing (I thought I couldn't), so it should be audible for most people. Not hugely pronounced or anything but there. Not that a 1db bass boost mightn't be something someone might like about this amp or anything. 

 

[LizardKing1]

How did you test for that 1dB? You have to account for what would result in a 1dB change in your entire setup, which includes output voltages, headphone impedance and sensitivity. It's not just decreasing 1dB on an equalizer
 
Remember output impedance just colors the sound, it doesn't distort it - that can happen, but due to other factors. I can understand your wish for a neutral-as-possible amp, and it's a very valid one. If that's what you want you should really look into the O2, ordered fully assembled from JDS Labs it's about 30$ more than an E9.

 

[nesf]

Quote:

How did you test for that 1dB? You have to account for what would result in a 1dB change in your entire setup, which includes output voltages, headphone impedance and sensitivity. It's not just decreasing 1dB on an equalizer
 
Remember output impedance just colors the sound, it doesn't distort it - that can happen, but due to other factors. I can understand your wish for a neutral-as-possible amp, and it's a very valid one. If that's what you want you should really look into the O2, ordered fully assembled from JDS Labs it's about 30$ more than an E9.

 
Sine wave test whether I can tell if a tone changes up or down 1dB (a different thing to whether a 1dB bump in the bass frequency response is noticeable but I was curious if I'd even notice such a change in a simple signal. If I can't identify it in a simple signal I probably won't notice it in music). I can't do it better than guessing with 0.5dB and below (can't tell a down tone from a flat one for some reason but can tell an up tone fairly reliably). I thought this was the case with 1dB. You're right I'm being too simplistic but I thought my ears were worse than they are, thus the comment about testing.  
 
I'm waiting for the desktop version to come out and will see what price that is. I'm happy enough with my E10 for the moment though. 

 

[stv014]

Quote:

You have to account for what would result in a 1dB change in your entire setup, which includes output voltages, headphone impedance and sensitivity. It's not just decreasing 1dB on an equalizer

 
The relative change is still +/- 1dB with simple equalization. Although one might argue that the same change may not be equally easy to perceive on different source materials (including already "equalized" versions of the same track). But within reasonable limits this probably does not have a huge effect on the results.
 
Quote:

Remember output impedance just colors the sound, it doesn't distort it - that can happen, but due to other factors.

 
Output impedance does affect distortion. If you do a loopback test with a high impedance source, you will notice an increase in the measured distortion (mainly in the bass range) with a headphone load. That is because the transducer also acts as a microphone, the movement of the voice coil in a permanent magnetic field induces voltage in the coil. The polarity of this signal is such that it reduces the current (from the amplifier) that made the coil move in the first place. The force applied to the moving parts is proportional to the current. If the movement of the voice coil/diaphragm is non-linear (distorted) for some reason, then basically non-linear current is drawn from a voltage source, or non-linear voltage from a current source. With close to zero output impedance (i.e. voltage source instead of current source), this acts as a sort of negative feedback, that improves the control of the amplifier over the diaphragm, because it will be pushed with more/less force depending on whether there is more/less mechanical resistance. It dampens resonance (typically in the bass range with a full size headphone), and reduces distortion. With a current source ("infinite" output impedance), there is no such feedback/damping effect. However, in practice the difference is usually not large, due to the high resistance of the voice coil itself.
 

 

[Fazel1010]

FWIW - I have had a pair of HD595's for several years. Just purchased an E7 and was surprised to hear the difference in sound. Very noticeable. The E9 should be delivered today. I'll try to post my thoughts (initially) on the difference later today. I'm no audiophile, but to me the amp provides a more "muscular" sound. Un-amped, my 595's sound "thin" to me now.

 

[LizardKing1]

Quote:

 
Output impedance does affect distortion. If you do a loopback test with a high impedance source, you will notice an increase in the measured distortion (mainly in the bass range) with a headphone load. That is because the transducer also acts as a microphone, the movement of the voice coil in a permanent magnetic field induces voltage in the coil. The polarity of this signal is such that it reduces the current (from the amplifier) that made the coil move in the first place. The force applied to the moving parts is proportional to the current. If the movement of the voice coil/diaphragm is non-linear (distorted) for some reason, then basically non-linear current is drawn from a voltage source, or non-linear voltage from a current source. With close to zero output impedance (i.e. voltage source instead of current source), this acts as a sort of negative feedback, that improves the control of the amplifier over the diaphragm, because it will be pushed with more/less force depending on whether there is more/less mechanical resistance. It dampens resonance (typically in the bass range with a full size headphone), and reduces distortion. With a current source ("infinite" output impedance), there is no such feedback/damping effect. However, in practice the difference is usually not large, due to the high resistance of the voice coil itself.
 

Thanks for the info, it's always good to learn. It's just that I never heard of distortion caused by output impedance >0. I didn't understand everything in your post, but give me time =)
So about the +/-1dB change: let's say I create an exact copy of a .wav file, except I increase the normal volume (line level?) by 1dB. When I play it, regardless of the rig, it will always play 1dB louder than the original file if the equipment is using the same volume (that is, no volume match)?

 

[stv014]

Quote:

So about the +/-1dB change: let's say I create an exact copy of a .wav file, except I increase the normal volume (line level?) by 1dB. When I play it, regardless of the rig, it will always play 1dB louder than the original file if the equipment is using the same volume (that is, no volume match)?

If you increase the volume by 1 dB, then of course the sound should be 1 dB louder unless one or more of the following happens:
  - the increase is not really 1 dB (it is not correctly calibrated) - unlikely with digital volume control, maybe with particularly poorly written EQs it can occur
  - the system changes between the tests
  - there is high non-linear distortion
  - dynamic compression is applied to the signal
Regarding damping factor and distortion, here is an article with some measurements.