[Sonic Atrocity]

Sorry to resurrect this thread! I just discovered that I am "double amping" being that I am driving my Pro 900 with a PA2V2 that is connected to the headphone out of my Clip+ (Rockboxed). I like the Clip+, especially for it's ruler flat frequency response (I am a neutrality freak). Is my double amping harmful to the neutral response here? I am concerned about distortion and changes in frequency response. 
 
FWIW: http://rmaa.elektrokrishna.com/Various/Echo%20Gina%20-%20PA2V2.htm This link says that PA2V2 is flat but I have read elsewhere that it is actually very coloured. I am confused! 
 
Regardless, I am not just worried about the native frequency response of the PA2V2. I am worried about the overall effect of double amping.

 

[Achmedisdead]

Quote:

Sorry to resurrect this thread! I just discovered that I am "double amping" being that I am driving my Pro 900 with a PA2V2 that is connected to the headphone out of my Clip+ (Rockboxed). I like the Clip+, especially for it's ruler flat frequency response (I am a neutrality freak). Is my double amping harmful to the neutral response here? I am concerned about distortion and changes in frequency response. 
 
FWIW: http://rmaa.elektrokrishna.com/Various/Echo%20Gina%20-%20PA2V2.htm This link says that PA2V2 is flat but I have read elsewhere that it is actually very coloured. I am confused! 
 
Regardless, I am not just worried about the native frequency response of the PA2V2. I am worried about the overall effect of double amping.

No need to worry with the rockboxed Clip+.....just set your volume on it to 0db. I'm sure there are players out there where double apming does have a negative effect, but that is not the case in your situation.

 

[Sonic Atrocity]

Quote:

No need to worry with the rockboxed Clip+.....just set your volume on it to 0db. I'm sure there are players out there where double apming does have a negative effect, but that is not the case in your situation.

Forgive me, but I am a little bit skeptical as to this claim. If I have the Clip+ (Rockboxed) in the negative volume region (ie: -12) there is still lots of volume. So do you mean to set it all the way down to the point that it's completely quiet? And why is it okay for the Clip+ but not for other players?

I don't mean to come off with an attitude or anything by any means. I have always appreciated our discourse on audio. I am just inquiring is all.

 

[Achmedisdead]

Quote:

Forgive me, but I am a little bit skeptical as to this claim. If I have the Clip+ (Rockboxed) in the negative volume region (ie: -12) there is still lots of volume. So do you mean to set it all the way down to the point that it's completely quiet? And why is it okay for the Clip+ but not for other players?

I don't mean to come off with an attitude or anything by any means. I have always appreciated our discourse on audio. I am just inquiring is all.

If the volume on your rockboxed Clip is set where it says 0db on the display, that is actually louder than the -12 you mention.....to max out the player it would go up to an indicated +6db.

 

[Sonic Atrocity]

Quote:

If the volume on your rockboxed Clip is set where it says 0db on the display, that is actually louder than the -12 you mention.....to max out the player it would go up to an indicated +6db.

But then, my lack of understanding lies in the fact that I do not understand why 0db is the key to my amp/cans/source functioning properly. It almost seems arbitrary. Why not -1? or +1? Furthermore, can I do this on other sources that do not have a line out? Perhaps I am lacking an understanding here but I am hoping you could help me clear this up. 
 
Also, would I be able to maintain the flat frequency response of my Clip+ and the PA2V2 (assuming of course that the link I provided on the PA2V2 is legitimate) http://rmaa.elektrokrishna.com/Various/Echo%20Gina%20-%20PA2V2.htm using either 32 or 64 ohm cans? 
 
A neutral frequency response is very, very important to me in regards to amps and sources. 

 

[Achmedisdead]

Quote:

But then, my lack of understanding lies in the fact that I do not understand why 0db is the key to my amp/cans/source functioning properly. It almost seems arbitrary. Why not -1? or +1? Furthermore, can I do this on other sources that do not have a line out? Perhaps I am lacking an understanding here but I am hoping you could help me clear this up. 
 
Also, would I be able to maintain the flat frequency response of my Clip+ and the PA2V2 (assuming of course that the link I provided on the PA2V2 is legitimate) http://rmaa.elektrokrishna.com/Various/Echo%20Gina%20-%20PA2V2.htm using either 32 or 64 ohm cans? 
 
A neutral frequency response is very, very important to me in regards to amps and sources. 

To be honest, I forget where exactly I read that 0db figure, but it has certainly worked fine for me, either with the FiiO amps I have used, or when using my Sansas plugged into "aux-in" jacks on various stereos. I can tell you that no amp is necessary with 32 ohm cans though. I don't use IEM's, but I've used headphones from 24 ohm up to 64ohm impedance....and only with the KSC75's
did I think an amp was necessary, and that was mainly for bass boost, before I used Rockbox.

 

[Head Injury]

The Clip players use digital volume attenuation to adjust the volume. I think the voltage output is always the same (I could be wrong there) and volume is instead adjusted by decreasing the volume of the digital files before they're converted to an analog signal. What this means is that adjusting the volume below 0 dBFS (the maximum digital volume) costs you bit depth. Every -6 dB loses a bit. Doesn't mean anything for normal use, just that the noise floor will be higher relative to the signal (because the noise floor is constant at a maximum -96 dB for 16 bit files).
 
When you amp the Clip's signal with an external amp that has an analog volume knob, it's usually a good idea to set the digital volume to 0 dBFS so you get the lowest possible noise floor. Don't set it above 0 dBFS because that is the maximum volume a digital file can be and any higher may (in the case of most modern songs, will) cause clipping. Analog volume attenuation is usually superior, because it lowers the noise too. However, some amps might have a problem with channel balance at low volume settings, which is arguably much more audible than a higher noise floor. If one ear is louder than the other at low volumes but not at higher volumes, lower the Clip's volume too.
 
Impedance is only one concern when determining how much a headphone needs an amp. Sensitivity is just as important. Ignoring volume, low impedance headphones will benefit most from a high quality amp, because amps tend to perform worse into low impedance loads.

 

[amiWul]

Err i have been using the sansa clip + with a diy amp bought from a guy in another forum with my tf10. So does this means all this while the amp doesnt help out in the sound quality department as the clip + does not have a line out thus adding an amp an lod to the tf10 and clip + is useless????

 

[Sonic Atrocity]

Quote:

The Clip players use digital volume attenuation to adjust the volume. I think the voltage output is always the same (I could be wrong there) and volume is instead adjusted by decreasing the volume of the digital files before they're converted to an analog signal. What this means is that adjusting the volume below 0 dBFS (the maximum digital volume) costs you bit depth. Every -6 dB loses a bit. Doesn't mean anything for normal use, just that the noise floor will be higher relative to the signal (because the noise floor is constant at a maximum -96 dB for 16 bit files).
 
When you amp the Clip's signal with an external amp that has an analog volume knob, it's usually a good idea to set the digital volume to 0 dBFS so you get the lowest possible noise floor. Don't set it above 0 dBFS because that is the maximum volume a digital file can be and any higher may (in the case of most modern songs, will) cause clipping. Analog volume attenuation is usually superior, because it lowers the noise too. However, some amps might have a problem with channel balance at low volume settings, which is arguably much more audible than a higher noise floor. If one ear is louder than the other at low volumes but not at higher volumes, lower the Clip's volume too.
 
Impedance is only one concern when determining how much a headphone needs an amp. Sensitivity is just as important. Ignoring volume, low impedance headphones will benefit most from a high quality amp, because amps tend to perform worse into low impedance loads.

So sorry I took so long to get back to your response on this. I remember seeing it and meaning to but my mind blanked. Very informative post. Thanks! I usually have my Clip+ (Rockboxed) set to about -2 without the amp. Am I still losing bit-depth even though I am not lowering the volume all the way to -6? Also, I am looking to get the KRK KNS 8400 and drive them with my Clip+. Do you see any problems coming from this?
 
Again, thanks for the informative post. I appreciate the new knowledge!
 
Edit: I also have another question regarding the bit-depth, volume and distortion. My pre-cut is currently set at -6db (to avoid distortion - especially when EQ'ing). Furthermore, I have my highs and lows (up to 150hz and above 10 000 hz) set at -5 and -8 decibels. I have this crazy EQ'ing done because I hate the native response of my Pro 900. Hence, I am looking to purchase the KRK KNS 8400. 
 
Would this reduction of decibel value in my precut and EQ lead to bit-depth deterioration? Furthermore, are there any other sonic issues this could cause? 
 
I am looking to purchase the KRK KNS 8400 but apparently they are a bit hard to drive even though they are 36 ohms. Of course, I will set all my EQ values to zero (or close to it) or even turn off the EQ once I get the KRK KNS 8400. Its native sound signature looks appealing. I looked at graphs on inner fidelity. I am thinking I can just turn off the precut too, that is; if I turn off the EQ. 
 
Thoughts?

 

[Achmedisdead]

I don't bother with pre-cut.....I just enable "prevent clipping" and ReplayGain. Easy as pie.

 

[Hero Kid]

Quote:

Err i have been using the sansa clip + with a diy amp bought from a guy in another forum with my tf10. So does this means all this while the amp doesnt help out in the sound quality department as the clip + does not have a line out thus adding an amp an lod to the tf10 and clip + is useless????

Listen to it and decide for yourself. An amp can certainly change the sound (for better and worse). Having an amp fed from a true LO is preferable, but it does not mean double amping is by default a sin.

 

[Sonic Atrocity]

Quote:

I don't bother with pre-cut.....I just enable "prevent clipping" and ReplayGain. Easy as pie.

Bah, I never use ReplayGain. In my personal opinion, ReplayGain interferes with the fidelity of the album. While the volume within each track is not compressed it is still so that the volume from track to track is made the same. Some tracks are supposed to be quieter. Or do I have an incorrect understanding? 
 
I wonder what "prevent clipping" is actually doing. I have a feeling there is some sort of trade-off.

 

[forsberg]

Bah, I never use ReplayGain. In my personal opinion, ReplayGain interferes with the fidelity of the album. While the volume within each track is not compressed it is still so that the volume from track to track is made the same. Some tracks are supposed to be quieter. Or do I have an incorrect understanding? 

There's an option in ReplayGain to do album gain instead of track gain. If you listen to an entire album, do album gain - which allows for tracks that are supposed to be quieter to be quieter. If you listen to tracks from different albums, do track gain.

 

[Achmedisdead]

Quote:

There's an option in ReplayGain to do album gain instead of track gain. If you listen to an entire album, do album gain - which allows for tracks that are supposed to be quieter to be quieter. If you listen to tracks from different albums, do track gain.

Exactly right!

 

[Achmedisdead]

Quote:

Err i have been using the sansa clip + with a diy amp bought from a guy in another forum with my tf10. So does this means all this while the amp doesnt help out in the sound quality department as the clip + does not have a line out thus adding an amp an lod to the tf10 and clip + is useless????

The headphone out of the Clip+ and Zip is nice and clean, so if your files are quality encodes, then there's no problem running HO to an amp.