Amping for AKG Q701 - Page 12

Quote:

Originally Posted by stv014 

The E9 works better with higher impedance headphones, which also make the noise less (if at all with 600 Ohm ones) audible. For the D7000 the E11 or E17 would be a better match, and the E11 even cheaper as well.

 

what about E11 with Q701? thanks

 

Quote:

Originally Posted by neuheadfi 

what about E11 with Q701? thanks

The E11 should work well, except the maximum power is not very high (it is enough for 107-108 dB max. SPL with low distortion, though). The best of the "cheap" amplifiers for the Q701 is most likely the O2.

I am debating about just ordering the LDi+ now.  I haven't received the Q701s yet but they should arrive this week.  I plan on using it with my computer, which has a Asus Xonar DG sound card, for casual listening.  The majority of my listening will be using my home theater setup with an Onkyo 886 preamp.  I don't have an external dac yet but I will look into one down the road.  I still listen to discs, sacd, bluray audio, cd, etc.  I very much doubt the headphone output of the 886 will be able to power the q701's properly.   

Quote:

Originally Posted by stv014 

The E11 should work well, except the maximum power is not very high (it is enough for 107-108 dB max. SPL with low distortion, though). The best of the "cheap" amplifiers for the Q701 is most likely the O2.

 

Can you suggest a dac to go with the O2 for the Q701?

Gamma 1 dac, is ideal (there are a few commercial builders). I also think the HRT MusicStreamer 2 is a great bargain, and the Grub dac, if you just need a basic USB dac and don't mind some DIY. 

1. Apogee mini DAC/Apogee Duet

2. Benchmark DAC1

3. Grace m902/3

All those DAC's are balanced and can drive the K70X out of the hps output.

Ok - once again, you are suggesting products 3-5x more expensive than the requestor (or anyone else thus far but you) has ever indicated being willing to deal with or suggested.

He's going with the 02 as an amp, my guess is he does not want to top $300 for an amp + dac combined. 

Quote:

Originally Posted by liamstrain 

Gamma 1 dac, is ideal (there are a few commercial builders). I also think the HRT MusicStreamer 2 is a great bargain, and the Grub dac, if you just need a basic USB dac and don't mind some DIY. 

X2 for the gamma 1. Recently had one built by Mr.X  and I'm very happy with it....for the price I doubt there's anything that can compete with it. Combine that DAC with the O2 and you'd have a good budget set up for not much over $200. Never heard the O2 myself though, to be honest.....only going FWIR.

Quote:

Originally Posted by lejaz 

So,  back to the topic of amps for the 70X ....will this phase shift that's been discussed be audible or not with the two budget amps that were being discussed, the E9 and the O2? Would I likely notice it with the ld mkV or something else in the $300 price range? Can I rest easy knowing that the ld mkV isn't producing audible frequency deviations or phase shift? What about the E9? I'm leaving aside the noise issue since I don't hear any on my set up.

Since no one else has answered;

This frequency dependent phase shift has been argued to death in various forums thru the years. 

To avoid this type of phase shift, you would us an amp with widest possible bandwidth, for example, -1.0 db @ 100 kHz would lead to very little high fequency phase shift in the audio bandwidth.

One thing to keep in mind:  distortion, phase shift, frequency deviations,etc. are all cumulative.

For example, if you have a DAC which is 0.3 dB down at 10 kHz and an amp which is down 1.2 dB at 10 kHz then when you use them together you are 1.5 dB at 10 kHz.

Same goes for distortion, when you are listening to headphones & amp & DAC combination you are listening to the cumulative distortion of all three pieces.  You could argue that the headphones are distorting the distortion from the amp which is distorting the distortion from the DAC!

Regarding the noise floor thing (I'm not referring to hiss), anyone notice their sound system sounds better at 3:00 a.m?

The specs for the LD mkV doesn't show 'bandwidth', AFAIK. Here's what you get from the manufacturer: http://www.littledot.net/forum/viewtopic.php?f=3&t=142&start=0  According to his specs it should be flat to within .5 dB. But wouldn't that depend upon the headphone used?
Here's the e9 specs....nothing about bandwidth here either: http://www.fiio.com.cn/product/index.aspx?ID=19 Will the specs for either show how well they will pair with the phones in question, the Q701? The E9 has a fairly high output impedance according to navguy's review....he claims it's not ideal for low impedance headphones. The mkV manufacturer refused to answer when he was questioned about the output impedance of the MKV on the LD forum. I wonder why that is. 

Quote:

Originally Posted by Chris J 

Since no one else has answered;

This frequency dependent phase shift has been argued to death in various forums thru the years. 

To avoid this type of phase shift, you would us an amp with widest possible bandwidth, for example, -1.0 db @ 100 kHz would lead to very little high fequency phase shift in the audio bandwidth.

One thing to keep in mind:  distortion, phase shift, frequency deviations,etc. are all cumulative.

For example, if you have a DAC which is 0.3 dB down at 10 kHz and an amp which is down 1.2 dB at 10 kHz then when you use them together you are 1.5 dB at 10 kHz.

Same goes for distortion, when you are listening to headphones & amp & DAC combination you are listening to the cumulative distortion of all three pieces.  You could argue that the headphones are distorting the distortion from the amp which is distorting the distortion from the DAC!

 

Regarding the noise floor thing (I'm not referring to hiss), anyone notice their sound system sounds better at 3:00 a.m?

 

 

Quote:

Originally Posted by lejaz 

Here's the e9 specs....nothing about bandwidth here either: http://www.fiio.com.cn/product/index.aspx?ID=19

It has been measured, however, and you can see the response on this and this graph.

Quote:

Originally Posted by lejaz 

The E9 has a fairly high output impedance according to navguy's review....he claims it's not ideal for low impedance headphones. The mkV manufacturer refused to answer when he was questioned about the output impedance of the MKV on the LD forum. I wonder why that is.

Well, someone who has the MKV could measure the impedance then. It does not require expensive equipment.