I say it's good, but I haven't spent so much time with it.
My goal was not to use an input buffer, although I know it needs it.
The thing is, the AD815 sounded better to me (even with output caps) and I put much more efford in developing a good compromise without an input buffer.
Don't take my word for granted, maby if I've done the same thing to the TPA6120 it would sound as good/better?
I say to everyone: try it.
In my implementation it was a little too "smooth" sounding, but I'm sure that it has to do with the caps.
P-A, if you don't use caps in the signal path, I'm sure you will have different results, of course.
As you have low DC, you don't need them.
As an headphone amp, this chip will put "slam" on your head, you will be surrounded by dynamics.
So, P-A, you have made a very nice board.
Have you listened to it?
Is it better than the op-amp+BUF634 solution?
My goal was not to use an input buffer, although I know it needs it.
The thing is, the AD815 sounded better to me (even with output caps) and I put much more efford in developing a good compromise without an input buffer.
Don't take my word for granted, maby if I've done the same thing to the TPA6120 it would sound as good/better?
I say to everyone: try it.
In my implementation it was a little too "smooth" sounding, but I'm sure that it has to do with the caps.
P-A, if you don't use caps in the signal path, I'm sure you will have different results, of course.
As you have low DC, you don't need them.
As an headphone amp, this chip will put "slam" on your head, you will be surrounded by dynamics.
So, P-A, you have made a very nice board.
Have you listened to it?
Is it better than the op-amp+BUF634 solution?
I have listened to the amp now a couple of hours and it may be the best I ever have made but the tricky part is to switch amps fast which isn't easy. The sound is excellent but it's hard to say how much different the sound is from my QRV-04 with AD8610 + BUF634. This combination is also extremely good. The major difference between the two amps is that QRV-07 consumes a bit more power. It seems that the groundplane cools rather much. The IC is warm not more.
If someone wants to try out a really exciting amp, TPA6120 is the one.
Bigger picture of the TPA6120 here
Bigger picture of the backside of the pcb here
If someone wants to try out a really exciting amp, TPA6120 is the one.
Bigger picture of the TPA6120 here
Bigger picture of the backside of the pcb here
According to CIAudio themselves they use also the TPA6120 in their new high-end headphone amp.
http://www.ciaudio.com/vhp1.html
http://www.ciaudio.com/vhp1.html
Test results can be found here
http://www.sjostromaudio.com/hifi_files/qrv/qrv07_testreport/QRV07_HD545.htm
http://www.sjostromaudio.com/hifi_files/qrv/qrv07_testreport/QRV07_HD545.htm
Hi Per-Anders,
unfortunately the measurement images don't get displayed. Forcing to display them produces an error message claiming the images 'contain errors'.
But the numbers look good. I've seen such results from RMAA on headphone amps (on tangentsoft's site), where the lower output impedance of the headphone amp is capable of driving the soundcard input at lower distortion than the soundcard output alone could. That's probably why we see less distortion with a 39Ohm resistor than with no DUT at all.
I think you're in the need for a better sound card, now.
Sebastian.
unfortunately the measurement images don't get displayed. Forcing to display them produces an error message claiming the images 'contain errors'.
But the numbers look good. I've seen such results from RMAA on headphone amps (on tangentsoft's site), where the lower output impedance of the headphone amp is capable of driving the soundcard input at lower distortion than the soundcard output alone could. That's probably why we see less distortion with a 39Ohm resistor than with no DUT at all.
I think you're in the need for a better sound card, now.
Sebastian.
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