Could it be that the certain amount of IMD is what gives it is magic? maybe It's an unexplainable aspect of the sound that just happens to show up as IMD? Just thinking out loud, I mean experienced ears mean more to me than measurements since things on paper aren't really always explainable in sonic terms yet.

I'm currently listening to my friend's SR-60 + CT's Krammer modded HD414 pads using the Focusrite 2i2 lineouts and the tiny-winnie Vali. I'm comparing this with what I get out of the Focusrite 2i2 headphone out.

The Vali sounds better. By better I mean more detailed, more soundstage, and more punch. This is indeed very unexpected, at least for me.

There are a couple of problems with this particular Vali prototype tho: It does ring for a while (eventually it settles), and it does seem to have a high noise floor with the Grado cans. This is very contradictory to the better detail extraction experience vs the Focusrite which is dead quiet when no music is playing, and does not ring. One possible explanation in my mind is perhaps more dynamic range out of the Vali, but dunno the specs.

I did a couple of quick measurements and there where no obvious differences in the FR when using one or the other amp. No back breaking distortion differences either.

Against expectations, the noise floor didn't creep up either in the measurements. Perhaps the noise floor in the music recordings and the tone sweeps (measurements) have higher noise floor which gets masked with music/tones anyway???

My question would be, what is the headroom of this amp into different loads?
EDIT: Answering my own question: 650mW into 32 ohms.

EDIT: Could be that something is going on with distortion, could be crosstalk (no obvious FR differences tho), and not ruling out expectation bias either.

Quick measurements results (90dB SPL Vali-blue Focus-red Left ear)





Quick measurements results (80dB SPL Vali-light blue Focus-light red Left ear)

Dunno, but according to IF, the SR60 (the ones I'm using with the Vali) are typically lower impedance and non-resistive. The HE-500 seem to have a little higher impedance (resistive), so they might actually may play nicer with the Vali.

EDIT: I think Marv liked the Vali + HE-500 combo:
http://www.changstar.com/index.php/topic,1160.msg31024.html#msg31024

It should be okay with 120 ohms plus headphones.

30 ohms or less depends I guess...

The ringing is indeed due to microphonics... turning on the amp, plugging the phones, or tapping the amp makes it happen.

The noise floor is still somewhat audible with the HD518 and the KSC-75.

I feel this amp is a little more aggressive (which may give a sense of detail) than the Focusrite, and it may be possibly due to distortion. Notice I said a little. Also note that both the Vali and the humble Focusrite 2i2 will not turn an SR60, HD518, and a KSC-75 into something else ala best-get-an-equalizer sort of way. The differences seem to be there but we are not talking huge coloration issues and measurements seem to back this up.

I think there is some kool-factor in having a Magni/Modi/Vali stacker... may be nice to have a Modi -> Magni/Vali switch then.

EDIT: Some measurements with the HD558 left channel (Vali is blue, Focusrite is red):

FR comparison (seems a Vali+HD558 is a better match than an Valhalla+HD558).



Distortion with Vali:



Distortion with Focusrite headphone amp: