i have a grado hf2 paired with a little dot 1+(we408a) and a vdac2
i'm thinking to upgrade the amp section, what can i consider?
I've used the Grado RA1 amp, the original Asgard, and the built in headphone amps from my McIntosh preamps (C32 and C42). So, not as many amps as some folks here, but some pretty well respected amps none the less. Asgard 2 man!
The Asgard 2 has some background hiss that is audible on low impedance, high sensitivity phones. Maybe it's not the best for your Grados.
You may consider the HeadRoom Micro, Musical Fidelity V-Can II (and V-PSU II for both your DAC and amp), HiFiMan EF5, or a NuForce amp.
The EF5 would be a good match for you, then. I had it for a short bit.
What about the EF2? That amp is generally very well liked. The DAC section is pretty lacking, but the amplification section is actually pretty good. Some users here, who have some really exotic amps, have commented how surprisingly good the EF2 is.