[floresjc]

I have used my Grados over the years with my Insight+ preamp and my slightly older Ultra EC preamp with no problems whatsoever. Grados being easy to drive and all. Just wondering if Frank or anyone could chime in, as to the the limit as to what the AVA headphone outs can drive, not looking to get Hifiman's or anything like that, but some harder to drive Sennheiser HD800's are on my list.

Nominal Impedance listed at 300 ohms. I know on the newer model preamps, there is a redesigned headphone circuit, but I'm hoping the older models have sufficient power to handle something like that too.

[avahifi]

Inasmuch as recent Grado headphones are a 30 ohm load and any recent AVA preamplifier will drive them just fine, the 300 ohm HD800s will be an easy load for your Ultra EC preamp, even though its headphone amplifier circuits are a generation out of date compared to all our current preamp designs.

Frank

[floresjc]

Frank -

How much wattage does your headphone circuit put out? Just curious. I'm amazed to see the range of possibilities on dedicated headphone amps.