Ah yes, I see now. Hmm, have you considered any of the Meier Corda DAC/amps? Actually, now that I've said that, I will have to check that they do a smaller DAC/amp now. I have used my Corda 2Move DAC/amp with the 300 ohm HD250 Linear 1s and it works rather well, with superb clarity and excellent timing. It doesn't have the sheer bass drive to have a really deep bass, but it does remarkably well with the built in DAC. I run the volume about 7-8 out of 10. Some folks used to drive the HD650s with it too when the 2Move was released. Addendum: Meier Audio no longer have DACs in their portable amps. So, I reckon I'm pretty fortunate to have kept my Corda 2Move, it's a very handle little critter! There might be second hand versions around, dakanao, they are very well made and easily portable, I've taken mine on many a journey, it's less than the size of a cigarette packet and a bit thicker, versatile in it's settings and takes a 9V alkaline battery to power it, or a small power pack up to 12V. Great sound, smooth AND lively and had great reviews in this very web site. Mine is staying with me until it dies and even then I will send it back for refurbishment if possible.