True Headphone AMP?

Sarcher30 raises some interesting points. A preamp having very low output impedance, and the ability to drive low impedance loads without significant frequency response issues or increases in distortion, should work well into many headphones (especially those that combine high impedance with good voltage sensitivity). But those are a lot of constraints, and if the preamp and phones were not chosen very carefully it would be easy to end up with poor sonic results.

Is there a non active way to drop the impedance down enough to work with headphones?

A suitably chosen step-down transformer would lower output impedance, while also reducing gain. I'm not aware of any transformers that are specifically designed to interface between preamps and headphones, though, and again I would imagine it would require careful selection of all of the components to achieve a good match. It might also cost more than many dedicated headphone amps.

Regards,
-- Al

Thanks Al.

I figured there was some good reasons that such a device does not exist. I thought there might be some issues but do not have the technical knowledge to know what they would be.

Might make an interesting project. But sounds like it would not work for but one combonation of pre and phones.

Sean

I bought a little tubed Bravo V2 headphone amp (cute) recently and drive it from a set of unused single ended outputs on my preamp. It allows the use of the preamp remote volume control, works perfectly, sounds great, looks cool (the amp, not me necessarily). I can see absolutely no reason why you wouldn't want to drive a phone amp from main outs...you can mess with the gain all you want...heaphone up/preamp down, vise versa...I run the V2 at about 50% or so of its gain to allow appropriate preamp adjustment headroom. It has no audible deletirious effects on the preamp's other outputs (balanced outs to the main amp, another single ended pair to an aux amp rarely used for extension/outdoor speakers).

How about a MiniWatt amp with the headphone out adaptor? And then bypass the MiniWatt's volume control, which I have read improves the sound of the MiniWatt

I haven't read all of these, so it might have been mentioned. Go over to HeadFi.org. This is a forum just for headphone enthusiest. You will find solid recommendations in any price range. This is a very knowledgable bunch.
Tim