Sweet, at least now I know I'm not crazy (or at least they're are other crazy people like me )

I know, I'm a jackass...what can I say?

-edit- Also, I got a pair of triple.fi's recently and am blown away by them. They have a huuuuuge soundstage for being an IEM. Seriously. Maybe even a tad bigger than the stage I get from HD650's...it's crazy. I love the frequency response, I love the detailing, and I love the bass. Of course, I need more time to live with them before any solid decisions, but these are making me wonder why bother with any fullsize headphones (except where I need open 'phones). The only thing they lack is a bit of weight and heft behind the sound when I'm listening at low levels, and the tone of instruments seems ever so slightly off, but that could be because I've only been listening to 650's for months.

I remember buying a pair of them; I couldn't stand the "in-ear" part of it. I ended up giving them to my sister who subsequently broke them about a month later.

Somebody double check me on this. I haven't really ever tried calculating impedances across a transformer before.

Say I use the 2.5k primary impedance transformer I mentioned before. Off the 16 ohm tap, the impedance ratio is 156.25, correct? So I multiply that number by the 300 ohms of the HD650 to get an impedance of 46,875 ohms reflected back on the tube. I know some run their tubes into high impedances, but that seems a bit too high. Will that just kill voltage output?

For a 300 ohm load, to get 5k reflected back on the tube I'd need roughly a 4:1 primary to secondary turns ratio, if I'm calculating right. Can anyone tell me how far off the mark I am?

Yup, that's about right. If you're worried about an overly high reflected impedance on the primary side, you can always stick a resistor in parallel with the headphones on the secondary. For instance, on my amp the impedance ratio is roughly 1000:1, so with a 400 ohm K340 on the secondary the tubes see 400k ohms. So I stick a 33 ohm resistor on the secondary to bring it down to a more reasonable value.

Thanks aerius. As I said, I'm having fun with the speakers and IEMs for now, but I don't really doubt that I'll want to revisit this idea and put together a nice tube amp.

I must say that if it weren't for current circumstances (new daughter) that I'd be very much up for a new PTP design. I had a lot more fun with the Menace than I thought I would. Granted, I'm still chasing a small ground loop but it was a huge learning experience doing my own layout, figuring how I wanted to route everything and having complete control of the overall aesthetic. I still feel that there is a lot of value in PCBs but there does come a point when PTP is the better way (for DIY anyway).

Yeah, I really enjoyed figuring out the layout for a Starving Student. It will be several weeks before I get to it, but I really liked doing a layout with something so simple.

you really want one of these... notice the price

EARMAX ANNIVERSARY TUBE HEADPHONE AMP - elusivedisc

Haha I know I'm late but wow I remember these from the time when ALO advertised them on Ken's old domain. They look nice but has anyone tried it yet?

Yeah, I believe Hirsch had one. It sounded great.