"Ross Fletcher" wrote in message
om

This may seem dumb question so don't take offence.
Leaving headphone access out of pre-amps seems to be a trend (although
a few such as Arcam still have headphone sockets) So how does one
connect headphones to such an amp? - in this case RF headphones -
where the manufacturer is too mean to include an outlet (despite the
rapacious prices they ask).

Since headphones frequently have impedances as low as 16 ohms, the use of
some kind of impedance matching device might be indicated.

This test report seems to describe one such impedance-matching device:

http://www.pcavtech.com/pwramp/boostaroo/

Here are some others:

http://www.pp.iij4u.or.jp/~shu-nkmr/...test-data.html

http://tangentsoft.net/audio/ppa/amp/bench/

http://members.shaw.ca/ifkovic/pdac/...o%201%20ad.htm


However, I suspect that your RF headphones have a far higher input impedance
than regular headphones, and can therefore be connected directly across the
line outputs of the preamp.