I am considering these options for volume control for my soon to
 arrive new system:
 1. Monitor. My Genelec 8030A has volume knob. I would guess, this
 method makes least noise...
 2. External mixer
 3. Volume pedal
 4. Some module capable of attenuating. For example, Analogue
 Solutions HP01 headphone amplifier, which takes only 6HP:
http://www.users.globalnet.co.uk/~concuss/concussor/hp01.htm
 "It has three main functions;
 Small mixer to take outputs from other sub-mixers in the system.
 Headphone Pre-Amp for those that wish not to use speakers.
 1/4" / large jack output so the main output signal from the system
 can be taken to a mixing desk without the need for special cables or
 adaptors."
 The discontinued A-139 has only headphone outs...
 (By the way, is it safe - for the equipment, not to ears - to
 directly monitor modules with headphones Mine are 2 X 100 ohms.)
 I would like to hear, how you more experienced people deal with
 volume control and what you use for amplification
 Best regards
 Jari Jokinen