Parasound Zamp

They're on the back.

I looked at a pic of the rear panel and couldn't see a volume knob (it wasn't a very clear pic, but I don't think there's a volume knob back there).

I think that -- like the speaker outputs -- some sort of a preamp would dictate the volume of the headphone output.

The official manual for the Zamp shows that there is actually volume level controls on the back.. they look kinda small.. almost like you'd use a flat-head screwdriver to adjust them. (scroll down to page 3 of the PDF manual for the Rear Panel view)

It also reads on page 5:

Level Controls
Each channel has a separate input level control. If your preamplifier has relatively high gain, it may be
necessary to reduce the input level control settings on the ZAMP. We located the level controls on its rear
panel, so you can set them once and leave them alone.
Headphone Jack
The built in headphone jack drives any headphones with an impedance of 8 W or higher. The ZAMP must
be triggered on with an audio signal or DC trigger before it will pass a signal to the headphone jack. The output
to the speakers is muted when you plug headphones into the Zamp.

Neil beat me to it.

They measure impedance in Watts now?

Hi have used a zamp v3 for the past two years - the back of the amp does have a pot for each channel, but they are poorly located, tiny and you would have to adjust volume separately per channel - a practical impossibility. As jude suggested volume is controlled via pre-amp (I used a parasound Zpre).

I think that's one of the oldest thread necromancies I've ever seen.  10 years!

Necromancy?

 

 

Yeah, as in this thread was brought back from the dead after a decade...

 

This is awesome in a necrobumpy kind of way...