Specifications

Wheatfield AudioWheatfield Audio HA-1 Owners ManualHA-1 Owners Manual
8/30/00 Page 5
Listening with the HA-1 and headphones
It’s best to start out with the volume control knob turned all the way down (counter-
clockwise) until you’re familiar with the HA-1.
Turn the amp on, using the font panel power switch. It’s OK to leave your headphones
plugged in when you turn the amplifier on and off – there is very little turn-on/turn-off
“thump” generated, since the amplifier warms up slowly.
Speaking of warm-up, the amplifier takes only a half minute or so to start working,
though you may find that it takes a couple of minutes for the sound quality to reach it’s
best.
Adjust the volume to your liking.
About Headphones
To get good sound from the HA-1, you need good headphones. Cheap headphones
driven by the best of amplifiers will still sound like cheap headphones.
The HA-1 is designed to drive any high-quality headphones of at least 30 ohms
impedance. Pretty much all of the headphones made by Sennheiser, AKG, Grado, Sony,
and Beyerdynamic fit into this category.
The HA-1 will drive headphones of lower impedance, but we don’t recommend it. The
mismatch of impedance between the amplifier and such headphones introduces larger
amounts of distortion.
You can’t hurt the amplifier by plugging in any type of headphones.
Using the HA-1 as a pre-amp
Using the line outputs provided on the HA-1, your headphone amplifier can double as an
excellent all-triode, zero-feedback pre-amp. It has more than enough gain, and a low
enough output impedance, to drive even the most difficult power amplifier.
When there are headphones plugged in to the front panel jack, the line outputs are muted.
Occasionally, the switch contacts on the headphone jack can become dirty, resulting in no
output from one or both line output with the headphones unplugged. If this happens,
blow the dust out of the jack, and repeatedly plug in and unplug your headphones. This
should remove any contamination from the switch contacts.