User`s manual

Wheatfield AudioWheatfield Audio HA-2 User's ManualHA-2 User's Manual
11/19/99 Page 7
Tweaks
We think that the HA-2 is a fine amplifier, right out of the box. It was designed with
what we believe is an optimal combination of components.
That being said, many audiophiles are never satisfied with any piece of equipment until
they’ve “tweaked” it in their own special way.
We don’t recommend that you make changes to the amplifier. If you choose to modify
the amp or change any components, your warranty is void, so you’re on your own.
We will make one exception to this rule, however. That exception is the tubes.
You may replace the tubes with others OF THE SAME TYPE if you desire, without
endangering your warranty.
Since the HA-2 is a manufactured product, we have to use components that are readily
available, in quantity, month after month. That means that we use Russian tubes that are
still in production, generally from Sovtek.
Though the Russian tubes we use sound great, it is possible that the sound could be
improved by the use of NOS (New Old Stock) tubes. Good NOS tubes for audio use are
tubes made between World War II and the ‘80’s, in the USA and Europe.
The best potential for improving the sound of the HA-2 is to replace 6SN7 voltage
amplifier tube with a good NOS tube, like one from Amperex. Replacing the 6AS7 is
likely to have less of an audible affect, and replacing the 5U4 rectifier will probably have
no audible affect at all.