Rear Panel:
Fuses:
½ Amp fuse for DC Voltage section
or 3 Amp AC fuse.
Speaker Jacks:
Plug speaker into specific jack for it’s rating (8ohm speaker
into 8ohm jack.)
Footswitch:
Use single button footswitch (supplied) to turn Overdose func-
tion on or off.
Master:
Controls overall amp volume and output tube compression. Turn full
clockwise for complete bypass. (RX JS only)
Care and Feeding:
While we hope you get years of worry free use out of your Dr Z Amp there are
some basic maintenance procedures to follow.
Changing Output Tubes: If your amp starts sounding a bit dull or lacks punch
it’s usually time for a new set of output tubes. Changing the EL84 output tubes
on your Prescription is easy. This amp is cathode (self) biased so there is no
need to rebias when changing tubes. Always use a matched quad (ES) or
matched pair (JS) of EL84’s. We use Groove Tubes EL84S as our standard
EL84. Always make sure the power is off and AC cord is unplugged when
changing tubes. Always use caution not to burn your fingers as tubes become
very hot quickly. With moderate usage output tubes should last 6 months to a
year.
Changing Pre Amp Tubes: When pre amp tubes fail it usually results in a static
type noise or a ringing microphonic type sound. Pre amp tubes are easily re-
placed. We recommend replacing them with the same brand/type that came in
the amp. We have hand selected these tubes to deliver optimal voicing.
Changing Rectifier Tube: Signs your rectifier tube needs changed are fairly
obvious. A bad rectifier will usually result in a fuse blowing. Power off, unplug
the AC cord and replace the blown fuse before replacing the rectifier tube. Use
caution as these tubes get very hot!
