User Manual

* Keep the amp safe from hard knocks and shocks. Tubes are fragile and tend
to suffer when exposed to mechanical stress!
* Let the amp cool down before you transport it. Ten minutes or so will spare the tubes.
* Tubes take some 20 seconds to warm up after you switch the power on, and
about two to three minutes before they are able to pump out full power. Make a habit of giving
your amp plenty of time to get toasty and flipping the Standby switch for short breaks.
* In order to spare the power tubes and prolong their lifetime, we recommend to set the
Stand By switch to Stand By (down position, that is) before you switch the amp on. After a period
of 30 seconds you may activate the poweramp by flipping the Stand By switch.
* Avoid storing the amp in damp or dusty rooms to spare jacks, switches and potentiometers.
If you don't use the amp all the time, I recommend that you drape a covering over it to prevent
the intrusion of dust. Even better, keep it in a transport cover or flight case.
* Never use caustic or scouring detergents to clean the amp's housing, front or rear panels.
Use a soft, damp cloth or sponge with diluted soapsuds or a standard brand of mild dishwashing
liquid instead. Never use solvents they can dissolve the surface (varnish) and the front
and rear panel labels. Keep liquids well away from the amp, particularly the interior of the housing.
* Make sure air can circulate at the rear and top of the amp to allow for adequate cooling,
which increases component life.
* Never operate the amp without an adequate load (a speaker, cabinet or suitable terminating
resistor, i.e. the internal Power Soak circuit).
* High ambient temperatures place an additional strain on diverse components; so if at all possible,
avoid operating the amp at temperatures far higher than 30°C (86°F) for longer periods.
Running the amp at mains voltages exceeding the nominal mains input voltage over longer periods
can also shorten component life.
* Replace tubes with selected tubes that satisfy ENGL selection criteria to forestall microphonic
properties, undesirable noise and unbalanced power amp signals.
Because power tubes' idle current (bias) must checked and possibly adjusted when replacing tubes,
this is a job best left to experienced and authorized specialists.
Handling and Care
Contents:
1. ENGL Tube amplifier
RockMaster Combo type E302 or
RockMaster Head, type E307 or
MetalMaster Combo, type E304 or
MetalMaster Head, type E309;
2. mains cord;
3. this manual;
4. a pamphlet entitled Instructions for the Prevention of Fire, Electrical Shock and Injury.
Space for User Notes: