15a Power Tube Monitor V1
This LED lights up when the current flowing through the V1 power amp tube is too high and the
power tube monitor system has switched that tube off.
See the tube layout chart to locate V1's position on the amp chassis.
15b Power Tube Monitor V2
This LED lights up when the current flowing through the V2 power amp tube is too high and the
power tube monitor system has switched that tube off.
See the tube layout chart to locate V2's position on the amp chassis.
15c Power Tube Monitor V3
This LED lights up when the current flowing through the V3 power amp tube is too high and the
power tube monitor system has switched that tube off.
See the tube layout chart to locate V3's position on the amp chassis.
15d Power Tube Monitor V4
This LED lights up when the current flowing through the V4 power amp tube is too high and the
power tube monitor system has switched that tube off.
See the tube layout chart to locate V4's position on the amp chassis.
An important note on the Power Tube Monitor (P.T.M.) system:
The electronic power amp monitoring system constantly gauges the current flowing through each
power amp tube. If it rises to too high a level the system shuts down the given tube.
This can occur when the amp is operated incorrectly (for example, if the impedance is wrong due to an
incorrect speaker load; refer to #26, #27 and #28 for permissible loads), at extreme power spikes, or
when a tube is defective.
Reset this electronic monitoring system by switching the standby switch off and on again. When you
press the standby switch to turn the amp on again, the system again measures the current sent to the
tube. If it is still too high, the power amp must be checked by a service technician, and the tube may
have to be replaced if it is defective.
IMPORTANT, PLEASE NOTE:
do not flip the Stand By switch off and on in short time intervals if a
P.T.M. LED indicates a tube failure. Let a few minutes pass by before you engage the poweramp again
after you have switched it off.
16 Stand By
Power amp standby switch: Use this switch to silence (0 position) the amp when you take a lengthier
break. The amp's tubes stay warm, which means that it is ready to roll immediately when you switch it
back to full power. To reset the power tube monitoring circuitry, press the standby switch briefly (see
Power Tube Monitor).
A tip from the designer:
I suggest you get into the habit of using standby during short breaks. In this mode, current is not piped
through the power tubes, so they don't get as hot (due to the lack of anode dissipation) and are
spared considerable wear. The amp is ready to run when you flip the Standby switch because the
tubes are already warm and don't require time to heat up. For breaks of 30 minutes and longer, I
recommend that you switch the amp off in order to conserve energy.
17 Power
AC power on/off.
Please note:
ensure that the Stand By switch (17) is set to Stand By (0 position) before you switch the
amp on. Let the tubes heat up for about 30 seconds before you activate the power amp. This
procedure spares the tubes.
CAUTION:
After an extended period of operation and higher ambient temperatures the amps's chassis
can become very hot, therefore avoid touching the rear panel surface !
