K&M Analog Designs LTD Owner's Manual - page 7
FOOT SWITCH
TUBE COMPLEMENT
V1- 12AX7, Lead channel
V2- 12AX7, Clean channel
V3- 5751/12AT7, Reverb driver
V4- 12AX7, Reverb / effects
V5- 12AX7, Phase inverter
V6, V7- Output
Each fine production tube is tested and matched to our exacting specifications.
External bias adjustment and test points are located on the chassis near the
output tube sockets.
A digital voltmeter and small screwdriver are required for bias adjustment.
BIAS ADJUSTMENT-Power up unit. Connect proper speaker load. Set master
volumes and effects return controls to zero.
Do not apply any signal to the input during the biasing procedure!
Take unit off STANDBY. Allow a few seconds for the circuit to stabilize.
Set meter to millivolt scale.( Or lowest volt scale.60 millivolts = .060 volts.) With
meter grounded to chassis and + probe at test point, measure voltage. A reading
of .055 to .060 volts is normal. If not in this range,adjust by turning bias screw
Page 6
Lead
(Blue LED)
Bypass
(Red LED)
Front
Rear
V1
V3
V2
V4
V5
V6
V7
The Tube Location