200313 ES TMS Amplifier Operating Instructions ENV12
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With the cabinet removed in the TMS 6060B and TMS 6060P, a row of 4 biasing
potentiometers can be found located on the right-hand side of the amplifier chassis towards
the back. The potentiometers are numbered, front-to-back, 1 to 4, and correspond to the
output valves, seen left-to-right, 1 to 4.
Each potentiometer controls the baseline current of its corresponding valve: Turned
anticlockwise, the current is reduced. Vice versa, turned clockwise, the current is increased.
A meter is located between the two output transformers on the top of the amplifier chassis
which measures valve current, and a 6-position selector switch to connect the meter to the
output valve being measured. The positions of the switch are from left to right:
Position 1: open – Position 2: valve 1 – Position 3: valve 2 – Position 4: valve 3 – Position 5:
valve 4 – Position 6: open.
During normal operation, the selector switch remains open, in positions 1 or 6 (fully left or
fully right).
During biasing, the valve which has been changed or replaced is switched into circuit with
the meter and the current adjusted with the corresponding potentiometer.
Replace the desired output valve(s) but not the cabinet. Plug the amplifier into the mains and
switch on. Allow the green panel light to come on, indicating the amplifier is ready for use
and power is applied to the output valves. Do not apply a sound signal to the amplifier, so
that the bias adjustment is done in the resting state. Turn the selector switch to the position
of the valve in question and adjust its current with the corresponding bias potentiometer
according to the following values:
EL34
18 mA
6550
25 mA
KT88
30 mA
KT120
40 mA.
Repeat this procedure not only for each valve which has been changed or replaced but for
all the others, then return the selector switch to one of the open positions.
When finished, turn off and unplug the amplifier before replacing the cabinet. Replace the
cabinet, sleeves, knobs (and glass top) in the reverse order described above for removal.
While Time Machine Sounds follows current official regulations regarding recycling (see
below), it anticipates that these may change in the future, in favour of more durable
products, in order to reduce electronic scrap. For this reason, we recommend that every
Biasing Procedure
Do Not power the amplifier on with empty valve bases. Caution High Voltages
Present. Do not insert metal objects into the holes of empty valve bases. Danger of
electric shock.
Disposal