Power Supply - SPL Transient Designer 9842 User Manual

Special care has gone into the design of the power supply of
the T D . The power supply is the heart of any elec-
RANSIENT ESIGNER
tronic system, and the better it is, the better the whole system
works. In an audio system, this translates into better sound
quality, lower noise and lower distortion.
The power supply is based around a 15 VA torroidal transformer
and is designed without an air gap to minimise induced hum and
noise. The primary voltage may be selected between 230 V/50 Hz
and 115 V/60 Hz by means of a recessed slide switch on the rear
panel and a ground-lift switch is fitted for use where ground
loops are causing hum problems. When the G
to off, the circuit ground is isolated from the chassis ground.
The detachable power cord is a standard 3-wire type fitted
with an IEC mains connector; the transformer, power cord and
mains connector have VDE, UL and CSA approvals. The fuse has a
value of 315 mA.
On the secondary side of the power supply, an RC combination
is used to filter out noise and hum. Both half-waves are smoothed
with 22,000 microFarad capacitors in the positive and negative
supply path, and both lines use precision voltage regulators for
optimum stability. Deviations of only a few millivolts can impair
audio quality, introducing artefacts such as loss of stereo imaging
or a diffuse sound character. Particular care has gone into the
circuit layout and component choice to minimise crosstalk
between the audio circuitry and control voltages.
Transient Designer
L switch is set
ND IFT

Power Supply

Internal 15 VA torroidal
transformer
Voltage selector
Ground-lift switch
Transformer, power cord and
mains connector with VDE,
UL and CSA approvals.
Fuses (primary voltages):
315 mA.
Positive and negative voltage
paths are smoothed with
22.000 microFarad
capacitors.
15