Dynavector PHA100 phono head amplifier - Manual (Page 2)

2. Adjustments
1) Cartridge Impedance matching
Select the position suited to your cartridge’s impedance.
„ upper position
30 - 40 ohms
„ lower position 4 - 7 ohms
When the pre-amplifier has a variable impedance, you should
set it to an over 30 Kohms position. Operation below 30Kohms
would cause a deterioration in low frequency response.
The PHA100 is a current maximising head amplifier. This
means that the output voltage of the PHA100 varies according
to the cartridge impedance. Please note that the optimal
output voltage is not achieved unless the PHA impedance
switch is set to match the cartridge’s impedance.
3)Note
„ Do not use the PHA-100 with a MM cartridge because the
PHA-100 is designed solely for MC cartridges.
„
To avoid any hum problems, the power supply unit of the
PHA-100 should be located as far as away as practicable
from the main unit of the PHA-100.
„
Before you change the cartridge or operate the impedance
switch of the PHA-100, you should ensure that the volume
control of the pre-amplifier is turned to a minimum or the AC
power to your audio system is turned off to avoid the
possibility of causing any damage.
„
Do not connect any components e.g. transformers,
capacitors or resistors between the PHA-100 and the cartridge
because the circuit of PHA-100 is of a design unlike that of
other voltage amplifiers.
3. Positioning
Be sure to locate PHA-100 where:
„
there is reasonable air circulation
„ it is free from vibration
„ it is not subject to magnetic fields.
4. Caution: Note for Reviewers
When the PHA-100 is being used by reviewers for listening
tests, particular care needs to be taken so that neither the
unit nor any part of the audio system suffers damage. This is
because, as mentioned above, the circuit of the PHA-100 is
of unconventional design and dissimilar to other voltage
amplifiers in that the current of the MC’s coil is maximised.
In other words, the MC’s coil acts as though it is short
circuited. If, therefore, the PHA-100 is tested by using the
usual signal generator, the current flow into the PHA-100
would be excessive with the result that the high current
seriously damages the IC’s of the PHA.
1.Connections
1) Connect the tonearm lead phono plugs to the inputs of
the PHA-100.
2) Connect the earth lead of the tonearm to the GND (earth)
terminal of the PHA-100.
3) The output sockets of the PHA-100 should be connected
to the MM phono inputs of the pre-amplifier or the
inputs of a MM phono stage. You should not connect them
to the MC phono inputs.
4) The power cable of the PHA-100 main unit should be
connected to the AC power output socket of the power
supply unit. Please ensure that you lock the power cable
firmly to the power output socket of the power supply unit.
We recommend that the power cable of the power supply
unit be connected to the Switched AC Outlet of the pre-
amplifier where such an outlet is available.
INSTALLATION PROCDURE
2) Polarity of power supply
We have found that the polarity of the power supply can
influence the character of the sound. Please therefore check
the polarity of the AC plug of the PHA100 when you connect
it to the power outlet. The ground (earth) is indicated by a
white dot mark on the AC plug. Use the polarity which gives
the best result.
16-15 Iwamoto-cho 2-chome Chiyoda-ku Tokyo
101-0032 Japan
Phone 813-3861-4341 FAX 813-3862-1650
http://www.dynavector.co.jp/