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Raysonic SP-120
Modification
A customer wanted to know whether
modifications could be performed on the Raysonic SP120 to
improve its performance.
After carefully analyzing the
circuit design in detail, we determined that improvements
could be performed on the circuitry. These
changes would allow this outstanding amplifier to reach an unprecedented
level of performance unattainable by the stock design.
The modification was a time
consuming process, and it entailed:
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Changing the filament voltage of
all input and power tubes
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Changing the biasing circuit of
the power tubes
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Adding AC balance on the 6SN7
phase inverter
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Adding decoupling resistor on
the KT88 power supply
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Replacing and redirecting PCB
traces with 18 gauge wires
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Replacing capacitors in the
signal path coupling stages
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Replacing resistors in various
stages of the entire circuit
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Applying heat shrink or Teflon
coating to all exposed leads
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72 hours continuous burn in
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Bypassing the remote control,
and changing the volume control
We performed a standard bench test
on the modified unit, and it showed significant improvements in
noise reduction, frequency response and channel separation.
These improvements were further confirmed by the listening test
which showed improvements in resolution, texture, inner detail,
control and transparency. The customer was extremely
satisfied with the results.
Total Cost of Modification: $
500 dollars
Turnaround time: 1 week |
