Sutherland PhonoBlock User manual

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“
The performance of the PhonoBlock has
been refined and improved. Its classic,
understated design is still there —
even more so.
— RON SUTHERLAND

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The PhonoBlock was introduced almost 10 years ago. It performs
beautifully and continues to please music lovers all over
the world.
Then came an opportunity to make it even better.
The circuit remains essentially the same. Improvements focused on
providing a better environment to more fully realize its potential.

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In the left shielded compartment is one
channel of phono preamp circuitry.
The front 2/3 is power supply filtering.
Audio circuitry is integrated tightly into the
back third. Signal path is kept to an absolute
minimum.
In the right shielded compartment is a well
regulated and filtered DC power supply.
There are two isolated power suppliers for
the two gain stages.
Each PhonoBlock chassis is a self-standing single channel phono
preamp. Two are stacked to provide two channels for stereo.

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— THE REFINEMENT —

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The best environment for delicate analog
audio signals is LESS environment.
A compacted area for the circuit with minimal
distance between components is a big
advantage. The musical signal will have the
tightest, shortest and purest connection from
one component to the next.
Another performance necessity is a low
impedance, low noise power source for the
amplifiers. That would be a bank of multiple
film and electrolytic capacitors.
Ideally, they would be paralleled with very
wide copper traces and a very short distance
from the amplifiers.
The PhonoBlock refinements are derived from the Argentum design.
The much more expensive Argentum is an all–out, hand-wired, silver–
signal path version of the classic PhonoBlock. Turns out, the same
extremely disciplined short signal path layout could be used to refine
the classic PhonoBlock audio board.

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Fortunately, there is an alternative to
compromise. ONLY signal path components
are placed on the top side of the circuit
board. With no power supply capacitors on
the top side, and a disciplined layout strategy,
the signal path is optimally short and direct.
A large bank of power supply capacitors is
located on the bottom of the circuit board.
All of the copper area on the bottom side is
dedicated to forming a robust power plane
that is located right under the amplifiers.
The tighter signal path gives uncluttered
purity and the robust availability to power
gives effortless ease to dynamic expression.
These improvements bring the listener even
closer to the music.
That’s a challenge—how to have a compact layout for the signal
path and a large area for multiple power supply capacitors and
shortest distance.

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The refinement provides an even shorter,
simpler pathway. The individual resistors plug
directly into the audio circuit board. Sockets
are located even closer and take up even
less board area. The signal path is now even
shorter and more direct.
Add flexibility is another advantage. The
most popular gain and loading values are
included. However, the user is free to explore
those values. Some will want to experiment
with different resistor types and/or
manufacturers.
For those using outboard moving-coil step
up transformers, you will have the means
of choosing loading resistor values that
appropriately reflect through the transformer
to the cartridge.
The original PhonoBlock used small plug–in circuit boards for setting
gain and loading options. They were compact, and provided a short
signal path from the plug–in resistor board to the amplifier circuit.

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— LINKING INTO YOUR SYSTEM —

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Grounding Options
Sometimes ground loops can cause hum in a phono system. Breaking ground loops can be easy
or it can be a nightmarish frustration. In the difficult situations, grounding options can save
the day.
For product safety and electrostatic shielding purposes, the metal casework of the PhonoBlock
is electrically connected to the ground lead in the IEC power cord.
There are, however, options on the audio circuit’s ground
reference. Each mono chassis has
three grounding options. They are selectable by moving a
gold-plated shunt.
- Audio ground can float with respect to the chassis
- Audio ground can tie directly to the chassis
- Audio ground ‘softly’ connected to the chassis
through a 50 Ohm resistor