Discrete Voltage Regulator Review – Bryston Preamp Processor


The SS78XX / SS79XX Discrete voltage regulators have been reviewed in a Bryston Preamp / Surround Processor.

Discrete voltage reg installThe voltage regulators made a significant improvement
in the Bryston over the legacy 78xx regulators.  The
Sparkos regulators really cleaned up the sound and
made everything sound much more clean and quicker.
You can see in the post pics that I have also added
the ElnA Cerafine caps.   The small surface-mount caps
were Panasonic FK and they actually did not work that
well.  After I replaced them with the Elna’s, the
sound became ultra clear and fast and much more
realistic.  The bass was completely unreal! There was
so much air moving that I could hear my Stewart
Film screen projector screen rattling – even with the
volume not turned up all the way.  The regulators are
a significant part of the puzzle, but you really need
top level capacitors to manage that power!

discrete voltage reg side_cI have also learned that you really need to put
polymer/oscon capacitors on any power supply line going
to digital circuits, such as the 3.3V/5V line to the
DAC and digital receiver.  Normal electrolytics (even
Elna Cerafine) can’t handle the very high frequency
voltage pulls that are required by DAC chips (internal
clocks run in the megahertz range, and audio is commonly
upsampled to 384khz or even 768khz).

The Bryston power supply board does not actually have
“through-hole” mounts for the voltage regulators. Instead,
it has slots cut into the board itself with the trace on
top of the board.  The pins of the regulator slide into
the slots (which are cut all the way through the board).
You then need to solder in the entire slot so that it
fills in the area between the pins and the board (almost
like pouring concrete into a slot).  I had to initially
use both a soldering iron and a de-soldering gun to remove
the solder.  Then I had to use a hot-air workstation to
heat all three pins up at the same time before all 3 woulddiscrete reg bryston
let go of the board.  Alternatively, you could cut the
original regulator pins and remove them one at a time, but
I wanted the original regulator in one piece in case I had
to put it back (which I won’t!).  The ceramic heat pads for
the regulators were cleaned and then coated with Arctic
Silver 5 thermal compound (a very popular high-performance
compound typically used for computer CPU heatsinks).
Cardas Quad Eutectic solder was used on all solder points.

Discrete Voltage Regulators Back To Reviews



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