Recording - August 2013 - 14

B Y PA U L V N U K J R .

During the 18 years of its existence,
Cajun audio company PreSonus has made
a name for itself with a wide range of
audio gear for live and studio applications.
Current standouts are the StudioLive digital
mixer series and the Studio One DAW
recording software, and audio interfaces in
the FireStudio and AudioBox lines, not to
mention the great regional recipes published in the back of every product manual,
including the killer Jambalaya served annually at the PreSonuSphere conference.

review, Stamler pointed out that many lower-end tube mic pres are simply solid-state
designs with a tube thrown in to add harmonic distortion. Not so the ADL 600—it is
an all Class-A, triple-triode design, with one 12AT7 and two 6922 model tubes as well
as high-end transformers making up its circuit. Additionally, each preamp runs on a
pair of high-powered 300V rails (300 X 2 is 600 and hence the name). In his review
Paul went into extreme detail about the unit’s design and make up, and it’s worth seeking out the back issue if you are into preamp design and detailed build specifics.
And now, the ADL 700
This month we bring you the ADL 700, a mono channel strip that starts with a single channel from the 600 and adds a FET compressor and an opamp-based 4-band
equalizer.

PreSonus ADL 700 Tube Channel Strip
A collaboration with designer Anthony DeMaria bears impressive fruit
Then there is PreSonus’ long-standing
history with microphone preamps. The
PreSonus MP20 (with the original Jensen
transformers) was my first serious mic pre,
now sadly discontinued!
Offering so much gear for the musicmaking masses, PreSonus is not exactly
known as a boutique shop, but one of the
nicest 2-channel boutique mic pre-amps
on the market, the ADL 600 that PreSonus
developed in partnership with renowned
audio designer Anthony DeMaria, has
been out for a while and is still available.
A look back at the ADL 600
Recording reviewer Paul Stamler
reviewed the ADL 600 back in our October
2006 issue and was quite impressed with its
sound, even preferring it in many instances
over his own custom-built reference mic preamp (homebuilders can learn more at
www.recordingmag.com/resources/resour
ceDetail/332.html).
The ADL 600 is a two-channel mic preamp with a true tube signal path. In his
14

RECORDING August 2013

Like its predecessor, the ADL 700 is an intriguing blend of boutique design and
mass-produced construction. It features a classy tailored look done up in tuxedo black
with brushed silver knobs, blue glowing LED lights and high-end silver switches. At its
center is a large orange glowing VU meter for both output levels and gain reduction.
The unit is solid and heavy and all knobs and switches are tight and smooth.
Something old: the mic preamp
Starting with the microphone preamp, signal flow starts with an input selection
switch. As you turn the switch you will hear the relays on the unit clicking.
The choices are:
~ Instrument: engages the front-side 1/4" hi-impedance instrument input.
~ Line: takes us around back to an XLR line level input.
~ Mic: engages a second, rear-mounted mic input with a choice of four impedances—
1500, 900, 300 or 150 ohms.
Above that is a 12 dB/octave highpass filter with a hard-click bypass that can be set at 20
Hz, 40 Hz, 80 Hz, or 200 Hz. Input level is handled by a stepped Gain switch with a range
of 30 dB to 65 dB in 5 dB steps, and finer adjustments are made with a variable Trim knob
for an additional ±10 dB. This gives the mic pre a maximum possible output of +75 dB.
The preamp section also contains switches for Polarity (phase), +48V phantom
power and a 20 dB pad.
Something new: the compressor and eq
The FET compressor was designed by PreSonus in-house designer Robert Creel, who
also designed the eq section. Mr. Creel is also the man behind PreSonus XMAX preamps
featured on the StudioLive mixers and in PreSonus audio interfaces of recent vintage.

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Recording - August 2013

Table of Contents for the Digital Edition of Recording - August 2013