Mesa Boogie Studio Pre User Manual
MESA/BOOGIE
The Spirit of Art in Technology
Studio Preamp
Owner ’s Manual
Studio Preamp
Owner ’s Manual
Congratulations on your purchase of the MESA/Boogie Studio Preamp! In this compact, rack-ready
package you’ll find all the basic tones that made Boogie famous – clean, warm, smooth rhythm
sounds; a screaming, vicious Lead voice; and enough control to produce anything in between. The
Preamp is simple and straightforward, yet sophisticated. Like all other Boogies, it’s based on a no
compromise, all-tube circuit with traditional style tone controls and instant Lead/Rhythm footswitching.
It includes a 5 band graphic EQ for tone customizing; a carefully tweaked, deep-sounding
3-spring reverb; a stereo effects loop that can accommodate either low-level or line-level effects; and
two pairs of stereo outputs (including Recording Outputs with speaker-simulator circuitry, which will
mate perfectly with either a mixing console or the front end input of most guitar amps.)
NOTE: If you are using the Studio Preamp in conjunction with a "dedicated" power amp, we strongly
recommend the use of a high quality, all tube amplifier such as our Stereo Simul-Class 295, or the
Strategy 400. Only then can you be assured of taking full advantage of the Preamp’s sound quality.
1. Connecting the Preamp: The simplest method for connecting the Preamp is to plug your guitar
into the front or rear panel INSTRUMENT INPUT, then run shielded cables from MAIN OUTPUTS
A&B into the inputs of your power amp. The two output level controls on the Preamp will determine the overall level being sent to the power amp. (If you are feeding into a mono power amp, use
either one of the Preamp’s Main Outputs Aor B.
If you wish to use the Preamp in conjunction with a "normal" guitar amplifier such as a Fender,
Marshall, etc., you can either 1) run a shielded cable from one of the Preamp’s rear panel RECORDING OUTPUTS into the front panel input of the amp; or 2) run a cable from one of the MAIN OUTPUTS into the effects return or Power Amp Input jack of your amp (assuming your amp has one of
these).
If the Preamp is being used for recording and you wish to connect it directly to a mixing console, we
recommend using the RECORDING OUTPUT(s), connected to a line level input on the console. Or,
as an alternative, you can use one or both of the Preamp’s MAIN OUTPUTS for this purpose. The
Recording Outs are EQ’d differently than the Main Outs, so the choice here is mainly a matter of
taste.
2. Using Stereo Effects: The Studio Preamp is capable of stereo operation if used with a stereo
effects unit (and, of course, a stereo power amp). To do this, connect a shielded cable from the
Preamp’s EFFECTS SEND jack into the input of your effects unit, and set the Preamp’s EFFECTS
LEVEL switch to either "LOW" (for using floor pedals or "inexpensive" rack effects) or "LINE" (for
using studio-quality effects). Then connect the outputs of the effects unit to the RETURN jacks on
the Preamp using shielded cables, and use the Preamp’s Main Outputs to feed the power amp. Use
the Mix or Blend control on the effects unit to set the "wet/dry" (effect/direct) blend.
Another way to run the Preamp in stereo with effects is to connect one of the Preamp’s MAIN OUTPUTS (or both, if the effects unit has stereo inputs to the input of the effect. In this case the Preamp’s
OUTPUT LEVEL control(s) will determine the send level to the effects; the overall level going to the
power amp will be determined at the effects unit.
3. The Controls: Let’s review the controls one at a time to learn their various functions and how
they interact.
Volume: This very powerful control determines the gain in the Rhythm mode and also the amount
of signal fed to the lead mode. Lower settings of this control will result in cleaner, brighter rhythm
sounds and lower gain lead sounds. Higher settings will result in fatter clean rhythm sounds and
tighter, more focused lead tones. By experimenting with the volume control you will discover a
"sweet spot", probably somewhere between 6 and 7 1/2, where you’ll find the ultimate shimmering
warmth in your clean sound, yet enough gain to keep your lead mode tight and singing. We’ve
found that settings of 6 3/4 to 7 provide a great clean sound and yet allow instant switching to a
great lead sound. However, players who put emphasis on the ultimate clean sound will probably
want to set the Volume at 5 1/2 to 6. If you never use clean sounds or don’t need "squeaky-clean"
rhythm sounds you’ll probably be more concerned with the Lead mode. In that case a volume setting of 7 1/2 to 8 may be in order. Of course, the best way to find the setting that is "the ultimate"
for you is simply to experiment.
Master: This control serves two purposes and remains functional in both modes. It is a master volume control for the rhythm mode and it is also in series with Lead Master. This means that low settings of the Master control should be balanced with higher settings of the Lead Master control if
equal levels are desired between Lead and Rhythm modes. Similarly, higher settings on the Master
will require lower settings on the Lead Master to achieve a balance. A good basic setting for the
Master control is 5. If you start around 5, you can still increase or decrease the setting to a degree
without having to alter the Lead Master setting.
The second purpose of the Master control is that it functions as the Effects Send level. Again a setting of 5 usually provides the right amount of signal to drive most effects units. If this setting is
incompatible with your effects, adjust as needed and then re-adjust the overall loudness of the
Preamp with the Output Level controls.
Lead Drive: As you might expect, this control adjusts the gain, sustain and sensitivity of the Lead
mode. Although it is affected by the setting of the
Volume control, it has enough gain to produce anything from a "bluesy", slightly dirty tone to an
insanely overdriven "metal" sound even at very low volumes. Touch sensitive! We’ve found that the
best tones seem to occur with the Lead Drive set in either the 2-3 or the 5-6 regions.
Treble: This control adds "highs" and "bite" to your tone. It also has the effect of adding gain and
sustain to the Lead mode. Adjusting this control while switching between Lead and Rhythm modes,
you’ll find a "sweet spot", probably somewhere between 6 and 8, which gives you the right amount
of bite and penetration without sounding harsh.
Lead Fat (Switch): This rocker switch "re-voices" the Treble control shifting it’s effective range
downward to the upper mid-range zone. Affecting only the
Lead mode, it adds fatness, gain and sustain to the tone.
Bass: This powerful control adds roundness, warmth and bottom to the tone.
Like the Treble control, it should be set with both modes in mind; high settings, which may sound
great for rhythm, may sound "flabby" in lead.
However, too little bass may leave you with a "flat", two-dimensional sound. Try setting this control
between 3 and 5 for starters.
Middle: This control is the least significant and easiest to use of the three tone controls. Although it’s
action may not seem dramatic, it adds midrange warmth when used with relatively "normal" setting
of the Treble and Bass controls.
Rhythm Bright and Lead Bright (Switches): These switches accentuate the "super-top" or extreme
high frequencies, adding shimmer and sparkle to the Rhythm mode and a "searing" quality in Lead.
The Bright switches are most useful at low settings; at high gain settings they are usually unnecessary and may cause excessive noise or feedback. To avoid this, you should either reduce the Volume
(and/or Lead Drive) slightly, or turn off the Bright switch when such extreme settings are desired.
Graphic Equalizer: The Studio Preamp is equipped with an onboard graphic EQ that is specifically
tailored for guitar. The center frequencies of each of it’s 5 bands were carefully selected as the ones
most useful and effective for the instrument. What the graphic allows you to do is drastically reshape the tone structure or frequency response curve of the Preamp. The
EQ comes "after" the rotary tone controls and distortion circuitry in the
Preamp and is generally used to enhance the basic tone after you’ve set the rotaries. However, it can
also be used to p-provide a separate set of "tone controls" for the Lead mode (see explanation of EQ
AUTO below). Although the
EQ adds tremendous flexibility to the Preamp, it is not necessary for achieving a good tone, and can
be switched out of the circuit at any time.
(All the tonal R&D that went into perfecting the Preamp’s sound was done with the EQ out).
The front panel EQ Switch has three positions: EQ IN, EQ OUT (the unlabeled center position) and
EQ AUTO. When the switch is set to EQ OUT, the EQ is not active but can still be switched in via
the optional EQ footswitch. When the switch is set to EQ IN, the EQ is active (and cannot be
footswitched off). In EQ AUTO, the EQ will automatically kick in whenever you are in the Lead
mode, and will automatically switch off when you are in Rhythm. In this way, you can create a tone
"preset" for Lead that is entirely different from your Rhythm tone.
Although there are many useful EQ settings, on "graph" seems to have found its way onto every coliseum stage at one time or another: the classic "V"! This setting produces a dramatically "fat" sound
by boosting the extreme lows and highs while cutting back the mids. Specifically, you move the two
outside sliders (80 & 6600 Hz) to a setting just below the highest line.
Then you position the 2nd and 4th sliders just above the centerline. Then take the 750 Hz slider,
center it at the lower line, and fine-tune it.
(You’ll find this region very responsive to even tiny adjustments - it’s like a pivot-point of the "V"
sound.) Of course, the "V" is just one of the many possible EQ combinations. Like all the other controls, the EQ is there to help you find the tones that sound great to you.
REVERB: The Studio Preamp includes a built-in 3-spring reverb unit. The reverb circuit has been
painstakingly "tweaked" to eliminate any buzzing, "boinging" or clipping that sometimes occurs
with springs. When the reverb control is set at zero, only the "dry" or non-reverberated signal is
heard. As the control is turned up, the "wet" or reverberated signal is gradually mixed in. Try a setting of 3 for a "medium" amount of reverb, or "season to taste". Once you’ve got a setting you like,
you can switch it in or out with the optional reverb footswitch (or other external switching) via the
rear panel FUNCTION jack labeled REVERB.
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