The Mitre Box is a high performance bass preamplifier/headphone monitoring system which I believe represents a carefully tuned balance of boutique performance and every-day value. I’ve spent a lot of time combing through the MPP-1’s design and identifying areas where the most cost could be removed with the least impact on sound and flexibility. I was able to do a lot of what I did in the MPP-1, but in different ways which yielded lower parts cost.
A few key infrastructure changes ended up saving me a lot of build time too. I was able to add an effects loop and a fully balanced stereo input to the headphone driver so it works great in a live in-ear monitoring system, in the studio as a self monitor, or as a ridiculously great sounding practice amp.
It’s small enough to slip in your gig bag which makes it a great choice to go along with powered speakers like the Bergantino IP cabinets. The end result is a much more affordable preamp that still performs like crazy.
-High performance, low noise and distortion
-Powerful Headphone driver with balanced stereo input for in-ear monitoring systems
-Same great EQ circuit topology as the MPP-1
-Small and compact.
-A great mate for powered speaker cabinets like the Bergantino IP’s
-Serial or Parallel effects loop
-High quality DI output with Pre EQ/Post EQ (and FX) switch
Front Panel Inputs, Outputs, Controls and Indicators
Input
Plug in your active or passive bass here. This is the first stage in the preamp. It converts any bass’s output into a steady, predictable low impedance signal. The input impedance is 1.0MegOhms.
Gain
This control increases the level to fully utilize the Mitre Box’s headroom. Turn it up until you hear distortion on loud notes, then back off a quarter turn.
Pre/Post button
This switch allows you to select the point in the preamp where the DI output gets it’s signal. Pre means immediately after the input stage and before the first “Gain” control. Post means the signal comes from the point after both the EQ stage and the FX loop.
DI Gain
This control sets the level of the signal coming out of the Direct Out on the back panel. When the DI is set to Pre-EQ this is the only control that affects the level of the DI. When the DI is set to Post EQ, the DI output level is obviously a function of the main gain plus any EQ levels AND the DI level control.
Tone Shaping
Treble
This control sets the amount of treble boost or cut.
Edge
This control sets the amount of upper midrange boost or cut.
Punch/Point button
This switch changes the frequency center of the Edge control. The “punch” position gives a great upper midrange bite for Neo-Jaco type sounds. The “Point” position offers great support to the upper treble frequencies when boosted, and is a nice slap contour when cut.
Midrange
This control sets the amount of warm, round lower midrange boost or cut.
Bass
This control sets the amount of Bass boost or cut.
Play/Mute Button
This button mutes the signal at the main output and the DI output. The headphone output remains on.
Master Volume
This control sets the output level. It controls only the MAIN output level. It never has any effect on the DI level regardless of Pre/Post setting.
Phones
This output has a mix of the post master volume control bass signal and the signal coming in the rear panel balanced stereo line input.
Rear Panel Inputs and Outputs
Tuner Output
Plug your tuner in here. This output is always on regardless of the position of the mute switch.
DI Output and Ground Lift Button
Attach the line going to the house sound system here. Push the ground lift switch in to eliminate any ground loops.
Effects Loop and Series/Parallel Switch
Attach any outboard effects you might use here. Connect the “send” jack to the “input” jack on your effects unit. Connect the “output” jack on your effects unit to the “return” jack on the Mitre Box. The effects send is picked up immediately after the EQ section and before the master volume. When the series parallel switch is set to parallel, the path through the effects loop runs “along side” the path between the EQ output and the master volume control. When the series parallel switch is set to series, the path between the EQ output and the master volume control is interrupted, forcing the entire signal through whatever is plugged in to the effects loop. More of your signal’s integrity is maintained by running in parallel and using the level control on your effects to determine how much gets mixed in with your main “dry” signal.
Main Output and Ground lift button
This is the main balanced output from the Mitre Box. Attach this to the input of your amplifier. If your amplifier has a balanced input, it is highly recommended that you use a “Tip/Ring/Sleeve” cable or a microphone cable with an XLR to 1/4” T/R/S adapter on it to interconnect the two. This allows the ground to be lifted in the event of a ground loop hum and offers generally improved performance over unbalanced interconnects. If your amplifier does not have a balanced input, use a standard guitar cable here…preferably a short one.
Line In
This is one of the coolest features on the Mitre Box. Whether you’re in the studio or playing live with in-ear monitors, or just practicing in the hotel room this feature is priceless. This is a true stereo, balanced input designed to accept signals from a wide variety of sources. What ever comes in here is found ONLY at the headphone output. This headphone driver is an audiophile grade design capable of driving any headphones you plug into it to extreme levels. BE CAREFUL. It can get loud.
Right/Mono
When using both the right and left inputs simultaneously, plug the right channel of your balanced or unbalanced source in here. When nothing is plugged into the LEFT channel input, the signal entering here is distributed to BOTH sides of the headphones. Great for play-along records like Aebersold’s where piano is on one side and bass on the other. Plug the piano side in here and play along.
Left/Stereo
When using both the right and left inputs simultaneously, plug the left channel of your source in here. When nothing is plugged into the RIGHT channel input, this input acts like a single-ended stereo input. Plug a 1/4” to 1/8” adapter in here and plug in your iPod or whatever stereo source you like to have it play back in true stereo.
Ground Lift Button
This breaks the circuit between the source ground and the Mitre box ground. This will be used most often in a live setting where there is a ground loop hum between the house system sending you the balanced signal and the Mitre Box.
With the Mitre Box, you are able to send a pre EQ signal to the house, and have them send you back a signal without bass. You can then mix yourself at your position to EQ and balance yourself the way you like to be heard in the mix without affecting the house mix or anyone else’s monitor mix. You can also send a POST EQ signal and still have individual control over your own level in your headphones.
Power Switch
This turns on main power to the Mitre Box
Power inlet/Fuse holder/Voltage switch
The Mitre Box is fuse protected both externally and internally. It is capable of 110V US voltage operation as well as 220V operation. The fuse and voltage switch are both contained in the “pop-out” drawer in the power inlet. In addition, there are two internal fuses which protect the unit in the event it is plugged into a 220V system while still set for 110V operation. Because replacement of these fuses requires the unit to be opened, these fuses should only be changed by a qualified technician while the unit is unplugged, and should only be replaced with the proper fuses.
