The Stealth Boost
The Stealth Boost is a passive device that performs two important functions in your FX loop by controlling your overall volume for both channels, and providing a continuously adjustable solo boost. It is also simple to hook up by running a cable from your FX Send to the SB's input, and running a cable from the SB's output to the FX Return. In a parallel FX loop, the FX Mix pot should be set as high as possible. Since the pedal is passive, it will not be affected by the impedance or voltage level of your FX loop and can not cause unwanted oscillations due to gain greater than one after the preamp.
Overall Master Volume
The Stealth Boost will act as a Master volume (LED = Green) over both channels. So, you can set channel 1 and channel 2 to match in volume for the best possible tone, and then bring the whole amp level down with the SB. The F-series is particularly good at this trick, because channel 2's master sounds much better cranked up to about 10:00 and reduced with the SB, than it does to the equivalent output volume on the channel 2 master (somewhere below 9:00). The SB will also allow you to get conversation volumes out of the F-series, but maintain the tone as if the amp was cranked up higher. So, if you set your F-series' channel masters to match, at a gig or practice, you only need to touch the Stealth Boost's left knob to adjust your overall level.
Adjustable Solo Boost
The Stealth Boost can switch into an alternate mode (LED = Red) where the right side knob is activated which is always some volume higher than the left knob. Most people would use this feature as a solo boost for soloing. I've used this principle effectively with my band for a long time. There is a lot of boost available with the left knob down around 9:00-11:00, but I generally only want 3 dB.
Stealth Boost as a CH2/Contour Volume Equalizer
You can also setup the SB to equalize the volume difference between Channel 2 and Contour, which makes the F-series a 3-channel beast. All you have to do is setup the SB as a 3 dB boost, but keep it on for channel 2. Then, when you switch to contour, you turn it off. Since Contour is +3 dB, but you're dropping 3 dB, everything stays the same volume. Then, if you want to solo, you can stay on Contour, but turn the boost on, which will give you a 3 dB jump of course.
So, that's what it does, but the real reason to use the pedal other than 1 and 2 above is that it is completely transparent and noiseless from switching and power supply hum. The DC portion of the design only drives the LED and is isolated from the audio path. In fact, since the audio path is passive, the pedal will work with no power at all. You just won't have any visual indication as to the mode. Obviously, boost will be louder, so you may not care. It can be run with a DC power adapter (Boss 9V type 5.5 mm x 2.1 mm, negative tip) or 9V battery (internal). In using the 9V battery, the LED won't turn on until a cable is inserted in the IN jack. You can also leave the battery in the pedal and use DC power at the same time because the DC jack will switch the battery out of the circuit.
Jeff's Stealth Boost #2