Boosty McBuffer

I care very much about low noise design because I use high gain effects and compressors and they tend to magnify any hiss to annoying levels. The DC resistance of pickups (5kΩ to 20kΩ) generates hiss due to Johnson (or thermal) noise. An average 10kΩ pickup's self noise is -113dBu when measured over the full audio bandwidth. BMB's output noise is significantly lower: -117dBu, so it will not add any perceptible hiss to the signal coming from the pickups. Remarkably, it achieves this without compromising on power consumption. Its current draw is a tiny 0.3mA, resulting in a batery life of over 1500 hours.

For more detail on the sources of guitar hiss and how an onboard buffer can both reduce noise and eliminate "tone suck", you might want to read this tech note. 

💡It's important to note that hiss (white noise) is definitely not the only type of noise coming out of pickups. Environmental noise they pick up from power transformers, LED lighting, phones and computers is a different story. BMB cannot help with this, as it's already part of the signal by the time it gets to it. Humbuckers and other "noiseless" pickups significantly reduce it, and properly shielding your guitar also helps.

Here are some suggested ways you can use Boosty McBuffer. 

Guitar: Try 12dB of flat boost on one side (bass boost is not usually useful on guitar). This helps pushing amps into overdrive, for leads or just extra dirt. The middle position always lets you quickly jump back to unity gain. On the other side, try a strong treble boost, maybe even all the way up to +22dB. This does the same job as dedicated treble boost pedals - but with less hiss. Use the first 3 DIP switches to set BMB's input impedance to whatever you feel sounds best with your pickups.  Higher input impedance results in a brighter tone, lower impedance warms things up. 10MΩ is high enough to use with piezo pickups, but probably too bright for magnetics. 500k is a good value to start for humbuckers, while 250k is common for single coils. Try the lowest impedance (145k) if you want to warm up some overly bright single coils.

Bass: 

• on its own: use it as a minimalist, unobtrusive, preset EQ. Instant recall, no fiddling with knobs, for those who know exactly what they want. On one side, 6 to 12 dB of treble boost, or even more, works great as a "bright" or "slap" switch. On the other side, try 6 or 12dB of bass boost for those deep R&B tones. Flat in the middle, as always.

• with Distiller:  place it ahead of the Distiller to give it LF and HF shelving boost capability. 

• with OKC: try it in front of the compressor to control what it tends to react to more: lows, highs, or just neutral in the middle. Pre-compressor EQ can be very transformative to the way it operates! 

For best performance, if you use a volume potentiometer right after BMB, it should be a low value suitable for active electronics. 25kΩ pots are commonly used. 10kΩ or even 5kΩ would be even better, but they may be harder to source in guitar sizes.

SPECIFICATIONS

Input impedance: user-configurable, see table below
Output impedance: 51Ω
Current draw: 0.27mA
Battery life (9V alkaline): 1500 hours
Output noise
(buffer or bass boost): -117dBu (21.6kHz BW, unweighted)
Output noise
(treble or flat boost): add boost dB to figure above
Maximum input level (buffer): +11dBu @9V, +18dBu @18V
Dynamic range: 128dB @9V (!), 135dB @18V (!!)  

MEASUREMENTS
Test equipment: Audio Precision System Two Cascade