The ProtoOD is based on the classic TS808 tubescreamer circuit, but with many modifications. First, the input & output buffers have been removed for increased transparency, increased input impedance & decreased output impedance. A toggle switch has been added to switch between true Mosfet clipping, 5mm Red LED clipping, and a diode lift (clean boost). The overall gain range is greater, although LED & Mosfet clipping has a higher threshold, so the overall amount of distortion will be slightly less than a TS808. I've installed a charge pump in place of the battery that up converts a 9V power supply to about 25-26V for greater headroom. Lastly, I have made the low-pass (or high-cut) and high-pass (or low-cut) filters variable. In brief, this means you have control over of the high & low end roll off -- giving you back control over your tone that the TS808 lacks. Inside, there is an internal trimpot to control the center frequency of the TONE control, but it will ship set at the stock 3.2kHz setting. I use high quality components throughout, including 1% metal film resistors & 5% metal film capacitors, and true mechanical bypass switching.
Here's a breakdown of the features of this pedal.
- True mechanical bypass via 3PDT footswitch
- Large controls are standard Drive, Tone, Level similar to the classic TS808 overdrive
- Added HPF control, which varies a pre-existing high pass filter in the drive section. Increasing this control reduces the bass cut.
- Aded LPF control, which varies a pre-existing low pass filter before the tone section. Increasing this control reduces the treble cut.
- Added MODE 3-way switch to toggle between Red 5mm LED, clean boost, and true Mosfet clipping (the difference between all three modes, especially Mosfet & clean boost, is most noticeable at higher gain settings when the pedal is run off of 18V)
- Internal FREQUENCY control sets the center frequency of the boost/cut from the TONE control. Ships at stock TS808 3.2kHz setting.
- 1% metal film resistors & 5% metal film capacitors for the purest signal flow -- NO electrolytic capacitors in the signal path
- Switchcraft enclosed jacks
- Audiophile OPA2134PA op amp used for increased fidelity & transparency
The pedal is hand-built and housed in a small 2.4" x 4.4" enclosure. Accepts standard Boss-style negative tip 9V power supplies only. Due to the charge pump installed in the space typically reserved for the battery, a battery will not fit inside the enclosure.