TC Electronics VPD1

[aron]

My friend let me use this on a gig. There are a lot of good ideas on this pedal.

There's a bass rolloff control, mid boost, flat, top boost, high pass rolloff, drive and volume. There's also a speaker simulator.

First the good news. Pretty well balanced overdrive that is much better than the overdrive on the old TC electronics line booster. The overdrive was a little too weak for me. Let's call it a booster when the "boost" switch is not on.

When the boost switch is ON, that's when the fun begins!

The bass rolloff, mid boost, flat, top boost do not work unless the boost switch is on. I would prefer that the bass rolloff always be on, but AFAIK that's the way it works; only when the boost is on.

With the boost on, this pedal goes way beyond "overdrive". It goes into LOTS of distortion and most of it is good. The top boost adds a high freq boost, the flat is as you expect - mostly a non-EQ tone and the mid boost sounds somewhat like a Santana tone.

The bass rolloff is very useful in boost mode. The high freq rolloff filter is very, very subtle, only taking off the extreme highs.

The unit is housed in an Eddystone box and the PCB is directly soldered to the jacks etc.... so I couldn't take it apart. The PCB has a foam "block" to prevent it from grounding out on the back of the box.

The switches are momentary and I miss the nice click of our 3PDT switches.

Summary:

A well built pedal that sounds a bit "tight" although very good.

My guess is that it's all IC with diode clipping.

I bet it's an op amp with a feedback loop w/diodes with a small value cap across the volume pot or from signal to ground for the high freq. control.

The boost is probably another op amp with some sort of bass rolloff tone circuit going into a standard ladder tone filter with maybe a Vox top boost type of filter, a mid boost preset and a defeat for the flat setting.

The two chained together provides a good amount of distortion. Perhaps there's even a diode to ground after or before the tone stack.