I recently got these two pedals in. They look like plain Boss clones; are they?

These pedals were made in Taiwan as part of a shared OEM effect design distributed under multiple brand names like Century, Vshock, Rockson, etc. They can usually be found quite cheap as little is known about them. You can find more brands in the Effects Database’s post on this pedal.

The circuit

The pedal is housed in an all metal enclosure that mimics the enclosure of a Boss pedal. The footswitch also holds the battery compartment. Three knobs are present to change the volume of the output signal (‘Level’), the EQ of the output signal (‘Tone’) and the gain of the output signal (‘Drive’). In and outputs are on the sides.

When opened up the units have a decent PCB that also mimics the Boss’. When you place the right pedal next to it, you can spot that they copied the PCB of the Boss SD-1. I wanted to trace the effect but found a good quality schematic at Freestompboxes.org. Note that all models share the ACA power supply design that can be found in early Boss SD-1’s. I changed both models into PSA design so I can feed it with a normal 9V power supply.

I checked the schematic with my units but there are some small differences:
– The used NPN transistors are 2SC732 in the Maxx and 2SC1328 in the Dixon
– The IC is a JRC4558DD in the Maxx and a AN4558 in the Dixon.

I expect these units to sound similar even though they have these differences.

The sounds

Compared to a Boss SD-1 they sound similar. They all share that smooth breakup sound and the ease to push an amp into overdrive. A very decent copy of an early SD-1!

The links

• An entry on the Effects Database about these pedals
• A schematic of this pedat at Freestompboxes.org