Retro-Sonic Compressor

The Retro-Sonic Compressor is an analog compressor pedal made by Retro-Sonic, and it is a straight take on one of the most copied circuits in the effect's history: the gray Ross Compressor. Retro-Sonic says the pedal is "based on the famous gray Ross Compressor known for is smooth compression and attack respon[se]," and that the Ross design has been "updated with the finest components, providing clean, smooth compression with low noise, while retaining the guitars tonal integrity"¹.

What that means for a player is the classic Ross behavior: even, leveled rhythm playing with little change to your original tone, and smooth pick attack and sustain for lead guitar¹. It is a simple, analog, true bypass box rather than a multi-knob studio-style compressor, which is exactly the appeal of this circuit family.

The Ross circuit and where it came from

The gray Ross Compressor is the pedal this one recreates. Retro-Sonic describes it as famous for smooth compression and attack response, and builds the Retro-Sonic version as an updated take on that design¹. The Ross itself has a documented parent: General Guitar Gadgets notes that "The Ross™ Compressor was copied from this compressor," referring to the MXR Dyna Comp, and that the Ross "is treasured by many players as being 'the one' compressor"³. So the Retro-Sonic Compressor sits two generations down from the Dyna Comp, in a lineage that also includes the OTA-based circuits behind pedals like the Keeley Compressor.

The Ross design has been reproduced several ways. General Guitar Gadgets sells a Ross Compressor Replica Kit that can be built on the same PCB as its MXR Dyna Comp replica⁴, and its announcement of that kit described "very nice sounding compression. Using the true and tested age-old design," built around the CA3080 IC⁵. Other makers with Ross-based pedals include Wilson Effects, whose Compressor V.2 is "a faithful recreation of the vintage Ross compressor with an added clean blend"⁶, and Xotic, whose SP Compressor is "based on the highly revered Ross Compressor"⁷. The Retro-Sonic is the plainest of these: the Ross circuit with an added attack control and tone toggle, without a clean blend or extra features.

The controls

The control set is small, and each knob does one clear job. Retro-Sonic describes them like this¹:

The Sustain knob is the compression control, working the way Sensitivity does on a Dyna Comp-family pedal: more clockwise means the compressor works harder and notes hold longer. Attack is a useful addition over the original Ross, which had no attack control; turning it clockwise lets more of each pick transient through before compression clamps down. The toggle is a simple two-way voicing switch, bright or dark, for tilting the tone without touching your amp¹²⁸.

Power and connections

Power is flexible for a pedal of this type. The maker lists it as "9v battery or 9v negative pin adapter"², so it runs on an internal battery or a standard center-negative 9V DC supply, the polarity most modern pedalboard power supplies use. Connections are conventional: a ¼-inch standard phone jack input and a ¼-inch standard phone jack output². The bypass is true bypass, switched by a heavy duty foot switch¹, so with the effect off the pedal is out of the signal path.

At 4.4 x 2.3 x 1.1 in a cast aluminum housing¹², it takes up a standard compact stompbox slot. Retro-Sonic lists it at US$165.00², which positions it above small-budget Ross-style clones and around the same territory as other hand-built takes on the circuit.

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