*Soundgas Type 636P (Grampian Preamp)

Note that the 636P we have available currently has the toggle switch. If you want a footswitch instead then we can do the swap although that will delay shipping slightly. Just let us know!

November 2022: we’re currently building a few more of the two channel Soundgas Type 636P2, however we will be producing another batch of 10 of this version at the start of 2023.

What is it? This is the hairy circuit you find in the mic preamp section of the Soundgas Type 636 – based on the Grampian Type 636 – famously used and abused by Lee Scratch Perry and Pete Townshend – and many others since. This is designed and built absolutely in the spirit of the original vintage units – no surface mount components or tone sapping DSP. 

How is this version different to the Prototypes? Photos are of the latest version. Based on feedback and our own testing of the original units, we have moved the input and output sockets to the rear of the box and added a three position attenuation switch on the output. This to tame the massive amount of gain produced when dialling in maximum overdrive/filth: now you can have all the dirt without overloading your amp/ears/signal chain. We have kept the industrial/functional aesthetic of the prototypes with a raw casing and just the switch, light and knob on the top.

More information:

The unit features a balanced input via combined TRS/XLR socket, vintage germanium transistor circuitry with original Grampian specification Mic transformer, overload lamp, input impedance switch, output 3-way attenuator switch and on/off toggle switch. Staying true to the original Grampian 636 design, the output is unbalanced on a ¼” jack socket and is out of phase.

Power is via a 12v external supply (included)

As with our original 636s, we have put tonal considerations ahead of all else. I was skeptical that we’d see a real benefit in using germanium transistors in the buffer section: all our original prototypes had used silicon and sounded great. However Ben and Dr Huw insisted that we build an all germanium version for comparison which proceeded to blow all the earlier versions out of the water.

The current situation regarding component shortages means that while we have secured enough vintage components to build 100 units, getting essential modern components is proving trickier with long lead times, a great deal of uncertainty and a significant outlay required. We are taking these preorders to help secure further components and to help fund the early stages of the production process. 

There’s more info on the build including photos and demos here.

To anyone reading this who has seen much cheaper versions for sale claiming they feature the Grampian ‘preamp circuit taken note for note’ we can categorically confirm that, while these units may be interesting in their own right, the circuit is certainly not an accurate recreation of the Type 636, nor do they sound at all close to either an original Grampian, or the Soundgas units. You get what you pay for. The mic transformer (one element of our design process that took a considerable amount of R&D to perfect) is not the correct value, and the circuit design means the Soviet germanium transistors are not actually being driven in any meaningful way. The overdrive/distortion these units produce is not the harmonically rich germanium distortion that is the signature sound of a Grampian Type 636. We have already spent a good deal of time researching whether we could build a modern unit at a much lower price point by redesigning the original circuitry but sonically it simply does not stack up.

And if you have seen a certain guitar pedal that claims to recreate the sound of the Grampian Type 636 aux circuit as used by Pete Townshend of The Who, we can confirm that what this digital processor actually does is create a slightly boosted signal with none of the harmonic richness of the mic preamp circuitry, which is what Pete actually used…