Scorpion mod


The Diff_Rev00x is an API 2520 discrete opamp based differential (balanced) line receiver mod kit for the Amek/TAC Sorpion I S1000/S1100 and Scorpion II S1001/S1101 input channels. It is based on the original API 2520 application notes and replaces the original "bottle neck" microphone preamplifier with a fully discrete unity gain line preamp.


To fit the Diff_Rev00x PCB to your channelstrip alll you need to do is remove some parts that make up the original preamp and slide the line receiver pcb in place. Together with a 2-ACA-BO, Capi-Gear's API summing and master fader booster, in the scorpions master section the Diff_Rev00x differential line input turns your Scorpion into a true vintage critter!


For the audiophile, lovers of clean hi-definition audio we designed a THAT1512/1510 based microphone pre-amp for the Amek/TAC Scorpion 1 S1000/S1001 and Scorpion II S1100/S1101 too!


This high performance balanced input IC, by far, exceeds the original SSM2015 specs, with higher slew rates and lower signal to noise ratio and excellent CMMR (Common Mode Rejection Ratio), this is a rather big step-up from the original preamplifier.

After trading our most prized posessions for cold cash, and an old recording console. We spent that money on some project, we can't even remember which, and weeped for loosing our OV560 Neumann preamps. The poor little Scorpion had been standing in our workshop for a long time before we even fired it up. We were not impressed with it after a quick and dirty first test. Amongst others, hums, buzzes, and pot-noises were some of the sonic disasters we were up against. After an internal inspection this Scorpion revealed an extensive but poorly executed modification. Almost all channels had been worked on, recapped with the wrong valued capacitors, and output transfromers where fitted to the mains, but badly inserted in the circuit. We had our work cut out for us!


We felt it was only the right thing to do to at least revert this little critter to it's original state! First things first so we overhauled the power supply first to get rid of dirty currents and gounding problems. The master section received a full recap with original valued Dublier capacitors supplied by Colin over at AML (, and we inserted the output transformers in the right spot. Only after we finished recapping a single input channel were we able to complete a thourough test, all the way from input to output. Although clean, almost clinically, and with a much improved lower-end we still did not like the consoles sonic performance. It was quite a while later that we found out about the Graham Langley designed microphone pre-amplifier mod for the S1000 and S1001 input channels. So we ordered and applied the modification to four of our channels-strips.


It was the simplicity of the Langley mod that made us believe that the Scorpion could be a great modification platform and somehow we even started liking the little critter. But even with the new preamps installed there was something we missed, character!