For sale is a Bel Canto Valve SEP II preamp which has been thoroughly and expertly upgraded taking it to a completely new level of performance. The work was undertaken by Dr. Slawa Roschkow, who is the Founder, Managing Director & Chief Audio Engineer of SW1X AudioDesign (https://sw1xad.co.uk/). In its stock form the SEP II is a great preamp with a wonderfull rich tone, portraying notable substance to the images in the music and exhibiting a warm realistic presentation to voices due largely to its use of valves. As to its design, Bel Canto describes it as follows: The SEP2 gain stage is a zero loop-feedback single-ended triode design. This gain stage provides high gain and low noise with very low distortion and low output impedance for load drive. It uses a pair of dual 6DJ8/6922 triodes having long life and ready availability. The output is coupled through a selected Polypropylene film and foil capacitor. The single-ended nature of the SEP2 with its single gain stage leads to an inverting output for all inputs except the loop through function. This means that for non-inverting output at your loudspeakers you will need to invert the loudspeaker connections. Connect the positive (+) power amplifier output to thenegative (–) speaker terminal and the negative (–) power amplifier output to the positive (+) speaker terminal to restore correct absolute phase. The SEP2 power supply uses a separate current source driven shunt regulator for each channel’s gain stage. This supply architecture provides the stability and isolation of battery power without the inconvenience and expense. Volume control is accomplished with a precision Crystal 3310 stepped analogue attenuator adjusted by a microcontroller. This device provides extremely low noise and distortion coupled with high accuracy However, the work undertaken by SW1X took the preamp to a completely different level. This included: Existing capacitors were replaced with rare high grade Black Gate and Audio Note oil filled copper mylar capacitorsResistors were swapped out for Kiwame 5W and 2W versionsThe stock stereo digital volume control (CS3310) was replaced with a higher performing chip along with 3 small chokes in the power supplyThe standard valves were swapped out with a more costly pair of Russian tubesInternal wiring replaced with silver wire and solder Sonically, as a result of this work, the window into the music got much cleaner, larger and deeper. The sound became more dynamic even at lower volume levels, with the preamp noticibly free from any residue of muddiness and sluggishness. This is an opportunity to acquire a one off preamp, great in its stock form, yet due to the inclusion of high grade internal audio parts, now performs way beyond its asking price. As such it is truly unique in its design and build with a beautful sound that one would have to spend considerably more to equal. Should you be interested please be aware that the preamp will need to be on for a couple of days before it will begin to sound near its best. This is due to the use of the Black Gate capacitors, that tend to revert back and will require a week to run in again, should the preamp not be in use for a prolonged time. As such it is better to either let the preamp be switched on at all times or to use it frequently (preferably every day).The overall condition of the preamp, given its age, is very good with only the odd slight mark which I have tried to capture in the pictures. However in normal lighting conditions these are hardly noticible. It comes complete with the original remote and box. Any questions please feel free to ask.