Gilbert Yeung C312 Preamplifier Review

Looking inside his work always made me wonder how the heck any repair work could be done? Seems it would be difficult. I am sure the unit sounds fantastic and I know first hand how good his hybrid amps sounded years ago. Lot of silicone to remove to access parts and solder joints.

Is the silicone used here easy to remove off of wires and solder connections? Or is it as I think and an absolute mess to deal with post build? Always wanted to ask these questions.

Again, his builds sound great as I have owned several of his pieces years ago. Never tried to mod one or repair one however. Sometimes parts fail and work needs to be done before the 20 year life of the electrolytic capacitors. Stuff just happens.

There are a lot of techs who are intimidated by this form of assembly, and I am sure some of that is also due to how AG carefully conceals the finite details of the amplification stages throughout. Truthfully I find it easier and more enjoyable working on his work compared to modern components because they have a sensible flow to them where a schematic isn't necessary. Most of the gear I get in for repair (newer components as I am also a warranty tech for a number of brands), do not have schematics or service manuals, and when many new PCBs have multiple layers, trace work can take me hours. 

The silicone isn't a pain to work with at all. Once fully set, the silicone is a complete solid and does not become gummy with time. AG did experiment with a couple other mounting adhesives in the past that did not hold up as well, and I imagine is one of the main reasons for using silicone throughout today. It works very well and lasts. 

Funny that you mention the hybrid amps, as I have a BC202 here that I hope to finish repair on this week. Over 20 years old, still fully serviceable and upgradable. Silicone that I had to remove I simply cut off, and replaced once I was done in that area. The adhesive around the tube section was some of the adhesive I spoke of that didn't fare as well, this was removed and replaced with silicone as well. 

Thank you for responding. Makes sense where the silicone meets solid parts like caps. Where he encases hook-up wire and soldering tabs on connectors it may be more problematic. Still an interesting approach to unwanted vibrations and potential noise/smearing.