Valve preamp III

This the third of these 12AX7 based preamps I have built. And each time they do not get any easier. This is the first I have constructed with the valves protruding. To do this you must mount all the bigger components on the bottom of the cct. brd. The smaller resistors have no problem fitting on the front side. The Sprague "orange drop" audio caps I use are huge so not only do you have to place them on the bottom of the board but you have to lay them over. In future Blogs I will show the inside of the compact die cast case and you will see how cramped it is.

There is a lot which makes this preamp special:- Pure silver (.7mm) hook-up wire for all sig. connections, snubbed amp and PS board, dampened stand-offs and dampened die-cast case, heavy brass isolation feet, RF choke of plug pack lead, gold plated isolated RCA connectors, Golden Dragon 12AX7s and valve rings. Speaker plastic/rubber dampening material is glued to the inside of the case which adds weight and helps control resonance in the case and ccts. A shield was also erected between the PS and amp brds. With the SMPS and two amp modules in the case there was little room left.

I have been pleased with all of these kits I have built but especially this one. It looks and sounds sensational! They sound so sweet and add a nice rich harmonically textured sound to dryer amps. I would not use it with my valve power amps but with my chip amps (LM2875 see other Blogs) and ZCA (Zero Component Amplifier-single MOSFet per channel) sound stage and total music depth are enhanced dramatically. They are a cheap Jaycar (Australia) kit which has now been discontinued. With a little help from some friends (much better parts and construction TLC) they do magic-relay magic.