The Bare-Ass Boost

[smallbearelec]

Here is the second build for the Bare Box #1. As you can see, it is two stages of JFET boost, biased like the BOSS FA-1, and married with a DS-1 tone stack.



I built it on perf first to see if it was possible. I did it, but I think most builders would find it too much of a PITA.



It was still worthwhile, because I got to work once again with and check out the "platform" that I came up with for the Oh My Darling Rangemaster. With the locations of the off-board connections fixed, laying out the stuff in-between becomes fairly logical and way easier.



Clearly, there are lots of possibilities depending on what you need to do: Bias for more or less gain and/or remove emitter-bypass caps, bypass stages with toggle switches, etc.

I will get a board made and a case painted and decorated in the next few weeks.

SD

[Electron Tornado]

You should call it the "Bear-Ass Boost".

[bool]

You should call it the "Bear-Ass Boost".

heh heh

[smallbearelec]

So I have this much done, and the etch pattern works for the power, bias and the first stage. A few mistakes in pad locations, but nothing I can't fix in production.



I jumpered the first stage to the output and have been having fun trying out a bunch of JFets and thinking about how to offer the kit. I have re-read the article on the Fetzer valve about six times. Does it make sense that Q1 should be something with a relatively low Vp, like a J201? That stage would be relatively low-gain, and Q2 would maybe be a 2N5457 or similar to tolerate a higher input voltage. The device in the pic is a J201 with IDss .88 ma. and Vp -.93. RD1 is 3.3K aqnd RS1 1.2K.

Any issues I should be thinking about in finishing the board? The pattern allows for either DSG or DGS pinouts. I may put in pads to allow switching the source bypass caps in/out; other suggestions welcome. Any ideas for what would make sense for the overall gain? Clearly, I'd like this to be a useful studio/gig-rig tool as well as a playgrond for Fetzer-valve/Sparkle Boost experiments.

SD