My rendition of the RA-100 amplifier by Fred Nachbaur.

First of all,I'd like to mention a bit about Fred.
He was one of the great guys I became acquainted with on RAT (rec.audio.tubes). These guys (The RAT's) are a great bunch,and some are quite tight-knit,a 'cyber-family' if you will.
Fred was a great guy,and taught me alot about tubes,and electronics.Practically everything I know about radio I learned from chatting with Fred in emails and online.I was always pestering him with dumb "noobie" questions,but he never made me feel like a dumb noobie..He had a very unique way of explaining things so that they made sense,and were easy to understand.He had a clever way of designing circuits,as you can see from some of his creations,there are a few neat 'tricks' to be gleaned.
He was definatly a character,and is greatly missed.  I miss being able to chat with him,and ask him dumb questions,and joke around. One of the things I really miss (and this may seem kind of strange?) is his knowledge. I miss being able to pick his brain about things -he knew alot. I'm sad I never got to meet him in person.

A while after he passed,his wife Sharon was selling some of his 'gizmos'.Among the stuff was an unbuilt 'kit' for the RA-100A,the newer version of the RA-100 prototype Fred had planned to build. So,my girlfriend and I made the trip from Portland to B.C. to meet Sharon (and Gregg!) and pick up the amplifier parts, and a few other  things.

So,This is my page about the "RA-100A" amplifier. Sort of my tribute to Fred,I guess.


The Beginning.

I had some trouble managing to get everything into the chassis,so I decided to build it as a stand-alone power amp.Later I'll build the preamp sections in a separate chassis.As you can see from the original RA-100 pictures,the chassis was pretty cramped.Fred was a master of "japaning" -managing to cram lots of stuff into a small space. I,apparently,am not.

So,what we have HERE is a picture of the preliminary layout. Trying to figure out the best layout for all the components.


The large power transformer in the rear-center,the filter choke infront of that,and the output transformers on either side.
The transformers are all Hammond- 282X Power,193H choke,and 1645 output trannies.
The output tubes,and driver boards,along with the power-meter boards on the front.
I decided this layout was pretty good,so I started drilling the chassis. It's now 90% drilled and nearly ready for paint.

I'm still not sure of the finish/color it's going to be painted in,but I've decided I'm going to use smaller 3mm LED's for the power meters,and make them  Blue->Purple->Red  Just to add a bit of "Cool factor" (or maybe Geek factor?).

-----
I've finally got the chassis  99% cut and drilled,just a few minor things,and then I can paint it! Still unsure of the color..
Still slowly collecting various parts.