The Build

Now that I pretty much knew what I was building, I went out and bought a decent sized blank stereo chassis. I didn't want to go through all the hassle of getting one custom made, and wanted to "roll my own." so to speak. I carefully plotted out where I wanted the controls to go, and marked them with a starter hole (the measuring was kind of a pain).

Then I drilled out the tube socket holes and the transformer holes, and mounted original antique Bakelite sockets for the 2E26s.

Here's a shot of the undercarriage...

Mr. Wang said he'd do the faceplate lettering for me. I was just going to use a metalic magic marker or something. He wouldn't stand for it.

I started off by first wiring the tube heaters...

See how nicely I twisted the wires?

Notice the cool old school hi-fi style ground wire across the power caps.

After the heaters, I wired up the pre-amp, including all the jacks and pots. This was all straight from the B25 schematics. Ampeg really designed a great circuit. No hums, squeals, grid noise, nothing. Worked perfectly. The only tricky part was properly wiring up the "super lo" switches.

I enjoyed making it all point to point, rather like an old radio or something. Felt very old school hi-fi.

I learned a lot about how negative feed back works to effect the tone. The thin green wire runnihg along the copper ground wire is the negative feedback back to the tube.

Here's what it looks like all completely wired. I just glued the power caps to the chassis like in a lot of old equipment (with a couple of mistakes). Note the power stage. This was all designed by Mr. Wang from years of tube experience, an old RCA handbook, a Fluke meter, and just knowing how stuff is supposed to work. The gold thing is the fixed bias.

Here's the finished amp. I had the transformers custom wound by the local hi fi transformer guy to match the values needed by the 2E26s. I tried to keep true to the old Ampeg fliptops retro feel. Check out the cool caps on the power tubes!

These RCA 2E26 tubes are stamped 1965 on the tube. Here's the spec sheet if you are interested.

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