Category Archives: Construction

Construction Toys In The Attic

A DIY’d Eico 615 Adaptor

This is a quick one.

I’ve recently been looking into playing with directly heated triode single-ended triode (DHT SET) amps, particularly 45s, 2A3s, and their cousin, the 6B4. So I’ve been buying them piece by piece on eBay, as inexpensive parts pop up here and there. The upside is the low low price! The downside is that my ‘modern’ Eico 667 tester doesn’t have the old UX4 socket. Eico did make an adaptor, however–the 615:

Eico 615 Tube Tester Adapter
Eico 615 Tube Tester Adaptor

It isn’t a terribly easy thing to come by these days, nor cheap when you can find one.

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Construction Toys In The Attic

A PCOXO Calibration Source

I have a 1GHz universal counter and a 5MHz function generator as well as an ancient RF generator, but I don’t really do a lot of super accurate frequency stuff to warrant a Rubidium standard (yet). In early 2012 I threw down an offer of $10 on a Bulova PCOXO-HP02 oscillator, and accepted the counteroffer of $12.50.

The Bulova PCOXO-HP02 oscillator
The Bulova PCOXO-HP02 oscillator

Now I needed to figure out how I could use the thing.

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A Dual-Mono AKAI M8 SE EL84 Amplifier, Part 1

This project really picked up steam in October 2012.

A couple years before this project came about, I built a box as the base for my second RH84 amplifier (design can be found here [opens in a new tab]) since my first build was based on the chassis of an unremarkable Claritone console amp (I assure you, no Project G stereos [opens in a new tab] were harmed in development of that project). The box was put together using red oak sourced from the clearance pile at Rona, cut on a not-quite-square compound mitre saw, and a table saw was used to rip the 6061 aluminum plate down to size. In the end the openings were not quite regular and I had to file the plates into fitment, but it turned out well.


Made form Red Oak
Made from red oak and 6061


Right, so I’ve got the box.

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