Article Revision History


Updated all the Newark part numbers, and made several other tweaks to the part selection guide.

Removed most of the Radio Shack references.


Updated circuit board alternatives section again.


Updated circuit board alternatives section to cover many more alternatives, now that the Radio Shack 276-0150 board is getting hard to find.


Typographic improvements, and several small tweaks to the text.


Added FAQ items describing what the CMoy is not, and why, and what you might want instead.


Updated the parts lists for Radio Shack, Digi-Key and Mouser.

Clarified several aspects of the assembly guide based on DIYer feedback.


Added a new section to the parts page, Circuit Board Alternatives. Happy New Year!


Greatly enhanced the Tweaks page. Happy Hallowe’en!


Greatly expanded FAQ page. (Previously called “Introduction.”)


Drew my own schematic, partly because the Headwize site has been going down for a few days at the end of the month recently, but mostly to renumber the components so there are no re-used numbers. As much as possible, I use the old numbers.

Removed mention of the Radio Shack 276-0170 protoboard. It was always a second-class citizen, and it just cluttered the presentation. (I’ve archived the pictures in a ZIP file (380 KB) for those that still need them.)

Removed mention of the PacTec HML and Serpac A-27 cases. I haven’t seen anyone using these, so they were just cluttering the article. Also, simplified the discussion on cases in general.

Simplified parts selection in general, and added mention of some improved new parts.

Lots of general polishing.


Rewrote a good portion of the text, for clarity and accuracy.


Added some new completed amplifier pics.

Reworked the buffered virtual ground section, adding new schematics and clarifying the text.


Significant revisions all over the place. Basically I’ve taken the things I’ve learned in the last 6 months and clarified, corrected, and expanded where necessary.


In the section defending the use of 1/8 W resistors, the calculations were skewed because I was considering the power supply resistors individually. In fact, they divide the load between themselves, so in reality only half the wattage I predicted earlier goes through each. (I measured it to be sure.) This means 1/8 W resistors can safely be used throughout the design.


Split the article up into multiple pages. ’Twas getting rather large...

Added the 276-0150 layout diagram. (PDF file)


Moved the technical op-amp info into its own article.


Added info on Welwyn premium resistors, and added the section on whether 1/8 W resistors are sufficient.


Added part numbers for RS Components, to provide an alternative to Digi-Key for those not in the US.

Now boldfacing favored parts' numbers.

Many other lesser changes today. It was, in total, a day for serious article polishing.


Added pics for layout based on RS 272-0170 protoboard.

Added info on DC wall warts to the external power supply tweak section.


First version.

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Updated Fri Dec 16 2022 12:23 MST Go back to Audiologica Go to my home page