I recently completed my Quickie with the headphone conversion and would like to share my experience. Everything went swimmingly until I pulled the Speco transformers from their boxes to find they were almost exactly nothing like those described in the post. Although the boxes were labeled as T7010 transformers, mine were physically smaller, only had two wires on the secondary side, had seven wires on the primary side none of which were .625W and a completely different color code. Worse yet, two wires exited from the last notch in the bobbin leaving me with no idea which should be connected to the signal. While I can follow directions well enough to assemble a kit the finer details of electronics are beyond me and not having found any specifications for this newer version of the T7010 online I was (after a trouble night) left with the brainstorm of measuring the relative resistances between the 10W brown wire and the other wires. Having done this I settled upon the Violet wire as being that labeled as .5W which was the closest value available to the .625W suggested in the original post. If anyone can suggest a better selection than the 10W/0.5W that I settled upon, I'd greatly appreciate your input. In fact, I would enjoy hearing any suggestions on my implementation that might improve the sound of this lovely little amp.
Correct or otherwise, the Quickie has turned into a quite enjoyable little headphone amplifier. While the output is not substantial enough to drive my inefficient AKG K501 to anything above barely acceptable levels, it has proved a wonderful match for the Beyer DT880 (250 Ohm).
If it should be of any help, as best I can determine, this is the color code for the version of the T7010 I received:
Primary
Common: Black, 10W: Brown, 5W: Red, 2.5W: Orange, 1W: Yellow, 0.5W: Violet, 0.25W: Blue
Secondary
Common: Black, 8 Ohm: Red
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