After almost going blind soldering everything and stuffing it into an impossibly inappropriate mint box here is a battery powered headphone amp sounding surprisingly good for the size of OPTs.
Everything runs off one battery and it plays decent 9 hours on one charge when using 3400 mAh cell (B+ set at 27V).
Component values were set by listening exclusively since I have no scope (aiming for slightly more gain then smartphone directly to headphones) so proper measurements would probably lead to some other choices but the way it sounds now more than surpassed the expectations.
Other than the tubes and resistors everything was recycled so monstrously looking coupling caps (which look tiny in grown-up amps) are there just because they happened to be present at construction time. I also regretted this decision as used components don't like being soldered again, to which burn marks on the insulation can testify.
Everything runs off one battery and it plays decent 9 hours on one charge when using 3400 mAh cell (B+ set at 27V).
Component values were set by listening exclusively since I have no scope (aiming for slightly more gain then smartphone directly to headphones) so proper measurements would probably lead to some other choices but the way it sounds now more than surpassed the expectations.
Other than the tubes and resistors everything was recycled so monstrously looking coupling caps (which look tiny in grown-up amps) are there just because they happened to be present at construction time. I also regretted this decision as used components don't like being soldered again, to which burn marks on the insulation can testify.
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Finished1.jpg479.1 KB · Views: 1,230
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RunningOpen.jpg595.4 KB · Views: 442
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Fitting.jpg703.6 KB · Views: 475
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BuildEarly.jpg332.7 KB · Views: 427
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BuildStart.JPG930.3 KB · Views: 1,030
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FinishedTop.jpg808 KB · Views: 1,057
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Finished3.jpg537.8 KB · Views: 1,042
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Finished2.jpg617.2 KB · Views: 1,132
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