Finding an USB supply to power a CMOY seems to be quite hard. I found this IC to be interesting: you provide it 4,5v to 16v, it boosts to up to twice the input voltage and also provides an inverted voltage. It can provide 50mA of current and should work to power a CMOY headphone amplifier. It's low-noise, and quite expensive: 7,7 euro at Farnell + 21% VAT.
I put in the effort of making a PCB as compact and optimized as possible, following the reference design. I ordered the PCB at OSH Park, they came finished with a gold coating (ENIG). Assembled it with SMD solder paste and reflow. Performance seems to be stellar: no noise I can discern, with a CMOY powered from USB. I would need a high quality DAC to do more investigation, but I don't have any at hand right now. With ferrites or inductors, some of the remaining ripple could be reduced.
I put in the effort of making a PCB as compact and optimized as possible, following the reference design. I ordered the PCB at OSH Park, they came finished with a gold coating (ENIG). Assembled it with SMD solder paste and reflow. Performance seems to be stellar: no noise I can discern, with a CMOY powered from USB. I would need a high quality DAC to do more investigation, but I don't have any at hand right now. With ferrites or inductors, some of the remaining ripple could be reduced.
Ah. The demo boards shows up for 130 euro here DC2235A Linear Technology/Analog Devices | Development Boards, Kits, Programmers | DigiKey
I don't think the Chinese would sell these. The IC is probably too expensive for them, and you'd feel the difference with bottom-tier capacitors. I'm thinking of putting a few of mine up for sale. I have no idea how much to charge. Parts are expensive, especially in small quantities. Maybe I can sell the first for 25 euro a piece. Shipping to the USA is 4,56 euro.
Send me a message if you're interested (if that doesn't breach forum rules)
I don't think the Chinese would sell these. The IC is probably too expensive for them, and you'd feel the difference with bottom-tier capacitors. I'm thinking of putting a few of mine up for sale. I have no idea how much to charge. Parts are expensive, especially in small quantities. Maybe I can sell the first for 25 euro a piece. Shipping to the USA is 4,56 euro.
Send me a message if you're interested (if that doesn't breach forum rules)
Hi Teus,
I am interested in 2 boards.
I am in Italy.
Please quote the cost and how to pay.
Best regards.
Pietro
I am interested in 2 boards.
I am in Italy.
Please quote the cost and how to pay.
Best regards.
Pietro
New dog, old trick -- we used the Sipex SP232ACP -- RS232 line driver charge pump for generating +/- voltages decades ago -- but the LTC design is much quieter and more robust. Nice work!
https://www.exar.com/ds/sp232a_100_051308.pdf
https://www.exar.com/ds/sp232a_100_051308.pdf
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