Just opened a new GB thread: Omicron 3rd GB. I took the liberty of signing up @Brakspear75 and @drof - feel free to correct the sign-up list if I made a mistake. The GB will close on Sunday, June 2, 2024. Be sure to sign up before then.
That's not a difficult load. Omicron's through-hole version in its stock version runs at 50mA quiescent current. It will stay in Class A while delivering 200mW peak into 25 ohm. The SMT version runs at 25 mA. It will leave Class A at about 60mW peak into 25 ohm, but even then Omicron will stay more linear than the vast majority of headamps.
Here are link to the updated Mouser projects for Omicron TH and SMT versions:
Omicron TH - Mouser shared project
Omicron SMT - Mouser shared project
The projects have been updated to the current availability of the parts. Note that all relays are currently available from Mouser.
I added these links to the first post of this thread as well.
Omicron TH - Mouser shared project
Omicron SMT - Mouser shared project
The projects have been updated to the current availability of the parts. Note that all relays are currently available from Mouser.
I added these links to the first post of this thread as well.
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Shared Mouser project for the PSU board
Does not include the power transformer (see post #174). Also, the project includes the heatsinks and the (optional) thermal pads, but not the hardware (2x M3x8 screws, 2x M3 nuts and washers) to attach the TO-220 regulators to the heatsinks.
Does not include the power transformer (see post #174). Also, the project includes the heatsinks and the (optional) thermal pads, but not the hardware (2x M3x8 screws, 2x M3 nuts and washers) to attach the TO-220 regulators to the heatsinks.
The Omicron power supply PCB has its own LCR filter on the primary side of the transformer, so filtered IEC inlet is not necessary.
The maximum power drawn by the Omicron (under somewhat unrealistic condition of delivering 30Vpp into a 32 ohm load) is about 10W. With 110VAC primary, a 0.5A or even 0.25A slow-blow fuse should be ok. It is also possible to omit a separate fuse and use fusible resistors in that primary-side filter, or to use short-circuit-protected transformer (e.g. BLOCK FLD).
The maximum power drawn by the Omicron (under somewhat unrealistic condition of delivering 30Vpp into a 32 ohm load) is about 10W. With 110VAC primary, a 0.5A or even 0.25A slow-blow fuse should be ok. It is also possible to omit a separate fuse and use fusible resistors in that primary-side filter, or to use short-circuit-protected transformer (e.g. BLOCK FLD).