I am coming to the end of a long build that ended up being 90% in the presentation, mainly because I hamstrung myself by aiming for a small footprint.
Anyway, now I am looking for something where the tube electronics take the forefront, so I have dusted a pair of UNSET Power Head (UPH) boards I bought last year.
Below is a mapping of the parts numbers on the UPH board to the original Unset BOM in the first post of that thread.
Next I looked at sourcing the PFET, FQPF9P25 or FQAF9P25, which has become obsolete, as mentioned by George in 2023.
Is this one a suitable replacement? IRFI9634G
CRSS is 40pF instead of 27pF, and that is cited as being a key parameter on the UNSET thread, but looking at other posts on other threads, the suggestions there are normally worse than this. The gate-source threshold voltage is 4V instead of 5V, and the max current rating is 4.1A instead of 6A, but otherwise looks to be similar to FQPF9P25.
Anyway, now I am looking for something where the tube electronics take the forefront, so I have dusted a pair of UNSET Power Head (UPH) boards I bought last year.
Below is a mapping of the parts numbers on the UPH board to the original Unset BOM in the first post of that thread.
Next I looked at sourcing the PFET, FQPF9P25 or FQAF9P25, which has become obsolete, as mentioned by George in 2023.
Is this one a suitable replacement? IRFI9634G
CRSS is 40pF instead of 27pF, and that is cited as being a key parameter on the UNSET thread, but looking at other posts on other threads, the suggestions there are normally worse than this. The gate-source threshold voltage is 4V instead of 5V, and the max current rating is 4.1A instead of 6A, but otherwise looks to be similar to FQPF9P25.
Making some headway on stuffing the UPH boards. I was going to ask about the fuses, but I saw in the build notes these are 2A Pico fuses.
After a lot of cogitation and prevarication I ended up buying the ones pictured from TME.EU: DMP45H4D9HJ3. They seemed to fit the bill, got the thumbs up on the SCG thread, where MOSFETs get discussed, but I ended buying the wrong packaging. I continue to learn; last project I had surface mounted by accident. It does not help that the picture is often generic, so the small print must be checked, and the part number compared with the packaging variants.
Is there a clip that will clamp them to the heat sink? Or should I bite the sour apple?
After a lot of cogitation and prevarication I ended up buying the ones pictured from TME.EU: DMP45H4D9HJ3. They seemed to fit the bill, got the thumbs up on the SCG thread, where MOSFETs get discussed, but I ended buying the wrong packaging. I continue to learn; last project I had surface mounted by accident. It does not help that the picture is often generic, so the small print must be checked, and the part number compared with the packaging variants.
Is there a clip that will clamp them to the heat sink? Or should I bite the sour apple?