A productive Saturday

Today I got a lot of stuff done at work. I have built a sound mixer box using two HA-400 headphone amplifiers. Pretty much works as a regular SO2R box but it’s made for two operators instead with two headphone outputs and possibility for each operator to select which sound levels they want from each radio and also if they want to listen to both radios or just one radio.

I also worked on the socket for the QBL amplifier that I got from SM3MXR, he also donated a tube in good condition. The mockup tube I am using was donated by SM3BDZ, it’s 90% OK so still good for legal limit power output. I first tried one idea which didn’t work so well, so I changed it and milled out another board which should work a lot better. The way I am doing it is inspired by SM2CEW and SM2EKM. It’s not really needed to have such screen decoupling on an HF amplifier but it was the easiest way to mount the socket, since I believe they are originally made in similar way.

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