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have such screen decoupling on an HF amplifier but it was the easiest way to mount the socket, since I believe they are originally made in similar way.

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I’ve been having it a bit slow lately. Haven’t really had much motivation to work on any projects which is something that usually happens to me during the dark winter month January and February. Even though I’ve still done some smaller stuff like some PCB design and programming its not my normal tempo. I have also been working quite a bit extra to get more money for the projects coming up. I have even received a couple of questions lately if I’m OK since there hasn’t been any updates lately. However now I’m feeling a lot more motivated again and this morning I woke up feeling like going to work and work on the QBL amplifier.

I did start with the RF-deck. I had said I wanted to fully complete the power supply before starting with the RF-deck but I am missing some parts and can’t really do much on it right now, so I decided to get going with the RF-deck. I started drilling all the sheets I had cut earlier and also made a shelf for the “floor separation” in the amplifier. I also tried to lay out some different combinations of how to position C1, C2 and the L + tube in the amplifier and finally decided that I will rebuild the roller inductor a bit and put them the normal way as in most amps. That way I can have some knob going out the front plate as well if wanting to tune them manually.

We will be working Russian DX next weekend as M/S and plans are also to work WPX SSB in the end of March with LB3HC coming back to us as guest op, also as M/S.

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