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American UA748 op amps are getting hard to find. Have a batch of UA748's from PRC but I do not want to use them because they show different test results. Anyone ever use a metal can type IC in pcb mounted DIP-8 socket?

get a set of Tetrode Boards, makes it easier and it's a fine circuit. I see that a gentleman in South America somewhere has upgraded the g3sek board and sells them online. His site includes the pcb prints and the material is free.

color of the cores inside of cans, this goes deep.

Today is the day I try to get it working on bench before I try to use it. Randomly reading posts about SSR's I saw several posts where people had them fail in batches/repeatedly. I'm taking that to mean they are fragile regarding current/polarity etc. Using only low current PSU's (<100mA to...

I have the datasheet but I'm not seeing anything that specific. It's an Opto22 series, DC60P, 3-24v control signal max. Preparing a mock-up w/ 2 DC supplies so I can get a feel for it on the bench before I try to use it. I get that it's a current device.

9/15/25 Many Improvements last few months on 2x 4cx300a amp. PTP wiring cleaned-up; RF pass-thru perfect, Xmit below 2. Resistive input dropped to 700 Ohms; Moddrd LPF relay board for switched Input works well all 4 bands 10,11,20,40. Still on DL, antennas soon. Blower runs quit, Slow...

Oh yeah, but it's so big and nowhere near the SO-239 where I'd expect a choke. Yet it makes sense. l was hoping for some magic find. Desperation when I'm looking for ideas from ebay pics, the rogues gallery. Thanks Nomad.

Thanks Brandon, It sounds good to the extent there may be a method to tame an unruly roller at HF.

Looks well designed but I do not recognize the big copper colored part attached between the roller and ground. What sparked my curiosity is the Roller itself. My project makes far less than the 8877 but my roller gets very unruly at times. Roller looks the same but arcs to ground at various...

I got it all inside with room to spare. Won’t miss that rotary band switch at all. Relay band switching sounds like a luxury to me. It will be a long time before I try it as I disassembled soft-start and other sections in a general housekeeping effort. Got a new set of IC’s just in case that...

Rebuilding RF deck to install relay controlled RF input board for 10, 11, 20 and 40. I’m replacing everything beneath sockets. The 10 pos rotary switch (mess) helped narrow the inductance needed for two 4cx300a tubes. I’m sure there were easier ways to do it but the formulas were over my head...

Lost my SMT virginity today. She was a 6k8 resistor and small, hard to see even. Part came with the LPF kit I will try using for input board. Also solder station upgrade delivered; Ceramic tweezer set & watched some YT vid on SMT work. Have 4 SMT diodes for the relay coils but they larger...

I scrapped the messy rotary switch inside blower box in favor of a relay switched, parallel inductance to RF ground for driving the grid-driven tetrodes. I re-purposed a four (4) band LPF board to reduce lead length and add a nice ground plane for the connections & components. The LPF board is...

K7UGA (SK) was Barry Goldwater.

I found this app helpful in drafting a diagram for a tuned input and best of all it's free w/ a DigiKey account. It has Symbols for cut & paste. Wish I knew about this a few years ago.

OK I'm feeling good at that. Last night I removed tube sockets from blower box to rewire before I start troubleshooting my bang event. Hoping it's not the Tetrode Boards. This time I'm going for minimalist: As few wires as possible to reduce inductance & capacitance.

Thank you for Reply. "...all manner of sloppy design...''' sounds workable without but I already ordered a 1/2 dozen so I'll use them on the rebuild where I can.

Since my big bang event a few months ago (homebrew 4cx300a amp), I’m planning on taking advantage of the required disassembly / troubleshooting to replace the RF input (parallel inductance a’la Pride) rotary switch circuit with a 4 band relay board fashioned from an LPF kit. It should fit...

While I was doing my audio thing these past few months, I found a good YT repair site: Mend-it-Mark, from the UK. The vids allow viewers to watch his repair of assorted devices. He recently received a Copyright Strike for his repair video of a phono preamp that sells for £25k. What's more is...