2022年4月4日 · On the 12SQ7, in many radios, there is often a mica capacitor hanging on the plate of the triode section- which can and does sometimes become problematic, causing the …

2013年10月6日 · or, the drugstore was out of 12SQ7's at the time, the owner looked in the sub book on the counter beside the tube tester, and purchased a 12SR7 so he could listen to the …

2011年8月11日 · Hi guys, I am having some troubles with pin reading on my 12SQ7 tube. I checked nostalgia air for the diagram, and found the diagram there was quite differen… Get a …

2023年11月23日 · Re: Testing 12sq7 Post by Chris108 » Nov Sun 26, 2023 1:12 pm The problem with 12SQ7s, 6SQ7s, and related types like the 6Q7/12Q7 is the design of the detector diode …

2011年12月24日 · 12SQ7's are cheap and available, and other than a burned out filament, or microphonics in the triode ...

2025年2月14日 · I had 53 volts on pin6 of the 12sq7. It should be 30 volts. The resistor R9 was 470k. I increased this to a 3.3 Meg. That brought the plate voltage to 30 volts. My problem is …

2024年12月18日 · While looking for my 12SR7, I found a 12SQ7 and tried it. Solved that issue. I then noticed the problem some triodes dual diodes like the 12SQ7 can have which is audio …

2025年1月9日 · Tube lineup: 12SA7, 12K7, 12SQ7, 35L6, 12SQ7, 35L6, 35Z6. Late 30s, maybe? Steel needle phonograph. BTW, I can't seem to get to the Mallory-Yaxley web site. Every time …

2025年1月12日 · That is a dual pole single throw switch, the AGC line should be grounded and plate voltage should be applied to the BFO tube when the switch is in the code position. So if …

2025年2月16日 · Double check the values of the two replaced resistors (3.3meg, 470K), the one's Sams calls number 28 and 24. Since you are at least getting a station, but have no hum when …