Ash and all, Jerry Gaffke provided a valuable link: https://ludens.cl/Electron/audioamps/AudioAmps.html the second circuit (without crossover distortion compensation) seems to me to be more than adequ

Mike, I think you are right about that...I looked at the schematics and they support your ideas. I shot from the hip on that one. Rod KM6SN

Hi Lenny, There is another possibility- the +5 power line may be shorted to ground. With the power supply to the rig disconnected, you could try measuring the resistance from the center leg of the 780

I, for one, am very tired of off-topic general discussions about radios and antennas on the bitx20/ubitx group. Please let this thread die, or move it to another discussion group. A good guideline: if

#bitx20help

Walter, LTSpice comes with a comprehensive library of parts. Rod KM6SN

Linear Technologies LTspice is a free, powerful and versatile program. You can easily draw excellent schematics and print them or email them. Many of the schematics you have seen on this reflector hav

Hi Allison, Thanks for your ideas on this subject. Curious about your 4x4: 1. is the circuit topology 2 instances of 2x4 in push-pull, with a combiner? 2. do you bias each IRF510 separately? 3. any at

Tilman and all, Per, I think, Raj's suggestion, I change R63 to 11 ohms, and that seems to work well. 0805 parts fit on 1206 pads, and power dissipation is not an issue with an 0805 11ohm. YMMV Rod KM

#ubitx

Hi Dean, Just yesterday I changed R250 (the input of the low-pass network for the sidetone) from 1k to 220k, and my sidetone is comfortably low at full volume. 100k probably would have been better, as

#ubitx

Hi All, I suggest staying away from the Kernighan&Ritchie C book. I used it in the late 70s to learn C. I have long mused that K&R C is the worst example of technical documentation that I have seen. T

Jack and All, attached 2 pix of remote display. Note that I used DuPont wires that came as a flat-group, not the helter-skelter loose wires. Probably helps reduce noise to some degree. The ubitx is in

Jack, I used 6 inch Dupont wires with no shield-no apparent problems. Rod KM6SN

Henning and all, I am not sure the individual-chokes-method is a mistake: my understanding is that technique results in a substantial improvement in IMD. Remember, every design decision is a tradeoff.

The LINUX program JAAA is an excellent audio spectrum analyzer..all the features you could want. Rod KM6SN

Hi All, Be aware on the projects where I have used an I2C LCD I get a burst of noise in the receiver at display-update-time. While the display is not being updated, the noise is low enough that 0.1 uV

Jim and All, There is no need for level shifters on the I2C lines. An I2C 1602 LCD runs just fine with 3.3v levels on the I2C lines, because the 3.3v is well above the 2.5V logic 1 threshold. I have u

Jack, I support the NO Push button notion. I have already wired one up on my ubitx unused digital input, but have not gotten around to implementing it. Probably the cleaner, more reliable approach. Ro

Nick, If you please, it is not ignorance, simply being unaware. THD is Total Harmonic Distortion, a measure of how distorted the audio will sound. 10% THD will drive one nuts, making it hard to copy s

#ubitx

Hi Nick, Looks like a nice amplifier, and flexible output options. I like the AGC feature. Wowsa! Look at the THD numbers! Might be better at lower levels of output. Some experimentation would give in

#ubitx

Jerry, and all About a year ago I went through the overhead of learning both Kicad and Eagle to see which I would want to use. My vote is firmly in the Eagle camp. I found Kicad to be laborious and aw