View Full Version : hy gain 623a

06-19-2017, 06:17 PM
hello from central ny just picked this radio up with no mic.need mic wiring info for a astatic 636l that i would like to wire to it. any help would be great. found this but not sure if its right audio -ring blue & sheild to the sleeve and red to the tip

06-22-2017, 10:18 AM
according my mike master wire notes- tip=tx, ring=audio and collar= shield/ground. hope this helps. 73s

06-23-2017, 04:19 AM
What radio are you wiring it to?

06-23-2017, 04:35 AM
The Hy-Gain model 623, also known as the "Utopia", Hy-Gain's top of the line 23 channel base station. This was a hybrid designed radio, which featured a vacuum tube transmit output final, with the rest of the circuitry being solid state. The 623 was equipped with the usual standard features you would find on a SSB radio, like Volume, Squelch, R.F. Gain, Mic Gain, Fine Tuning, and a large S/RF meter with SWR function. These were all laid out on a no-nonsense utilitarian, and professional looking front panel. There weren't many "gimmick features", what was there was designed strictly for performance. This radio also employed an early design discrete chip 23 channel phase locked loop (PLL) frequency synthesizer, which was cutting edge technology in 1974, when most other radios were still employing crystal synthesis. The radio was also unique in that all of the major electronic sections were situated on plug-in boards. The 623 had a fantastic receiver which included superior adjacent channel rejection, which was a must if you lived in an area (like mine) which had a lot of CB'ers on many different channels. The huge, linear, and very sensitive S-meter was great for zeroing in exact beam headings, which was especially helpful for DF'ing purposes, comparing changes in antennas, or other people's power levels. On most other CB radios, the RF output meter was a simple relative indicator, with no real accuracy. But on the 623, the power scale is calibrated in watts, and it tracks accurately with an external wattmeter. Transmit audio can only be described as "studio quality". While not especially loud or punchy, it had a natural flat tone quality which gave the user that "in the room with you" sound. This radio was also modification friendly. One of the most popular mods for this radio was opening up the clarifier for increased range. Once modified, this radio would slide up nearly 2 channels, and down as many as 20! Needless to say, fine tuning an SSB signal was really touchy at that point, so more practical people limited clarifier travel to less than -5 channels (Good thing Hy-Gain had the forethought to include a large 10 turn vernier dial). SSB power output could also be increased by moving a wire jumper to increase the tube's plate voltage. SSB power output would increase to around 25 watts after the mod. There were also published mods, which called for replacing the final tube with a "stronger" one, for even further increases in SSB power out. However, the strain of creating that extra power often caused power supply reliability issues. For that reason, I never recommended those mods. Also the radio suffered from cold solder joints and bad connections on the Molex type connectors which mated with the plug in circuit boards. This often led to intermittent operation. An easy problem to fix, for those of us with technical know-how, but way too frequent an issue for those who didn't.

06-23-2017, 04:57 AM
​Here is the Astatic wiring guide. I hope you find this useful