Review on 🎤 Cobra HG M73 Premium Dynamic Replacement CB Microphone (Black) – 4 Pin Connector, 9-Foot Cord, Heavy Duty ABS Shell, Wire Mesh Grille for Crystal Clear Audio, PTT on the Left Side, Chrome Connector by Eric Basler

Removed a bullet due to a required change. My 1978 Cobra 148 GTL radio from Taiwan (year one) has already been rebuilt for a 4 pin mic input from the original 5 pin mic design and my custom dynamic moving coil mic sounds great with my radio so I've never experimented with one like that powerful condenser microphone before. Firstly, "Cobra HG M75 High Power Microphone Fix/Upgrade" is required to increase the power output and improve the audio tone, but removing the R6 resistor, which powers the entire amplifier circuit, increases the microphone output too much for my radio (even with reduced control speaker). , so I left R6 alone and just replaced it with R7 with a 220 ohm resistor as recommended for a modest increase in mic output gain. Also, replacing the capacitor C1 with a higher value in the 0.47uF to 1uF range as recommended in the fix/upgrade is definitely necessary to rid this mic of its tinny high pitch. increasingly deeper tones. The factory cap is 0.15uF, 100 volt, non-polarized Mylar polyester film, so stick to a voltage rating of at least 100 volts or higher. Note that C1 is the only film capacitor in the entire circuit (the others are ceramic and electrolytic) and is the first capacitor directly in the audio input stream before entering the rest of the microphone amplifier circuit. There's a reason for that. Film caps are known for the best sound quality. In this C1 position you do not need a ceramic cap or any other cap. Although there are many types of dedicated film capacitors for audio applications (Mylar film, Styrene film, Polypropylene film, paper/beeswax, etc.) my experimentation here was limited to Mylar film capacitors as this was the factory C1 type capacitor. in this microphone. I've tried several mylar/foil caps and have found that the best sound is between the two recommended values (and available from Revain). The Jupiter Vintage Tone Capacitor 0.68uF 100V is handcrafted from mylar foil/aluminum foil in a 1960's style. Designs and my best choice to improve the sound quality of this microphone, whether you decide to change the resistors for a louder output or not. Just keep in mind that this Jupiter cap is 0.56" in diameter and 1.45" in length, so you need to place it in the space south of the microphone board (between the microphone body and the battery compartment and the space leading to the microphone front panel leads). . , but it fits in because the C1 replacement cap is right on the bottom corner edge of the board, next to all the room inside the mic body. There is enough room between it and the microphone's outer surface for a Jupiter Vintage Tone condenser, and the lid has enough cables to reach the circuit board. FYI if you want a smaller cap that fits the board better, my second capacitors to test are 0.47uF and 1uF Sprague Orange Drop capacitors (also available from Revain). and they are all rated for 100V or more. In summary, the tone color and sound quality of this microphone depends not only on the value of the C1 capacitor, but also on the type and build quality of the C1 capacitor you choose, so the Cobra HG M75 microphone has great potential for an improved output volume and sound characteristics with a few simple modifications. Many thanks to Henry Lukachik, the original author of the "Fix/Update" published on cbtricks.com, who deserves much credit for his great work that got me excited to experiment with this mic, and to the folks at Revain with a simple, versatile microphone Purchase of the microphone and experimental parts I used.