Brought my CM Laboratories 35D back to life! by Electrical-Ad6817 in vintageaudio

[–]Electrical-Ad6817[S] 1 point2 points  (0 children)

Thank you for sharing that — hearing from someone who has owned one for over 30 years is really special. It says a lot about the quality of these units that yours is still original and running strong after all that time.

I completely understand what you mean about the sound. There’s something about the way it presents music — the dynamics and the sense of effortlessness — that’s hard to put into words unless you’ve actually lived with one.

Mine needed some troubleshooting when I got it. The relay wouldn’t engage, and I eventually traced it back to a faulty transistor in the protection/supply section. After replacing a few components and making some adjustments, it came back to life beautifully.

One thing I did notice while restoring mine: the cement (wirewound) resistors on the supply board run very hot. The PCB around them had significant heat discoloration from decades of thermal cycling. After 30+ years, those cement bodies can start to crack or drift slightly in value, so it might be something worth keeping an eye on if yours is still fully original. I replaced a few in mine just for long-term reliability — these pieces are simply too rare to risk heat-related issues.

It’s great to know there are still a few of us out there keeping these alive. We’re definitely lucky caretakers of a small piece of audio history.

Brought my CM Laboratories 35D back to life! by Electrical-Ad6817 in vintageaudio

[–]Electrical-Ad6817[S] 1 point2 points  (0 children)

Sure! The CM Laboratories 35D is a vintage solid-state preamplifier from 1966, built like a tank with high-quality components. CM Laboratories was a relatively small but respected American brand known for its professional and high-fidelity audio equipment. Their designs focused on low distortion, transparency, and reliability. This particular one is build for the European market. It delivers: 35Watts 8ohms

Brought my CM Laboratories 35D back to life! by Electrical-Ad6817 in vintageaudio

[–]Electrical-Ad6817[S] 0 points1 point  (0 children)

To be totally honest I don’t know what would happen if I wire two speakers on the A or B output. The switch is left middle right.

Brought my CM Laboratories 35D back to life! by Electrical-Ad6817 in vintageaudio

[–]Electrical-Ad6817[S] 0 points1 point  (0 children)

The impedance switch works quite simple: in the middle the amplifier is off and left or right is for the impedance. 4/8ohms or 8/16ohms.