A very simple, but useful PCB. A power supply for the Muffsy Relay Input Selector (or anything else that can be powered by 5V DC/1A):
While there are lots of quality kits for preamplifiers, I have never really found a decent way of adding more inputs to a preamp. The existing ones are either of dubious quality, spec'ed like a spaceship, or both.
So I decided to make my own input selector. With relays. And an ESP-32 module! A year,...
Several people have been in touch lately with questions on how to modify the PCB into something it isn't right now. Popular requests are balanced inputs and/or balanced outputs, and DC servo on the outputs.
I just got a request from someone who wants to CNC a front panel for his Muffsy MC Head Amp, and he wanted to use the logo and the font that are on the printed circuit boards.
The font used on the PCB is the built-in vector font in Eagle, which is proprietary. The Eagle font is ...
Behold the new Muffsy Phono Preamp!
It'll be available on Tindie, very soon. Actually, it is available: https://www.tindie.com/products/skrodahl/muffsy-phono-preamp-kit/
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Total Harmonic Distortion: 0.00081%
Total Harmonic Distortion + Noise: 0.01935%
Signal to Noise Ratio: 82.3 dB (0 dBV output)
Intermodulation Distortion: 0.0195% (ITU-R)
Crosstalk:-102 dB
Dynamic Range: > 110 dB (THD+N < 1%)
RIAA Compliance: +/- 0.15 dB (20-20.000 Hz)
RIAA Equalization: Passive
Gain at 1 kHz: 32-43 dB, in four steps
Input Impedance: 17k-150k ohm, in fifteen steps
Input Capacitance: Optional
PCB Size: 84 x 56 mm
Total Harmonic Distortion: < 0.1%
Total Harmonic Distortion + Noise: < 0.1%
Signal to Noise Ratio: 71.8 dB (rel to 0.5 mV input)
Intermodulation Distortion: 0.001% (ITU-R)
Dynamic Range: > 110 dB (rel to 0 dBV)
Frequency Response: +0 / -0.1 dB (20-20.000 Hz)
Gain: 24.6 dB
Input Impedance: 50-300 ohm, in four steps
PCB Size: 84 x 59.4 mm
Measurements at 1 kHz, 0 dBV output, if not stated otherwise
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