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Muffsy Phono Kits
Hifi Preamps for your Record Player

Audio Wiring for the Muffsy Phono Preamp

With the phono stage and the back panel built, you can now connect the audio wires.


The audio wires will connect the phono stage and the back panel, making these connections:

  • Audio input
  • Audio output

Here's the back panel, with the grounding (gray cable) already done:

Phono stage back panel with grounding

Audio in/out - Back Panel

Next in line is to cable the input and output RCA connectors. You will need two audio cables, one for the input and one for the output. The lengths of the cables are decided by the distance between the phono stage and the back panel.


Here's a close-up of the back panel with the output cabling already soldered:

Close-up of audio output cable and ground screw

The cable used here is a two-lead audio cable with shield. You should always use a shielded cable for the audio input, as the signal from your turntable is very low. Such a cable is of course included with the Muffsy Phono Preamp Kit.


For audio cables, you will always see these colors:

  • Right Channel: Red
  • Left Channel: White or Black

I decided to use the top RCA connector for the RIGHT CHANNEL, so the RED cable goes in the center of the top connector. 

The WHITE cable, which is the LEFT CHANNEL goes in the center of the bottom RCA connector.

The shield of the cable goes to either one of the "pins" of the RCA connectors, as they are all connected to each other. 

Use another audio cable for the audio input and connect it in the same way, and connect the ground screw to both input ground pins. 

Your back panel audio wiring is now done.

Both input and output audio connected to the back panel

Audio in/out - Phono Stage

The two audio cables connected to the back panel now need to be hooked up to the phono stage terminal screws like this:

Audio wiring - Phono stage

It is advised to keep the input side of the phono stage board closest to the back panel. Keeping the input cable as short as possible will help avoid interference, and the cable capacitance will be kept to a minimum.


Should you decide to use unshielded cables, make sure to twist or braid them to avoid any unnecessary noise entering into the circuit.


With this step done, you have finalized the audio wiring, and you are ready to go on to powering the Muffsy Phono Preamp..

Muffsy Phono Preamp Specifications:

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

Muffsy MC Head Amp Specifications:

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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