Skip to main content

The Muffsy Store

Muffsy Phono Preamp PP-4 - Kit

The Muffsy Phono Preamp PP-4 kit is available from $99 + shipping. Visit my Tindie shop to buy your own Muffsy Phono Preamp Kit!

Choose between NE5532AP and Burr-Brown OPA2134PA + LM4562 operational amplifiers for your Muffsy Phono Preamp PP-4.

Buy the Muffsy Phono Preamp Kit

The full kit includes:

  • 1x Muffsy PP-4 Printed Circuit Board
  • 2x NE5532AP or OPA2134PA/LM4562 Operational Amplifiers
  • 2x Machined DIL Sockets
  • 8x Wima MKS2 Polyester Film, Box Type Capacitors
  • 2x 22 uF Electrolytic Capacitors
  • 4x 100 nF Multilayer Monolithic Ceramic Capacitors
  • 30x Resistors, 0.25W Metal Film, 1% Tolerance
  • 2x 4-Way DIP Switches
  • 2x 2-Way DIP Switches
  • 2x Terminal Blocks, 3 Connections
  • 30 cm Two-Lead Shielded Audio Cable


Muffsy Phono Preamp PP-4 Kit Contents

Please note that an enclosure is not included in the kit. See this page for options.

 Muffsy MC Head Amp MH-1 - Kit

The Muffsy MC Head Amp kit is available from $99 + shipping. Visit my Tindie Shop to buy it.

The Muffsy MC Head Amp lets you use a low output MC cartridge (LOMC) with the MM phono stage of your choice.

The full kit includes:

  • 1x PCB, White with gold plated solder pads
  • 2x Linear Technology LT1115 Operational amplifiers
  • 2x Analog Devices OP177 Operational amplifiers
  • 4x 8-pin machined DIL sockets
  • 18x Multicomp MF25 resistors, 0.25W metal film, 1% tolerance, ±50ppm/°C
  • 1x 4-way DIP-switch

  • 4x Wima MKS2 Polyester Film, box type capacitors
  • 2x Wima FKP2 Polystyrene Film, box type capacitors
  • 2x 100 uF Electrolytic capacitors
  • 8x 100 nF Multilayer monolithic ceramic capacitors
  • 1x Terminal block, 3 connections (Power connector)
  • 30 cm Two-lead shielded audio cable

 Muffsy Hifi Dual Power Supply - Kit

The Muffsy Hifi Dual Power Supply Kit is available at $45 + shipping.

The Muffsy Hifi Dual Power Supply uses a 15-18 VAC wall adapter, so you don't have to handle mains power.

I Sell on Tindie

Please note that the AC wall adapter is not included in the kit. See this page for options.

This +/-15V regulated dual power supply has only 0.1 mV ripple. The PSU provides up to 200 mA of power, with heat sinks mounted. It will power four of the Muffsy PP-4 without the heat sinks.

It is designed for hifi equipment, such as the Muffsy Phono Preamp or other high quality preamps.

There is also a second regulated DC power supply on-board, capable of delivering 0.5A of 15V DC. It even has space for a current limiting LED resistor.

 Muffsy Back Panel

The Muffsy Back Panel is a perfect fit for a B0905 cabinet, and is delivered with the all necessary components at $29 + shipping.


  • The back panel
  • 4 gold plated female RCA chassis connectors (2x red + 2x black)
  • Power button
  • 2.1mm power jack
  • M3 ground screw with thumb nut and washer
  • 4 mounting screws

The Muffsy Phono Preamp is made to fit perfectly into a B0905 cabinetwithout any need for drilling or other modificatons. Here's the back panel to complete the build.

Muffsy Relay Input Selector

The Muffsy Relay Input Selector is a simple, reliable, high quality, DIY stereo input selector that's controlled by an ESP-32 and is slightly larger than a Post-IT note.

This kit is meant to be paired with a preamplifier circuit, such as the Muffsy BSTRD Class-A Tube Preamp, Pass Labs B1 and many others.

Muffsy Relay Input Selector - Kit

  • PCB Size: 75.6 x 81.3 mm / 2.82 x 3.20 in


  • Four stereo inputs and one mute circuit, switched with Panasonic TQ-2 relays
  • One stereo output
    Power/GND for ESP32 and relays separate from signal power/GND
  • Programmable 5V output for Solid State Relay, can turn on and off mains power
  • Break-out for all ESP-32 pins
  • "Safe" ESP-32 GPIOs control the relays, leaving the most usable pins available
  • IO pins go high when activating a relay, can be used for indicator LEDs
  • Fully open source, no strings attached

Muffsy BSTRD - Class A Tube Preamp

This great Class A Tube Preamp is sold as two PCBS, the preamp itself and a power supply. Visit the project page for a wealth of information.


  • Input voltages: ~80V DC/0.1A, 6V DC/1.5A (Power supply info)
  • Valves: 6J5 or equivalent
  • Gain: 2.2X / 6.85 dB
  • Frequency range +0/-3 dB: 10 Hz to 30 kHz
  • THD at 1V out: 0.35%
  • SNR at 1V out: 93.2 dB (A-weighted), 83.5 dB (non A-weighted)
  • Circuit clips at: 17V rms output

Due to the fact that this preamp is sold as PCBs only, there is no support offered on this product. Everything needed to build the preamp is available on the project page, including shopping cart for the components.