Printed Circuit Boards for RJM Audio Projects
Download design manuals and schematic files. Order boards and parts.
Phono Stages : Line and Headphone : Power Supply
This is the place for ordering kits, boards, and parts for various projects featured on my website. Send me an email (Richard Murdey, rjm003.geo@yahoo.com) listing what you want, and I'll send you a PayPal invoice for the total. Kits include the boards, instructions, and all the parts needed to complete them. Generally, you need to supply a transformer, diodes, the chassis, connectors, wiring, and a volume control. Boards ship as bare boards. I only accept PayPal payments. Prices are in US dollars and listed below. Shipping is free.
The parts lists for each project are available in the design manual (Excel .xlsx) which you can download below. They normally have a pre-formatted bill of materials you can import directly into your shopping cart at Mouser. The design manuals also contain schematics, worksheets, and other useful information.
I've written a construction guide for the phono stage projects, with details of the power supply and connections.
Problems? Questions? Email (address above) or check out the Emerald Help Desk or search the related forums at diyaudio.com. As well as being a valuable general resource, there are many threads there concerning the projects featured below.
Sept 2026: Gerber files have been added to the file downloads for each project.
Phono Stages
The Stereo VSPS
For moving magnet or high output moving coil cartridges. The stereo VSPS is a dual-layer 5 cm x 8 cm board, and takes a dual op-amp of your choice. Simple and convenient. Only one board is needed for stereo. LM7x12 regulation. Board only $18 / Kit $60.
Design Manual / Files (RJM Audio VSPS Project Page)
Emerald Dual-Mono MM/MC Phono Stage with S-Reg
A two-stage op amp circuit, the Emerald has switchable voltage gain and loading options and features an active-passive hybrid RIAA with exceptionally accurate response. Single channel, dual-layer 10 cm x 8 cm board. The S-Reg voltage regulator circuit is built into the boards; no additional regulation or filtering required. Boards only (set of 2) $30 / Kit $225.
Design Manual / Files (RJM Audio Emerald Project Page)
The SwitchBoard
This small 5x8 cm board provides additional cartridge loading options for a phono stage with fixed input resistance like the Emerald or VSPS. Board only $18 / Kit $45.
Line and Headphone
Sapphire Headphone Amplifier
Headphone amplifier or line stage. The Sapphire is a fully discrete, all-solid-state current-feedback amplifier circuit with a built-in Z-Reg voltage regulator circuit. Provides low distortion and excellent drive characteristics. There is an option for switchable gain settings, and the output buffer can be configured to operate in open- or closed-loop mode. Boards only (set of 2) $30 / Kit $225.
Design Manual / Files (RJM Audio Sapphire Project Page)
Power Supply
Dual-Bridge Rectifier Board (DBRB)
A 5x8 cm board which conveniently holds 8 rectifier diodes, with output for split rails or dual supply. Board only $18 / With 8x BYV27-100 diodes $35.
rjm003.geo at yahoo.com