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Completed July 2021
This preamp was built for one of my kids, and is a design from RJM Audio called the "Very Simple Phono Stage" or VSPS for short. Its basically a one PCB design based around a single dual op amp, requiring only an unregulated power supply (regulators are on the board), and input/output connectors.
Complete details are available on the RJM website, here:
http://phonoclone.com/diy-pho5.html
The website has very complete documentation, including the schematic, performance data, bill of materials, and calculators if you want to experiment with various level of gain.
There is also a great deal of information on this preamp on DIYAudio, at the "VSPS Helpdesk" thread, here:
https://www.diyaudio.com/forums/analogue-source/57398-phonoclone-vsps-pcb-help-desk-440.html
Note this thread is over 4,000 posts, indicating the wide interest in this design!
This is the PCB layout from RJM Audio. I bought my PCB some time ago, and there's a newer version available on the website referenced above.
Rectified DC input at the left, with power supply filtering and voltage regulators next. The actual phono preamp takes up the remainder of the board, with the IC at the center surrounded by the phono equalization resistors and caps. The audio inputs and outputs are on the far right.
This shows the populated PCB before wiring it up. Resistors are mostly all Dale 1% metal film, equalization caps are Wima FKP film, and electrolytics are Panasonic FC. The output couplers are a pair of Jantzen Cross-Cap film caps I had on hand.
Component assembly in the chassis. The transformer is a dual 12V Antek toroid. The IEC connector and fuse-holder are visible on the back panel, and the diode bridge to the left of the transformer. The power supply filter caps are on the PCB along with the +/- 12 volt regulators. Since the current draw is so low, no heatsinks are needed.
The RCA jacks are Vampire PCB2F/S gold/teflon connectors.
Top view of the assembled preamp. Power switch and LED are on the front panel to the left.
Rear of the preamp. IEC at the bottom left, fuse-holder above it, ground lug top center, and the input/output RCA's on the right.
Front of the completed preamp.
As the name suggests, very simple!
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