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ESP P05-Mini+P06+P99 - Phono Preamp
Given I still have a good quality direct drive turntable with a high quality cartridge and hundreds of vinyl records, the ESP P06 Hi-Fi Phono Preamp (RIAA Equalization) seemed like a great project. I purchased the P06 board (along with the P99 Subsonic Filter for Phono preamps and P05-mini power supply) from ESP back in February of 2018, then spring came and I shelved the project until now (Winter 2018/19).
I found a case on eBay for $38 US, and started my layout. Given the size of the case and height of the transformer and boards, I discovered I could mount all components on a piece of Plexiglas (acrylic sheet), eliminating a lot of drilling into the case. This type of construction allows for easy mounting, and a rework if needed (the acrylic sheet is less than ~$4.00 US).
The schematic below is a modified combination of the Phono Preamp (ESP P06) and the Subsonic Filter (ESP P99) from Elliott Sound Products. I like to experiment, so for the first test, the coupling capacitor C5 (P06) has been eliminated (C104 will block any DC from the phono preamp). To simplify the design, I’m testing if only one 18dB/octave filter will suffice to eliminate turntable rumble. The input resistor R103 (P99) has also been eliminated given it would be in parallel with R9 (P06). A cartridge loading capacitor as also been added to the input, the manufacture states a 47K ohm load with 100 - 200pF capacitance (just giving it a try for test 1).