DIY RIAA preamp with FETs

[vs music]

Hello ! In 2004, Elektor magazine published a phonopreamp scheme with field-effect transistors . I decided to make such a preamp for myself . I didn't have transistors 2sk389 and BF245 . But on the other hand, from one long - standing project ( 10-12 years ago), the 2sk170 and 2sk117 transistors remained unused . I applied them .... Changes were made to the original scheme.... Of course-I developed the printed circuit boards myself anew ... Changes were made to the bias circuit of the first transistor to expand the dynamic range of the first stage ... With transistors of the 170th and 117th series, a gain of about 48 db ( 1 kHz) was obtained . This is too much - so the nominal value of R10 was changed to 91k . Now the gain is about 40 dB ... The power supply circuit is used differently - Teddy Reg ( according to the publications of Teddy Pardo ) . As a result, we got a preamp with a good sound and a small noise level .

[vs music]

The original 2004 Elektor publication with a detailed description of the original scheme is available at this link - https://usermanual.wiki/Document/RIAAPreampwithFets.1630098376.pdf

[vs music]

I made several measurements - using RMAA and the Asus Xonar U7 interface . Here are the graphs of the frequency response and the distortion spectrum . The measurement was made at the signal level at the output of the preamp about 1 volt ( from peak to peak ) . The preamp sound is good .

[niclaspa]

Nice build!   

[vs music]

Nice build!   

Thank you for evaluating my work !

[niclaspa]

Thanks for sharing!  I really enjoy to see your creations and I love your super tidy schematics!