Build a discrete all-transistor RIAA phono preamplifier.
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- Опубликовано: 19 сен 2024
- The discrete RIAA-equalized preamplifier project is based on the phono MM input stage of a vintage Nakamichi 630 and 410 Control Preamplifiers. Both models have nearly identical phonograph preamp circuits.
The phono input stage consists of a three-transistor common-emitter amplifier coupled to a complementary class A push-pull output stage. The design cleverly minimizes the overall noise by a factor of one-third. Such a reduction not only improves the clarity of the signal but also boosts the S/N ratio significantly, which substantially improves the preamp to achieve clearer, more precise, and higher fidelity in audio reproduction.
Listening to heavy music (hard rock genre) albums by "Creed" Greatest Hits and The Story So Far: The Best of "Def Leppard," these are difficult to listen to on an average sound system. However, I was surprised this preamp can make a significant difference to hear more clarity and depth of the music it reproduced. It is not fatiguing to the ears but something unexpectedly calming.
Furthermore, the audio quality is warmer and more real due to the analog nature of vinyl records, which preserve the original sound without compression, which digital formats do and often struggle to match. It is, in my opinion, a nostalgic listening experience that I had a long time ago.
Parabens , Execelente
Thank you. FYI, I have finished another PCB prototype of a discrete RIAA-equalized phono preamp using 16 transistors for a 2-channel system. I will eventually publish it here soon on this channel, after two more RIAA-equalized opamp phono preamps are posted to complete the series!
Why do some people still believe that a transistor grab is better than an OpAmp in which all transistors are automatically matched and thermally equalized?
C10 is the wrong way round in the schematic.
Good catch! Sorry for the error in the schematic, but the part placement guide is correct if you have requested the plans. Thanks.
Awesome project. Well done.
Is the copper strip underneath the circuit board to reduce interference /noise?
Correct. The project's enclosure is made of plastic, so the copper tape is connected to the preamp's ground by soldering a piece of hookup wire to it, which helps in reducing noise issues.
Do you offer circuit boards and plans so other DIYers can build this phono preamp?
Sorry I don't sell circuit boards; you have to make it yourself. If you need the PCB layout, send an email request to support@buildaudioamps.com. Thanks!