Hello! For a couple of days now I have an urge to build myself a MM phono pre, based on (ripped off from) Pioneer's SA-9800 phono stage with some added bells and whistles like Signal Transfer's Devinyliser and Pass Labs' H2 for a sort of "tube mode" switch. Problem is, I'm sort of a dummy when it comes to electronics, I can solder, I've successfully serviced some turntables and cassette decks, but when it comes to schematics and PCB design i'm out (It will be my first time attempting something like this). I thought I'll just chuck a scan of the SM's PCB pattern into KiCAD and trace the whole board out, but do I need the whole board? Schematics show some rotary selector, but I don't need such things as I planned to make only one input and that's the MM only one (Phono 1). Could someone put me on the right path there and maybe help with determining what (if anything) could be removed from the board? Thanks in advance. P.S. Any pics of the board itself would be appreciated as well
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@6L6 i just read around about what vintage amp has the best phono stage (because everywhere I read about how the 70s/80s amps had the best phono stages because it was THE way to listen to music and engineers put more care in designing them) and people seemed quite enthusiastic about top of the line pioneers from the 80s, and I just downloaded the SM for the toppest of the line and went with it. I'm not too far in with work, so if you got some other suggestions on what amps' stage was better I'm all ears
Replicating a 70's-era preamplifier could be challenging. That was back in the days when dual transistors/FETs were a lot more prevalent. Choices these days are far more limited, and probably would require some design changes to get a properly working circuit.
It also would require at least some electronics knowledge. For instance, what component tolerances do you think would be necessary? If you're looking at the RIAA equalization network, you want very tight tolerances (and channel-channel matching). But other components aren't so critical. Are you knowledgeable enough to know which is which? Or are you just going to throw more money at it (in terms of more-costly Q's,R's and C's) and hope for the best? Do you know when it's OK to use a ceramic capacitor instead of a film cap, and why that's so? These minutia are what make the difference between a good-sounding amp and a mediocre (or worse) one.
I think a better approach would be to browse these forums until you find a design that suits your needs and electronic abilities. In many cases even the PCB has been designed so you wouldn't even need to do that. For starters, you can search for preamps that use the 5534 opamp. It's pretty good, in terms of noise and distortion. Another very good (but more expensive) alternative is the OPA1656, it has even better noise and distortion specifications. Of course, you also will find all-discrete designs if that floats your boat....both solid state and tube-based. Your biggest problem may be deciding which one to build!
I wish you luck with whatever route you decide to take, it will be an educational journey.
It also would require at least some electronics knowledge. For instance, what component tolerances do you think would be necessary? If you're looking at the RIAA equalization network, you want very tight tolerances (and channel-channel matching). But other components aren't so critical. Are you knowledgeable enough to know which is which? Or are you just going to throw more money at it (in terms of more-costly Q's,R's and C's) and hope for the best? Do you know when it's OK to use a ceramic capacitor instead of a film cap, and why that's so? These minutia are what make the difference between a good-sounding amp and a mediocre (or worse) one.
I think a better approach would be to browse these forums until you find a design that suits your needs and electronic abilities. In many cases even the PCB has been designed so you wouldn't even need to do that. For starters, you can search for preamps that use the 5534 opamp. It's pretty good, in terms of noise and distortion. Another very good (but more expensive) alternative is the OPA1656, it has even better noise and distortion specifications. Of course, you also will find all-discrete designs if that floats your boat....both solid state and tube-based. Your biggest problem may be deciding which one to build!
I wish you luck with whatever route you decide to take, it will be an educational journey.