As the title suggests, I’m building a unity gain preamp. Some of you will probably ask “why? Why not passive preamp?”. To that, I would simply answer: “for reasons” ;)
The real reason for this post is to ask for a peer review of the schematic, in order to spot any possible mistakes before moving on to the PCB design stage.
I’m open to any suggestions.
Hey guys!
I’m completely new to DIY audio and electronics in general. I’ve recently developed a passion for hi-fi, and my autism kind of kicked in—I’ve set myself the goal of building a custom preamp tailored exactly to my needs.
The system will feed my Luxman M-120A power amplifier, and the design aims to solve a few specific requirements:
After several weeks of research starting from absolutely zero electronics/audio knowledge, I’m excited to present my project diagram. Please don’t pay too much attention to the layout of the traces themselves yet—there’s still a lot of refinement to do before PCB design.
I also want to mention that I haven’t finished the power supply stage yet. I’m currently planning for dual ±12V rails for the audio stages, as well as a separate 12V rail for the input selection/control logic. All grounds will be referenced in a star-ground configuration, centered at the 0V point of the power stage.
My main question is: do you see any mistakes, whether small or major, that I should correct at this stage?
I also want to mention that the project will be modular (each stage on its own PCB), so I can later add features like output mute/delay, and potentially even a control logic section or a gain stage if needed.
All feedback is welcome and greatly appreciated!
Hello,
I’m a beginner in electronics. I’m trying to design a system where a logic circuit remotely controls relays via MOSFETs. I’m now relatively confused about ground returns.
The relay loop seems logical to me: its return path is interrupted by the MOSFET used as a switch, and is therefore from the source pin of the MOSFET. As for the return path of my logic circuit loop, I don’t really understand it. Should it be independent, or should it also go through the source of the MOSFET? Especially since I have a pull-down resistor between the gate and the source.
I should also mention, in case it matters for the cleanliness of the ground return, that this is an audio-related project.
Thank you in advance for your help!
Hey guys,
I’ve inherited a Luxman C-120A and C-120M, Elipson 1303D speakers, and a Technics SL-1700MK2 turntable. I stream via an Octavio. I’ve also added an Infinity SV10/230 subwoofer. Runned the system for almost 2 solid years.
Unfortunately, the Luxman preamp was badly “tinkered with” during an old recap / stabilization attempt. I’ve always had issues with it, especially on one channel. I’ve had it “repaired” a few times, I’ve proudly diagnosed and fixed some issues (with Reddit precious help of course) but in reality it was just band-aid fixes over a deeper problem. A lot of components have been added in a very haphazard / messy way, and the PCB itself is in rough shape, with a lot of trace jumpers and patchwork repairs.
In my opinion, despite its sentimental and collectible value, a proper factory restoration feels unreasonable at this point. I think I’ve finally started the grieving process, more or less at the same time as I freed up a bit of budget.
So I’m looking to replace the Luxman gear. I recently came across the Yamaha RN800A, which looks pretty interesting, but I honestly feel a bit lost in the sheer number of options out there. I’d like to stay within a reasonable budget.
I’m calling on you, dear budget audiophiles, to help me find a new setup that can proudly replace my Luxman gear and do justice to the rest of my system!
Thanks!
PS: The Elipson speakers are in impeccable condition—I even replaced the suspensions. The amplifier itself is also in very good condition and has been recapped. The turntable is likewise in perfect condition.
