As I was cleaning up my room a couple of days ago, I found this old NAD 5120 turntable hidden between school stuff and papers. We already have one of those around the house that my father used to listen to from time to time. Looking around the web for ways to get my "new" turntable to output sound, I realized that these devices need something like the main amplifier before being connected to anything else. Turns out my father has one, but it's linked to his turntable and keeping mine right next to his wouldn't be very clever (I only used it to make sure my turntable works). That's why I set out on a quest to get a pre-amp for myself. From what I've read online, you can buy them or build them yourself. I'm not an audiophile so I wouldn't need a 1000$ Sennheiser pre-amp... so I decided that I wanted to build my own.
Upon reading even further and looking at local electronics stores for parts, I came across this: a kit that has all necessary parts, except the actual case, ports and power supply. Exactly what I wanted. And guess what: it does not cost a fortune: I spent 10$ for it [I will look for one and link it at the end of the article, as usual, even if it looks like I spent a little less buying locally].
After that was done, I went looking for everything else. I replaced the original stereo-audio-DIN connector on the output cable of the turntable with a 3.5mm jack for convenience (and because it is easy to adapt to stereo RCA further down the line) (1.25$). I would also rather connect the pre-amp with the amplifier via 3.5mm jack or adapt it to RCA. Therefore i needed 2 3.5mm female audio-jack connectors (2x 0.75$).
The case is the best I could find: it's a simple box-shaped, gray plastic case, held together by 4 screws. Does not need to be special, it needs to work (3$).
In order to avoid interference, the power supply needed to be external. Since this little board can take anything (when it comes to power) from 10V to 30V, I bought a random 12V external PSU. I also needed a way to connect that to the board, so I also purchased an inexpensive, round, compatible connector (2$ for the PSU, 0.5 for the connector).
A power switch was also required so I wouldn't have to keep plugging/ unplugging the thing from the wall every time I wanted to listen to old records (0.25$).
All of this would be enough to build the pre-amp, but I figured it would look too simple like this. Playing around with a Raspberry Pi at the store, the idea struck me: why shouldn't my pre-amp have a display, that tells you if it's on or not... so I ended up spending an additional 5$ on two of those seven segment displays (like on most non-scientific calculators or digital watches) - one for the letter "O", the other for the letter "n". Next to each other: "On". Very clever idea I had.
Now I could finally walk home happy and get building. As you will see, I will have to drill the removable side-panels on that case to fit all the things I bought. To make it easy, I used some post-its to sketch my preferred layout on. I then cut out the spots that would eventually be cut out from those plastic panels on the paper. Overlaying the paper on the panel will allow me to use a marker and outline the cut-outs directly on the plastic without sacrificing much in terms of resemblance with the initial sketch. Actually drilling those holes and the cut-out for that panel is another story. It is true that that plastic is very soft and easy to work with, but I still needed to drill some very small holes as a guide before drilling for the I/O (for reference, it turns out that the headphone-jacks were 6mm in diameter, the hole for the button 9mm and the one for the power-plug 8mm).
Next came the complicated part - mounting everything together, soldering some sort of cables to connect everything, that kind of stuff. I also found out that powering that display with the 12V provided by the PSU would not work, since those displays only required 2V to operate normally. Some resistors were in order. Go figure. Those get hot (even now, after optimizing best I could), and heat is the last thing I wanted next to the things I barely soldered with my lack of skill. Cable-management was also something I thought would be easily achievable, but God was I wrong. Such a mess in there. I had to draw a wiring diagram just to make sure this thing is repairable/ upgradeable/ modify-able in the future.
All in all, I think it was worth it. It looks really cool on my shelf and performs almost as good as any pre-amp. The best part is, it did not cost a fortune and since I was on spring break, it was a pleasure to occupy my time with this little project.
I hope you found this article useful. It has little to do with the "Going Mobile" part of the blog, but it is nonetheless something about tech... and if my blog is about something not mobile, that would be tech.
Thanks for reading, folks, that's all for now. If you liked this article be sure to check out my other articles, you can find those at the bottom of the page or if you click these 3 lines in the header. Be sure to let me know what you think in the comments down below. If you loved this article I'd appreciate a thumbs-up, or even a follow. If you are interested in buying some of the stuff I talked about in this article, check them out below:
Upon reading even further and looking at local electronics stores for parts, I came across this: a kit that has all necessary parts, except the actual case, ports and power supply. Exactly what I wanted. And guess what: it does not cost a fortune: I spent 10$ for it [I will look for one and link it at the end of the article, as usual, even if it looks like I spent a little less buying locally].
 |
| It does not come pre-assembled, its instructions were clear enough and my lacking soldering skills were good enough to build it |
After that was done, I went looking for everything else. I replaced the original stereo-audio-DIN connector on the output cable of the turntable with a 3.5mm jack for convenience (and because it is easy to adapt to stereo RCA further down the line) (1.25$). I would also rather connect the pre-amp with the amplifier via 3.5mm jack or adapt it to RCA. Therefore i needed 2 3.5mm female audio-jack connectors (2x 0.75$).
The case is the best I could find: it's a simple box-shaped, gray plastic case, held together by 4 screws. Does not need to be special, it needs to work (3$).
In order to avoid interference, the power supply needed to be external. Since this little board can take anything (when it comes to power) from 10V to 30V, I bought a random 12V external PSU. I also needed a way to connect that to the board, so I also purchased an inexpensive, round, compatible connector (2$ for the PSU, 0.5 for the connector).
A power switch was also required so I wouldn't have to keep plugging/ unplugging the thing from the wall every time I wanted to listen to old records (0.25$).
All of this would be enough to build the pre-amp, but I figured it would look too simple like this. Playing around with a Raspberry Pi at the store, the idea struck me: why shouldn't my pre-amp have a display, that tells you if it's on or not... so I ended up spending an additional 5$ on two of those seven segment displays (like on most non-scientific calculators or digital watches) - one for the letter "O", the other for the letter "n". Next to each other: "On". Very clever idea I had.
Now I could finally walk home happy and get building. As you will see, I will have to drill the removable side-panels on that case to fit all the things I bought. To make it easy, I used some post-its to sketch my preferred layout on. I then cut out the spots that would eventually be cut out from those plastic panels on the paper. Overlaying the paper on the panel will allow me to use a marker and outline the cut-outs directly on the plastic without sacrificing much in terms of resemblance with the initial sketch. Actually drilling those holes and the cut-out for that panel is another story. It is true that that plastic is very soft and easy to work with, but I still needed to drill some very small holes as a guide before drilling for the I/O (for reference, it turns out that the headphone-jacks were 6mm in diameter, the hole for the button 9mm and the one for the power-plug 8mm).
 |
| "OMG it's 2017 and I'm not using RGB lighting!!!" |
All in all, I think it was worth it. It looks really cool on my shelf and performs almost as good as any pre-amp. The best part is, it did not cost a fortune and since I was on spring break, it was a pleasure to occupy my time with this little project.
I hope you found this article useful. It has little to do with the "Going Mobile" part of the blog, but it is nonetheless something about tech... and if my blog is about something not mobile, that would be tech.
Thanks for reading, folks, that's all for now. If you liked this article be sure to check out my other articles, you can find those at the bottom of the page or if you click these 3 lines in the header. Be sure to let me know what you think in the comments down below. If you loved this article I'd appreciate a thumbs-up, or even a follow. If you are interested in buying some of the stuff I talked about in this article, check them out below:
Velleman Stereo RIAA-Preamp DIY (kit no. 2573): https://amzn.to/2JYNcsX
Comments
Post a Comment