My name is Bay and I am a senior in college about to complete my formal studies of the music industry and recording arts. For my senior thesis, I decided to finally pursue what you all inspired me to do; build a lathe and emboss some records in my home studio. I started this journey in September of last year researching as much as possible and making a plan. I was awestruck when seeing the work of pentlandsound on YouTube and this forum. He has been extremely helpful throughout this process and I owe him much of my success. My school has also been a great resource for me by funding most of my project and allowing me access to 3D printers, laser cutters, and CNC machines on campus. Many of the parts used in my build were donated to me by alumni, students, and my current boss/mentor. So, once again, thank you all for your continuous support.
Over the winter, I constructed a large box with the same dimensions as a Technics SL-1200 flight case. The goal here was to give my turntable a sturdy base while providing an area inside to mount my electronic components. It's just some spruce project board reinforced with steel corner brackets. I made the bottom out of peg board for airflow and a place to run wires. I made several tops for this box to support different models of turntables (a Technics SL-1200 MKII and a Presto Pirouette broadcasting turntable). The tops lift right off to allow access to the electronics inside. There's lots of empty space on the inside because I anticipated buying an amplifier board but was given an old Sony TA-3200F Amplifier by a former professor instead (more on this later).
I downloaded David's freeCAD files, made some modifications to work with my hardware, and printed them in Nylon 12 with a Fuse1 SLS printer. This material is lightweight and very solid, but still provides the necessary flexibility for parts like the v-spring. One of the modifications I made was to the side bracket that holds a dashpot. I needed more room for a YZ linear stage, so I crudely cut the piece in half and used metal standoffs to make space for the adjustment screw. I also had to design an adapter to connect the cutting assembly to my ball screw actuator. I read on here that ball screws tend to leave undesirable resonances in recordings, but I found this one in a bin of spare parts and a professor was kind enough to give it to me. I figured I should take my chances with it before I make any unnecessary purchases. It also came with a NEMA 23 stepper attached, which is definitely more motor than I need. I was concerned that a motor this size would cause resonance in my records, too. Even on the highest microstepping settings it makes a lot of noise. I designed a motor mount that utilizes anti-vibration M3 standoffs to try to reduce this as much as possible. I mounted it on the side of the box and connected it to the ball screw with a timing belt.
One of my biggest obstacles has been figuring out the best way to control my lathe's transport. Ideally, I would like to use Maxuino, a program that integrates Arduino with Ableton Live. It allows you to use MIDI signals in Live to control just about anything with an Arduino board. I plan on using Live to build my mastering chain, so the ability to control my lathe directly from the same program would be perfect. Unfortunately, I'm very new to the Arduino IDE and failed my high school computer science class.
If anyone has any experience using Maxuino for lathe control, I would love to chat! Just send me a PM! For now, I plan on building a much simpler circuit with a motor on/off switch, a motor direction switch, and a pot to control the motor's speed (groove pitch). I had some initial success with the circuit outlined in this video (https://youtu.be/iY_4YOlpqyI). I taped a pen to my ball screw actuator and was able to trace a record spiral fairly accurately. However, this circuit does not include an on/off switch for the motor and I'm unsure how to code one in properly. It would also be nice to have some LEDs to indicate the switch positions like in this video (https://www.youtube.com/watch?v=X_u8PZKqjX4&list=LL&index=1). The DRV8825 stepper driver in this video doesn't have the right specs for my motor, so I can't just use their code. I purchased a DM556 driver that is very similar to the one used in the first video. Does anyone with more experience have a suggestion on the easiest way to solve this problem? Are there any other controls that you think would be nice or necessary to have? Another complication I ran into was the Sony TA-3200F amplifier. This thing is one beast of a power amp when functioning properly with 130w per channel and less than 0.1% THD. Sadly, mine was a bit of a mess when I received it. Every cap was leaking (not an exaggeration), all four output transistors were shorted, and it was full of dust and dead roaches. I work as a repair tech in a record store, so I have seen horribly maintained amplifiers before. My Sony was one of the worst. After lots of soldering and de-bugging, it is working properly and will hopefully produce nice sounding records. It will be powering coin exciters in my cutterhead from Dayton Audio (DAEX19CT-4) that are the same dimensions as those that David used but with a 4 ohm impedance. The only other modification that I made to David's cutterhead is the implementation of 3D printed "cones" that will be glued to the exciters. These were made to hold a 2mm titanium rod with a set screw that will push/pull on the torque tube. I just didn't trust myself to cut out cones as accurately as David.
Once I find a solution to my control circuitry problem, I will be ready to emboss my first record. I plan on using CDs as my blanks because they're cheap, although I would like to try some polycarbonate discs at some point. I'm using conical tungsten styli with hopes of upgrading to a sapphire stylus from recordlatheparts.com. Does anyone have any experience embossing CDs with these styli? I would love to hear your results. I'll post mine here, too, once I get something worthwhile.
Graciously,
Bay