Now that I sort of have PCB design figured out, I figured I would brush my notes off for the TR John Mayer Signature and see if I could make something interesting. I have learned a lot about the real JM Sig since my first build which was a modified Ceriatone JM100. You can read up on my analysis of the real John Mayer Signature here:
This Fairfield County Signature is a 1:1 circuit of the 25 limited edition TR John Mayer signatures. Cross-referenced with two real JM sigs as well as two rogue post-JM sigs. TR made an Oak Cliff Special (SSS #002 clone) and the name was a play on where Stevie Ray Vaughan was raised so I decided early on calling this amp the Fairfield County Signature where John Mayer grew up in Connecticut. Special thanks to the anonymous sources who approached me to share info about the circuits.
Design
As for PCB Design, I had a few design goals in mind:
Needed to be easily serviceable in the future. PCB gets a lot of criticism because of the ability, or inability, to service them. I knew I could figure this out.
The design needed to avoid crosstalk while taking advantage of PCB traces.
Rigid board manufacturing.
Needed to withstand 500v AC and DC.
Small enough to drop in a 19" chassis or retrofitted in other chassis if desired.
The result:
Hybrid eyelet hole size & smaller holes for single-ended connections.
2mm thick circuit board manufacturing.
High voltage DC connections and grounds are physically on the bottom layer intersecting at 90 degrees, or close to, the signal runs on the top side of the PCB.
Silkscreen artwork displays the real JM Sig values. You can round up or down to the closest value to parts you can buy off the shelf. I do not know where you can buy carbon film in E96 series like the ones used in the real JM Sig. For example, 1.54k can be substituted with a 1.5k carbon film that is easily found at Mouser or other sites OR you can find all Dale RN65D metal film in the correct E96 values.
DIY Build Your Own!
Kindly remember that taking on any DIY project assumes you take all the responsibility in sourcing, fabricating, building techniques, and troubleshooting. I believe my projects are documented well and I will provide you with enough resources to successfully build your own. If you find any mistakes, please let me know and I'll update my documentation accordingly. I cannot dedicate many cycles to troubleshooting individual builds so I encourage you to leave a comment on this post or ampgarage.com for community support and documenting your issue to help others in the future. Be thorough in your post and include any troubleshooting steps when making a troubleshooting post. Please take your time while building this project and be observant of anything that could go wrong. That said... let's get to the good stuff...
Between the following two pictures, I built my JM Sig. On the left is Amplified Nation's documentation and on the right are the corrected values based on my observations of 2x real JM Sigs and 2x post-Mayer sigs.
I will be updating layout documentation on my GitHub repository for this project. Included will be a layout for using a Ceriatone JM100 Chassis. The chassis I used for the build in the picture was from Taylor at Amplified Nation as sold on ampgarage.com .
https://github.com/colganr/tr-jm-signature GitHub with DIYLC editable layouts, faceplate files, eyelet layout and files, (basically all supporting files).
https://photos.app.goo.gl/VmgVuEo9qTDXYwNo8 Google Photo Album
https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=70e10ecf4c Mouser BOM
https://docs.google.com/spreadsheets/d/1BbafnF-2HcADyuAplFohnbDM42QoTJAhegSehpVstJY/edit?usp=sharing Amp-specific parts BOM
Here are some PDFs that you can print out 1:1 for test fit purposes.
DIY Faceplates
If you're also interested in creating your own faceplates and backplates, I have PDFs published here. I also created a free guide for customizing and buying your own faceplates for Taylor's chassis as well as the Ceriatone JM chassis. I include templates as well for no-brainer effort. The faceplates are pretty cheap at the end AND they'll be customized to your liking. It could be done in 45 minutes probably. https://docs.google.com/presentation/d/1ocvXL5-ojGjsDHo-Hw9XbM6T3_gasqukuVvoa3Vs6UQ/edit?usp=sharing
YouTube Videos
And here is a great video for those using the Ceriatone JM100 chassis
-Ryan
