The way we grounded the circuits was based on the amount of current noise that the section carries. For example, the power, 6v6s, 50v bias rectification, and speaker COM are apart of the high noise ground, the cathodyne and reverb recovery is apart of a high-medium ground, many potentiometers and preamp triodes are connected to a low-medium noise ground and the op amp circuits are connected to a very low current GND. All of these grounds attach to exactly 1 star point on the chassis, (the 4 wires connected to the large bolt next to the 6v6s on the underside of the chassis as shown in the google drive (SEE BELOW). and then there is another bolt connected to the IEC input for the earth ground.
A) is this grounding setup good? I verified with a multimeter that nothing was connected to the chassis prior to the ground bolt attachment and I even fixed the self grounding input jack. Anyways i know the star ground is in fact a star ground.
B) we are using a push pull 6v6 config with a cathodyne 12ax7 as shown in the schematic on that first post, but out OT, (which is this: https://www.amazon.com/Push-Pull-Transf ... 140&sr=8-3) seems to not be self grounding via the 0 ohm reference. I added a seperate com wire to the high current ground that connects to the negative terminal of the speaker (Hardwired speaker). does this make sense to do? there should be a video in the drive that shows this Green wire, it is 16AWG.
C) the heater windings come with a CT and I attatched those to the high current ground aswell.
ANYWAYS, My Partner and I have been working on the amp for a hot minute and we have some updates! here is a google drive folder that has videos of us working on the amp:
https://drive.google.com/drive/folders/ ... zRSuNpfRqc
Keep in mind not all of the photos in this folder are photos of the completed amp. the final few files showcase the final amp, specifically IMG_4627.HEIC and IMG_4628.MOV. How does it look? its our first amp but I would say the wiring looks okay comparing it to other hand-done rat nest amplifiers? I have verified so many times with a multimeter that all the connections are correct and match the schematic. All of the wires that connnect turret to turret were done underneath the turret board to maximize cleanliness and proximity to the protection of the aluminum chassis shielding effect.
We are planning to turn the thing on tomorrow. We have been looking into startup procedures, but we wanted to get some of your expert blessings before we hit that switch. I bought a variac and we are planning on making a light bulb current limiter aswell. I understand that i put the two in series. Any tips for making one? what is an efficient yet safe first start up method? is there anything that yall see in this amplifier that is alarming?
Let me know if you have any questions! Hopefully we can get some advice by around 3:45PM EST today, Wed May 6.
- Fynn and Sam
