Hopefully fixed
I’m sorry, but I still have the same problem.
Hopefully fixed
Still working on the ground buss. First pic is a rough mock-up of a couple of grounding schemes. You can se that unlike our fearless leader's build, my power supply caps are at the opposite end of the chassis from the input jacks.
1) Should I ground the buss close to the input jacks (black text) or near the four big caps in the power supply compartment (white text)?
2) Should I leave the LED's grounded midway along the ground buss as in the second picture or split them off and bring them back to the D3A cap as shown in the white dashed lines of the first pic?
3) In general, should the noisier components be grounded nearest the chassis ground point of the buss or further away?
4) Other ideas welcome as always?
View attachment 17979
View attachment 17980
I would run the ground buss from the PS caps over to the 5687 tubes, then up between the tubes to the middle of the D3a tubes. All of the ground connections would tie into the buss. As for the input jack connections, I also view that wiring as an extension of the interconnects. I use some short wires, twisted together, running from the jacks to the audio circuitry. The ground wire separates and is tied to the buss; the signal wire goes on the gridstopper R on the D3a.
The main difference between your description and my build is that I placed the final PS caps close to the tubes they are feeding so the ground buss connections are short and direct. This seemed like a good idea but I don’t know how important it may be.
I do feel strongly that signal and ground connections should be made using component leads wherever possible. In other words, avoid jumper wires. Tag strips are ok since the electrical connections can still be made with component leads soldered directly to each other.
I posted a photo of the inside of my audio chassis in the other D3a phono thread, but I am posting it again here to illustrate the component lead connection approach. It looks messy, especially in a 2-dimensional photo, but the connections are secure and reliable. Even though it has never left my listening room, I wouldn’t have any concerns if I had to ship it cross country.
Yes, the earth connection for the signal ground should be between the input jacks.
You could remove your center divider and drill it out for the caps, then have the cap terminals available for convenient connection inside the audio portion of the chassis.
You definitely do not want to run those long grounds back to the power supply caps, that's what the ground buss is there for.
I would run the ground buss from the PS caps over to the 5687 tubes, then up between the tubes to the middle of the D3a tubes. All of the ground connections would tie into the buss. As for the input jack connections, I also view that wiring as an extension of the interconnects. I use some short wires, twisted together, running from the jacks to the audio circuitry. The ground wire separates and is tied to the buss; the signal wire goes on the gridstopper R on the D3a.
The main difference between your description and my build is that I placed the final PS caps close to the tubes they are feeding so the ground buss connections are short and direct. This seemed like a good idea but I don’t know how important it may be.
I do feel strongly that signal and ground connections should be made using component leads wherever possible. In other words, avoid jumper wires. Tag strips are ok since the electrical connections can still be made with component leads soldered directly to each other.
I posted a photo of the inside of my audio chassis in the other D3a phono thread, but I am posting it again here to illustrate the component lead connection approach. It looks messy, especially in a 2-dimensional photo, but the connections are secure and reliable. Even though it has never left my listening room, I wouldn’t have any concerns if I had to ship it cross country.
@izzy wizzy . Thanks so much for that clear and complete view of grounding!! I may be too far down my path to revise the whole grounding plan but will incorporate what i can.
One question HaHaHa. I don't understand the statement "Reference the layout in post #522. What concerns me is the distance between what should be tight common reference points. The cathode LEDs and the grid resistor should go to the exact same point. Sure there can be a small distance between stage 1 and 2 but not too far. Close to stage 2 common point, should be the RIAA EQ connection to ground as it's the reference for stage 2's input. So to tighten this up, wire the cathode of 5687 to the other end of that LED string and put the grid resistor above as we look at the pic and attach it to the same point as the 0V connection of the LED string."
Is not the grid resistor the Rinken 300Ω? I thought it runs between the input and pin 2. I don't see where it goes to ground and how to tie it closer to the LED string(s).
great to have you here.
Yup. Very clear. I'll work on that.Here's a suggestion how to wire it for the physical layout we've been discussing. Hope the messy picture is clear enough.
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