Quick PCB question

[Khron]

I've whipped together a through-hole and slightly altered version of the sE 2200A circuitry (with a DC-DC converter on another board, and a pattern selection switch added), and i'll have a batch made (10 of each board), most likely at Itead.

If, by some miracle, others are interested as well, i can easily add more batches to the order - the boards would come out around 1$ each, plus shipping.

Now, my (minor) concern is, would that red trace (top layer) coming from the center pad on the left edge of the board, affect the high-impedance area of the circuit in any way?

The 1G resistor will be between the octogonal pad on the top left (below the mounting hole/pad) and the grey "target" (a hole for the teflon stand-off).

 

[Khron]

Anyone..?

All i'm looking for is "yeah, it'll be fine" or "no, move that track outta there"

 

[Matador]

Anyone..?

All i'm looking for is "yeah, it'll be fine" or "no, move that track outta there"

It would be difficult to answer yes or no, as it's a nuanced situation, and depends on several factors.

In principle it should be fine, but you have to prototype it, with your board house using their formulations for the various PCB layers, and then test/experiment.

 

[Khron]

My only (mild) concern is with that one trace that goes underneith the 1G resistor - everything else should be quite fine.

 

[Matador]

My only (mild) concern is with that one trace that goes underneith the 1G resistor - everything else should be quite fine.

I mean: what specifically is the concern?

First, what potential(s) are the traces at?  What kinds of materials are separating the two things?  If you have a standoff in the board, and the resistor going "over" the trace through the air, potential leakage has to go through both the air, as well as the surface finish of the PCB.

Just eyeballing it, I wouldn't be worried.

 

[Khron]

Well, i'll admit, i'm still quite the "n00b" when it comes to this very-high-impedance and leakage and noise stuff, so i'm just kinda wondering what might the pitfalls be, by running that trace there.

That particular one (the one going from that center pad, on the left edge of the board) is the signal coming from the FET drain, and going to the smaller-value cap in the high-pass(ed) section. Actually, i just re-checked the schematic, and it actually has a 100n cap before going to the switch, so there's only gonna be the audio signal there.

As mentioned in the initial post, one leg of the 1G resistor will be on that octogonal pad in the top left, and the other leg, together with the FET gate, will be mounted on a stand-off, where that grey "target"-sorta thing you can see on the board.

Since i'm planning to have this board professionally made, it WILL have soldermask on both sides, and all that.