Critique my Layout / lead dress

[txstrat]

So what do you guys think about the fact that when I touch the probes to the wires the weird sound doesn't happen? That seems significant to me, that disturbing the circuit with a probe seems to help.

That's why I was asking about your grounding scheme. Some day I found sorta this in one of my builds too and the culprit was a not sufficient grounding (don't remember if it was a cold solder joint or something). The circuit somehow took ground over my DMM.

[cminor9]

That's why I was asking about your grounding scheme. Some day I found sorta this in one of my builds too and the culprit was a not sufficient grounding (don't remember if it was a cold solder joint or something). The circuit somehow took ground over my DMM.

I will certainly do some more experimentation with it, and I'll try moving a few things around on the grounding.

Like I told Tubeswell, I will certainly report back with whatever I try and the result. Thanks for all of your good suggestions!

[cminor9]

I think I have this thing fixed, even if by a hack.

First, I tried switching out tubes. This didn't fix the problem, but interestingly, it changed the tone of the weird sound. It went from being a loud clicking to a more high pitched sound, almost like a car engine revving real high.

I changed some grounds around, and this didn't fix anything.

I took the presence knob out of the loop, since this was an easy mod and not destructive at all, but changing the presence knob would bring on the weird sound. Taking this out had no effect.

Then I think I stumbled across the fix. Now, I can turn the knobs anywhere I like at any volume and it's all good! Check out the attached schematic to see what I added. It's in the trem circuit, and I called out with some big text.

So, it's a hack. I am a software developer. Sometimes hacks in code are needed. In code, though, it's a predictable system where I can usually see why a hack is needed. I am enough of an electronics n00b, though, where I cannot really do this and it's frustrating. Can anyone tell me why such a hack would work? BTW, I zenered my voltages down so that they are within a couple of volts of the spec.

I have attached an updated schematic. Does anyone have any theories on why this fix worked?

[tubeswell]

ICan anyone tell me why such a hack would work? Does anyone have any theories on why this fix worked?

Hi cminor9

Good to see you've worked out a solution (and handy to know what it is - Ta)

My guess is that it must've been that the voltage swing from low frequency waver from the oscillator was too intense causing the bias of the output tubes to be thrown too far out of whack, and you have now 'dampened' it a bit more and brought it into line. Either that or the cap next to it is dodgy, and the new resistor has compensated for it. (Funnily enough - on the 5G9 schematic the cap and resistor are in the opposite order - I guess because the 5G9 trem has a CF feeding the bias and it needs a coupling cap at the cathode.)

I now recall that I did something similar when I first built my 5G9 - and accidentally left out the 1M (which was in a similar location) and I had a similar problem with the intensity control on full, although the trem was deeper. Have you tried maybe experimenting with the value of your new resistor, to get the optimum value (for depth) without getting the ice-picky, chopper-like noise? (or replacing that other cap?)