With Speedball the voltage at start-up seems to run higher. It's millivolts, not volts by the way. Manual states 9mV-DC with stock version. There is nothing in the Speedball manual that suggests the voltage is higher. I brought the question up after I installed Speedball. I measured 9mV DC after building stock and 22mV DC after Speedball upgrade and film caps. Another member measured 14mV. You should be fine if all your other measurements are in line. I have not yet connected the switched contacts to ground. I turn the amp on for 30 seconds or so before plugging in headphones. BUT, with headphones connected, that small voltage at startup would be even lower and probably non consequential. I just use extra caution and plug phones in after the 30 seconds. Grounding those switch contacts should remove that small voltage. But keep in mind that some folks use different headphone jack (like the Neutrik locking jack) that doesnt have the switched contacts. So, it isnt mandatory to ground those contacts. Crack was out for a while before the guys posted about grounding those contacts. Long way of saying that your 21mV at switch on should be fine and seems normal ... as long as it falls back to zero. Also, after it falls to zero, you may or may not have noticed digits on the meter rapidly jumping all over the place, too fast to keep track of unless maybe you have a peak hold function. This is also normal and, as Paul J. explained it, it is "leakage" from the electrolytic caps. Also normal and inconsequential.
I didnt notice Crack any quieter either after speedball. Mine was dead quiet in stock form. But I think some of that extra detail and/or clarity may be due in part to a quieter/cleaner background with Speedball installed. Eventhough the background seemed "black" in the stock build.
Anyway, sounds like all is good now. Happy to hear that you got her up and running. The problems you had just makes for a good learning experience for the future. Congrats and enjoy. Really sweet amp, Im still loving mine. Next up for you ... maybe film caps and tube rolling? ;D It can be hard to leave alone. I stopped at the film caps internally. BUT, I do have a pretty good stock of tubes to roll. I think that mods get more subtle once Speedball is in, and maybe film caps in place of the electrolytics for the output coupling caps. That's what seems to be reported by many. If you do have plans for future mods, enjoy it as it is for a while before doing so. But it sounds fantastic, even in bone stock form.
...now that I have some lessons learnt.
