Tube Screamer Hiss

[highwater]

Car straps: tires used to build static electricity just rolling. To the point that little springs were put in wheel bearing caps to bleed wheel-hub to spindle, to reduce discharge static in the radio.

That's not as ancient as it might sound... Chrysler, sometime in the mid-late 2000s, issued a service bulletin for the PT Cruiser recommending the installation of grounding wires between the rear struts and the chassis. Apparently, they had a substantial number of wheel-bearing failures which were traced to static-electric buildup, presumably generated by the many bits of rubber between the road and the chassis.

I was thinking earlier that I only see the grounding chains on ambulances.

I wonder if that's because they have high-voltage equipment (like defibrillators) or because they might need to drive near downed power-lines? Either way, the closest I've seen to a grounding chain is a dragging muffler (though I hear they used to be required on trucks that carried certain flammable materials).

[pgorey]

I'm really thankful for the smarts and info in this thread!  This has sent me down many a tangent   Regarding the diode between emitter and base on the transistor, do many people solder diodes on the input transistor to make this hiss issue moot?  I have never heard of it until now but it seems like a necessary component for any circuit with an input transistor just to surely avoid an inevitable issue. 

What would be the proper way to power down my pedal board?  I have a furman surge protector and then an isolated power supply brick broken out to the pedals.  I tend to just plug in / unplug my furman with the switch always in the on position.  Perhaps this is a bad method?

[PRR]

> proper way to power down my pedal board?

The turn-off failures I saw at another forum were on a circuit VERY different from anything that could fit on a pedalboard.

In general you defend against Bad Influences by putting some resistance in line. Inputs on guitar-cord stuff can usually tolerate 10K-33K in series without harm; that protects up to voltages you do not want near your pedals. I can't think of any small-signal audio device prone to turn-off damage.

[pgorey]

Thanks!  That's good to know.  I also ended up replacing the transistor as well and the little bit of hiss that was initially present is now completely gone.  Thanks everyone.  Onto the next project!  Goss a Ross mod scratch build waiting for a few resistors I ran out of and also have a friends Blackstar HT-DIST I'm trying to troubleshoot.