Optimizing old tube guitar amp's routing of analog 0V

[freshtapescent]

TL,DR however I’ve never had a bad result by adding a hum-dinger pot, and balancing at least the first supply filter. Merlin says "If there is an additional stage of smoothing immediately after the reservoir capacitor then it is beneficial to split the dropping resistance into two parts to create a balanced filter..."
It’s also relatively easy to implement before ripping up a layout chasing a dB or two.

 

[Newmarket]

Guitar pickups have inductance too... I was crudely ball parking that. A 10k resistor might understate the HF noise. To do it right maybe use an actual guitar pickup, shielded inside a metal box. For tweaking layout I don't think the 50k-100k resistive termination will steer you too far wrong.

JR

Yes, of course. The inductance is the 'engine' (well not really but you know what I mean).
I was basically wondering if you were thinking to account for that or just thinking to 'overdo' the DCR to increase sensitivity of layout. Actual Pickup seems best method although I guess the issue there is what pickup - as they vary greatly in electrical / frequency characteristics - so your 50K - 100K suggestion might be best option for repeatability.

 

[musipol]

Would you need a mu metal or some other magnetically permeable enclosure for the pickup in this type of arrangement, or would simply a metal box suffice?

 

[JohnRoberts]

I am not really encouraging this exercise. IMO a resistor termination should be good enough for better/worse tweaks, and won't be affected by magnetic fields.

JR

 

[fazer]

For tweaking layout I don't think the 50k-100k resistive termination will steer you too far wrong.

68k used in fender and Marshall. 8k-16k is dc resistance not impedance so 50 to 100k is 10 times. Seems reasonable

 

[Tubetec]

Regarding having someone with serious guitar chops in the design chair , might or might not happen . I was lucky ,I shared a workshop with a luthier for many years , there was no end to serious players coming through the door and they were always willing to chunk out sound and test out my latest amp tweak or even just as a proof of a succesful repair job , I sound like a roadie when I play the guitar , probably always will , I can crank out a few chords no worries but you need a proper lead player to test out how things sound in solos .