Tube Amp, Preamp upgrades -- what did you do that improved your units?

As an example, if you have the standard QS Linestage, then the top two things you can do are:

- replace the Alps Blue pot with the same exact value TKD pot from Japan. Big jump in resolution and realism.
- replace the film coupling caps behind the tubes with Vcap Odams. The same value. 
Just these two things will make you smile big. These parts will fit. Top two things you should do. Yes you can do more, but these will have more impact than any other upgrade .

@grannyring Thanks for weighing in. Much appreciated. I've got some nice closeups of both the Line Stage and the Monoblock 60s on my system page, now:

https://systems.audiogon.com/systems/9064/edit

I'm a noobie. I wonder what more experienced people think of the stock caps which came with my amp. My feelings won't be hurt and I know this is very affordable quality gear. But, getting down to the quality of the parts, what do you see in these photos?

Thank you, all.

I upgraded my input tubes on the phone and amp. The phono got a NOS Telefunken 12AX7 and the amp got 2 x 6922 NOS Siemens. Huge increase in soundstage and much more air around each instrument. Highs are crisp and clear, not sibilant. YMMV of course.

Tubes are, i had thought, already a given. I’m thinking of alterations to the machine.

Also, learned this: the Orange Drop caps are 90 cents (.90) a piece at Tube Depot. 
https://tubedepot.com/products/orange-drop-715-series-022f-600v?utm_source=google&utm_medium=cpc&adpos=&scid=scplpCP-OD715-022-600V&sc_intid=CP-OD715-022-600V&gclid=EAIaIQobChMIsIa6_8yH9AIVeQytBh0nbQ4EEAQYBCABEgICr_D_BwE

some of us remember swapping in Orange drops into a Hafler…because they were an…upgrade… it’s all relative….