Drifted NFB resistor in 2203 JMP '77

[LyseFar]

Recently I was changing tubes in my JMP 2203 and as I had it open and as the presence knob isn't doing much, I decided to check the NFB circuit.
Took the 100k NFB resistor out of circuit and measured it to 170K. I guess that a higher value here will add to more distortion - and - in a way - what's not to like

My speculation/question is now: would it be wise to change with a "new" in spec 100K (I have some 100K NOS pihers in stock) or just leave the old one? If it just continues to drift the sound will gradually change I guess.
Ran through the rest of the resistors and they were all within specs.

The amp is great sounding so I am a bit concerned that changing it will take the personality out og the amp.
I am considering to piggy-back a 200K-something resistor over it to get near 100K and test how it sounds.... hmmm

What would you guys do..?

 

[PelliX]

Replace it with a new resistor of 100k (of course you MIGHT want to experiment with different values, but that's what the Presence knob is for, right). Don't waste your time on flaky old parts that have exceeded their expected lifetime, else you're just asking for the same to happen again sooner or later.

 

[LyseFar]

Replace it with a new resistor of 100k (of course you MIGHT want to experiment with different values, but that's what the Presence knob is for, right). Don't waste your time on flaky old parts that have exceeded their expected lifetime, else you're just asking for the same to happen again sooner or later.

Thanks for bringing me back to reality!
That was the push I needed

 

[Ronquest]

Next question may be, what tap on the OT is the NFB?

 

[LyseFar]

Next question may be, what tap on the OT is the NFB?

8 ohm tap.