Carbon Comp Resistor Treatment

[Chemo64]

I found this tip for treating AB resistors on a British electronics store webpage, does this sound like good advice?

http://www.hificollective.co.uk/compone ... stors.html

As stated Allen Bradley resistors are carbon composite, being made of an organic material they do have the tendency to absorb water from the atmosphere. This absorption can increase the actual resistance of the component, hence the slightly higher than normal tolerance published on this page. To fix this simply remove the water from the component and seal it. The best method is to place the resistor/s on a baking tray set, your oven to 80 degrees centigrade and leave in the oven for 8 hours. The secret is to remove the mositure slowly if you rush it it will become noisy in circuit. Once cooked seal the body of the component in Shellack (preferably the flakes) to stock any further water absorption. At the end of this procedure you will have a much lower noise, more closely tolerance resistors.

[briane]

I've heard something like that before...but I heard 100F for 3 hours for carbon film.

Sounds like overkill. not needed unless those resistors have been sitting in a garage for the last 40 years. Did they even have carbon comp back then?

of interest, I 100% rebuilt a wurli 200 pre-amp a while back. Every single resistor (I mean every one, out of 77 checked, all but 2 of those replaced) measured 15% high, or more. Those old carbon films do drift. The 2 I did not replace actually sounded better with the drifted value.