Value drift over time
On Saturday, 18 May 2019 16:22:32 UTC+1, Cursitor Doom wrote:
On Fri, 17 May 2019 21:19:07 +0100, Mike Coon wrote:
I can hardly wait!
Then I shall keep you in suspense no longer.
Here's what I found from a random selection of old components I snipped
out. Firstly, pretty much *all* the capacitors were fine. The 350VDC
Hunts capacitors could easily have been new. An Erie plate ceramic of
0.01uF likewise. A Dubilier type SM22 50pf cap, however, had gone up to
62pF. That one was one of the ones used for tuning. The biggest changes
were as expected in the carbon resistors, all of which aged to higher
values like so:
27k became 38.6k
another 27k ---- 29k
100k ---- 107k
10 ---- 10.7
3.3k ---- 4.2k
4.1k ---- 5.2k
15k ---- 20.7k
220k ---- 246k
8.2k ---- 9.9k
400k ---- 509k
These were all marked with a silver tolerance band, so clearly Taylor
back then at least not *that* bothered about accuracy.
Most Rs in valve kit are far from critical. 5% would have cost them more than 10%. 20% were more common.
NT
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