[Milsurplus] Resistors and capacitors

[Jim Whartenby]

CharleyI haven't seen any replays so here are my thoughts:
I would answer your resistor question with a negative.  I feel that the issue with resistors is precision and stability over time.  There are no 2% carbon composition resistors  AFAIK.  The best one can get is 5%.  10%, 1/2 watt units go for about $3.50 each at Mouser, if you can find the value that you need.  Pickings are slim.  How long that resistor remains within that tolerance is not certain.  Carbon film resistors can be had with 1% tolerances and are more stable over time then CC resistors.  They go for about $0.15 each for 2%, 1/2 watt units.  Metal film resistors can be had with 0.01% tolerances and are very stable over time.  They are about 5X the cost of CF resistors which still makes them cheaper the CC resistors.
Capacitors depend much more on where they are used.  The higher quality units are used in critical circuits like timing or frequency so cost will be high.  Modern aluminum electrolytic caps are so small I leave the old disconnected can cap in place and mount the various sections of the replacements near where they are used in the circuit.  Film capacitors are perhaps the most used for coupling and bypass functions.  About $0.65 each for 0.1uF 10% metalized polyester.  
On eBay you can find deals on NOS capacitors, 800 for less then 3 cents each including shipping, 0.1 uF @ 760 volts DC.  Going series or parallel with several of these and you can just about make all of the common capacitor values that you need and still have plenty of room left over when replacing the old paper-foil caps.Regards,Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy 

    On Tuesday, August 19, 2025 at 11:40:29 AM CDT, Charlie L. <mjcal79 at gmail.com> wrote:   

 I used to be on a couple of forums on vintage stuff, but quit as I could not stand the bad info, and lack of knowledge by the list experts.  I have milsurp  and amphone as my only ones now.  

So here is my question since the carbon resistor thing was brought up.  I know that wirewounds should not be in tuned circuits unless the non-inductive style and those are a bit iffy, , but after that, with all the options on non wirewound we all use for prices I have seen as low as .007 cents each and $1 buys you 140 of them, is there a composition style more suited for each circuit?
The next is small value capacitors,  film, polystyrene, polypropylene, polyester,  MLCC ceramics.  I have used the most economical from a known manufacturer for most of my changeouts involving the old paper caps, and in audio interstage coupling, but again, is there a rule of thumb for picking and choosing a cap material based on circuit use, bypass, audio, etc?  Again, the audiophile sites have their opinions based on fidelity.  Prices for cap styles can swing greatly too, silver mice and stacked silver mica can cost you several dollars just for one, even on Amazon.
I have some old gear, especially my Heath TX1 that still has good and the original electrolytics in them, but from manf. info and actual work experience where we changed out every single aluminum electrolytic cap in power supplies on a 7 to 10 year cycle to maintain system reliability, how have the aluminum caps been holding out for everybody else.  The aluminum caps also age as they sit on the shelf and have a nominal 10 year life expectancy.

Charlie in NC
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