2W Carbon Film Resistors

[DonaldStott]

Having completed a number of restorations now I'm gradually building up my stock of standard value components e.g. just sent off for some mix-and-match packs of capacitors from the BVWS Spares Dept.

When trying to retain some semblance of an authentic look with vintage radios I always like to use 2W carbon film capacitors as they are roughly the same size as the originals.

But why is it I never seem to have the correct value of resistor or the nearest equivalent. Don't know if it's Murphy’s Law, Sod’s Law or Finagle’s Law, either way it's a real nuisance.

So advice please on the best source for mixed packs of carbon film resistors covering the standard values - UK if possible? I'm also a victim of being stung for excessive p&p charges for such items!

Thanks

[MrBungle]

I'm not sure such a thing exists above about 0.25W. I usually buy the larger sizes from RS in small quantities. Free next day delivery on everything too:

This series:

https://uk.rs-online.com/web/p/throu...stors/7078827/

[Herald1360]

So.... ten of each value in E6 series from 1R to 10M would cost you about fifty three quid. 10R to 1M would be about thirty eight quid.

There are some Chinese kit packs on Ebay- example:

https://www.ebay.co.uk/itm/1K-Ohm-to...edirect=mobile

[DonaldStott]

Thanks Mr Bungle - order placed with RS Online.

Thanks Chris - point well made!

[GrimJosef]

Are some of the values significantly less popular than others, allowing them to be left out if cost is a real issue ? Obviously limiting ourselves to E6 helps a lot. But I seem to need 180k for anode loads more often than I do 150k. In fact I can't remember the last time I needed a 150k. Or a 68R. Or a 3k3. Perhaps I should start keeping a tally ? Or we could all scribble down what we use for a month and then total up our lists for a more representative sample.

Cheers,

GJ

[MrBungle]

I’ve learned to just buy the values I need. I have a Royal Ohm sample book here that cost me £150 and about 60% of the values I will never use.

[G6Tanuki]

Remember that the old carbon-resistors used in decades past were usually 10% tolerance at best - which means you can cut down the range of modern close-tolerance parts you need to stock.
The E12 series covers everything I've ever needed in terms of vintage restorations

1.0 1.2 1.5 1.8 2.2 2.7 3.3 3.9 4.7 5.6 6.8 8.2

I generally designed stuff so that if I specified, for example, a 3.3K resistor, the circuit would still function OK with a 2.7K or a 3.9K.

[Herald1360]

A quick calculate suggests that if you keep just 1, 2.2, 4.7 (E3) and you don't mind using up to two at a time (series or parallel), you can get the following values:


R......Use

1.......1
1.2....1+0.22
1.5....2.2||4.7
1.8....2.2||10
2.......1+1
2.2.....2.2
2.7.....2.2+0.47
3.2.....1+2.2
3.9.....4.7||22
4.7.....4.7
5.7.....1+4.7
6.9.....2.2+4.7
8.2.....10||47


Which covers E12 pretty well.

For many (most?) applications just using the nearest of 1, 2.2, 4.7 and decades will do just fine.

[Herald1360]

Originally Posted by MrBungle

I’ve learned to just buy the values I need. I have a Royal Ohm sample book here that cost me £150 and about 60% of the values I will never use.

Use odd values instead of the correct ones where the application is suitably tolerant?