How much do tolerance levels matter?

[DSP_Geek]

When I'm selecting parts, is there any benefit for seeking out tight tolerance versions? Is getting 1% resistors functionally better than 5%?

A boffin at LIGO found temperature coefficient and manufacturer can be useful predictors of resistor noise:

https://dcc.ligo.org/public/0002/T0900200/001/current_noise.pdf

 

[sofaspud]

I don't understand what you mean

My apologies to you.


This LM317 datasheet in front of me uses the word "tolerance" twice.
The second use is "ESD tolerance."
The first is "Guaranteed 1% output voltage tolerance."

 

[nigelwright7557]

Not much difference in price between 1% and 5% resistors.
I use metal film.

 

[cbdb]

I've used only 1% metal film resistors (if the power level allows) for many years.
And you can hear a difference, so try it for yourself, no DBT is needed.

You can hear a difference between a 1% tolerance and 5% if there the same resistance?

And if there not, as stated before, it depends where you use them.

 

[rayma]

That meant metal film vs other types.
But, using 5% parts in an RIAA network instead of 1% parts would be audible,
especially for their worst case deviations between channels. And in a stereo attenuator as well.

 

[cbdb]

Yes, using 5% resistors in both channels to set the gains can have a worst case imbalance error
of about 20% (1.6dB) between the channels.

I get a resistive divider will have worst case of 10%. But resistors from the same batch are usually within less than 1% of each other then the channel imbalance is much less.

For DIY you can measure them and adjust for the few places where tolerance matters.

But as has been said 1% aren't expensive so use them.

 

[rayma]

One cannot assume that 1% resistors will be better than their rating. Good design includes the worst case.
In any event, buying less than a case or a reel at a time does not imply they will be from the same batch,
or even the same year, of production.

 

[GoatGuy]

Well ... all and good, but I once was quite happy with a whole collection of 5%, 2% and 1% resistors; however, not being a trusting kind of electronic geek, for any application benefitting from 'better balancing' (of say a pair of the lil' devils), I'd just fire up the 4-1/2 digit scope and measure a handful. Say for that LM317 circuit cited above. First hook it up on a breadboard with run-of-the-mill values, and suss out the regulated voltage. Substitute in one (or the other) resistors from 'the pile' until it is much closer to the ideal value. MAX, a minute of fiddling or two.

Just saying...
GoatGuy