matched components

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matched components

Postby jkhuri44 » Wed Sep 14, 2016 10:29 pm

heya all,
does anyone know of a seller on ebay, or a store which will sell me matched resistors? for a DIY project?
i could buy scores of them, but i dont do enough projects really at the time being to do so.
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Re: matched components

Postby chrisp » Thu Sep 15, 2016 5:06 pm

Hey Jamil

Pre-etched circuit board? Not sure I would bother, 1% metal films are not likely to be the source of serious mismatch. By all means spend time in Jaycar with a multimeter selecting matched ones, buy a pack of 10 and pick the best pair, etc.

If you are really serious and have design flexibility you could do a search for laser trimmed resistor array, something like the 8 pin LT5400 that gives four resistors accurate to 0.01%.
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Re: matched components

Postby jkhuri44 » Thu Sep 15, 2016 9:33 pm

all i hear about in higher end diy builds for stuff like amps is "matching resistors"
even with kit PCB stuff.
so, these laser trimmed things sound good, but i bet their exxie if you need a few for 1 project right?
when you say flexibility, are you referring to mounting space?
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Re: matched components

Postby Linear » Fri Sep 16, 2016 2:12 pm

i see no idea why you would need more than 1% matched resistors. anything more than that is just snake oil i reckon. sure, if you're building test/measuring/scientific equipment then by all means, get 0.01% matched resistors. or if you're building a satellite or nuclear weapon, then the more accurate the better.

but for music equipment - really? i almost think 5% is good enough, both my big consoles would be full of 5% carbon resistors and it all sounds pretty matched to me (for tolerances, the resistors are the least of our problems)

i remember seeing 600 ohm stepped attenuators from the 60's would have big-ass 10% carbon resistors with a bunch of holes drilled in them to match them up. if they had 1% resistors back then, i'm sure they'd have been more than satisfied with stock.

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Re: matched components

Postby jkhuri44 » Fri Sep 16, 2016 2:35 pm

Hey ChrisP and ChrisV :)well thats good to know
i honestly here sooo much talk about it, i figured its "what ur supposed to do"
good to know a simple check on a small packet will be good enough!
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Re: matched components

Postby zenelectro » Sat Sep 17, 2016 2:10 pm

Linear wrote:i see no idea why you would need more than 1% matched resistors. anything more than that is just snake oil i reckon. sure, if you're building test/measuring/scientific equipment then by all means, get 0.01% matched resistors. or if you're building a satellite or nuclear weapon, then the more accurate the better.



About the only DIY project I can think of that would benefit from 0.01% resistors (or better) is a discrete R2R ladder DAC of which there seem to be a few kits kicking around ATM. In fact that is one of the very reasons
IC fabs moved away from that style of DAC's - too costly to make and they got better specs turning resistor
mismatch into noise with Delta Sigma DAC's, such is progress.


but for music equipment - really? i almost think 5% is good enough, both my big consoles would be full of 5% carbon resistors and it all sounds pretty matched to me (for tolerances, the resistors are the least of our problems)



5% when they were new... if they are carbon comp = hygroscopic so they drift and get even noisier over the years.
Still, many PPL love the warm musical sound of Carbon Comp R's.


i remember seeing 600 ohm stepped attenuators from the 60's would have big-ass 10% carbon resistors with a bunch of holes drilled in them to match them up. if they had 1% resistors back then, i'm sure they'd have been more than satisfied with stock.

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