resistor quality on attenuators

[warpie]

hi there,

I need to staff my Elma rotary switch with some quality resistors for controlling the gain , so here is a couple of questions...

> Is 0.1% tolerance a bit of exaggeration (bad audiophile habbits)?
> What brands do you guys prefer for such tasks?
> Metal film or something else? I read somewhere that metal foil are nice too.

I know the 'buy and test' option and I do it quite often. However, I think any personal experiences you have to share
will put me on the right track.

hope I'm not asking too much... 

thanks
w.

 

[radiance]

I always use the cheapest metal film 1% resistors I can find....well..not THE cheapest but say between 1 and 10 cents a piece depending on the quantity sold. As soon as you enter dale/vishay territory you'll pay much more, like 1 euro a piece.
When doing a dual deck 24 position it add's up and you'll be better of buying a pre-assembled one from ELMA.

 

[rob_gould]

Yeah 1% here too.

I use the own-brand metal film from www.rapidonline.com.  No complaints so far.

Obviously the smaller the tolerance on the resistors,the greater the accuracy between steps on your attenuator.  Unless you need really accurate steps, then 1% should be fine.

Check the Poor Man 660 thread (I think) to find an excel spreadsheet value calculator posted by [silent-arts] that actually allows you to type in the required total resistance range of your attenuator plus number of steps to get correct values for all your resistors.  The other cool thing that this tool did (again if I recall correctly) was show the different plots for different tolerances of resistor, showing how accurate each tolerance would be to the preferred value.

 

[tv]

+1

( 1% "metal", 0.6W ) ...

 

[warpie]

thanks guys!

I think I'll go for the 1%. I already have some pf the values in 1% anyway..

+1

( 1% "metal", 0.6W ) ...

why 0.6W and not the usual 1/4W???  Can you elaborate please?
1/4 will be also smaller, thus easier to solder all the resistors on the elma.

I found some 1% Multicomp but I'm not sure about the quality. I also found some Xicon....

 

[tv]

0.6W "metal" are usually the "usual" ones. (Same size as 1/4W carbon).

IOW, the 1% metals that look like 1/4W are usually rated for 0.6W.

 

[PRR]

In the good old days, gold-stripe (5%) was always good enough. See emmr's post.

These days 5% are so cheap we pick our teeth with 2% parts, which leaves only 1% for your attenuator.

 

[mcs]

I found some 1% Multicomp but I'm not sure about the quality. I also found some Xicon....

Sounds like Farnell. Can't you get the "normal" MRS25 1% 0.6W from Farnell? They are made by Philips/BC/Name of the month, and are cheap and good for this purpose. I usually pay $0.03 each, and that's the retail price...

Best regards,

Mikkel C. Simonsen