7.9k resistor

[natezaps]

what would you do?

I have two viable options for a problem I have. I'm looking for any experienced opinion on this.

My BOM calls for a 7.9k resistor - which obviously isn't standard. I found some 7.9k resistors at Mouser. However, I got them the other day and they huge. idk what's up with that. They're 1/4 watt. I'd have to mount it vertical keeping in mind it would be taller than most electrolytic caps. anyway, I also have some 7.5k and 390ohm resistors I can put together to make almost 7.9k (close enough for this anyway).

which option would you with?

 

[Robert]

Which project is this for?

 

[natezaps]

for the SWAH

 

[Robert]

Gotcha. That resistor has a 50K trim pot in series, so I'd say 7.5K is close enough.

 

[finebyfine]

For non standard/common resistors I sometimes just grab a few that are near and test them until one is close. Thank goodness that 1% is sometimes a lie

 

[Sturdag Lagernathy]

I usually series/parallel two values to get an odd value that tayda doesn't sell. Close enough for rock n' roll

An EXCELLENT reason to learn Ohm's law.

 

[Mcknib]

I'd agree 7.5K will do with the 50K bias trimmer in series that'll give you plenty to play with

Here's a wee circuit breakdown you may find useful

Mad Professor - Snow White Auto Wah

The Mad Professor Snow White Auto Wah is a cool little envelope filter. Designed by Bjorn of BJF effects it always was going to be a dece...

revolutiondeux.blogspot.com

 

[fig]

An EXCELLENT reason to learn Ohm's law.

I agree. In the meantime you can use a parallel resistance calculator. Check your favorite app store for a freebie, or google it.

 

[Chuck D. Bones]

Bjorn sure loves to use obscure resistor values. I think he must like certain patterns of color bands. I know I do.

 

[zgrav]

I'd agree 7.5K will do with the 50K bias trimmer in series that'll give you plenty to play with

Here's a wee circuit breakdown you may find useful

Mad Professor - Snow White Auto Wah

The Mad Professor Snow White Auto Wah is a cool little envelope filter. Designed by Bjorn of BJF effects it always was going to be a dece...

revolutiondeux.blogspot.com

Thanks for posting that link. I just finished the vero build last week for the Snow White Auto Wah. Even as a standalone effect it has some really nice shimmery settings in addition to the "quack mode" I got as close as I could to the spec'd value with a few subs. The project is also interesting because it includes a 5 volt regulator in the build.

 

[zgrav]

also -- in the linked article there is a link to the forum about this pedal on freestompboxes.org. very nice to see in that forum that Bjorn also posted a suggestion for troubleshooting one of the builds.

 

[Chuck D. Bones]

Revolutiondeux is a great resource. I have found many a schematic and links to more pedal info there.