can this be done..?
i just need to nip the last bit of range/turn off the 5k...so it will behave as a 4.7k...on a fussy speed control...
this is the problem in the uk..we have 4.7k's...the rest of the world has 5k's...for some reason.. :icon_rolleyes:
I highly doubt you'll get your desired results, but you can try: http://www.diystompboxes.com/analogalchemy/emh/emh.html
I would say that 4.7K and 5K are the same if you consider the tolerance -
us in the UK just understand decimal points better !
the tolerance is unreasonably bang on for a change..4.9x..
Yeah, have you actually tried measuring the max resistance of the pot? It may already be a 4.7k, lol.. (edit: nevermind, just read your post!)
That said, I think you can wire up a 300 ohm resistor in series with a 5k pot to get 4.7k, if I'm remembering that correctly.
double post
yep , measured it..
ok i'll try the 300r..as it makes sense math wise... :icon_wink:
that would be signal>300r>lug3 then right?...
Quote from: jefe on February 23, 2011, 10:44:26 AM
Yeah, have you actually tried measuring the max resistance of the pot? It may already be a 4.7k, lol.. (edit: nevermind, just read your post!)
That said, I think you can wire up a 300 ohm resistor in series with a 5k pot to get 4.7k, if I'm remembering that correctly.
Sorry Jefe, that's backwards. :( That would make it a 5.3k. (You add series resistors and parallel caps.)
hmmmmm yeah...
what if i stick the 300r on the lug2 out?..to outgoing signal?
This is a speed control? I'm sure you've checked this, but the taper is Linear right? Maybe try a reverse audio taper if the speed is all bunched at the end.
Another trick is a 10kB pot w/ a 9k across the outer lugs. That will get you uber close. Of course now you have to go find said parts... Okay so maybe a 8.2k across the outer lugs.
Quote from: jefe on February 23, 2011, 10:44:26 AM
Yeah, have you actually tried measuring the max resistance of the pot? It may already be a 4.7k, lol.. (edit: nevermind, just read your post!)
That said, I think you can wire up a 300 ohm resistor in series with a 5k pot to get 4.7k, if I'm remembering that correctly.
You didn't remember correctly ;-)
Edit: Oops...just seen your follow up post!
To convert a 5k pot to a 4.7k pot, you need to wire a resistor in parallel across the two outer lugs . Assuming it's a linear pot, then to convert a 5k pot to 4.7k, needs an 80k resistor, I'm stupid & lazy to boot, so I lethargically use one of these calculators....
http://www.1728.com/resistrs.htm
Yeah, thanks for the correction guys.
yep its linear... ok i'll try the 80 (82k ) across outer lugs now...cheers guys,..
brilliant!... gurner wins the prize....i now have a 4.61 pot....yay!..
thanks so much!.. .....strange maths though!...:icon_cool:
That's a cool trick, isn't it? :icon_cool:
yeah very cool...have to remember that one!....cheers guys!.. :icon_cool: :icon_cool: :icon_cool:
QuoteTo convert a 5k pot to a 4.7k pot, you need to wire a resistor in parallel across the two outer lugs . Assuming it's a linear pot, then to convert a 5k pot to 4.7k, needs an 80k resistor, I'm stupid & lazy to boot, so I lethargically use one of these calculators....
I thought of that too but I think you'll find the results you were wanting using my 10k pot trick above. However I also realize you are working with what you have. Carry on!
yeah i get what you mean, would have been best to lower a 10k i guess, as thats the normal thing to do, just didnt wat to rip this apart after doing a neat-ish job on it :icon_mrgreen:...thanks all.. :icon_wink:
Quote from: deadastronaut on February 23, 2011, 11:10:41 AM
yeah very cool...have to remember that one!....cheers guys!.. :icon_cool: :icon_cool: :icon_cool:
It is cool, but just note that the sweep will change.
It will make little difference in this case since the difference between 4.7 & 5 is relatively small.
But if you took a 100K pot and put a 100K resistor across the lugs to get 50K, it will not act the same as a 50K linear pot. The sweep will be milder at the beginning [ie, you'll hit 25K after turning half way] and then a sharper climb to 50K nearing the end of rotation...more heavily weighted to the upper end.