Orange Squeezer External Bias Problem, can I use a 2K pot instead of 10k?

zindra · October 30, 2009, 12:38:08 PM

I just finished the GGG OSQ. It is only my second diy pedal. I want to have the bias control outside and I ordered a 10k linear mini pot to substitute the internal trimpot. I received a 2K pot instead of the 10K. Will the 2k pot work instead of the 10k trimpot? What could happen?
Thank you

theehman · October 30, 2009, 12:40:53 PM

You could use the 2k with a 4.7k on each outside lug.

zindra · October 30, 2009, 12:49:34 PM

4.7 caps or resistors...? Just starting out, excuse my ignorance! Just for curiosity, what would happen if I used the 2k directly?
Thanks

theehman · October 30, 2009, 12:51:48 PM

4.7k resistors.

I don't think 2k will give you enough room to bias it correctly.

zindra · October 30, 2009, 12:52:58 PM

That was fast! Thank you very much.

zindra · October 30, 2009, 01:28:05 PM

I just read your answer again and realized that adding resistors to the 2K pot will lower the value, not raise it, right? What I should do is turn the 2k pot into a 10k, Is that possible?

jacobyjd · October 30, 2009, 01:30:35 PM

you'll want to add those resistors in series, not in parallel

I'd also suggest trying the 2k pot in series with 1 4.7k resistor first, otherwise, even with the pot at 0R, you'll have almost 10k of resistance already.

In fact, you could start with a 4.7k. If that give you a usable range on the pot, keep stepping up that series resistor until the range of the pot is workable

zindra · October 30, 2009, 01:37:41 PM

Ok, I need a fast electronics for dummies course. Can you please explain me how I add the resistors in series? If I only use one resistor which lug should I connect it to? Looking from the back of the pot: LUG1 LUG2 LUG3 $:-\$

thedefog · October 30, 2009, 02:37:19 PM

Quote from: zindra on October 30, 2009, 01:37:41 PM
Ok, I need a fast electronics for dummies course. Can you please explain me how I add the resistors in series? If I only use one resistor which lug should I connect it to? Looking from the back of the pot: LUG1 LUG2 LUG3 $:-\$

Solder one end of the 4k7 resistor to lug 3 of the pot, and the opposite to a wire running to where lug 3 goes on the board. Since Lug 1 & 2 are linked together, solder the 2k2 resistor through both lugs 1 & 2 on the pot, and a wire to the opposite end running to where either lug 1 or 2 goes on the board.

Hopefully that helps.

chi_boy · October 30, 2009, 03:00:49 PM

You may want to search some more and make sure you really want that external pot. When I was researching for mine I found most people said the external was pretty useless. The advise I followed was to buy a multi turn internal pot to make finding the sweet spot a little easier.

thedefog · October 30, 2009, 03:11:10 PM

Quote from: chi_boy on October 30, 2009, 03:00:49 PM
You may want to search some more and make sure you really want that external pot. When I was researching for mine I found most people said the external was pretty useless. The advise I followed was to buy a multi turn internal pot to make finding the sweet spot a little easier.

Agreed. I built one of these guys that is regularly used on my live pedal board, and I only have the volume pot externally mounted. And if I built it again, I'd just use trimmers for both, as I just leave the volume at max anyhow. It's really a set it and forget it kind of effect, especially if you are always using it first in your signal chain.

doc_drop · October 30, 2009, 03:30:00 PM

I just built one of these a couple of weeks ago. I really like it. It is subtle, but just makes things sound "better", with a crisp attack and nice sustain and fade out on notes.

The way I am using it is I set the trim pot so that if I crank the volume pot, it starts to overdrive the next pedal. I think having the external volume pot is very useful in that I can overdrive or not, depending on what I want.

Just my $.02.

zindra · October 30, 2009, 06:09:50 PM

Frustrating. After much thought, I finally build it using a mod by Theo Hartmann that involves using an external 2K pot in series with the 10k trimpot. I wasn't sure of the correct setup so I just fit the 3 last wires to the PCB without soldering and... it worked great! The external trim worked perfectly with huge range. But... then I soldered the wires, assembled the pedal and now there is a huge volume drop when it's on. Even with the volume knob all the way up it's not even unity gain. I've revised everything and redone a few solders, I can't come up with what's gone wrong. Any ideas? it was working great!

zindra · October 31, 2009, 08:17:19 PM

Done! It works great. Nice range of compression with the external knob, not a "set and forget" pedal anymore. But I wired it another way (or I just plain didn't understand Hartman's diagram and got to the same place). I am going to open a new topic with a very easy sketch, that way beguinners like me can understand it and save the two days of trial and error I've gone through. In case any of you who know see something weird, please let me know. Thank you.

zindra · November 01, 2009, 04:15:20 AM

Here is where I posted the easy sketch:
http://www.diystompboxes.com/smfforum/index.php?topic=80001.msg660967#msg660967
http://picasaweb.google.es/ohwowmail/OSQMOD#

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Orange Squeezer External Bias Problem, can I use a 2K pot instead of 10k?