potentiometer question

[DBDbadreligion]

i want to build a fuzz pedal and it calls for 50k pots, i have some 100k pots from another circuit.  can i use those or will there be problems?

thanks

nick

[Barcode80]

solder a 50k (or 47k) across the outside lugs, instant 50k pot.

[Paul Perry (Frostwave)]

solder a 50k (or 47k) across the outside lugs, instant 50k pot.

I don't think so!
A 100K across the outside will usually be better, but it isn't exactly the same, even so.
Whether you can get away with it, depends on the circuit involves.

[Austin73]

Hi Paul, as your in the know,how do you go about increasing a pot say from 10k to 100k. Is this possible, I did try using the parallel resistors formulae and it cam out pretty pants lol  i.e 10meg 100 ohms and 1k but my maths but was pretty tired when i tried that one. The reason being wanted to add expression sockets to a few fx for fun but some have 100k and 500k pots and my EV5 is 10k.

Cheers for any info

Aus

[GREEN FUZ]

want to build a fuzz pedal and it calls for 50k pots, i have some 100k pots from another circuit.  can i use those or will there be problems?

I would just try it with the 100k pots. You may find that you are happy with the result. If not you can always change them.

[DBDbadreligion]

solder a 50k (or 47k) across the outside lugs, instant 50k pot.

thanks that's exactly what i was looking for.

[Barcode80]

solder a 50k (or 47k) across the outside lugs, instant 50k pot.

I don't think so!
A 100K across the outside will usually be better, but it isn't exactly the same, even so.
Whether you can get away with it, depends on the circuit involves.

WOOPS! you are absolutely right. it was late...

a 100k across the lugs will bring a 100k pot to about 50k

[DBDbadreligion]

solder a 50k (or 47k) across the outside lugs, instant 50k pot.

I don't think so!
A 100K across the outside will usually be better, but it isn't exactly the same, even so.
Whether you can get away with it, depends on the circuit involves.

WOOPS! you are absolutely right. it was late...

a 100k across the lugs will bring a 100k pot to about 50k

oh ok, where do you get this information from?  i would like to be able to learn more about this.

[The Tone God]

Obligatory Geofex link:

http://www.geofex.com/Article_Folders/potsecrets/potscret.htm

Andrew

[Mark Hammer]

i want to build a fuzz pedal and it calls for 50k pots, i have some 100k pots from another circuit.  can i use those or will there be problems?

thanks

nick

It will depend where and how they are used.  There are many instances out there where the original schematic employs one value, and some folks find that a smaller or larger value works better for them.  In those cases, you simply stick in the other value in place of the original and reap the benefits.  In other cases, a substitute value with a modification works out great.

Also, note that the part may be a "pot", but pots can be used as voltage dividers (like a volume control) OR as variable resistors (where only the resistance between the wiper and one outside lug matters).  Subbing pot values for variable resistors can often be much less trouble and less picky in what can and can't work, than voltage dividers.

Can we ask what the circuit is and where you plan to stick the pot in the circuit?

[DBDbadreligion]

i am making a "shin ei fy-2 companion fuzzmaster" clone with scoop knob.  it calls for 50k linear on all the pots.

[Mark Hammer]

As the guy who drew that, I can say after some experimentation that you don't really need much more than about 10-15k of resistance.  I imagine some people will feel that more than 5-10k does everything they need it to do.

If you are trying to fit it into a small space, you might even feel that 3 settings with a toggle switch are sufficient for your needs.  For instance, run a 12k fixed resistor from the ground side of the 0.1uf cap to the centre lug on a 3-position (on-off-on) SPDT toggle.  Run a  3k9 fixed resistor from the same end of that cap to one outside lug of the switch, and a piece of wire from that same point to the other outside lug of the switch.  You will now have full scoop, some scoop, and negligible scoop.  My own experience with pots suggests that the "ideal" taper of pot for this function does not exist, so a 3-position switch may well be more usable than any pot.

So, why does it say 50k?  Because I know that's more than what was required to completely negate the scoop, plus it is a common value.  In practice, only a modest portion of its full range turned out to be really useful.

NOTE:  You're gonna like this pedal!