Timmy Mod (beginner question)

[ToneJunkie]

Hi I use a real timmy pedal that I just love to leave on all the time.  I use it to add a little magic to my clean sound and I don't really want any clipping from it.  There is a tiny sweet spot very low on the gain knob and I was wondering if it was possible to change the gain pot out for a smaller value to make the pedal have a much larger sweet spot.  I never use it for overdrive and I thought that this would make the pedal easier to use for me.   So I'm a beginner at this and I was thinking I could switch the 1M gain pot out for a 250k or even a 100k pot and it would do what I am asking.  Any help would be appreciated. ?

[thermionix]

Where in the 1M pot's range is the sweet spot?  You may have to desolder it to measure.  Then you could use a 100K pot with a resistor in series on one or both ends to make up the other 900K and keep the tone the same, if that makes sense.

[ToneJunkie]

Its wired as a variable resistor right?  Oh for some reason I assumed at the least resistance it would be the least overdrive... is it the opposite?

[thermionix]

No idea, got a schematic?

[ToneJunkie]

Here is a guy who wrote an article on the schematic... http://www.coda-effects.com/2015/11/jan-ray-in-1590b-with-coda-effects-pcb.html .  I hope its OK if I post this 

[nocentelli]

The stock gain pot is a 500kB as a variable resistor in the feedback loop: You can happily replace it with a 250k or 100k pot to reduce the maximum gain and widen the low gain sweetspot

[Keppy]

There is a tiny sweet spot very low on the gain knob and I was wondering if it was possible to change the gain pot out for a smaller value to make the pedal have a much larger sweet spot.

Yes.

Its wired as a variable resistor right?

Yes.

Oh for some reason I assumed at the least resistance it would be the least overdrive... is it the opposite?

No, your first assumption is correct. This gain stage is a variation on the one used in the Tube Screamer, so you can read more about how the gain control works here.

The schematic you link to shows a linear (B) taper pot. Most pedals use an audio (A) taper pot in this configuration. From an auditory perspective, a linear pot will appear to increase the gain quickly as you raise the gain from minimum, then allow for finer adjustment in the upper ranges. In contrast, an audio taper pot will give smooth adjustment over the entire range, not favoring any particular setting. Assuming this schematic matches your pedal exactly, you could get a wider sweet spot without losing any range just by switching to an audio taper pot with the same 500k value. You could widen it further by using an audio taper pot with a lower value like you suggested, but that may not be necessary.

[Rob Strand]

The schematic you link to shows a linear (B) taper pot. Most pedals use an audio (A) taper pot in this configuration. From an auditory perspective, a linear pot will appear to increase the gain quickly as you raise the gain from minimum, then allow for finer adjustment in the upper ranges.

The B tape pot is probably the real cause of narrow sweet spot down low.

[Mark Hammer]

Assuming you can access it, the simple solution is to tack on a fixed resistor in parallel with the gain pot.  That way, you don't have to remove anything.  Moreover, while pots come in standard values that MAY not dovetail with what you seek, resistors come in a much wider range of values such that the combined parallel value can be tailored.  For instance, a 500k pot with a 330k tacked on in parallel yields a maximum combined resistance of just over 198k...and so on.

[ToneJunkie]

I installed a 100kA pot for drive... and the verdict is.  It worked perfectly :-)  Much larger sweet spot for what I use it for.  In general its not till around 2 o clock when I get some overdrive.  Anything before that just adds a little compression and sweetness to the feel and sound.   Thanks for everyones help!

[ToneJunkie]

Here is that very Timmy and the sound I'm after in general...  335 -> Timmy -> Strymon Timeline -> HOF Reverb -> Bandmaster -> G1265 Speaker

[thermionix]

See now, that 335 ain't no good.  Send it to me and I'll get rid of it for you.  No charge.

[vigilante397]

See now, that 335 ain't no good.  Send it to me and I'll get rid of it for you.  No charge.

Generous offer. I could never quite get used to the necks on 335's. Plus the hassle of working on the electronics. Not to mention the price tag Then I discovered the ES-333, all three problems solved in one guitar