Mixing Modes on the Hyped Fuzz with a Potentiometer

[debrad]

A friend of mine has asked if I can build him a Hyped Fuzz with a "Blend" or "Mixing" knob instead of the 3 way Mode toggle.

In my research, I came across a post from @Grubb (Hyped Fuzz Mode Blend) who was trying to do the same thing but didn't receive any answers to his questions so I will ask again with the hope that someone more knowledgeable than I will chime in with some words of wisdom (or maybe @Grubb ploughed ahead and can share the results...):

1) Can I replace the 3 way toggle with a potentiometer which would give me Fuzz 1 at one end of the rotation, Fuzz 2 at the other end, and a blend of the two in between (I realize that I may lose the boost function, he's OK with that, but I am also thinking that I could use a switch to toggle between the blended fuzz path and the boost path if he wants...).

2) Would it work to install the potentiometer where @Grubb suggested below (Scooped path goes from R26 to one outside lug of a pot, Full path goes from R27 to the other outside lug of a pot, and lug 2 connects to R28)?

3) What would be an appropriate resistance for the blend/mix potentiometer...something small (under 50k to minimize the impact on the values of R26 and R27), something between 100k and 500k, or something larger?

 

[jwin615]

I think using a MN or AC dual pot here could work. You could try a regular pot but I think you'll have adverse effects from the loading of the opamp output. I would stick to a low value pot for that reason. I don't think I've seen MN in less than 25k.
A dual linear pot may work as well.
I would cut the carbon trace on each wafer at the extreme(off) end of whatever dual pot you use. That way, when the wiper hits that position, there is absolutely no signal.

If that doesn't make sense, I can maybe elaborate some more to ight. A little busy this afternoon.

 

[Grubb]

@debrad I haven't tested it yet (due to the long and constantly-changing list of projects I'm working on), but my schematic did end up with a B10K pot blending both paths. The advice I got on another forum was that the proximity to the opamp stages was a benefit - but @jwin615 has pointed out a potential issue with that so I'd also be keen to hear more.

 

[debrad]

Back again to let you know that I finally got my Hyped Fuzz built now that Canada Post's strike is over and my parts were delivered.

I implemented a blend between the "Scooped" and "Full" paths by replacing the toggle switch with an 200k MN dual pot as outlined by "WalterW" in this thread on the TalkBass forum:

https://www.talkbass.com/threads/ultimate-no-load-ungrounded-blend-pot-pics.1096449/

It seems to work in the sense that I definitely get Scooped at one end of the rotation, Full at the other end of the rotation, and a 0/50 combination of the two at the centre of rotation; however, I'm not really hearing much of a gradation in between...it's more like Scooped from 0-49%, both at 50%, and Full from 51-100%.

Do you think I've done something wrong, is this the "nature of the beast", or do you think I need a different pot value (higher, lower)?