Who knows the real trick to get more bass? (RAT)

[JackSkellington]

Hi! With my second Rat building I tried some tricks I read around here and there to get more bass from this pedal.

I tried with my first Rat the Ruetz mod with the pot control (replacing the R6 47R with a 1k Linear pot).
Now I tried to replace the C7 2.2uF with a 10uF. Then I back with the stock caps.
Then I replace the C6 4.7uF with a 10uF, and even the R7 560R with a 220R.
Nothing of that gets more bass, I got just a slightly dull sound, but this is not a Fat/Bass Boost mod I mean.
I guess it's very hard to get more bass from this circuit!

Who knows the real trick to get more bass?

Thanks!

[jimilee]

So, here is what I do. uF caps don't carry audio. Film caps do. So I would take the first film cap in the audio path which looks like a 22n, and make it a 220n, then I would do the same thing to the last film cap. I've never done this with overdrives, but I have done it with filter pedals.

[diablochris6]

Have you tried looking at how the VFE Alpha Dog adds the Fat control? Might be a good possibility.

[reddesert]

The Rat is not a bass booster. It's not in the nature of the circuit. The Ruetz mod replacing the 47R with a 1K trimpot is the correct answer to reduce the fizzy quality of the Rat (you will also reduce its gain somewhat, I think), but it won't be a bass booster. You don't need to change any of the caps. The 47R + 2.2 uF cap has a corner frequency of 1500 Hz and because of its location - it's part of the feedback voltage divider for a non-inverting op amp amplifier - it makes the gain of bass frequencies less than treble frequencies.

If you want more control over EQ, you can build an Idiotbox Blowerbox, which is a Rat with a Baxandall/James tonestack, giving you treble and bass tone controls. I did this, but I also still did the Ruetz mod to it.

[Aentons]

The only way I could ever get a rat to have the bass I wanted was to blend in some clean signal and use a hpf and lpf.

All the ones I have tried worked well this way... Rat2, Whiteface Reissue, Duecetone(all settings), VFE Alpha Dog. I have a two loop mixer/blender and a variable lpf and hpf that I used to experiment with.

[JackSkellington]

I don't know if I like the blend mod. So the Rat really seems "bass unboostable"?

But the Fat Rat version has a bass boost, some demos show it works pretty fine.
I heard that it adds a 6.8uF in parallel to the C6 4.7uF, thing I tried replace C6 with a 10uF, but... it's not a really bass boost.

[diablochris6]

Maybe you can add a gyrator that can boost and cut at a low end frequency?

[JackSkellington]

Some clue how I could do it?

Please?

[Rockhorst]

Google Geofex, Equalizer and Gyrator, or alternatively Electric Druid Metalzone Analysis. Two excellent examples with gyrators.

[JackSkellington]

Thank you very much, I'll try to take a look.
Unfortunately, it's not a very simple solution I was thinking.

[midwayfair]

R7 and C6 are already dominated by the gain from R6 and C7. The corner frequency of those is 1500 Hz (as reddesert already told you).

You can boost the base as much as you're boosting everything else by making C7 220uF. You'll boost literally every frequency. You might as well remove R7 and C6 now as they aren't doing anything. If you turn the treble cut all the way up, ta-da, you have a bass booster. Of course, now you sound like you're playing underwater, but you did ask for a bass booster ...

[marmora]

http://baritones.tumblr.com/post/92511266453/darrell-rants-about-the-proco-rat-and-the-ruetz

Further reading...

[JackSkellington]

[...]
You can boost the base as much as you're boosting everything else by making C7 220uF. You'll boost literally every frequency. You might as well remove R7 and C6 now as they aren't doing anything. If you turn the treble cut all the way up, ta-da, you have a bass booster. Of course, now you sound like you're playing underwater, but you did ask for a bass booster ...

I would like to increase the bass without cut the treble (or the gain) this is the problem.

http://baritones.tumblr.com/post/92511266453/darrell-rants-about-the-proco-rat-and-the-ruetz

Thanks for the link. I tried some mods like that, but the all of them are pretty subtle about the increasing of the bass. Rather those was a cut treble.

[flanagan0718]

This has worked really well for me in the last 2 or 3 rats I modded.

[thesmokingman]

small improvement? remove the 560R/4u7 rc filter completely. the bigger improvement is the proco fat rat  style of changing the filter
I also like the timmy treble cut values in the rat