Ruetz mod for German rat clone vs adding a clean blend?

[H3R3T1K]

So I was gonna buy the rat by Musikding. I'm a bass player. I was looking for a way to add a switchable mod for a more even eq response letting more bass through hopefully without mud (add bass after distortion?)... The Ruetz mod came up. I'm wondering what this mod would look like with the Musikding rat as in which parts would need to be changed. Or if I should just use a BB Case and add a clean blend and call it a day. This tone demo sounds so good I don't know if I actually NEED a clean blend but the switchable Ruetz mod would be cool either way:

Here is a very rough explanation of what this mod accomplishes. The value of
the resistors sets the gain of the circuit: the lower the value of the resistor, the
higher the gain. But notice that in the original circuit there are two resistors, of
widely different value. This would suggest two different values of gain. But, of
course, the circuit as a whole is going to exhibit only one overall gain value.
This is where the caps come into play. The 2.2uf cap has a certain low-end
cutoff frequency; above this frequency, the gain will be set by the 47 ohm
resistor. But the 4.7uf cap will have an even lower cutoff frequency: the gain
for these lower frequencies will be set by the 560 ohm resistor. But since the
560 ohm resistor is a much larger value than the 47 ohm, the gain for these
lower frequencies will be much lower. The overall result is: the gain of the
circuit is less for the bass response, and more for the midrange and treble
response.
Cutting the 47 ohm/2.2uf pair out of the circuit means that the gain and
frequency response of the circuit is determined solely by the 560 ohm/4.7uf
pair. This lowers the overall gain of the circuit, but also smooths out the
overall frequency respone of the circuit: the amount of gain is flat across low-
end to high-end.
This simple mod suited my uncle perfectly: he loves it! Now, you might want
to try this mod in the other direction: you might want to cut out the 560
ohm/4.7uf pair, for a higher overall gain and even tighter low-end. Or, install a
switch to make one or both of these mods switchable for even more
versatility.

 

[Popnfreshbass]

Ruetz mod is cool and helps on bass for sure. But if you really wanna use a Rat on bass, I suggest using red LED’s for the clipping diodes. That’s what I use on bass, and it adds just the right amount of bass and clarity to the signal, while still being a Rat.

 

[tcpoint]

I'm a big fan of red LED's for the clipping diodes for guitar.

 

[H3R3T1K]

@Popnfreshbass @tcpoint At this point I'm contemplating Ruetz-Mod plus red LEDs. Could you tell me what the mod woud look like on the this rat clone (schmematics in the first post)?

Would it be possible to both make the Ruetz mod and alternative red LED clipping switchable?

 

[benny_profane]

If you run the Rat at higher gain levels, the Ruetz mod has diminishing returns. Regardless, it won’t help as a clean bass pass through (it will add more clipped bass frequencies). You could also try the @Chuck D. Bones CONTOUR mod here instead.

If you’re trying to get clean bass presence, a clean blend may be your best option.

 

[H3R3T1K]

@benny_profane

The rat would go before a preamp or a Wampler-modded Boss ODB-3. I want the rat as a higher gain pedal. I could add bass back in that way couldn't I?

Could you explain to me what I would need to do to this specific rat for the contour mod? I'm gonna pass this on to the friend building the pedal for me.

 

[H3R3T1K]

Also what are common clipping mods to the rat? I'm inclined to try red LEDs but I'm also looking for something really nasty that moves it further towards a fuzz. I do love that fuzzy type distortion. I'll add a 3-way switch to access stock, red LEDs and option 3.

 

[jesuscrisp]

Haven't played a Rat on bass, so I can't comment on the Ruetz mod for that, but I really hate it for guitar. Just makes it darker, lower gain, kills the Rat's bite, actually makes it not a Rat anymore. If you want something more nasty sounding, don't do it. A Rat will go into fuzzy distortion territory with no help at all needed. If you want something more flexible, you can run a small resistor + a 1K log pot in series instead of the 47R resistor for a "sweep" knob.
LEDs are great for clipping in the rat, but personally my favorite combination is 1 silicone diode + 1 LED asymmetrical clipping. What you can do to achieve this is put in LEDs in the diode slots, use a DPDT on/off/on switch and put a single silicone diode on one side, a pair of antiparallel silicone diodes on the other side. So you would have asymmetrical, LED only, silicone only.

There are however PCBs/kits that already include both some sort of Ruetz and clipping diode mod, such as the Ratt Deluxe or Aion Helios.

For a clean blend you can add a Buff N' Blend kit to the Rat, also available on Musikding. Just don't get confused with all the extra things you're adding by the end.

Other mods you can do:

• Increase the pull-down and bias resistors to 2M2 for better input impedance (not necessary in my experience)
• Change the tone capacitor to a smaller value like 1n or 2n2 to make the sweep of the filter knob a bit different (less treble roll-off)
• Use a C100K pot for filter and wire it in reverse so it works the "right" way around as a tone knob
• Try different op amps by socketing both the op amp and compensation cap (you will get an IC-socket with the kit, just add a 2-pin inline socket with your order). Some single op amps don't need the compensation caps, in others you can achieve different results using different cap values. OP07 with 33pF will be standard that you receive, some people say the cap there is uselessfor that IC, some say increase to 100pF to sound more like an LM308. You can try an LM301 with a larger compensation cap (47-100pF) to get closer to the LM308 sound, at least it's one of my go-to options. Otherwise you can try LM741, TL071, NE5534 (all these without compensation cap) for a different tone. LM741 is nice in my opinion, TL071 and NE5534 sound a bit stale and less saturated than I like on guitar but maybe they work on bass? Either of these will be less fuzzy than an LM308, LM301 or OP07 though.
• For bass you may or may not benefit from a larger input cap, 22n is standard, maybe 47n could help a bit with bass frequencies but will also make everything saggier and fuzzier. Plus if you have a clean blend you should get back plenty of bass frequencies.

 

[thesmokingman]

imo ... the Ruetz mod is kinda garbage for a rat on guitar.

That isn't to say that the concept isn't without merit wrt to bass guitar, as the proco juggernaut simplified the feedback loop arrangement of the rat by cutting it down to a single 220R resistor and 47u capacitor (15Hz corner frequency for those running their calculators) ... also doubled the size of the coupling cap after the op amp to 10u and the tone stack cap got bumped to 10n and the 1k5 series resistance got eliminated (159.2Hz corner at 100K) and finally the output cap got increased to 10u ... oh and utilized the 1458 op amp (dual op amp of the 741) ... all easily doable mods to a diy rat board. now if you wanted to add blend, should be no problem as I don't believe the rat inverts phase ... only feature you'd be missing at that point is the master volume ... or you could request the juggernaut be a future pedalpcb project, js