Yoa01, the design you show in post #12 on this thread has a number of problems.
1. Your "clipper on/off" switch is wired wrong. If you look carefully at the circuit you will notice that both sides of the switch are connected together! So the switch will have no effect, and the clipping diodes will always be connected.
2. The clipping diodes probably won't have any effect anyway, because they only start to conduct when the voltage across them reaches about 0.5~0.6V. From my experience, most guitar pickups can't generate this much peak voltage. I could be wrong in your case though.
In any case, the effect of clipping is not to make the sound warmer. It makes the sound harsh and distorted, or a bit "buzzy" if it's gentle clipping. Clipping is what fuzz boxes do.
If the effect of connecting the diodes is subtle, and you're not sure whether it's real or not, you can run an approximation of a double-blind test if you have a friend to help you. This will tell you whether you're REALLY hearing a difference, or whether you're only IMAGINING that you can hear a difference. It's surprising how easily we can fool ourselves into hearing what we EXPECT to hear. Here's how to do the test.
Get your friend to toss a coin, but not to tell you the result. In fact your friend must not communicate with you in any way. If the coin landed heads, your friend turns the diodes ON, or if it landed tails, he turns the diodes OFF. He writes down what he did on a piece of paper that you can't see.
Now, you play the guitar for as long as you want, and listen to the sound. You figure out whether you think the diodes are ON or OFF, and write that down on a separate piece of paper that your friend can't see.
Now, you repeat this process ten times, or more if you can be bothered. During all the testing there should be no communication between you and your friend, other than a signal from him that you can start playing, and a signal from you that he can move to the next test.
At the end of the test run, you compare your notes, and count the number that you got right. If you ran ten tests, and you got five right, there is no correlation between the switch position and your opinion, in other words you have failed to prove that you can even tell the difference between the switch being ON and the switch being OFF.
A higher score implies correlation and that you are successful. Obviously, 100% correlation is pretty good evidence that you can not only tell the difference, but identify which switch position is which. The more tests you run, the more confident you can be.
This is the sort of test that is not normally done by people who like to say "this sounds better". If they took the challenge, they would be able to prove that they're right, but they are often scared that they might fail. Doing the test is the only way to know for sure whether they can even tell the difference between the two options.
3. The value you have for C1, 220 nF, is FAR too high. Such a high capacitance directly across the output of a high-impedance pickup will CLOBBER the treble and turn the sound into a muddy mess. You can calculate the reactance of a capacitor at frequency f using the formula Xc = 1/ (2 pi f C). For C=220e-9 and f=1kHz, Xc is only 723 ohms. Compared to a pickup with an output impedance of say 33k, this is practically a short circuit. I would reduce C1 to around 2.2 nF and try again.
4. C2 is also probably much too high. In this case, there will be little bass rolloff. A lower value, such as perhaps 10 nF, would be better.
5. Your suggestion that the circuit is in any way like a "2-band graphic equaliser" is WAY off the mark. Graphic equalisers have filters with relatively narrow bandwidth and high Q factors; your circuit uses single pole filters, which have a very gentle rolloff, without the limited bandwidth that a graphic equaliser has. The best you can claim is that they're "tone" controls, like on old-fashioned stereos.
Edit:
6. I just looked at the data sheet for the diodes you've specified. They're great huge metal things, rated at 35 amps! They mount through a steel chassis! They're totally unsuitable for this job and will be quite expensive. If you want to try normal silicon diodes, use 1N914s or 1N4148s (they're almost the same). If you use germanium diodes, such as OA91 (if you can still get them), there's a better chance you will hear some audible distortion effects, because germanium diodes have a much lower forward voltage than silicon diodes - around 0.2V instead of 0.6V.