Tried out my PedalPCB Splendiferous OD again...

H

HamishR

Well-known member
And tried to dial it in differently this time. I always go for a low gain, clear tone and discovered that the Splendiferous OD gets loud fast and the bass can be overwhelming. So I pulled out the Les Paul and let it get loud and raucous. Wow - this thing can really pump out some gain! It can chug too. Now this isn't my normal sound but it is a lotta fun. What's impressive is that if you pull the gain back and dial the bass down to around 9.00 it can still do a good lower gain drive. So I'm think that if I build this again I might go for an A taper pot for the bass rather than the stock B and maybe an A500K for Gain rather than 1M.

It's interesting to try things out again a while after you first built them. Usually I'll build something, see if it works for what I do and if it doesn't I'll either make a few mods or just stick it on the shelf. I still try things out again after a few months and usually it goes back on the shelf if it's in the NO pile. But this time I think this one might get a bit more use and I may mod it a little. It's got quite a cool sound of its own.

Has anyone else built this and liked it?
 
Wow - that's a very cool build!

Funny thing is that I actually owned an original Royal Blue when they first came out. I liked it back then. So I built one and thought yeah it's ok but... And now I think that if I change the taper of the bass pot I may like it all over again. :) I guess it comes down to the sound you are chasing at the time. Ok I admit it - I'm fickle.
 
You may be onto something with changing the pot taper. I'd be interested in hearing your thoughts when/if you decide to try it out. I tend to treat the Splendiferous (Royal Blue OD) similarly to how I'd use a Boss OD-3 with my rig. It can be a little bass heavy and the distortion sounds somewhat Marshall"esque", but it works very well in the right situation. Both of them have what I'd consider natural and musical distortion.
 
I just built a Splendiferous again, this time on Vero because I couldn't wait for the PCBs to get here! The only changes I made were to use an A50K pot for Bass, an A500K for Gain and I used BAT41s for the clipping diodes as I have an aversion to LEDs as clippers. On my PCB version I used a quartet of 1N4148s - two pairs.

The bass pot works much better now for me. Obviously it still gets chunky/boomy at higher levels but now I get better control in the ranges I would want to use it. The A500K/BAT41 pair combo works in a similar way to the 1MA/1N4148 quartet does - the Gain pot is in a similar position for equivalent levels of dirt. But the interesting thing is that somehow the tone has warmed up a little. My guess is that it's the BAT41s, but why I haven't a clue! Maybe it's just parts tolerance but the newer version is a tad fuller/warmer sounding - in a good way unless you prefer the more Marshall tones of the original. The only downside to using BAT41s is that you lose a fairly significant amount of level. I need to have volume higher to get the same volume.

So for me the bass pot taper change is better. I also think I like the BAT41s better, but they may not be better for everyone. Probably putting the clipping diodes on a switch might be a good idea.

All of this has made me appreciate the Royal Blue OD much more and I think I'm liking it more than the Snozberry now. The RB is kind if a simpler version of the Snozberry in a way and has a less pronounced low-mid bump.
 
The Royal Blue is essentially a TS distortion stage followed by a James tone stack.
The TS section is voiced differently, shifting the emphasis from the mids (720Hz) up an octave into the treble region (1.4KHz).
R8, R9 & C7 provide a treble cut similar to the TS, but the amount of treble cut is limited by R9.
The James tone stack provides more control over the bass & treble content.
The last stage provides volume recovery after the lossy tone stack, with a little roll-off in the high treble region (C14).

With a James tone stack, the pot tapers end up being a compromise between A-taper & B-taper. If you only use the BASS knob above 9:00, then B-taper has a better sweep. If you want the bass cut to be more gradual below 9:00 then A-taper will get you there, at the expense of a more abrupt sweep above 3:00.

About the clipping diodes...
Schottky diodes (BAT41 are Schottky) are leaky. Not nearly as leaky as Ge diodes. That leakage has the same effect as turning the GAIN down a bit.
The TS soft clipping circuit has a built-in clean bleed because the output of the first stage is the sum of the clipped signal and the unclipped input signal. BAT41s have a low Vf, which makes the clipped signal smaller. Since the unclipped portion of the signal is the same, when we reduce Vf, the blend of clipped and unclipped is tilted in favor of the unclipped signal. That will have a major effect on dynamics and harmonic content. The lower Vf also reduces the overall volume. The volume can be increased by increasing R17. Don't get crazy or the last stage will clip. C14 will need to be decreased proportionately to keep the same voicing.
 
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