Bastion Overdrive (MojohandFX Rook)

MichaelW

Well-known member
Build Rating
5.00 star(s)
I actually built this one a couple weeks ago.

At first I was a bit underwhelmed with it. But after looking up the usage on the Mojo website and figuring out how to use it, I've come to appreciate it a bit more.

Is it a YATS? Yes it is...heh, but like the Virgil it's a YATS with some extended eq controls. In fact, from a design perspective, it's very similar to the Bad Monkey in that it's got an active EQ. However, they don't sound quite the same. The Virgil Monkey has a huge range in the tone controls. Whereas the Bastion is a bit more pedestrian.

One cool thing about the Bastion is that with the tone controls turned fully off, it's your basic mid-hump TS808. So you can use it in any application you'd use an 808 for, like driving an amp to tighten up the low end, etc. But pulling in the treble control you can also dial out the mids and have a more neutral (dare I say "transparent") overdrive.

The toggle switch toggles either the complement of 4148's or LED clippers. (Or whatever else you want to use). The retail pedal has a "no clipper" middle position but the BOM called for an On-On, which is what I used. I'm not sure if this is a mistake or not. Having said that, I never use just opamp clipping in these types of circuits so not a biggy for me. But if you want to build it to the original specs, then use an On-Off-on for the toggle.

Cool pedal, sounds great, but it also sounds like a lot of other overdrives. Nothing really stands out about it. So no demo for now. Unless someone really wants to hear it. Just holla and I can pull something together.

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Is it a YATs or a Timmy (I have not done a schem comparison between the two, though they do seem similar. Baxandall tone control being the biggest obvious difference) derivative? I have one of these going into a combo build which will be bd-2-> bastion. Player using a rook as the higher gain of the two.
 
Is it a YATs or a Timmy (I have not done a schem comparison between the two, though they do seem similar. Baxandall tone control being the biggest obvious difference) derivative? I have one of these going into a combo build which will be bd-2-> bastion. Player using a rook as the higher gain of the two.
It's more YATS than Timmy.

Here's the schematic.

Edit: My bad that was the schematic for the Virgil
 

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Weird that the schematic shows two ICs. I swear I can only see one in the pic.

I too was underwhelmed with this one. Def YATS. Just having two-band EQ doesn't make it better; the EQ has to be in the right (musical) places. The Bastion sounds to me like someone just whacked some EQ in and didn't test it to see if it sounded any good. Similar to the Royal Blue OD. The bass knob is too low in the frequencies.
 
Weird that the schematic shows two ICs. I swear I can only see one in the pic.

I too was underwhelmed with this one. Def YATS. Just having two-band EQ doesn't make it better; the EQ has to be in the right (musical) places. The Bastion sounds to me like someone just whacked some EQ in and didn't test it to see if it sounded any good. Similar to the Royal Blue OD. The bass knob is too low in the frequencies.
My bad. that was the schematic for the Virgil.
 
It's come up in another thread but something I'm still curious about is the LPF after the clipping stage. I trust that the schematic is correct, though I'm wondering how the values of 8k2/100n (corner frequency of 194 Hz) don't result a very muffled sound. For comparison, the TS values are 1k/220n (724 Hz) and if anything, most YATS I've seen tend to push the frequency higher.

I admittedly haven't wrapped my head around the Baxandall EQ that follows, and I imagine that plays a role here.
Screenshot 2023-05-18 at 07.57.09.png
 
It's come up in another thread but something I'm still curious about is the LPF after the clipping stage. I trust that the schematic is correct, though I'm wondering how the values of 8k2/100n (corner frequency of 194 Hz) don't result a very muffled sound. For comparison, the TS values are 1k/220n (724 Hz) and if anything, most YATS I've seen tend to push the frequency higher.

I admittedly haven't wrapped my head around the Baxandall EQ that follows, and I imagine that plays a role here.
View attachment 48893
It's the active EQ that makes the difference. When you roll off the tone controls it acts/sounds like an extra muffled TS808.
I'll record a demo that shows this affect. Actually, once I figured this out, I started appreciating the pedal a lot more and it's growing on me.

It can do the YATS thing but it also has a lot more range and can also be a more "transparent" drive. Pretty versatile actually. It's not unlike the Bad Monkey with some slight differences in the gain timbre.
 
I still have that board sitting around, never got around to building because of that low pass filter there. Replacing the 8.2k R6 with a 1k would make it a 1.5khz LPF and the treble control would be more useful imo, but I haven't tried it out to determine for sure.
 
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