Switching Question

[jstogsdill23]

Hey, right off the bat this is a nOOb question so fo'give if I come across as idiotic. Second, I'm noodling here before I start into a build next month, trying to get my head around the pedal and how I'm going to use it so this is academic at the moment and boots are not on the ground yet. I'm a bassist and frankly not at all a pedal guy so this world is all kinda new to me.

On the Glitterati build (BB Preamp) I love the way the BB overdrives, but it would be nice if there was a bit more clean to pull from a la RC Booster (Quasar). On the Glitterati, if I wanted to mod in a switch to pull the clipping diodes in and out, is that possible? Aaaaaannnnd...  how would one go about doing such a thing? The ultimate question would be: without the diodes in the path would it retain the same tonal character as before, just without the dirt? Of course it is obvious that I'm not entirely clear as to the role of each piece within the build so this will help me understand the components of the build and how they work together to create the whole. Teach a man to fish and all that.

I saw this: http://www.diystompboxes.com/smfforum/index.php?topic=64578.msg510599#msg510599

But not sure if this scheme would work with bypassing three diodes with one switch if ultimately that is what I would have to do.

Here is the Glit pdf: http://www.madbeanpedals.com/projects/Glitterrattii/docs/Glitterrattii.pdf

Thanks for any help. Really fascinating stuff here at MadBean and I appreciate the knowledge running around this board.

[mgwhit]

From looking at the circuit, you'd just need to lift D1 and D2.  You can do that very easily with a DPDT switch like in the diagram you linked to.  Just wire your diodes in parallel/reverse across the top two lugs, jumper the bottom two lugs and then connect the middle two lugs to the PCB pads for D1 (or D2).  Leave the other diode pads unjumpered.  This would be really easy with the DPDT board they sell at guitarpcb.  (All you really need is a SPST switch, but I don't have time to diagram it.)

I'm not familiar with the Glitterratti, but I can't imagine that it would affect the core tone very much at all.  The Aristocrat/KoT can lift the soft clipping diodes without too much change.  Nothing a small tweak to the volume/eq can't solve.

[jstogsdill23]

Right on. No need to diagram it. I'll socket those and build it stock so that I know it works then play around with bypassing those diodes. Learn as I go. I just needed help in focusing where to pay attention and how to start into the mod.

Thank you!

From looking at the circuit, you'd just need to lift D1 and D2.  You can do that very easily with a DPDT switch like in the diagram you linked to.  Just wire your diodes in parallel/reverse across the top two lugs, jumper the bottom two lugs and then connect the middle two lugs to the PCB pads for D1 (or D2).  Leave the other diode pads unjumpered.  This would be really easy with the DPDT board they sell at guitarpcb.  (All you really need is a SPST switch, but I don't have time to diagram it.)

I'm not familiar with the Glitterratti, but I can't imagine that it would affect the core tone very much at all.  The Aristocrat/KoT can lift the soft clipping diodes without too much change.  Nothing a small tweak to the volume/eq can't solve.

[jstogsdill23]

Also, thanks for the heads-up on the DPDT pcb. Looks like a nice tidy way to experiment! I will definitely go this route. Just this week I was trying to figure out a DP3T pup selector plus Series/Parallel mod to my jazz bass and realized the DP3T switch had crapped out at some point along the way. A lot of wasted head scratching and wasted $13. Thanks again.

[jstogsdill23]

Here is a portion of the Visio I've been working to help visualize the wiring scheme. I mocked up how it would look using the DPDT pcb. This seems like the diodes are in series the way I have it here. Am I wrong? To put it in parallel would I just put both diodes into one set of pads or am I seeing it wrong?



Thanks!

[gtr2]

with regards to the original question.. I didn't check the diagrams...

I'm not sure why you want to leave out the diodes on the glitt?  You can use the glitt as a clean boost without doing this by turning the gain down and the volume up.  For this overdrive, leaving off the diodes leaves a pretty unpleasant overdrive.  The circuit sounds real "raspy" in a bad way without the soft clipping of the waveform in the feedback loop.  Before getting to crazy with adding a switch just leave out diodes and see if you like it this way.  I've built two glitts.  What I would recommend is that you change the volume pot to an 100kA and the gain pot to 500kB.  Lowering the gain pot will allow you to keep the gain a little more manageable.

Josh

[jstogsdill23]

Ok, excellent points and I'll try your suggestions.

The idea sort of was to only take the overdrive out so that the BB was more like an RC Booster then flip a switch for the gain stage when needed. Again just noodling. But, yeah, from what you said it sounds like the gain all the way down is clean and I can get boost from the volume knob.

On the same note, how do you like the glit? I'm very excited about this build! The only "pedal" I have is a tuner. HA! So this is a lot of fun getting to know these circuits and how they work.

with regards to the original question.. I didn't check the diagrams...

I'm not sure why you want to leave out the diodes on the glitt?  You can use the glitt as a clean boost without doing this by turning the gain down and the volume up.  For this overdrive, leaving off the diodes leaves a pretty unpleasant overdrive.  The circuit sounds real "raspy" in a bad way without the soft clipping of the waveform in the feedback loop.  Before getting to crazy with adding a switch just leave out diodes and see if you like it this way.  I've built two glitts.  What I would recommend is that you change the volume pot to an 100kA and the gain pot to 500kB.  Lowering the gain pot will allow you to keep the gain a little more manageable.

Josh

[gtr2]

Removing the diodes via switching is more effective when the diodes are connected to ground.  For example: the Slow Loris (aka Rat) clips to ground.  You still will get IC clipping which I find undesirable in my applications though.

Lowering the gain pot to 500kB will put you closer to what your looking for.  You could also add the extra 1n4148 diodes in series with D1 and D2 like the RC booster.  Take a look at the schematic.

http://www.madbeanpedals.com/projects/Quasar/docs/Quasar.pdf

Josh