# UberDrive MOD questions



## droneshotfpv (Apr 24, 2021)

Hello fellow DIY addicts! 
Today is a lovely day to get to building some of my PedalPCB projects that I have laying around. I have built several already, and love EVERY one of them, but I have a question about this particular PCB. Lets start with a quick bit of information.

Back when I was starting out playing, and wanting to be Zakk Wylde (many, MANY years ago... I am old.. haha)  I bought an SD-1 and loaded up one of my guitars with EMG's, because I was going to be Zakk come hell or high water... I didn't REALLY know how to use OD's at the time though, and I thought cranking everything to 10 was appropriate to grind that heavy distortion...... in my Solid State Behringer V-Tone amp.... insert lulz here... Anyway, I sold that pedal, because it was broken, am i right? 

Fast forward about 15 - 20 years, and I have been really into FX. Buying vintage, buying new, and building. I am NO expert when it comes to designing or really understanding Audio circuits, but being in Technology my whole life, as well as building Drones and other components, I figured I could easily follow instructions for building Guitar Pedals, amps, etc, and I have successfully done so. What I lack though, is the absolute knowledge of how to change what component to make sounds that I WANT to change.. I have some basic understandings of clipping diodes, resistors of course, and Capacitors simply from other things I have built that use those components. I understand that changing the DIODE with a lower forward voltage introduces earlier clipping, etc etc. 

What I don't know is in a circuit that already exists, such as the UberDrive, what happens if / can I swap out the 1n916 DIODES for Germanium 1n34a's I have laying around? (Yes, the REAL deal, old Vintage ones for my Klon builds  ) Also, what if I used a combo of a series 1n4148 in D1, a single 1n4148 in d2, and a 1n34a in D3, will that work, but sound like garbage? Am I introducing noise? Then of course, what if I just used 3mm Red LED's? I know they can introduce greater gain characteristics, but would that be advisable in this circuit? What about messing with the POTS? I saw a MOD from Wampler that swaps out the POTS and some resistors, as well as CAPs, to give the boutique MOD, but it references removing C6 completely... Is C6 in this diagram the same C6 as in the BOSS variant?

Ultimately I know I need to understand and learn Audio circuits better, and I am a little at a time, but for the immediate needs, I wanted to ask the amazing members of this forum for some help, and some understanding, as well as if I am being an idiot with these ideas and MOD thoughts?

Many, MANY thanks in advance, and I apologize for the book I wrote, but I wanted to paint a picture, and I am a decent story teller (wife tells me I talk to much lol)

I look forward to your answers!


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## Chuck D. Bones (Apr 25, 2021)

You're not being an idiot.  The best way to try out mods is to build a breadboard.  If you have tech skills, then you can do that.  You can try all of the mods above and see for yourself what sounds good to you, what works, what doesn't.  If you want to know which cap is C6 in the Boss SD-1, then you need to scour the 'net for a Boss factory schematic.  They are out there.  As it turns out, C6 is the same cap in the Boss SD-1 & the Uber Drive.  C6 rolls-off the treble above 1.6KHz and has the strongest effect when TONE is above noon.

A search on these forums for discussions on Germanium diodes will yield the following information: Germanium diodes are leaky.  Most of them are very leaky and will kill the gain when used as soft clippers in a circuit like this one.  If you are willing and able to test them, you _might _be able to find some Ge diodes whose leakage is low enough to work in this circuit. Leakage adds noise, so there is that consideration too.

LEDs don't increase or decrease gain, they raise the clipping threshold which reduces compression.  Changing the clipping diodes will alter the harmonic structure, touch response and compression of this pedal.


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## droneshotfpv (Apr 25, 2021)

Chuck D. Bones said:


> You're not being an idiot.  The best way to try out mods is to build a breadboard.  If you have tech skills, then you can do that.  You can try all of the mods above and see for yourself what sounds good to you, what works, what doesn't.  If you want to know which cap is C6 in the Boss SD-1, then you need to scour the 'net for a Boss factory schematic.  They are out there.  As it turns out, C6 is the same cap in the Boss SD-1 & the Uber Drive.  C6 rolls-off the treble above 1.6KHz and has the strongest effect when TONE is above noon.
> 
> A search on these forums for discussions on Germanium diodes will yield the following information: Germanium diodes are leaky.  Most of them are very leaky and will kill the gain when used as soft clippers in a circuit like this one.  If you are willing and able to test them, you _might _be able to find some Ge diodes whose leakage is low enough to work in this circuit. Leakage adds noise, so there is that consideration too.
> 
> LEDs don't increase or decrease gain, they raise the clipping threshold which reduces compression.  Changing the clipping diodes will alter the harmonic structure, touch response and compression of this pedal.



Thank you so much for your response! I have studied and written down MANY of your suggestions in these forums over the last year or so. I guess I am one of those "long time readers, first time poster" types. lol 
I knew the Ge Diodes were somewhat lower on the clipping side of things, with the lower forward voltage and all that, but I did not know they were leaky, and introduce noise. I learned something in that part alone that will most likely fix some other annoyances in other pedals I have built (noise, etc.. Not the worst noise, just that little bit of annoying noise that no matter what you do you can't seem to dial / tweak out lol).
I was thinking of running some leads where the DIODES in this circuit connect into a breadboard where I can easily swap them out before soldering them in so I can swap without de-soldering anything.... I HATE de-soldering with a passion.

I will probably forgo the LED's aside of maybe just for giggles while I have it "semi breadboarded".

I will however most likely remove the C6 cap, as the audio samples I have heard on the SD-1 variants sounds pretty awesome in my opinion, but again, I might also try different values of CAPS before completely omitting.

Mr Bones sir, you have been a most excellent (said like Bill and Ted) help as always! 
Might I trouble you for one more question if possible? 
Since you have pretty extensive knowledge, do you happen to have any first hand information as to what I could do to make this UberDrive sound like the Custom mode of the SD-1 Waza Craft edition? Oddly enough I didn't even check to see if a "Waza Craft similar" board was available (I will do that now), but I know that the Custom mode for me sounds pretty amazing compared to the original SD-1.

Anyway, thank you again, I owe you one, so if there is anything I can ever do, please don't hesitate to ask. My skills are vast in the Tech Industry (From simple computer repair to Large Scale multi point Network Infrastructure using Active Directory, LDAP, with MacOS, Unix / Linux, and Windows varieties,  and the Drone Industry from racer drones, to large agriculture and search and rescue!) lol


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## Chuck D. Bones (Apr 25, 2021)

Hey, you are welcome.  

Try to keep the jumper leads from UberDrive board to breadboard as short as possible or you will end up with a radio receiver.

I'd be interested to see an SD-1W schematic.  A quick Google search has not yielded up anything so far...


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