# Complex OD vs Dirty Sanchez or Thermionic



## Bucksears

Putting the cart before the horse a bit here because my boards aren't even here yet (but should be within a day or so), but is the architecture THAT different for Complex OD? 
Asking because it would be pretty incredible to modify the Thermionic Deluxe to be a Thermionic/Complex.

Thx!
- Buck


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## Robert

You can absolutely do it, in fact that's how I verified the circuit before ordering the first batch of PCBs.   The Complex is closer to the Dirty Sanchez than the Thermionic because of the added mid control, so the Deluxe fits the structure perfectly.

I will say though, after a few minutes with the Complex you'll probably forget all about the Thermionic side....


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## jubal81

Speaking of the Complex, I started stuffing my board today and I'm wondering if the LEDs are just red diffused.


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## Robert

Yep.


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## jubal81

Robert said:


> Yep.


Dude.
Just got the Complex rocking and I might be done building MIAB. I'm seriously impressed. Dirty Shirly sounded to me like a typical fizzy distortion but this thing is a whole different beast. The clipping is smooth and the EQing is next level - sounds very sophisticated with a very usable tone control set.


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## Bucksears

jubal81 said:


> Dude.
> Just got the Complex rocking and I might be done building MIAB. I'm seriously impressed. Dirty Shirly sounded to me like a typical fizzy distortion but this thing is a whole different beast. The clipping is smooth and the EQing is next level - sounds very sophisticated with a very usable tone control set.



Man, you’re making it worse!  
I’m hoping this will be ‘the one’, as the production version has gotten (almost) unanimous rave reviews.

I have a Brown Betty and Thermionic Deluxe almost ready to box up; if the incoming Complex boards are all-that-and-a-bag-of-chips after I build them, I may have to do some tweaking on the previous two.


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## Betty Wont

Does the Complex have as much gain as the Thermionic? I was dissapointed to find the brown betty does not.


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## Bucksears

Torgoslayer said:


> Does the Complex have as much gain as the Thermionic? I was dissapointed to find the brown betty does not.



No, from what I gather the Thermionic is higher than the Brown Betty/Dirty Sanchez and the Complex.
Not that that's a bad thing. It's sounding like the Complex/Smallbox OD is hitting a sweet(er) spot for the hot-rodded Marshall sound.


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## Robert

One resistor swap can bring the gain up to Thermionic levels, if that's what you wanted to do...

I'd try it "stock" before making any changes though.


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## jubal81

Bucksears said:


> No, from what I gather the Thermionic is higher than the Brown Betty/Dirty Sanchez and the Complex.
> Not that that's a bad thing. It's sounding like the Complex/Smallbox OD is hitting a sweet(er) spot for the hot-rodded Marshall sound.


That pretty much describes my experience.
I think of the Sanchez as a DS-1 with more EQ controls. The Complex is much more like a hot tube amp. If you want more out of it, it responds really well if you hit the front of it with a boost - especially a mid boost. I'd be inclined to pair it with a Tube Screamer, Klon or other mid-hump OD of choice.


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## Bucksears

Got my boards today, and spent some time tracing out the board compared to the Dirty Sanchez schematic. 
I found (what I think are) the differences to convert a DS to the Complex - @PedalPCB mind if I post my findings, or is that a no-no?


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## Robert

Nope that's perfectly fine.   I'll have the full schematic posted in a few days.


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## Bucksears

Thx!
Ok, going by the Channel B (Dirty Sanchez side) of the Thermionic Deluxe, found these differences:

*R25B* *(4K7) +* *TIGHTB* *(100KC)* - replace with 22K (or just leave in place and dial that combo down to 22K?)
*C8B (120p) *- replace with 220p
*TRIMB (100K) *- replace with 27K (or leave trimpot and adjust to 27K?)
*R18B (2K2)* - replace with 47K + 470p in series
*MIDB (100KC)* - replace with 100KA
*TOGGLE* - use SPST to toggle in/out 470K resistor in parallel across lugs 3/2 & 1 of the 1M gain pot; guessing adding the resistor is 'low gain' and toggling it out is 'high gain'?
*C20 (100uF)* - in the power section - replace with 47uF (or leave as is?) - the rest of the power section looks the same
Might be more to it than that (and I could be mistaken), but that's what I've got.


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## Chuck D. Bones

Thanks for doing that!  Seems like pretty minor tweaks.
I think you mean:
*R18B (2K2)* - replace with 47K + 470p in _parallel._
Strange that the *MID *would be changed to A100K. C100K has a nice even feel.


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## Bucksears

Chuck D. Bones said:


> Thanks for doing that!  Seems like pretty minor tweaks.
> I think you mean:
> *R18B (2K2)* - replace with 47K + 470p in _parallel._
> Strange that the *MID *would be changed to A100K. C100K has a nice even feel.



Yeah, I thought that should be in parallel as well, but still appears to be in series. I’ll triple check it tomorrow night or this weekend.
I could map out a trace in Adobe Illustrator this weekend to be sure on everything, but I probably should just wait for the schematic.
I’ll leave the 100KC MID in place in my Thermionic Deluxe build.
Thx!


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## Bucksears

Chuck D. Bones said:


> Thanks for doing that!  Seems like pretty minor tweaks.
> I think you mean:
> *R18B (2K2)* - replace with 47K + 470p in _parallel._
> Strange that the *MID *would be changed to A100K. C100K has a nice even feel.



Confirmed, you are correct:  it is a 47K + 470p combination in parallel replacing that 2.2K resistor.

I'll build out the PedalPCB Complex board and test drive that before tweaking the Thermion Deluxe.


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## Barry

Chuck D. Bones said:


> Thanks for doing that!  Seems like pretty minor tweaks.
> I think you mean:
> *R18B (2K2)* - replace with 47K + 470p in _parallel._
> Strange that the *MID *would be changed to A100K. C100K has a nice even feel.


Would the addition of the 470pf to the 47k really make an audible difference?

Or is it a 47K resistor with  470pf in parallel which makes sense now, duh


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## mjh36

I couldn't hear anything with the R18 47k/470p. So I used a socketed 4n7 and a 47n. I could hear a definite boost with those. Room to play there I'll keep experimenting. 

Other than that all I changed was the C8 (220pf) and adjusted Trim and Tight to taste and let the rest be. So not quite a Complex but it rocks!


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## ThinAir

Robert said:


> One resistor swap can bring the gain up to Thermionic levels, if that's what you wanted to do...
> 
> I'd try it "stock" before making any changes though.


Which resistor and what value would one use to get higher gain from the Complex overdrive?


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## Chuck D. Bones

If you want to do it "by the book" you change...
R14 to 10K
R16 to 100K (same as Thermionic with the internal trimmer dimed)
C8 to 120pF
C9 to 100pF

Just changing R14 or R16 will get you half-way there.
Changing both will get you to the Thermionic's gain.
Changing the caps will brighten it up a tad to match the Thermionic.


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## ianmarks

jubal81 said:


> That pretty much describes my experience.
> I think of the Sanchez as a DS-1 with more EQ controls. The Complex is much more like a hot tube amp. If you want more out of it, it responds really well if you hit the front of it with a boost - especially a mid boost. I'd be inclined to pair it with a Tube Screamer, Klon or other mid-hump OD of choice.


What about a Haunting Mids?


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## ThinAir

Chuck D. Bones said:


> If you want to do it "by the book" you change...
> R14 to 10K
> R16 to 100K (same as Thermionic with the internal trimmer dimed)
> C8 to 120pF
> C9 to 100pF
> 
> Just changing R14 or R16 will get you half-way there.
> Changing both will get you to the Thermionic's gain.
> Changing the caps will brighten it up a tad to match the Thermionic.


I really like the voicing of the Complex, so I only changed R14 and R16.  Wow, gain machine!  Exactly what I was looking for!  Thanks!


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## renatofuza

Anyone noticed a little bit of hairy-fluffy-fizziness on the Complex? I did the mods on my Thermionic Deluxe (DS channel) and loved it, but this little thing is intringuing me. Double checked everything and looks like is allright. There is anything that can cause this? I mean, a wrong type of capacitor or something?

Thanks!


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## Chuck D. Bones

Where do you have the gain trim set?  It should be down near the bottom to mimic the Complex.

Wrong parts could definitely mess up the tone. A little visual inspection can't hurt and you might find something.


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## renatofuza

Chuck D. Bones said:


> Where do you have the gain trim set?  It should be down near the bottom to mimic the Complex.
> 
> Wrong parts could definitely mess up the tone. A little visual inspection can't hurt and you might find something.


I replaced the trimpot by a 27k resistor

Only thing that's not like I wanted to be is some ceramic capacitors that I can't find tantalum or mica at the requested values


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## Boukman

Robert said:


> One resistor swap can bring the gain up to Thermionic levels, if that's what you wanted to do...
> 
> I'd try it "stock" before making any changes though.


Hi!Which resistor is that in the Complex OD circuit?Also does it have a difference if the leds are not diffused? Thanks!!


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## Chuck D. Bones

It's not one resistor.  Read the entire thread, it's not that long.  Or at least read this post:
https://forum.pedalpcb.com/threads/complex-od-vs-dirty-sanchez-or-thermionic.5001/#post-48083
LED diffused or clear makes no difference.


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## Boukman

renatofuza said:


> I replaced the trimpot by a 27k resistor
> 
> Only thing that's not like I wanted to be is some ceramic capacitors that I can't find tantalum or mica at the requested values


I`m too sceptical about that...Does the original has mica?Would it benefit from that?


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