# Modding Greengage for better bass/bass guitar?



## jrhevron (May 5, 2021)

Has anyone done this? It sounds "fine" but has some low end loss that could be fixed. 

JohnK over on talkbass said that it's just 2 caps and a resistor... but that's an old thread and he may not respond to a query on what caps to change. Any thoughts? Is it just C1 and C6?


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## phi1 (May 5, 2021)

C1 appears to be letting all the bass through as is. Upping it won’t hurt be I doubt it would help. C6 sets the frequency of the tone knob, changing it may or may not be what you want.

the place where bass loos is occurring is C4 & R6. It’s cutting bass around 340Hz, which is already more bass than the typical TS pedal (cuts bass below 723Hz). I’d experiment with either increasing C4, or adding a bass pot (something like the picture, experiment with values).


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## jrhevron (May 5, 2021)

Thank you for the response! 

What would you change C4 and R6 to? 

Over on PCB Effects layouts, the suggestion is to change C4 to "anything from 1 to 10uF"


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## phi1 (May 5, 2021)

Experiment and see. Or put an on-off-on switch to select different values in parallel with C4. Above 1u the differences will be slighter. I’d focus on experimenting between 100n and 2u2.

C4 and R6 together affect the frequency cutoff. But, R6 also affects the amount of gain. So, I’d probably keep R6 as is to avoid altering the gain range, and just mess with C4.


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## ErickPulido (May 5, 2021)

as Phi1 said experiment with the cap, one good example is the dwarven hammer look at the schematic for reference and the stockade overdrive is another good one


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## jrhevron (May 5, 2021)

Sounds like I should have a go at socketing C4 to try some different values. 

I do wonder what two resistors John K replaced, though.


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## jrhevron (May 5, 2021)

ErickPulido said:


> as Phi1 said experiment with the cap, one good example is the dwarven hammer look at the schematic for reference and the stockade overdrive is another good one


Looks like the Dwarven Hammer uses a 220n in a similar spot on the schematic. I'm not great at reading schematics, but that seems close to where I'd want to be looking. 330n on the stockade.


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## ErickPulido (May 5, 2021)

jrhevron said:


> Looks like the Dwarven Hammer uses a 220n in a similar spot on the schematic. I'm not great at reading schematics, but that seems close to where I'd want to be looking. 330n on the stockade.


it uses 8 different caps : 470n, 330n, 220n, 100n, 82n, 68n, 47n and 33n


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## jrhevron (May 5, 2021)

ErickPulido said:


> it uses 8 different caps : 470n, 330n, 220n, 100n, 82n, 68n, 47n and 33n


I need to go higher than 100n, so seems like 470-220 is a good range to try.


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## phi1 (May 5, 2021)

I think 1 resistor, and 2 caps, right?  He seems to be a bit cagey about it in the post intentionally,at be he didn’t want to share for some reason. C4 is the main low end loss culprit, maybe I’m wrong and upping C1 is a bigger difference than I thought. Or he changed one of the many caps that control high frequency cut off. Not sure why he needed to mess with an R, there’s plenty of things you could tweak slightly. My recommendation would be to focus on C4 area.


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## phi1 (May 5, 2021)

Here’s you formula for bass cutoff frequency.
F = 1/(2piRC) with R being R6. This formula gets you a long way with several configurations of single order high pass of low pass filters.


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## jrhevron (May 5, 2021)

phi1 said:


> I think 1 resistor, and 2 caps, right?  He seems to be a bit cagey about it in the post intentionally,at be he didn’t want to share for some reason. C4 is the main low end loss culprit, maybe I’m wrong and upping C1 is a bigger difference than I thought. Or he changed one of the many caps that control high frequency cut off. Not sure why he needed to mess with an R, there’s plenty of things you could tweak slightly. My recommendation would be to focus on C4 area.


To be fair to John, sometimes I think he does the mod that sounds good and then doesn't really write down what he does and that's why he can't share it. For his pork loin mod, he documented that one pretty well.


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## jrhevron (May 5, 2021)

Here's what he just posted to talkbass: I would up C1 anywhere from 220nf-1uf and C4 up to 470-680nf, but i'd experiment to taste


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## phi1 (May 5, 2021)

Very cool he replied with that detail. Background about my comments regarding C1 in case you’re interested.

33n followed by 10M to ground. This forms a high pass (bass cut) filter with the values of C1 and the 10M resistor (in parallel with the input impedance of the op amp, which I don’t know, but I think is pretty high). Even if the input impedance of the op amp were as low as 1M (I doubt it is), 33n and 1M puts the cutoff frequency at 4.8Hz. Again, I could be missing something, so if you find there is a difference, please let me know.


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## jrhevron (May 6, 2021)

Gonna have to try this tonight... I have an actual Plumes pedal that I'm going to mod-- and build a greengage if I can't. The eqd photos all had through hole components, but my pedal is SMD. I can see that you can carefully make regular caps work here... will just have to figure that out tonight. I've never done that myself.


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## phi1 (May 6, 2021)

Option 1: the plumes seems to be extremely popular, you could probably sell it as is
Option 2: mod existing. R4 on EQD seems to be R6 on pedalpcb. Verify that with multimeter continuity check (beep setting). Then using continuity check, fugues out which cap is pedalpcb C4. I don’t recommend removing this smd cap. Rather, add another capacitor in parallel. (With caps in parallel, add values for total capacitance.)

ive heard caps are the most damageable smd part for hand soldering, so I’d recommend adding some wires to other solder joints that connect to the cap (like from the op amp and R4).


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## jrhevron (May 6, 2021)

There are literally 100 plumes for sale right now on Reverb... so I'm probably not going to sell it. So likely option 2. 

Adding a cap in parallel is a good idea!


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## jrhevron (May 6, 2021)

I think that maybe the ideal test, if the cap values add up, is to hook up my looper to the open pedal and send a bass loop through. Then just try a few different caps and press the leads up against the sides of the SMD cap to see how that changes things.


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## NSJ (Nov 23, 2021)

I think that maybe the ideal test, if the cap values add up, is to hook up my looper to the open pedal and send a bass loop through. Then just try a few different caps and press the leads up against the sides of the SMD cap to see how that changes things.
Did the cap mod work for you? I’m waiting for greengage to come back in stock to try this.


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## jrhevron (Nov 23, 2021)

I'm not sure why, but I couldn't make this work... it was kind of a half ass strategy anyway. That said, I've come to appreciate my plumes more lately. It's a fine standalone OD that does lose a little low end. However, I'm finding that it's really good as a sweetener before a muff. Really gives the muff more of a mid/3D kind of feel. Also, when I run my Diamond bass comp at the end of the line, it adds all of the bass back into the signal. Let me know how your build goes.


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## NSJ (Nov 24, 2021)

Thanks. Was it the doing the mod itself or the tone you got was not satisfactory? 

Seeing very few threads about this, I wonder how much this mod really works. Plus your experience tells me maybe I should just go with the obsidius preamp or something else. Hmm. 

If I do build I’m thinking to socket both c4 and c1. I kinda agree with Phi1 logic why upping c1 should not affect low end but just for my sake I’ll socket both.


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## jrhevron (Nov 24, 2021)

I honestly couldn't get the tone to change all that much, but it might have been user error as much as anything. 

Still, I will say that it took me a while to appreciate the Plumes, but I feel that it may be a situation where it's not so much that it cuts the lows as much as it boosts the mids so much that you get a perceived drop in lows. I think there is some actual drop as well, but I had the same experience with a bass klon build. I think that the plumes is a great tone shaping tool in that it gives you a ton of presence in the mix and has a lot of clean power to the tone. Not sure if that's the impedance or the voltage doubling or what, but it's a great tool especially before other pedals. It does a great job of driving my modulation pedals as well as my muff. 

If you want a straight up bass OD, though, I'm not sure you'd be happy with this. I built a Son of Ben that is much better as a full range boost, OD, than the plumes. It's more "generally" good while the plumes has more specific uses and a more specific sound.


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## jrhevron (Nov 24, 2021)

thewintersoldier said:


> If your looking for a bass overdrive look at the hot bod I did Here


sweet build. I'd like to check that one out.


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## NSJ (Nov 24, 2021)

That makes sense! So, your mod worked and maybe very subtle tonal change. That’s what I’m preparing myself for. 

That hot bod blend looks handy - but with symm clipping. Not hard to mod it for asymm to AB with greengage - Clean blend vs high headroom, I guess.


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## jrhevron (Jun 4, 2022)

Bumping this. Going to give that bass mod a go soon. Anyone tried it?


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## jrhevron (Jun 10, 2022)

I ended up adding a 300n to the 100n at C4. I think that might be too much. Makes the bass a little too much and the pedal jumps into overdrive with even the slightest turn of the drive knob. I'll have to crack it open again this weekend and switch that 300n out for maybe a 100n to make C4 200n total. I do think that this is the right area of the pedal to mod for bass, it's just about finding the right value.


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## Feral Feline (Jun 13, 2022)

When you mentioned in your SoB thread adding a 100n to the existing Greengage one, I guess you meant C4 on the PPCB Greengage schematic.

If you left the input cap C1 at 33n, then you're not letting enough bass into the circuit to begin with, and I'd go with 100n, 220n... 

I know it's mentioned in this thread that C1 is already letting all the bass through, but nonetheless — for example, Jack Orman's MOSFET Boost has a 1n input cap, and has said increasing it won't really improve it's bass response as it's already flat and let's all freqs through. Yet the Catalinbread crew took that circuit, changed the input to 10n and called it the Sogrado Poblano Picoso ...

You could try the Orman Phat mod, detailed in GGG's PDF list of mods, but you'd have to change R6 from going to ground to go to Vref (like GGG ITS8 schematic's R6).

Greengage C8 & C9 are 1uF, for a smidge more bass let through, try replacing those with 2u2 caps. That might give you that smidge-extra girth you're after. You could try C2 as well, it's also 1u, but bumping it to 2u2 might feed too much bass into the clipping section after it.

I compared the Greengage with the TS-808 tone-stack and EQD tweaked it, so I'm not sure what's been done to it, but flattening the tone stack of the TS ( ie taking out the mid-hump) would help perceived bass. I just read on EQD's website EQD already did that I guess: "The reimagined tone control is finely tuned to sculpt low end, clear top end, and focus midrange with blooming sustain."

Back to SoBen...


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## jrhevron (Jun 13, 2022)

Feral Feline said:


> When you mentioned in your SoB thread adding a 100n to the existing Greengage one, I guess you meant C4 on the PPCB Greengage schematic.
> 
> If you left the input cap C1 at 33n, then you're not letting enough bass into the circuit to begin with, and I'd go with 100n, 220n...
> 
> ...



Thank you! All good info. Maybe I'll start with the input cap and see where that gets me. 

And yes, I meant adding to C4 on the Greengage schematic.


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## Feral Feline (Jun 13, 2022)

The treble with people mentioning "all the bass" getting through, often they're referring to geetar's E2/83Hz. 

I love the Bass E1!


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