# Wonder Drive



## Mourguitars (Jul 24, 2021)

Long time Guys !

I have another Wonder Drive PCB to build and was wondering if i could make that Tight control a little more responsive ....more tight

Chuck B ?......Anyone..

Thanks for looking and everyone stay safe !

Mike


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## jubal81 (Jul 24, 2021)

You'd reduce C1. Going to 100n, even, would make a pretty noticeable difference.


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## Mourguitars (Jul 24, 2021)

jubal81 said:


> You'd reduce C1. Going to 100n, even, would make a pretty noticeable difference.



Man you guys are the best here on the Forum !

Thanks for a quick reply !

Mike


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## Mourguitars (Jul 25, 2021)

So...before i put this info in my notes...if you want to increase bass or treble you lower the value , them up the value if you want to take out ...correct ?

Mike


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## Feral Feline (Jul 26, 2021)

No.

Generally speaking, a larger cap lets more bass through, the smaller the cap value the more treble (ie it's blocking bass), but you also need to consider what's surrounding it, ie how it's being used.

It also depends on how the cap is implemented into the circuit, though.

If you want more bass in your circuit, a common way to do it is to increase the input cap value. Doing so might overload the circuit (which may or may not be desirable). If the circuit is undesirably overloaded with bass, you could decrease the input cap, and to compensate for choking off the bass, then increase the output cap's value. Some circuits boost the highs at the beginning of a circuit, then reduce them at the end — all in the name of reducing noise/artefacts.






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						Difference Between Low Pass Filter and High Pass Filter | Electricalvoice
					

Filters are a special type of circuit that lets signals having a frequency within a specific range pass through it. The frequency range can have a lower cut-off frequency and no upper cut-off frequency or an upper cut-off frequency and no lower cut-off frequency or both upper cut-off and lower...




					electricalvoice.com
				











If you plug in some values here: http://www.muzique.com/schem/filter.htm
... you'll get an idea of the corner frequency thingermabobbie.
If C1 & R1 above are .047uF and 4700Ω (47n/4k7), then the corner frequency is 720.8Hz (Tube Screamer's corner) and bass will be reduced below that corner and pass on the highs above it.
Reverse the positions as in R2 & C2, retaining values 4k7/47n respectively, the corner frequency hasn't changed, but instead C2 is dumping highs to ground and bass freqs are being passed along to the output.


A pF bleed cap on a pot, for example is going to let some treble bleed through. Increase the value and you're letting more "bass" through, but really letting more signal through in general and because the pF value is so small the "bass" that you're letting through is actually still well in the treble range — so effectively you're just letting more treble through, ie a wider band of treble.







To reiterate: increase a cap value for more bass, decrease for more treble.


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## Mourguitars (Jul 26, 2021)

Thank you for the very detailed reply Feral Feline !...again thanks !

At 59 im having a hard time learning to read schematics for some reason ....i know a lot more than i did when i first started but still do a lot of head scratching....i dont mind asking questions tho, and will...lol....., i watch guys like Jason at Headfirst amps doing his mods...explaining things in great detail from the schematics on his amp mods

I can change parts at least and dont mind being that one guy who all ways raises his hand to only answer the question wrong....one day this will click...i have faith !

Thanks again and ill print out your reply and put that in my notes !

Mike


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## Feral Feline (Jul 26, 2021)

You're not that much older than me!

It's taken me a few years to wrap my grey matter around this stuff, and there are so many here on the forum that are light-years ahead in their knowledge and understanding — I'm still scratching my head and asking questions on very basic stuff. A good way to test if you understand something is to try to teach it to one of your peers.

I keep working on reading schematics, it's really helped — more than that, it's given greater satisfaction and enjoyment to the hobby. The most recent thing I just picked up was chassis-ground. There are many ways to scratch out a ground symbol and I figured it was a matter of style/preference; but I just learned from my amp sifu the difference between a common-ground and chassis-ground symbol.

Q: Can you guess which is chassis ground?







A: No 5020





Apparently not everyone is in agreement...







I'll go with my very knowledgeable mentor's version of chassis ground, ie the "trident".

What grounds are there for having so many different symbols?





Some more reading up for me to do.



I'll stop learning when I'm dead. Maybe.


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## Mourguitars (Jul 26, 2021)

Feral Feline said:


> You're not that much older than me!
> 
> It's taken me a few years to wrap my grey matter around this stuff, and there are so many here on the forum that are light-years ahead in their knowledge and understanding — I'm still scratching my head and asking questions on very basic stuff. A good way to test if you understand something is to try to teach it to one of your peers.
> 
> ...



Ok .....lol.....this kinda thru me for a loop !   But good stuff !

Im used to seeing the ..well what i called common ground (earth ground ) ive heard that term before, always thought ground wire always goes to the chassie...and was the same symbol

I just looked at my schematics for the Rocktron Valvesonic Plexi ....i see those chassis grounds now ! 

They have a note that the symbols  are PCB_GND .... TP_GND  .... CH_GND

On my Ceriatone 800  schematic all ground symbols are next to a  screw/nut that is grounded to the chassis ...earth ground and not Common like i called it before

When i get a chance , i will take the top off the pre amp and take a chop stick and trace and see what that TP_GND is ...i see quite a few in the schematic

Good stuff Feral Feline !

Learned something today !

Mike


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## BigK (Aug 8, 2021)

Comparing the circuit to two savage drives (my friends and mine) these are some tweaks to make it very similar to the actual savage drive. main ones for more tight would be R15 & C7

R4 - 220r (I used a trimmit with a 100r 1/8w resistor in series with a 500r timpot)
R8 - 100r
R9 - 15K
R15- 470r
R19 - 4.7K
C7 - 2.2nF
C10 - 100n on some gut shots and my friends v3, 150 on others controls the top end sharpness (I put on a on-off-on dpdt switch with 56nf 100nf & 120nf caps)


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## Mourguitars (Aug 11, 2021)

BigK said:


> Comparing the circuit to two savage drives (my friends and mine) these are some tweaks to make it very similar to the actual savage drive. main ones for more tight would be R15 & C7
> 
> R4 - 220r (I used a trimmit with a 100r 1/8w resistor in series with a 500r timpot)
> R8 - 100r
> ...



I found a rev 2 PCB that i have ....has anyone done these changes above on that board ?

Also BigK do you have a gut shot you can post ?

Mike


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## Chuck D. Bones (Aug 12, 2021)

I know I'm late to the party and all, but...

C7 determines how much bass gets thru when TIGHT is full CW (maximum tightness).
C1 determines how much bass gets thru when TIGHT is full CCW (maximum fatness).

If you want it to go tighter, make C7 smaller.
If you want it to go fatter, make C1 bigger.

Note: you can do both.  They interact a bit, so dial-in one cap, then the other.  Then repeat.

The effect of the TIGHT control is more pronounced at higher DIRT settings.  When DIRT is at zero, the TIGHT control does almost nothing.


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## Mourguitars (Aug 13, 2021)

Chuck D. Bones said:


> I know I'm late to the party and all, but...
> 
> C7 determines how much bass gets thru when TIGHT is full CW (maximum tightness).
> C1 determines how much bass gets thru when TIGHT is full CCW (maximum fatness).
> ...



Thanks for the info Chuck !

I usually have the Dirt about 10 am ...well i set pretty much all my OD's that way , looks like we have some bad weather coming via a few storms  so that will give me some free time to build...!!!!


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## BigK (Aug 17, 2021)

Mourguitars said:


> I found a rev 2 PCB that i have ....has anyone done these changes above on that board ?
> 
> Also BigK do you have a gut shot you can post ?
> 
> Mike


I can't attach pictures for some reason.. (if you do a google image search there is a few) but I've built two like this for friends with the 3 way bright switch but in the centre (100nf cap) it sounded identical to my Airis savage drive - so much I sold that and have another Wonder drive board to build up for myself with my tweaks as I like the ability to to change the bright caps and play with the frequency of the Tone/bite knob to dial it into my different amps.

The other thing is that Airis put over the top amounts of gain into the circuit to R15 on the board for the wonder drive was actually a 47r on my friends portal drive (savage drive with rick and morty graphics) but when I used that it often caused some oscillation with different opamps so increasing it to 470 lowered it enough to remove that.

Incidentally my VFE ice scream turned me onto the trim for the tone frequency and I put it on all my OD builds. Another pedal worth building its adjustable mid boost is brilliant.


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## BigK (Aug 17, 2021)

worked this time


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## Mourguitars (Aug 18, 2021)

BigK said:


> worked this time



Cool and thanks for the pics BigK !

I figured work would most likely slow down some  but instead it speed up like a rocket...the Fishing tackle biz is crazy , people cant get anything but i work on getting stuff in...i kinda created my own monster with me being Pro active working late nights....all i want to do is relax and build a pedal or two....lol

Mike


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## Mourguitars (Aug 20, 2021)

Pulled some of my parts, need to print out the build docs...trying to decide Blue or Purple for the enclosure...its nice having all the parts for a build here for once...Saturdays project ! 

Hope it goes smooth.....Lol

Mike



https://imgur.com/EOhRvOO


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## Alsassius (Aug 29, 2021)

Hi there! Good evening, what can I modify to get a little more volume? I'm also going to play around with the C7 and R15 values a bit to see how it sounds. Greetings and thanks in advance!

Ariel.


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## Chuck D. Bones (Aug 29, 2021)

This thing should be insanely loud in stock form.  Are you sure it's working correctly?  What control setting are you using?


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## Alsassius (Aug 29, 2021)

I'm going to check it just in case, with all the controls at 12 o'clock and the volume at maximum there is no difference between the volume when the effect is turned on and when it is turned off, it is just the volume, the rest of the controls work fine.


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## Chuck D. Bones (Aug 30, 2021)

With those settings, the gain should be around 20dB (10x).  Try it with DIRT at max and TIGHT at zero.  This thing does not have a lot of gain, but it should be louder than what you describe.  You might want to verify all of the resistors and caps are the right value.

Anyone else with a Wonder Drive want to chime in?


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## eightbitinfinity (Jul 9, 2022)

I changed the values as mentioned above to my Wonder Drive and it sounds JUST LIKE my V3 Savage Drive 🎉!!!! I used a 68n in place of the 100n and you get more bite sooner on the potentiometer. Thanks a bunch for sharing and mentioning which components to swap; I’m buying more Wonder Drive boards now bc this sounds much closer to the original!


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## Robert (Jul 9, 2022)

So what values did you end up settling on?


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## eightbitinfinity (Jul 10, 2022)

I used:

R4 - 220r
R8 - 100r
R9 - 15K (I didn’t have 15K, so used 20k)
R15- 470r
R19 - 4.7K
C7 - 2.2nF
C10 - 100n (I used a 68n)

The original build list gets you close (80% there). For me when following original build list I noticed maxing out the bite knob would be around 1 o’clock compared my original Savage Drive V3. Wanting more sharpness I went lower then 100n for C10 (68n ) and the response is dead on to how my original responds plus a little extra! It saturates the same too! Sounds amazing now just like the Dwarven Hammer, Isosceles, and Triangulum! A new favorite to build 🤘


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## HamishR (Jul 23, 2022)

I've learnt a ridiculous amount from people here over the past year or two. But the number one thing I've learnt is that Chuck knows.


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## HamishR (Jul 24, 2022)

Is true!


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