sticking things in holes is fun.

[derp]

this circuit
https://www.wamplerpedals.com/wp-content/uploads/2020/05/tone-control1.png

https://www.wamplerpedals.com/blog/latest-news/2020/05/how-to-design-a-basic-overdrive-pedal-circuit/


But a TL072
1m log gain
25k log tone
100k linear ( i think) volume.

PLUS a 1458 Opamp at the end with two 4148 diodes circleing back through the 4148. Why? becoz shuttup.

Now the question, what pedal/circuit if such a thing exists, is closest to this thing above?


I dont have much room left on board, what should i add or move whatever.

[antonis]

PLUS a 1458 Opamp at the end with two 4148 diodes circleing back through the 4148

More specific, maybe with a schematic, plz..??

[Mark Hammer]

Now the question, what pedal/circuit if such a thing exists, is closest to this thing above?

Oh, probably a few hundred, if not more.  But they would likely include just a little more circuitry.  Not a LOT, but at least a little.  Not sure what you are referring to with the 1458 comment, though.

The 1k/220nf pair provide for a fixed low-end rolloff beginning around 720hz.  The 500k pot and 100pf cap in the feedback loop provide for a treble rolloff that varies with gain setting.  When the gain is set low (e.g., 11x with the gain pot at 10k resistance) there is NO audible treble cut, such that any treble taming must be done by the tone control.  Increase the gain to 101x (Gain pot at 100k) and there is still NO audible treble cut.  With Gain at max (501x), the treble cut is introduced around 3200hz; still not especially dark, and not much bass, either.  When the Tone control is rotated fully in the direction of the Volume pot, there is a rolloff starting around 720hz.  But note that both the actions of the Tone control and the 100pf feedback cap are VERY gentle.  You won't get anything approaching a "warm" sound unless both Gain and Tone are near max, and a tone perhaps a tad shrill when they are less than that.

Were it MY build, I'd replace C28 with a 150nf cap, to raise the bass rolloff of that pair to around 1khz.  To reclaim the bass, I would stick a second RC pair in parallel with R46/C28 to provide a second "ground leg", using a 3k9 resistor in series with a 220nf-470nf cap.  That provide a maximum gain for content below 1khz (down to around 90hz) of around 130x, instead of 501x.  Even though max gain is reduced by that path, the inclusion of more bass will still push the diodes a little harder.  I would also recommend increasing C31 to something around double its' value (e.g., 180-220pf).  That will provide a lower treble (though not a steeper one), reducing demands on the Tone control.

The intent of these recommendations is to provide something with more "body", and less "fizz", at more settings.

[ElectricDruid]

Oh, probably a few hundred, if not more.

+1 agree.

It's *very broadly* a tubescreamer-type circuit, so there are literally hundreds of similar ciruits. I had a go myself, if you want to compare-and-contrast and a bit of historical perspective!

Designing a classic OD-1/TS-808/SD-1 Overdrive

PLUS a 1458 Opamp at the end with two 4148 diodes circleing back through the 4148. Why? becoz shuttup.

This part is the part that doesn't make sense, and that suggests to me that's there's something you're not understanding properly. There's no 1458 op-amp anywhere in Wampler's design, and the two 4148 diodes deal with the positive and negative peaks of the waveform when compared to the bias voltage. There's no "circling back" going on, unless you're meaning something to do with the negative feedback that sets the gain, but that's independent of the diodes - it's set by the gain resistors, the diodes simply alter that basic equation.

[derp]

Not sure what you are referring to with the 1458 comment, thoug

This part is the part that doesn't make sense

Those parts were infront of me, so I thought its a bit like the tl072 part of the schematic, so why not.



I was trying to build a timmy on a breadboard and i kept @#$%ing it up so i cracked the shits and gave up. Then i found this simpler schematic to try and it worked. Remembering back to the timmy had two opamps, and two is better than one and I had the 1458 there, so WHY NOT ADD IT(and hope that it worked)
It did work suprisingly, and it doesnt sound to bad.

and that suggests to me that's there's something you're not understanding properly

Yes, you have stumbled upon my one failing, I have no idea what im doing!
But you find out what works, what smells, what hurts and what catches fire. :life:


     

More specific, maybe with a schematic, plz..??

The same as the  wampler schematic opamp/diode part but without a 100p capacitor.

SO the whole thing goes wampler schematic, output into 1458, two 4148 in parallel (sort of), back to 1458, then output (to a big amplifier sitting on a cab)


_ input         
  |         _____output
  |        / 
  |        |
  |---1458----|
  |              |
  |------>|-----|
  |------|<-----|


well theres my shitty attempt at a shcematic descrption. Did it makes sense or  is everything worse now?

[bluelagoon]

Yes think that pretty much covers it.
All makes complete sense now LOL
Good Effort

[FiveseveN]

the timmy had two opamps, and two is better than one

A TL072 already has two op amps, as does a 1458.

Did it makes sense?

No, not at all. A dual op amp has 8 pins. You've "drawn" 3... 4? None of which are labeled, so how should we know what goes where?
Use pen and paper please.

[amptramp]

When you move the tone control all the way to the left, you essentially have a capacitor of slightly less than 22 nF to ground from the output of the op amp.  Most op amps will not tolerate this as the output impedance of the op amp combined with the capacitor forms a low-pass within the feedback loop and it oscillates.  Most op amps do not tolerate more than a small amount of capacitance to ground.