SarnoMusicSolutions wrote:Nice answer Waldo!!
To be fair, it belongs to a huge family of overdrive topologies that relate back to the ubiquitous Ibanez Tube Screamer. But that shouldn't be considered a fair association. There are essentially, generally, 3 types or distortion/overdrive pedal topologies. Fuzz types are related to the old Fuzz Face and Tone Bender where two transistors are used, one slamming the next one creating that distinctive sound we all know. Then there's the "Distortion" pedal topology based on clipping a pair of reversed diodes that live between the signal and ground. This would be the MXR Distortion+, the Rat, the Boss DS-1 for the most well known examples. Then there's the family of "Overdrive" types. This is what most boutique overdrive pedals are built around. The idea here is that there are reversed diodes that generate the clipping, but the diodes live in the feedback loop of an opamp. This creates a milder, more compressed, more amp-like kind of clipping and a slightly more rounded "squarewave" when they clip. But there are so many thousands of ways you can set up this type of circuit, how you voice it, how you color it with diode symmetry/asymmetry and types, whether it's inverting or non-inverting, buffered, pre-EQ'd, post-EQ'd, etc. It's a very basic template for a gazillion ways to carve out a unique sounding overdrive circuit. So Waldo's right. It's pretty much its own design, but it does belong to this particular family of overdrive pedal circuit types with clipping in the feedback loop. But beyond that major generality, it's its own animal.
It was first inspired by my wife Auset. She plays a '62 Strat into a sweet '68 Fender Deluxe Reverb. A lot of our gigs are very quiet and there's no way for her to push the amp into that zone where it does its thing with 6V6's singing. So she wanted a way to get something like that at any volume. We lined up more than 10 boutique or classic pedals in our collection like the Zendrive, AC Booster, Nobels ODR-1, Tubescreamer, OCD, Timmy, Turbo OD, Rat, MXR+, Barber LTD, and more. They all did something cool, but not one of them was exactly right. She wanted one with a very natural EQ that didn't really change the guitar, something that would tame the ice-picky top end without over-dulling it, something that retained some fullness in the low mids, and something that generated a symmetrical clipping kind of like a push-pull Fender amp like a Deluxe, Pro, Super, Twin, Princeton, etc. that had that clean-ish-ness even when pretty dirty. So that sent me on a mission, and a few prototypes later we settled on this circuit.
Okay... So... is it inverting or non inverting. Does it use germanium diodes, transistor, silicone? What kind of clipping setup- symmetrical or assymetrical? Pre-EQ, Post-EQ? Buffer?
I think its easier to answer this with something like based on a ts9 but with an improved buffer and assymetrical clipping- or something like that... I'm not a genius or anything, its not like I'll be able to copy the circuit- but someone probably will soon
. The pedal DIY'ERs are overdrive fanatics!
I built an mxr dist + clone and have not really liked it much- i'm about to post a new thread about it. I've been contemplating the earth drive but I thought I read somewhere its got a similar topology to the dist +, but it sounds a lot better and different to me. the dist+ is so fizzy!
To be fair- most major differentiations have been done already apparently. I'm sorry if the earth drive is completely unique and I implied that it was based off something. I'd love to try it out!