Overdrive Distortion Pedal Categorys

BluesHarp

Member
Messages
8,574
Is there a way we could seperate all OD's into categorys based on the type of basic design? Or better yet, just name the categorys themselves. I will name the category and then a example:

(1) Opamp based = Ts-9's
(2) Non-opamp based?? ( What technical name for here? )= Menatone's, ect
(3) Treble boost cot50 types??? What name am I looking for?? = Beano, ect
(4) Cascaded gain stages = SCOD
(5) JFet Circuits = SubDecay Liquid Sunshine, ect
(6) Transistor types = Fuzz's???
(7) And so on...

Just name all the possible categorys a pedal could fall under. If I make a mistake above, please chime in and I will correct it. Maybe after we get this nailed down, we could take a poll on what your fav pedal is under each category.
 

re-animator

Senior Member
Messages
8,240
subdecay liquid sunshine is a JFet circuit.

also there are many transistor'ed ODs that aren't fuzzes. Technically JFets are transistored, but there is also the Fulldrive Mosfet.
 

pgissi

Member
Messages
2,478
Non Op-Amp types generally can be known as Discrete for the componentry they use (individual compo's versus a monolithic IC) and can include all listed below to be included in 1 category known as Discrete and broken down into the "Type" subcategories from there-

JFETS
MOSFET (metal oxide)
Germanium
Silicon

(the latter 2 come in 2 types NPN & PNP)

Then there is a Discrete/Op-Amp Hybrid Category like the Roger Mayer Mongoose which uses a 2N3904 NPN Transistor and a LM308N IC in one circuit. You dont see too often


OD Types can maybe use these Type flavor categories
OD only
OD and Comp hybrids (Visual Sound Route 66 )
Booster/Pre-Amp
Fuzz
Fuzz and Comp hybrid

Some additional subcategories can be-
Single or Dual Type (1 or 2 types in 1 chassis)
Signal Routing Direction Option with dual types (SCOD??)
On Board EQ or Not
Full Bypass Type
Buffering when Bypassed
DC Requirements (9v unipolar or 18V uni or bipolar)
LED Clipping
Diode Clipping
 

PaulC

Member
Messages
1,949
My problem with this way of thinking is you're going to group a bunch of pedals by ONE PART of a circuit. Because a pedal has a non-inv opamp/diode clipper doesn't mean it's a TS pedal. That's the clipping part. The voicing circuits are just as important - if not more so - than the clipping section. If you don't have the voicing circuit of a TS in a opamp/diode clipper it wont perform or sound the same.

Take it a step further. You have non-inverting op/diodes clippers in pedals. You also will find invertering opamp/diode clippers. They perform very different, and don't have the same clipping characteristics. Another common setup is opamps driving diode voltage clamps. These perform/sound different than the other two above. You've also got tons of ways you can screw with these to make them sound different.

Most people think of opamps as these little black squares. That's not an opamp - it's a chip. Integrated circuit. you'll see pedals that don't use a chip, but still use an opamp. they'll use a discrete circuit which means the opamp is built using individual parts instead of a chip. Still the same basic thing, but somebody tracing it out may think it's a totally different circuit because of all the parts when in fact it can be pretty much the same thing just built a different way. It can also perform different than any IC chip can because it allows a designer to get into the guts of the op circuit to modify it's responce.

Then of course you've got the designs that just slam an opamp without any diodes in there at all.

So really that 1st list could read more like:

1) opamp clipping
2) non inverting opamp/diode current limiting
3) inverting opamp/diode current limiting
4) opamp/diode voltage limiting

All of those could have sub columns for discrete or integrated opamps.

You also have designs that use two or more of the methods above in the same circuit.

You'll see designs that use discrete transistors all of one type. those can be all mosfet based, all jfet based, all bjt based etc... You'll also see designs that combine those elements. There are designs that use those parts along with diode voltage/current clamping. You've got a column for cascaded gain stages, and then one for jfet circuits. The jfet circuits can fall under the cascaded section. Cascaded has nothing to do with what active part you use. It just means you've got several of them in series. There are circuits that have cascaded opamps.

some of those series sections can also have parallel sections and feedback sections messing with the pure cascaded idea...

There are designs that us IC chips along with discrete transistors and diodes...

then you've got opamp based pedals driving tubes etc...

You can make a treble booster with an IC... It doesn't have to be a take on a rangemaster.

You'll have a REALLY big list by the time your done:BEER

Later, PaulC
Tim & timmy pedals
 

jads57

Silver Supporting Member
Messages
6,355
Instead of the technical aspects of the pedal, how about categorizing them sonically. say TS 808 ( Tubesreamer type ) , treble boosters, compressors, distortion, fuzz,etc. I know that this too, may be hard to do . But it sure gets confusing when trying to sift through all of the pedals out there.
 

AL30

Member
Messages
3,003
How about this?

Tube Screamer
Fuzz Face
Fet (some amp emulations)
Boosters (different categories of these too)
Big Muff
MXR+

That covers a lot of ground for distortions/overdrives. A good portion of pedals will be from one of these groups.

AL
 

pgissi

Member
Messages
2,478
I like how PaulC broke it down, its the devil in the details that make each pedal so individual and there are so many varieties. Wish the manufacs would be more forthcoming with this info so you dont have to stare at the circuit to determine the nature of the beast.

For some more clarification-

You have non-inverting op/diodes clippers in pedals. You also will find invertering opamp/diode clippers. They perform very different, and don't have the same clipping characteristics.

Inverting types are those where multiple stages are used for whatever reason, could pre/post buffering, eq or additional tonal/dynamics processing. Typically these are more complex circuits.

The most basic types are non-inverting ala the MXR Dist+ using 1 IC which is an General Purpose 741 Op Amp in the MXR.

An op-amp circuit using the + input is non-inverting and vice versa for those using the - input.

One thing to remember is when an Inverting Op-Amp stage is used, at some point it must be inverted again to have the signal returned to its original phase matching the input source, unless its feeding an additional output to derive a stereo output etc. and needs to be out of phase

Here is a great page with circuit schematics of some popular and more easily understood types and notice the Marshall Blues Breaker, the 1st example of 2 inverting op-amp stages used, all of these Marshall pedals shown on this page are using inverting stages in 2's or 4's etc. to correct the output phase-

http://users.sa.chariot.net.au/~gmarts/ampovdrv.htm

The problem with classifying them is it can get tedious but it is a more accurate way to describe them for comparison
 

Stratman76

Gold Supporting Member
Messages
1,123
My problem with this way of thinking is you're going to group a bunch of pedals by ONE PART of a circuit. Because a pedal has a non-inv opamp/diode clipper doesn't mean it's a TS pedal. That's the clipping part. The voicing circuits are just as important - if not more so - than the clipping section. If you don't have the voicing circuit of a TS in a opamp/diode clipper it wont perform or sound the same.

This, I learned, is why saying a pedal is "based on a TS circuit" does not classify the tonal characteristics of said pedal.

So really that 1st list could read more like:

1) opamp clipping
2) non inverting opamp/diode current limiting
3) inverting opamp/diode current limiting
4) opamp/diode voltage limiting

All of those could have sub columns for discrete or integrated opamps.

You also have designs that use two or more of the methods above in the same circuit.

You'll see designs that use discrete transistors all of one type. those can be all mosfet based, all jfet based, all bjt based etc... You'll also see designs that combine those elements. There are designs that use those parts along with diode voltage/current clamping. You've got a column for cascaded gain stages, and then one for jfet circuits. The jfet circuits can fall under the cascaded section. Cascaded has nothing to do with what active part you use. It just means you've got several of them in series. There are circuits that have cascaded opamps.

Paul, among clipping circuits, there are also:
5) JFET
6) MOSFET
Others?

JFET clipping circuits are often cascaded but are JFET and MOSFET clipping circuits ever used WITH an opamp? Or worse (as in harder to classify), is JFET or MOSFET technology ever used to CREATE an opamp in a pedal design?

What type of circuits are used for voicing? Are were talking primarily EQ here?

I think the purpose of this attempt at classifying OD and distortion pedals is to gain some insight as to what to expect from a given pedal based on it's design. What I am gauging by this is that there may far too many variations on both clipping and voicing circuits to effectively classify the tonal characteristics of dirt pedals based on a few general circuit designs.

I'm just trying to uncover the facts and really appreciate your post! Right on and thank you!

On the flipside, there are many Tube Screamer-based pedals which change little in the complete TS circuit and therefore sound reasonably similar.
 

Stratman76

Gold Supporting Member
Messages
1,123
AL30`s idea sounds good to me!

I don't know...it can also be misleading. To say a pedal is simply "Tube Screamer" based is so vague. There are so many wild variations of the fundamental tube screamer circuit; some are so loosely based they produce sonic qualities that aren't even remotely akin to a tube screamer.
 

AL30

Member
Messages
3,003
I don't know...it can also be misleading. To say a pedal is simply "Tube Screamer" based is so vague. There are so many wild variations of the fundamental tube screamer circuit; some are so loosely based they produce sonic qualities that aren't even remotely akin to a tube screamer.

Yes it is vague. I can't argue with that. And, while Paul C is hard to argue with... if you're not really sure what's going on inside a pedal and you can't read a schematic it's hard to understand those statements. Although I completely agree with them.

So stating it's a tube screamer based pedal is easier for someone - without the technical knowledge - to understand. Yes there are certainly going to be (and are) different sounding "TS style" pedals. A good portion of this can be contributed to some modifications and component choices. You can break things down into sub-categories for weeks but only a small portion of the population here is going to understand it. :)

AL
 

BluesHarp

Member
Messages
8,574
Hey guys.. I have a bad flu, 103 degree fever and all that junk. Havent been able to follow up on this thread, but am real glad to see some interest and from what I ve seen ( briefly ) some very intelegent responses. I have a HUGE migrane, but will be back to see what I can learn from you guys. I feel very lucky to have such a great wealth of knowledge at my fingertips, and I couldnt imagine how I survived on my quest for tone years ago without the TGP. See ya soon...
 




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