Designing a Pedal - need some help

[Snyder]

Hello All,

I want to design a pedal to emulate that crunch sound on Marshall amps. Basically, I want the pedal to have a potentiometer for the amount of distortion, and i want it to cut the bass and mid almost entirely (or out and out entirely) out of the signal. Now I dont know a lot about electronics or sound, but I think that would create a crunch sound similar to, oh, for example, the second guitar that comes in in the song "The Wicker Man" by Iron Maiden. I think. I could be wrong, and if i am, please correct me, but if I were trying to design that kind of circuit, how should I go about it. I dont understand electronics all that well and this is my first circuit design.

Thanks

[plankspank]

What type of Marshall head are you trying to emulate? The non master volume "Plexi" tone, or the more modern JCM master volume series?. A Range master clone in front of a good tube amp will give a good Plexi crunch. Check out the projects on ROG's website:http://runoffgroove.com/articles.html for some cool Marshall tone pedals, i.e the Thor or the Eighteen.

[demonstar]

I'd say marshalls generally have a pronounced midrange. Well certainly in the likes of AC/DC and Thin lizzy and led zep etc. Althougth the newer models do allow for a more scooped tone. I've got a dsl100 head into a 4x12 cab with greenbacks in it and I'd definitely say theres plenty of midrange there. It certainly isn't scooped out in my opinion.

If you really want to get that valve tone a marshall head and cabinet are best or a combo but stay clear of modelling amps. They're never as good asd the real thing or sometimes just too good and don't caputure the character of the originals.

What amp do you use? If you use a marshall I can't believe you can't get the tone you say your after because every marshall I've had, the tone your after can't be avoided particularly in the all valve models. Yopu may be interested in this...

"http://guitargeek.com/rigview/351/"

That really is the way to get the tone. You must remember that tone is also in the fingers. a pedal may help but probably won't get you exactly where you wana' be just close. The amp is most important imo then use a pedal to get even closer.

[Snyder]

Yeah, I thought of a rangemaster clone. I'll try it out. The thing about a rangemaster is that it boosts the treble, right? I want to boost the treble and kill the middle and bass.  And no, I'm not using a marshall, I'm using a peavey bandit. I can get very close to the tone I want using the vintage setting, high at max, mid and low at zero, pre gain at 5, but I'm looking for a way to get that tone from  a pedal so that I can switch between it and my heavy tone, which is a boss ML-2. I know what you're about to say: effects loop. But I'd really rather not use the peavey footswitch due to the slight delay when changing fx loops. Besides, I've made pedals before (and sold them) and this tone is in popular demand with my friends, who might buy one from my if i could design and build this pedal. Like I said, I dont know how to design it...

[R.G.]

Snyder, I apologize in advance if this is offensive. It's not meant to be.

If you want to design audio circuits, you need to learn at least a moderate amount about electronics and sound. There really aren't any quick tricks which we can tell you where you can just go "Oh, OK. Got it." and then go off and design circuits.

Learning to do design well takes some time and application. It's not the kind of thing you do over a weekend so you can sell pedals to your friends. If you get some training and do some experimentation you can be modifying circuits in useful ways (other than random substitutions) in six months to a year. True design-from-scratch will take longer.

[Toney]

Don't be too discouraged...
'Design' and 'build' are quite different things...have a search around, grab a coffee, crack a beer if you' re able and sit in for a long read.
You'll find plenty of people have toyed with the Marshall in a box thing...

[Cliff Schecht]

Snyder, I apologize in advance if this is offensive. It's not meant to be.

If you want to design audio circuits, you need to learn at least a moderate amount about electronics and sound. There really aren't any quick tricks which we can tell you where you can just go "Oh, OK. Got it." and then go off and design circuits.

Learning to do design well takes some time and application. It's not the kind of thing you do over a weekend so you can sell pedals to your friends. If you get some training and do some experimentation you can be modifying circuits in useful ways (other than random substitutions) in six months to a year. True design-from-scratch will take longer.

Quoted for truthiness. It took me a few years before I did my first real design work. I've done a few simple things like tremolos using VCA's and some other cool stuff to demonstrate different things to fellow students (a lot of my engineering buds still don't know what a transformer does ) but honestly, you're not going to get very far unless you are truly interested in electronics. Even then, it takes a lot of patience and a certain knack to really get anywhere with electronics. I do understand just about everything I've built and modded now but I've still got about two and a half years until I get my MSEE .

[newbie builder]

+1 for truth in R.G.'s post.
I've been building for more than a year, and I can mod a circuit to make it do something I want to do, I can fuse simple building-block circuits together and figure out how to make them work, and that kind of simple stuff. But designing a truly original circuit from scratch is beyond me.

Building a marshall-esque circuit from a place like Runoffgroove.com, however, is not too difficult for anybody with a little time and desire to make something cool, so I'd recommend researching a bit about what parts you may want to change in order to achieve the sound you desire (in this case, cutting most of the bass/mids out of the signal), and then go and build it!

[Processaurus]

It sounds like you want a really trebly, thin, telephoney sound, in a box.  I like that sound too.  I would try some of the Marshally voiced designs that people have contributed here, and modify one by making the output capacitor much smaller, to make it cut out the bass, post distortion.  You can use a socket to audition different capacitors until you find the right one. 

Good luck