Heavy distortion, split to low pass+delay and more distorted, considerations?

[ruddwijk]

First post on here, been lurking around for a little, hope i'm staying within policy with this medium sized post!

In short, i'm sketching out my first design beyond building pure clones, hoping to get some guidance to avoid the worst missteps from the get go.

First of all, i'm aiming for a box that can do a dirty as gravel distortion for a 6 string guitar tuned down to A.
My plan is to split up the signal in a slightly cleaner signal low passed through a big yet short delay (for that big yet not too obviously echoed sound), then a overly distorted signal to blend that with out to a single output, possibly some kinda eq-filter in the end. Have had luck getting dirty yet big and kinda defined sound in such fashion previously. My intentions are to pack it all in a single box with a minimum of knobs in the end, as i hate fiddling around too much once gig/rehearsal is going.

I have a few ideas on initial modules to work out from, current plan is something like:

ts9 kinda boost/buffer - split - 1. low pass - big muff   - blend  - eq
                                          - 2. hm2 on steroids

I am a bit curious how i should deal with "modules" loading each other when it comes to joining the designs, would you add buffers between the individual modules or rather tweak it out in the bigger scheme?

I am also thinking about power options, would there be any problem sticking to a single 9v battery? I guess i'd need to look at overall power consumption, but might it be a good idea to make a 18v (2x9v) setup and build a small circuit to divide the voltage through to separate parts?

With regards to splitting and joining, how would you work on blending the signal? I expect to be able to adjust the blending while prototyping but possibly omitting a blend knob once i settle on a ratio.

Also i expect there to be noise issues, anything i should generally consider when it comes to physical placement or specific parts? I expect to work with ordinary wire through prototyping and switch for shielded wire in crucial spots.

I have basic knowledge about circuits, fet/opamp-setups, as well as filter design, but would be happy about other pedal specific read ups (went through the "electronic projects for musicians" book, and looking at the "advanced diy" pdf/book from Wampler atm, fine reads).

Cheers

[Transmogrifox]

Blend should be as simple as a single pot -  wiper is the output and each end is one of the effects.  Best to buffer the wiper of the pot, but plenty of tube amps combine interactive passive networks that work.  You can use simple BJT buffers with 10k emitter resistor for most of these purposes.

Are you thinking active EQ or passive (like a Big Muff tonestack)?

Best design practice is to provide buffers between circuit blocks.  Exceptions would be for example, if you have a low output impedance already.  For example the HM-2 final clipping section is buffered going into the EQ.  If you were taking your "HM-2 on steroids" circuit output from before where HM-2 already places the EQ then it is already buffered and there would not be any reason to add a second buffer.

That interface between the final clipping stage and the EQ on the HM-2 is a good example of how to join circuit modules in a way that minimizes interaction.

I suggest placing the delay in front of the distortion because a distortion generates a lot of high frequency garbage that is more likely to alias in a typical lo-fi sampled delay chip.  The best place to put the delay would be right after your low pass feeding into the big muff.

Just some ideas. 

[ruddwijk]

Thanks for the reply, makes sense.

I'm not actually thinking tone stack or even proper eq section, more like potential eq buffs/notches, which i often tweak around with to make a blended sound "sit". So that'll need to be worked out, possibly just a light notch around 400 and a peak somewhere high mid.