General question about DIY stomp boxes

[datazing]

Howdy all... I've been playing the bass now for about a year and a big fan of envelope filters.. Im playing thru a digitech bass envelope filter currently with a digitech "big squeeze" compressor and a boss EQ.  

Im kinda at that stage where I want to discover my "own sound".  Yes the envelope funk has in a way been played out but I just love it... After seeing the prices various effects pedals, I think I wanna get crafty and build some boxes to: 1)save money and 2)find a envelope sound thats somewhat original.  3) have some fun playing through my own boxes.

So heres my questions:

1) Any suggestions on plans/kits for BASS envelope filters and compressors?

2) Does it matter if you are playing a bass or guitar through any said stomp box?  i.e. If I find some plans for a filter I would assume the filter is designed for a guitar and not a bass but does it really matter?

3)Assuming the frequency from the bass guitar is different than that of the guitar do you know of any links related to the creation of bass stomp boxes?


Thank You all for your time,

Regards,

Will H. of Seattle, WA. good ole USA

[AllyP]

Glad to hear your enjoyin the bass!!!  I love Primus....

Have you tried searching the forum?  I'm sure there was a thread about converting guitar effects schematics to bass.....

The Bass will have frequencies an octave down(correct me if I'm wrong guys! ) So filters with envelope followers will DEFINATELY need to be adjusted!

I recently built the Nurse Quacky from www.runoffgroove.com . I built it for guitar...I love the sound.....*AND* it was a simple circuit to build...A great starting point!!!!   I believe it was based on the Dr Quack from AMZ which, in turn, was based on the EH Dr Q.


Just one little note.....  By the time you have bought the components, built the circuit, soldered it, debugged it and put it in a lovely new box your likely to find it tisnt much cheaper, or not cheaper at all than buying the original box!! :wink:

Still....Enjoy stompboxes I hope you find what your looking for!

[Ge_Whiz]

I have Digitech RP-100 (guitar) and BP50 (bass) boxes and the envelope filters on both sound pretty similar irrespective of instrument used. This is because the major part of the sound arises from the filtering of upper harmonics, not the fundamental note. Go ahead and build 'guitar' boxes, and if not completely satisfied, learn how to tweak 'em. I have a project on the cards to build a Bazz Fuss and Nurse Quacky into a Jazz Bass copy. I reckon that these two effects (separately or together) are the most expressive bass sounds.

[moosapotamus]

An envelope filter might be a difficult project, if you're just starting out. There are some specific things that you can do to get them to sound better on bass, too. For example, the Neutron (MutronIII clone, project at GEO) uses a state variable filter that allows selection of either high-pass, band-pass, or low-pass filtering. Of course, low-pass would be the setting of choice for bass.

The MXR envelope filter project at Tonepad is probably a bit easier, and perhaps some others could comment on how it could be modified to give better bass response. But again, I don't think these would be considered good beginner projects. Simpler is better for learning how to get started.

The Bazz Fuss or the Buzz Box (two Bazzs in series) is probably a much better choice. They sound fantastic on bass without any mods. Highly recommended! In addition to the clips at Runoff Groove, listen to the Buzzsaw! on my web site. It's based on the Buzz Box.

Another great thing to do for bass effects is to have the ability to blend in some of the clean bass sound with the effected sound. There's another box on my site, called the ParaLooper, that will let you do this with any effect you want. Check it out.

Hope that's helpful...
~ Charlie

[Mark Hammer]

The standard change for adapting most envelope controlled filters for bass is to simply shift the filters downward by an octave or so.  This involves identifying which capacitors are responsible for that, and doubling their values.

So, the DrQ/DrQuack/NurseQuacky uses a pair of .0047uf caps (often shown as .005 but just try *finding* .005uf caps!).  Swap these for a pair of .01uf caps, and your whole filter range drops by a tad/smidgen/hair over an octave.  If you feel the need to go lower the change if frequency range is proportional to the change ratio (so .015 would move 1.5 octaves down and .0022 would move a little more than an octave up).

The other thing to address is time constants.  Many envelope controlled filters (and make sure you read the "technology of..." paper here:  http://hammer.ampage.org/files/Autowah.PDF ) for guitar assume you want something a little less percussive and more suited for strumming.  Well, if you play bass you won't be strumming all that much so you may want to play with the attack and decay times.  You can do that by changing the component values (if you know what you want) or you can do that by installing variable attack/decay if you want more flexibility.

Finally, bass pickups often have a heftier output then guitar pickups because of string thickness so the device sensitivity  and what ranges it needs to be sensitive over may be different.  Not a huge problem, though.

The DrQ/DrQuack/NurseQuacky is not all that fussy with respect to parts and certainly not all that different from any other DIY project in terms of the usual nuisances like cold solder joints, wiring up the board, pots/switches, and packaging.  It has virtually nothing on it that is static sensitive so even beginners' construction techniques will be sufficient (I love the MXR unit at tonepad but CMOS chips require a wee bit of mileage under your belt before using so save it for #2).  We've collectively talked plenty of folks through from a bug-ey board to a fully functioning unit, so don't let the risk of problems deter you.  It is not the "best" unit of its type but it can sound pretty decent, has lots of mod potential, is dirt cheap and a quick build for what it does.  Gentlemen, start your ducks.

[Mark Hammer]

Let me just add that basses often sound better when swept in a downward, rather than upward, direction.  I suspect this is largely because:
a) You want to retain some bottom, and sweeping up (with a bandpass filter such as the filters mentioned use) robs the bottom when you need it;
b) There isn't a whole lot of high end to filter once the initial transient has passed so sweeping downward makes the best of what you have while you have it.  The normal loss of high end as the note progresses, in addition to the filtering also tends to accentuate the perceived action of the filter.

There were some posts in past about replacing the usual NPN transistor in the DrQ/Quack/Quacky with a P-channel JFET for downward sweeping.  I think you can see some examples of this in one of the envelope-controlled filters at Tim Escobedo's Circuit Snippets site.