...if there is one?
I am a total beginner as far as building goes and I have found a few EQ's on this site but the schematics are too complex for me to tackle. I guess this means they are beyond my skill level at this time, but I would very much like to build some kind of tone control EQ, even if its simple like bass mid treb, or something. I'd prefer a more graphic type EQ though.
All my experience building pedals comes from GGG because of the easy to follow pictures and wiring diagrams, at this point I could not even build pedals without them. I can read simple schematics like boost and fuzz or compressors or other simple distortion circuits but without the wiring diagrams I find myself guessing where to connect pots, switches, and jacks.
Any recommendations for simple "spelled-out" projects for an EQ?
Thanks, Matt.
This is very good question and the honest answer is that it is not very difficult to wire up a tone control.
I know exactly how you feel, but to be honest with you, that's one of the reasons why I advocate perfboard wiring for beginners. Doing a perfboard layout helps you take one more step towards understanding how things connect rather than just populating a PCB. I guess the same could be said for breadboarding, but to me, a perfboard layout can be just like the schematic and more "intuitive".
Take the time to figure out how jacks and pots are wired. It's not that difficult. Try your hand at a simple circuit from scratch or even one that you made from GGG and see how the jacks/pots connected and figure out why?
That way, you will be ready for some of the tone contols I will post soon. :)
I'm not exactly a beginner anymore (I've built 5 pedals, 2 practice amps, and modified 2 other pedals), but I still rely on Aron's FAQ for wiring pots and jacks. Also, Peter Snowberg provided the details on wiring my new favorite jack, the Marshall type (which would be a great addition to the FAQ, IMHO):
Quote
Now on the tabs.... as you insert the plug,
you will see the contacts flex upward. On
one side the metal will lift up and
the other side is like a hinge, it will
stay put and just flex a little.
You want the connections on the side that
stays put. The tab closest to the hole
for the plug is the ground, and the other
tab on that same side is the signal lead.
When you get a stereo jack of that style
you will have an additional tab between
the first two. That new tab will connect
to your battery lead.
(+ for a PNP fuzzface or - for an NPN fuzzface)
Anyway, I agree with Aron about the perf. It really builds a couple of different skills, it vastly improves your soldering, because you are making all of the connections with either solder bridges or with component leads, it helps you see how things can be laid out differently (see the layouts at Runoff Groove for good perf layouts), and it helps you figure out offboard wiring better.
RG Keen'sdocument on "Parametric made easy" (http://www.geofex.com/Article_Folders/EQs/paramet.htm) does a very nice job of illustrating how simple it is to make something like this. This is a highly expandable system, so if you plan it out right, and leave the appropriate room on your perfboard, you can start off with a few bands and elaborate from there once you get your feet wet.
PLEASE NOTE
Which bands are critical for changing the "voicing" of an instrument will be different from instrument to instrument. Things that will radically transform a Strat may have much less effect on a 335-type instrument, and so on. Since no manufacturer can predict what their EQ unit will be used for, their strategy has traditionally been to stick in as many equally-spaced bands as they can so that SOME combination will do SOMETHING useful for SOME user. If you know what bands are critical to alter your tone, though, you can probably have very satisfactory functioning with fewer bands than you might think. Four well-placed resonant filters with location-appropriate selectivity can probably do more than 7 or 10 bands of poorly placed EQ sections.
For that reason, my own recommendation would be to look closely at the schematic for the parametric EQ sections early on in the document, and incorporate trimpots in place of the 1meg chassis pots for setting frequency. You can use these to seek and find those frequency bands that do the most tonal changing for you. You *could* choose to implement them as chassis-mount controls for full parametric control, but devoting more panel space to frequency controls reduces the amount of space available for other bands. Your choice.
Probably the most flexible control with the lowest parts count and chassis size would be a 4-band unit, where the resonance is preset to wide and centre frequency is fixed, for the highest and lowest band, and you have two relatively narrow or selective "quasi-parametric" filter sections in between, with variable frequency in addition to boost and cut. That would require 3 dual op-amps, and 6 pots/knobs. That would all easily fit inside a 1590BB and run off a single 9v battery. It would likely offer far more control than a 7-band.