Daniel Sorbera Posted December 29, 2004 Report Share Posted December 29, 2004 can I somehow buy/make an active preamp for my guitar equpied with passive pickups that gives me 3 knobs for treble, mid, bass. is it possiable? or do I need to buy like EMG stuff? does EMG even make stuff that was a 3 band EQ like that? Quote Link to comment Share on other sites More sharing options...
Drak Posted December 29, 2004 Report Share Posted December 29, 2004 Why do you want that? Quote Link to comment Share on other sites More sharing options...
Kyle Cavanaugh Posted December 29, 2004 Report Share Posted December 29, 2004 I know a number of companies that produce those types of preamps\EQs for bass, but not guitar. I'd check out Bartolini, though. Carvin makes and sells one fo $80 but it only has treble and bass I believe. The midrange control is definetly more complex to design so I think that's why they left it out. I'm working on designing exactly what you're talking about right now though, so if you have no luck, maybe I could hook you up later down the line. Quote Link to comment Share on other sites More sharing options...
Daniel Sorbera Posted December 29, 2004 Author Report Share Posted December 29, 2004 (edited) drak, Why I would want to do that is so I could boost the bass/mid/treble on demand. Also It woudl provide a way to color the distortion. If you EQ before distortion it colors the distortion. If yo uEQ after the distortion it changes the signal more. Try it out with an EQ pedal. It really makes a difference. Edited December 30, 2004 by Godin SD Quote Link to comment Share on other sites More sharing options...
lovekraft Posted December 29, 2004 Report Share Posted December 29, 2004 (edited) Headwize Pocket EQ project - scroll down to Fig. 2. Build as-is, or read further for the necessary math and tweak as desired. Or you could always use a Fender/Marshall style tone stack, with a buffer in front of it and a gain makeup stage after it. Edited December 29, 2004 by lovekraft Quote Link to comment Share on other sites More sharing options...
Daniel Sorbera Posted December 29, 2004 Author Report Share Posted December 29, 2004 so your telling me that I can put that curcit in my guitar? So all I do is build it per schematic any stick it right before the output jack? Dang it looks like that thing gives you 20db each way! on all 3 controls. Holy cow thats a LOT of tone shaping possiabilitys! Quote Link to comment Share on other sites More sharing options...
lovekraft Posted December 30, 2004 Report Share Posted December 30, 2004 so your telling me that I can put that curcit in my guitar? So all I do is build it per schematic any stick it right before the output jack? Well, you'd build it as recommended with two 9 volt batteries, and install it between your pickup selector switch and your volume pot, but, yes, basically, that's all there is to it - if you'd like a bit of gain boost, change R2 to 120K or 150K. You might want to adjust the filter center freqs towards the guitar's range (~65Hz - 6KHz), but it will work as drawn (you'll just be boosting/cutting frequencies that your amp won't reproduce, which is not a problem unless your guitar is noisy). Quote Link to comment Share on other sites More sharing options...
Daniel Sorbera Posted December 30, 2004 Author Report Share Posted December 30, 2004 (edited) ok so I put it between my selector and volume pot. Now how do I move the center freqencies to (~65Hz - 6KHz)? I understand that shifting c5 and c4 will shift the frequency of the mids, any sugestions on what to try as there values? And yes I see that you would need a battery for each opamp. One more thing, will this thing change the impedence of my signal to low insted of high? If so will this cause any bad effects? will I need to change any of my pot value (just so you know my guitar is wired like this minus the coil split on the humbucker.) Edited December 30, 2004 by Godin SD Quote Link to comment Share on other sites More sharing options...
lovekraft Posted December 30, 2004 Report Share Posted December 30, 2004 ...how do I move the center freqencies to (~65Hz - 6KHz)? I understand that shifting c5 and c4 will shift the frequency of the mids, any sugestions on what to try as there values? I wouldn't worry abut changing the mids, it's the bass and treble freqs that go way beyond the range of your axe. The article has all the necessary math in the text. And since you're tone-shaping rather than using it for headphones, you can ignore the info about the Fletcher-Munson curve(s). Or breadboard it as-is and give it a try, you may be perfectly happy with it with no mods....I see that you would need a battery for each opamp.No, you can run both opamps from the same supply, but you'll need a +/-9 volt supply to get sufficient headroom to avoid clipping when you start boosting....will this thing change the impedence of my signal to low insted of high? If so will this cause any bad effects? will I need to change any of my pot valueJust get rid of your tone pot and insert the circuit between the selector switch and the volume pot - don't change anything else. Quote Link to comment Share on other sites More sharing options...
Daniel Sorbera Posted December 30, 2004 Author Report Share Posted December 30, 2004 (edited) ok forgive me for being stupid, I understand everything but the power situation. If I only need 9 volts. than cant I use one battery? I dont understand the power. Everything else I get. Also do you know where I can get some sliders that have center detents to use as the pots? I would just get rid of my tone pot and put 3 sliders where it was(of course I would get a new pickguard with nothing cut in it) Edited December 30, 2004 by Godin SD Quote Link to comment Share on other sites More sharing options...
lovekraft Posted December 30, 2004 Report Share Posted December 30, 2004 No, opamps run from a bipolar supply, so you need +9 volts and -9 volts with ground between the two, hence two batteries. I'm not trying to sound insulting, but if you don't already know that much about basic electronics, this might be more than you want to attempt. Probably be a good idea to do some more research before you try building one. You can get slide pots from either Mouser or Digi-Key. Quote Link to comment Share on other sites More sharing options...
Daniel Sorbera Posted December 30, 2004 Author Report Share Posted December 30, 2004 (edited) I understand now. Yes my electronics skills are somewhat limited. But my dad knows a LOT. I will have him help me. I just havent had time to show him the schematic yet. He will be there to help me along the way so I dont think there will be any problems. (just talked to my dad and got it all cleared up. I understand everything now. Now I just need to get the parts and get working on it) Edited December 30, 2004 by Godin SD Quote Link to comment Share on other sites More sharing options...
lovekraft Posted December 30, 2004 Report Share Posted December 30, 2004 Excellent- if he's got your back, then you shouldn't have any problems! Quote Link to comment Share on other sites More sharing options...
Ton Posted December 31, 2004 Report Share Posted December 31, 2004 That would actually be nice, with one turn on a knob you can give treble, mid or the bass a boost. It isn't that easy to change a pedalEQ's setting while playing! Quote Link to comment Share on other sites More sharing options...
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