Extra OP Amp: Active tone, or passive with a boost?

[Earthscum]

Hey all. I did search on this, but really couldn't get a definite answer. Basically what I've built (and it sounds so sweet) is a D(FET)-1. So far the first stage is pretty much half of the AMZ Booster 2.5 using MPF102's. They creat just a bit of distortion on their own, but it actually gets attenuated somehow going into the next stage... anyways, the second stage is the DS-1 OP Amp stage, using a TL082.

So, here's my question: I'm only using half of the TL082, and was trying to decide if I should use it to make an active tone stack to replace the BMP style DS-1 stack, or should I use the passive stack and use the extra amp as a buffer/slight post gain? This is actually a question of tastes and preferences. I want to keep the essence of the DS-1 as intact as possible, and not really sure if I should include the post buffering (and pre-buffering, for that matter, but I am using fets, so that should give me the proper impedence without a buffer, right?)

I tried out a standard Baxandall Tone stack, and even yanked it and tried again, thinking maybe I have a bad spot on my board, or was using the wrong values... anyways, the "bass" control did virtually nothing, and the "treble" control basically controlled gain. I tried it with a LM741. I also tried it at the end of the circuit I listed above with the same results (I even swapped pots, thinking I had one that was bad).

I'd like to keep the pots to a max of 2, and would actually prefer 1, this being part of what's making me lean towards the BMP stack. I just don't wanna really let the 1/2 TL082 go to waste.

As a small side question, if I don't use it, do I just leave the unused section floating, or tie it to ground? I've only read a couple things about what to do with the unused amps, and they said something about tying stuff to ground to reduce battery usage? (same with the 4066 cmos switch).

Anyways, back to the stacks... This thing easily has enough juice to push a passive stack. I just really haven't had much luck getting anything to REALLY work, except for the stock DS-1 stack. I'm sure part of that is because I'm familiar with the response. Most stacks I've been playing around with don't have the range I'm looking for. This may be something with the equipment I have (I really should bring home some of my gear). Right now I've been testing through a Boss TM-7 Guitar Monitor, playing through a detuned (Dflat) DeanZ Autograph with a plate-locked tremolo (DeanZ Signature is same thing, but different colors, and maybe humbuckers at the neck? Girl in "Addicted To Love is playing the Signature). Anyways, it's a turd, but I'm a bassist, so... lol. This guitar really doesn't have much for tone to begin with, but the stacks didn't really react to my bass either (Ibanez... almost TOO much treble/presence).

Even some ideas to play around with are fine. Also, say I decide to do a stack in front somewhere to shape the distortion, since this is a full fet drive, would I have problems with an active? Or (I like to keep it somewhat simple), just another BMP type between the 2 stages?

Alright, enough questions. Like I said, this is more of a question of taste and preference. Recommendations?

BTW, I've tried stock DS-1 stack, SWTC 1 and 2, Baxandall active (2 variations), and many simple bass/treble cuts. None of them really seem to do much except make mud on one end, broken glass on the other, and blah straight up (generally worse than what I get without the controls). Only active I tried is the Bax.

[aziltz]

have a look at some schematics by Xotic.  They have op-amp clipper circuits with some present voice, but then then run them into an active Treble/Bass control using 1 op amp stage.  I'm not sure if this is different from the baxandall that you mentioned but worth a look!  i would recomend leaving in the BMP set to your favorite tone (perhaps fix it with set resistors or use a internal trimpot, and add this after that stage.  Since it is active, I believe it starts off with a gain of 1 and can increase from there.


if you can't find schem's on the internets, i can help via PM.