Mr. EQ: what to do with other inverters

[Ben N]

I'm just putting together a parts order, and Mr. EQ is on the list.  On a search I found a report of someone adding a TSF (or Tim Escobedo's Calavera) in the same box (presumably the 2-inverter EPFM version).  I am wondering if anyone has any other suggestions for using that pair of leftover inverters.  One thought that occurred to me was an enhancer, since CMOS distortion is supposed to be the sweet kind, but I don't really know how to do it.  Can one inverter be used as a unity gain distorter, and other as a mixer to cancel out fundamentals?  Whatever.  Any ideas?
Oh, and since I'm here, any thoughts on the age old question of order:  Mr.EQ>>TSF or TSF>>Mr.EQ?
Ben

[Processaurus]

headphone amp?
Booster?
Buffered FX loop (I like this idea the best, you could use Mr. EQ on any pedal with one stomp rather than two)
phase reversal option for something
the enhancer type high frequency distortion sounds interesting.
Some more EQ stuff, like a LPF speaker sim.  Or a resonant filter of some type.

[Ben N]

Good ideas, all!  Now--how to do them?  (There ought to be a collections somewhere of circuit snippets like that.)

[Ben N]

Bump?

Anybody have any concrete circuits that can use one or two of them thar inverters?   

OK, and here is an enhancer thingie I fouind, that looks like it might be adaptable to use with, say, a couple of inverters and a dual opamp, but I'm not really following how it works--can anyone help with that?

http://www.montagar.com/~patj/harmswtn.gif

Thanks

Edit: OK, I just came across a number of old threads talking about the Harmonic Sweetener, which, it turns out is the parent of Mark Hammer's Woody.  (I participated in some of those--damned Alzheimer's!)  But anyway, the point is, its is a steep highpass filter feeding a clipper, then mixing back in with the buffered straight signal.  OK, so now the question is how to do this best using a couple of inverters! 

[Mark Hammer]

Given the requirements for adding any sort of enhancer function (steep highpass filter plus clipping plus mixing circuit), my advice would be to simply ignore the two spare invertors.  Alternatively, I suppose you could add one or two more identifiable peaks in other locations than the existing ones.  For instance, the zone between the LO (100hz) and MID (700hz) strikes me as a huge (almost 3 octaves) gap to be filled.  Two more stages similar to the MID stage (with peak or dip selectable) would make an extremely flexible unit with lots of different voicings available.

[Ben N]

Thanks, Mark.  I was just finding more old threads that my first few searches didn't come up with, like this:
http://www.diystompboxes.com/smfforum/index.php?topic=34050.0

And as a result was also concluding that it can't really be done with just the 2 sections.  BUT--theoretically (not necessarily for this project) inverters ought to work well for the clipping section of an exciter, no? 

Anyway, if I were just to go with the TSF in this package, would you recommend that it go before the Mr.EQ, after or in the middle somewhere?

Thanks,
Ben

[Mark Hammer]

Anyway, if I were just to go with the TSF in this package, would you recommend that it go before the Mr. EQ, after or in the middle somewhere?

I've had good luck sticking a resonant booster (similar to the MID and LO function on the Mr. EQ) in front of the TSF to get ranges that were more prone to clipping than others.  But there is also something to be said for having tone shaping after it for accentuation. 

T'wer I, and if the intent were to always use the Mr. EQ with a clipping circuit, I'd probably want to stick a couple of resonant section before, and a couple after as well.  Of course, since the goal is to do something productive with two spare invertors, following up on my suggestion would likely result in the need for more than 6 invertor sections.  It would also involve some switching issues.

Probably just smarter to use the 2 invertor sections, and add one or two more lower-mid/upper-bass sections.  Then you can stick that complete thing either before or after whatever the heck you want.

If I'm following the pattern right, the rule of thumb seems to be to use the nearest common value that result in an approximate 7:1 ratio of the cap to ground vs the bypass cap (e.g., 680pf/100pf, 15000pf/2200pf, etc.).  Extrapolating from that, an additional low-mid section could be built around a 5th invertor (pins 11, 12 seem to be available) by duplicating the section built around U1c.  Substitute 560pf for the 330pf caps, and 3900pf  (3n9) for the 2n2 caps, and you're there.  That should give a peak/dip in the vicinity of around 410hz.