sweepable mids control?

[G Kresge]

Does anyone know how to make a sweepable mids control for a TS9? Any tips would be appreciated!

[aron]

I guess I would look at geofex.com especially the article on EQ/parametrics.

Great idea.

Aron

[G Kresge]

Thanks, I'll check it out!

[R.G.]

It (finally...!!!) occurs to me that the TS is already set up for pretty complete parametric hacking.

The tone control on the TS is the standard pots-between-the-plus-and-minus-inputs of the archetypical graphic EQ. You are free to add more sections to that thing to get boosts and cuts in different places.

Even more usefully, you could put a gyrator based inductor in there with the cap that's already there and not only get boost and cut, but also sweep the resonance point with a pot to change the gyrator inductance.

Sigh. Now I got *more* drawing to do.

[G Kresge]

That sounds like what I'm looking for RG! If it's not too much trouble, I'd really appreciate some assistance in getting this happening. Possibly with a dual-concentric pot in place of the existing tone control?

[G Kresge]

<bump>

[puretube]

get your inspirations from all those HM pedals floatingaround the web...

[G Kresge]

That actually *was* my inspiration for it.

[Eb7+9]

funny, I looked at this a while ago ...

Kerry's post on parametric Zappa filters got me into thinking how you could make the TS mid-boost circuit variable and more hi-fi like at the same time by sticking a gyrator simulated class-A cut/boost circuit in the second half of the TS topology ... similar to the Acoustic 360 Variamp EQ circuit but bumped up in frequency for guitar ...

Compared to a passive inductor based ckt the added noise in any gyrator simulated filter can get noticeable in the maxed cut/boost positions but using one within a single-ended class-A stage has the added advantage of offering better transient transparency than with going through an op-amp based circuit (that's my theory) ... the tuning capabilities of a gyrator can provide a good noise trade-off as long as you don't expect to use too much cut or boost from the filter stage ...

I'm calling this TS-gyrator circuit "Easter Island" - it's dedicated to Frank, the Duke himself

http://www.lynx.net/~jc/EasterIslandSchm.gif
http://www.lynx.net/~jc/EasterIslandStrip.gif

the circuit arrangement I chose allows for a x4 boost at all frequency peaks and a cut that brings the signal down to almost nothing at the notches ... the cut/boost control can live between 20% and 80% rotation and provide quite an effect while introducing little noise ... the variable cap values are used to determine boost/cut frequency and Q profiles ... the 50k pot operates as cut/boost control ...

I took this new critter to the pub a few weeks ago along with a basic delay, an old CryBaby and a Twin and it was pretty xclnt I will say ... I tried a few settings throughout the evening and it was nice not being stuck with one tonal shape - didn't miss my TS clone at all ... ended the jam trading off with our local 11 yr-old blues prodigy over a loose 7sus4 modal vamp ... Frank woulda been proud :)~

peace ...

~jc

[Mark Hammer]

Very nice, and a fitting tribute.

One of the things I've become enamored with in recent years is using series switching of caps, rather than parallel switching, to produce more pop-immune devices.  Is this circuit friendly towards using, say, a DPDT on/off/on toggle to shunt combinations of caps in series and avoiding pop while "twiddling the guitar"?  (The caps in question would be those setting the centre/resonant frequency of boost/cut)