I need a fast limiter for lap steel guitar

Started by mark_tpfd, January 11, 2012, 05:18:54 PM

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mark_tpfd

An unusual requirement: a stompbox compressor that kills the punch of the note as much as possible. A good example is the beginning of Pink Floyd's Great Gig in the Sky. Usually lap steel guitar is swelled with an expression pedal but I need it Floyd-style. Of course I could use a studio rack-mount compressor but in a live rig, rack space is heavy=expensive=precious. I reckon an attack of 1ms would be great but maybe 5ms might do it. Any ideas for circuits - or even a boutique solution?

Mustachio

I built a flatline compressor with a vtl5c2 , I believe the on time for 63% final resistance is 3.5ms and off time around 500ms.
Its defiantly a cool comp, and id say it has limiter type tendency since its so transparent and clean. it doesn't squeeze your sound like a dynacomp or similar for chicken pickn.
I used an OPA2134 in it as well. With the right settings id say it has the swell effect you want. You can really tell on long drawn out notes/chords. It reminds me of an LA2A in a box more for guitar/bass.
I haven't tried it on vocals yet but i bet its decent.

Bass player loved it as well.

I used it in conjunction with a CS3 i did the optomod from monte allums and got some great sounds. Getting ready to build a Dynacomp clone with the jangle mod soon just waiting for my ca3080s to come in the mail.

I don't know what David Gilmore used specifically on what your trying to mimic in sound but i remember hearing he used dynacomps but who knows what they used in the studio probably LA2a's. Good luck with your tone search!
"Hhhhhhhnnnnnnnnnnnnngggggggg"

gigimarga


Mustachio

I actually did the opto mod plus it was one of the first mods I ever did to a pedal. Its not bad id say it brought out some life in the compressor. I usually leave my comp on all the time its a little noisy but it does the job. gonna build a few more ca3080 based compressors and see if I like them more.

here's a link to the monte mod

http://www.monteallums.com/pedal_mods.html#cs3optoPlus

heres a link to the vero layout of the flatline I built

http://www.aronnelson.com/gallery/main.php/v/ulysses/ulysses_layouts/ulysses_jh_flatline_compressor/ulysses_jh_flatline_vero_1_01_p1.gif.html?g2_imageViewsIndex=1

I think I changed r6 220K with a 470K resistor. Been a while since Ive been inside that box to recall tho I believe it gave the sustain control a lil more range .
"Hhhhhhhnnnnnnnnnnnnngggggggg"

petemoore

  Photocells are a bit slow compared to other compressor types.
   Ca3080 [Dynacomp] is a good strong/fast [can be made faster with mods] compressor.
  Orange Squeezer...very fast but not really 'strong' [also has mods to make the comp more 'apparent'...
   
Convention creates following, following creates convention.

Rob Strand

If the turn-on time of your opto isn't ridiculously slow (the response varies widely depending on the model), then there's no real reason to dump the opto.  Opto's are fairly problem free.

I'd suggest using a sharper knee compressor ie. one that has a higher compression ratio above the threshold.  You can keep the basic gain control section of the flatline then play with the rectifier section.  See for example the Ibanez CP-830 compressor on this page.  The rectifier is the three transistor circuit that drives the opto LED.  Might be better off adding the two diodes as shown on the CP-9 circuit.  Get the schems from here,

http://www.eserviceinfo.com/index.php?what=search2&searchstring=ibanez+cp9+compressor.pdf

Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

MR COFFEE

This would be a circuit worth checking out as a superfast limiter, but it's not a "here's a stompbox schematic for ya"...
It needs a JFET buffer, probably with a little gain. Really well behaved circuit to kill the pick attack on a steel however.

Check it out

http://users.ece.gatech.edu/mleach/papers/limiter.pdf

Sorry I don't get by here too often lately.

mr coffee
Bart