TonePad Small Clone build: IC1 opamp choice notes and impedance question

[bluesdevil]

Just finished up the Small Clone project from TonePad and luckily it fired up right away!! Did the usual "Depth" pot mod, delay time control mod(replace 150pf cap with 250pf and replace 39k resistor near it with a 4.7k resistor and a 100k pot), "Speed Range" cap switch choice between standard and slower speeds and pulsing LED... all well documented at the site.

     Well, the thing that actually intrigued me the most while experimenting was the difference in tone when comparing opamps (IC1: input/output). Here are the results:
TL072 - First one I tried. Clean, but seemed a bit too dark sounding. Volume was below bypassed signal.
NE5532 - Very clear, clean full range sound. Almost sterile. Volume is closer to unity gain.
JRC4558D - This is what they mean by "warmth". Somewhere between the 2 other chips as far as treble goes with a slight lo-fi graininess to it which seems to soften attack. Below unity gain as the rest.
   Please share your choices and why... I'm torn between the NE5532 and 4558. Really wish there was a way to toggle between 'em!

  I thought I would try tackling the volume drop issue by reducing the 10k resistor feeding into the output half of the opamp. 6.8k did the trick but either my ears are playing tricks on me or I'm going insane, because I swear it's adding more treble as well..... am I messing with the impedance by lowering that resistor?
   Thanks for reading this mess.

[bluesdevil]

Well alright. After much switching of IC chips back and forth and driving myself nuts I went with the TL072! Replacing the 10k at the output with a 6.8k resistor brought the volume and treble up where I like it.
     I almost went with the NE5532, because it was very clear, but too hi-fi if that makes any sense.
Although this thread got zero replies, I'm hoping it'll come up on a search when somebody needs advice on this build.
I want to give a big thanks to Tonepad for making such a great project available!!

http://www.tonepad.com/getFile.asp?id=97

[differo]

ther is always someone reading it when help is needed:)
you never know who can you help..

[Fp-www.Tonepad.com]

Very cool. IC comparison reviews are useful.

Fp

[Canucker]

I know I'm sounding like a total amateur for asking this but how do different 4558s compare? I know that the letters before the numbers signify the manufacturer but in shopping today there was another IC I required and they had three different versions each with a different letter at the end. There were no 4558's to be found at the two shops I visited so I'm going to have to order. So I guess I'm asking what should I be looking for and if there is much of a difference to look for does anyone have any strong preferences? Thanks in advance for any advice!

p.s. I want these to build a small clone (obviously) as well as an Orange Squeezer Compressor!

[deadastronaut]

just for the hell of it...

i just built a small clone, i used

tl072...

lm358 (lfo)

when effect is on, its way louder than bypassed, in fact i'm adding a volume control to it, as i like chorus with distortion (alex lifeson) .

i find that you can trim it to be unity, but when adding distortion it just needs that bit more lift...plus i',m a fussy bugger too.

as for different 'sound' of opamps...hmmmm...i'm fine with the good old 072.  

[Canucker]

tl072... in place of the 4558? those I have one or two of but I just want to build the "vintage" version as is nothing fancy at this point....I'll get fancy if it actually works for me  A superfuzz is my most complex build to date so this will be a level up!

[deadastronaut]

yep 072 in place of 4558..

i doubt you'll notice much difference....if any ,  try different ones and see...i'd be interested out of curiosity too...

[Canucker]

Totally afraid that if I start thinking about testing out variations and mods I'll just be getting to far ahead of myself seeing as at this point I just wanna build one that works....I have some other things to order so I'll just go with the parts listed on TonePad and then explore after I get it working! The electronics stores around here are really hit and miss for stuff I need as far as IC's and Transistors.