'SPITFIRE' Metal 'n' Blues Pedal...

WGTP · February 07, 2012, 01:09:35 PM

You might try a 220pf or 100pf instead of the 470pf if it gets too bright.

You guys are building some gorgeous pedals.

deadastronaut · February 10, 2012, 06:34:13 AM

just been tweaking a little...as the tone control goes too bright imo......

so i'm trying resistors across pin 3 -1 on the tone pot using my resistor sub box......very tweakable..as long as i don't lose any bass too..

@ian: i tried cutting one leg of the 470pf.. just to try that....didn't hear any noticable difference...soldered it back..

try the pot resistor mod ..very noticable........i'm not settled on a value just yet as there are a few possibilites....

back later...i'm on it now!!!!...

8.2k - 10k sounds pretty cool...

edit: 5.6 k seems to be best....btw i stuck with a 47k lin pot, and a 4.7n-6.8n cap selection.....

WGTP · February 10, 2012, 01:45:42 PM

With the caps across the pot, it does nothing at max. Turn it down 1/2 and you should be able to hear the treble boost effect that it creates. 470pf may be too much 100pf may be to little. It's used in guitar amps as a bright switch typically.

Ronan · February 11, 2012, 01:59:31 AM

Here's a rough sound clip with a digitech synth wah thrown in on top of the spitfire in the last few seconds. Sorry bout the guitar playing guys, best I could manage today

deadastronaut · February 11, 2012, 04:21:01 AM

@wgtp..oh i see...

@ian.. cool,..not effin satriani..

....don't apologise, sounds good man!....love that wah too...

WGTP · February 11, 2012, 06:35:03 PM

Robert, I hope you don't mind. After further study of Mu/Srpp gain stage behavior to cap/resistor changes, I refined my mods to add a little more SPIT and included a BSIAB2 mod (converting Q5 from a buffer to a gain stage)(in RED) to add some more FIRE.

http://www.aronnelson.com/gallery/main.php/v/WGTP/Spitfire-BSIAB+mod.jpg.html?g2_imageViewsIndex=1

deadastronaut · February 12, 2012, 09:53:53 AM

@wgtp: cool...i'm all for more improvements.....any clips?...

Ronan · February 13, 2012, 06:18:56 AM

wgtp, Q5 still looks like a buffer, cap in wrong position maybe.

Rob, I tried the circuit with no tone control but left the dual 2K2 and 2n2 low pass filters in place. Sounded quite good, and maybe a bit strong in the mids. The original tone control has been put back now, but it made me wonder, what if a simple mid cut control were used, as well as a straight treble cut aka the Crunch Box . The treble cut, or not cut, might give a balance between bass and treble, and the mid cut control would fill in the hole in the middle. Just ideas...

deadastronaut · February 13, 2012, 06:36:37 AM

yep thats very similar to what wgtp was suggesting early on with this project,

i did do a layout which was just the distortion with no tone at all, to be like a distortion module, that could have any tonestack added...(i wish i'd built that now just for experimental purposes...

i see what your saying..

i haven't got this on bread at the moment, as i'm working on other stuff, as soon as i finish that , i'll get it boarded again
and do some more experimenting!..

WGTP · February 13, 2012, 03:00:45 PM

Whoops, forgot to move the output of Q5 from the source to the drain. Thanks. It's fixed.

As a bonus, I added a FAT mod that boosts the mids and almost makes the tone control flat at the mid point.

Any cap size from 2.2n to 22n can be used there for varying the mids and action the control. Pick the 2 values you like for the switch.

Replacing R13 with a 25-50k pot will function as a Bass/Mid control and should be very useful for many different tones.

Keep spitting fellow Dragons.

seedlings · February 13, 2012, 04:43:37 PM

This project and it's threadspawn rule!

CHAD

WGTP · February 13, 2012, 05:41:18 PM

Cool to watch it evolve.

More Tone Control Mods.

http://www.aronnelson.com/gallery/main.php/v/WGTP/Spitfire-BSIAB+mod.jpg.html?g2_imageViewsIndex=1

mr_deadmaxxx · February 15, 2012, 10:02:40 AM

Is this better than the dr. boogie?

Pretty simple schematic and no more trimmers for biasing.

deadastronaut · February 15, 2012, 10:18:14 AM

imo ...more versatile

and yes, no bloody trimmers..yay!...

mr_deadmaxxx · February 15, 2012, 10:32:06 AM

so your spitfire V3 is better build than the original spitfire? schematic changed?

thanks..

deadastronaut · February 15, 2012, 10:36:23 AM

yes, less switches etc...more to the point!..

but people are suggesting mods all the time too....

mr_deadmaxxx · February 15, 2012, 10:38:51 AM

Can I please ask what are the changes in the original schematic to get the V3? I want to get that V3 sound on your Youtube video..

Thanks..

deadastronaut · February 15, 2012, 10:45:04 AM

here ya go, v3 pdf's..

rock on......

http://www.diystompboxes.com/smfforum/index.php?topic=94608.msg826603#msg826603

mr_deadmaxxx · February 15, 2012, 10:51:49 AM

oops!

BTW, I assume this doesn't have the noise/hiss issue like the Dr. Boogie?

Thanks..

I wish I could have all that guitar skills you have on your demo videos..

WGTP · February 15, 2012, 01:18:17 PM

Can't say for sure about the noise since some is due to construction, but just looking at Dr. Boogie again and with all those resistors and gain stages the Spitfire is surely quieter and easier to build. The basic design has been around awhile and is used in some of the most popular DIY boost overdrive/distortions.

Check this out for some theory and Mu mod to SRPP for more gain. Look for 7.7.01 article.

http://www.geofex.com/

SRPP mod (for more gain and lower output impedance) and Hiss Reduction, if needed.

http://www.aronnelson.com/gallery/main.php/v/WGTP/Spitfire-BSIAB+mod.jpg.html?g2_imageViewsIndex=1

Whoops, did I already suggest trying it at 18 volts with 2 - 9volt batteries. No need to rebias.

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'SPITFIRE' Metal 'n' Blues Pedal...