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

[deadastronaut]

cool, glad you got it sorted....hows the guts, spaghetti 

[BoogiemanX]

It's a birds nest. Hahaha

[BoogiemanX]

Stay tuned.........
Working on some Sick graphics for this bad boy.

[BoogiemanX]

Is there a place to download pre made 2D drill templates for Google sketchup? All I'm finding are 3d models.

[doctord02]

Any further developments on the baritone tonestack tweaked circuit? Inquiring minds want to know...

[Cozybuilder]

Any further developments on the baritone tonestack tweaked circuit? Inquiring minds want to know...

Lots of 'em 

[doctord02]

Aye, but has Rob posted any? Wanted to see how the TMB stack was implemented before I go off and munge up the v3 circuit into something horrid.

[deadastronaut]

not yet....

[BoogiemanX]

Here is a rough preview of what I have been working on. Still got to do some editing, blending, and shading between letters but you get the idea. 

[deadastronaut]

nice, looks great..

[drummel]

Hello DIYS community!

>>>>>>>>> introduction rant <<<<<<<<<<<<<<<
First post here and I registered because of this thread. I stumbled on this circuit a couple of weeks ago and curiosity got the better of me so I breadboarded it and... whooooa! This is the best high gain guitar sound I ever had! ...ever! I've been playing for 30 years with various setups and DIY stuff so I got some reference. I have built several amps and stompboxes, tube and SS, but never been completely satisfied though very close. Now my quest for "the tone" is finally over and I am very thankful to you DA for sharing this with us. I tried some different component values here and there and must say you really nailed the sweet spot on this one. Some small changes could just ruin it completely and had it been me there's no way I would have the patience to take it where it is. Awesome work man!
>>>>>>> end of introduction rant <<<<<<<<<<<<

I'm feeding the clean channel of a R*land c*be-15 with it. Smooth and chimey over the whole range on the drive pot. Wish my Marshall-ish tube amp did that.
My plan is to gut the cube and replace the preamp with the spitfire. The amp has a 4-way switch controlling 5 fet switches for different sounds. I want to tinker with the circuit to see if I can find tweaks that takes it towards the cleanish pick attack breakup land and back to stock spitfire via these four settings. I have been tinkering a bit but have not had much time with it but I have played around with LTspice so I have some ideas to try out, hopefully very soon.

The clean channel is a fet buffer -> op-amp stage with a huge treble peak -> FMV tonestack.
The FMV stack works great with this setup for me anyway. I thougt it was worth sharing this as it has been some requests for extended tone control. I have a bit more treble rolloff at the end though. Probably to compensate for the treble peak.

If anyone have some hints how to lower the gain in the first stage I would appreciate it very much if you would like to share.
Internet doesn't seem to see the point in find ways to lower the gain of a mu amp.
I am going to try with negative feedback and padding here and there to see if I can come up with something.

Cheers and thanks again!

[deadastronaut]

hi and welcome...

cool, glad it worked out for ya man..

you may want to tweak the first (input) fet R/C values to ground a little... maybe just the resistor

to alter it a bit...happy tweaking 

[stallik]

Welcome Daniel to the forum. Yup, this is one amazing pedal but before you lower the gain, please try lowering guitar volume. Mine cleans up so well i can play albatross with it on. Have to add loads of reverb mind....

[BoogiemanX]

Daniel you beat me to the post! Lol I was going to pretty much say the exact same thing. I finally got some free time yesterday and got a chance to actually play a couple of songs plugged into my 2 half stacks and I was completely blown away. I have searched my whole life for this sound and wasted dollar after dollar buying all kinds of high tech digital rack mount processors from Digitech to ADA and countless other configurations, but always ended up disappointed. This pedal Crushes All! And Rob I can't thank you enough for sharing this pedal. It's my most prized possession. ............"my precious"...........

[PRR]

> how to lower the gain in the first stage
> Internet doesn't seem to see the point in find ways to lower the gain of a mu amp.

First Google hit: http://www.geofex.com/Article_Folders/modmuamp/modmuamp.htm

"If anything much less than 1M is connected to Vout, voltage gain starts falling."

So... connect anything much less than 1Meg to the output. Maybe make it adjustable. Better look what else is affected, such as coupling-cap.



It *may* be that with this mod the "Drive" pot becomes pointless, or at best a set-and-forget internal trim.

Agree that lower axe volume IS a first step. But I can see how the Mu-Amp may be too-too-much gain for many situations.... won't non-dirt until your level is below the weeds.

[drummel]

I have done some tinkering.
My setup doesn't even come close to albatross clean when rolling back the volume all the way so I started with FET swapping to see if I had a gainy combo but no.
After I was done finding all the tweaks I think i need before transplanting the circuit into its true operating environment it struck me... oh waaait a minute... My drive pot is linear taper...: I put a 1k resistor under the drive pot so I could turn it all the way down and yes, it cleans up well. The range of this circuit is remarkable.

I hope I don't offend anyone by screwing with this piece of art    . It is not that I really need to cover all that range as there is a clean channel already but, you know... there's a switch sitting there demanding to be utilized.

Anyway, I did the input pad and tried 1Meg and 10Meg NFB resistor between the gate and drain. When I put the DC blocking cap and a treble compensation cap over the padding resistor I realized that I had built a trioderizer with a FET on its head. Wrong values though, but it sounded really nice.

These are some tweaks I have come up with but not decided on if I will use them or combination:

-1M/1M input pad. There is a fet buffer on the amps input and I put the pad between the buffer and spitfire input. With the "trioderized" setup it works great to lower the overdrive but without feedback, only the pad, I felt like it sucked the tone somehow with or without treble bypass cap. I think it should not do that, could be my imagination after sitting with it too long.
-Feedback resistor gate-drain on Q2
-C3 bypass cap, as in the original design
-Drive pot treble bleed cap value
-330k resistor on the drain/source of the second stage to load it down a bit. I'm not sure whats going on there, if it alters the bias for Q5 or loading down the second gain stage or a combination of both but it cleans up what I think is the buffer clipping.
-different value of R11 Q5 source resistor alters the clipping behaviuor. I thought it was best as it were but worth mentioning.
-Series resistor between C2 and drive pot.
-Series resistor between the junction C2,C4 and the drive pot to move its sweep into the lower range.

BoogiemanX, did you do a open A-chord with a silly grin on your face again and again and again too? -zzzinggg -zzzing  -zzzzing

PRR, Thanks for the tips. I have read both geofex articles about mu amps and tried loading the first stage but I think it sucked out the tone. I tried some variations with series and bypass caps but did not find a combo that I liked, worth exploring more though. When you mention it I realized I forgot to experiment with the source resistor of Q2 as described at the end of the article. Thank you for reminding me. I must try it out next time.

I modded the amp so that the aux input is routed straight into the tonestack and a buffer after the volume control is definitely needed.

I believe this circuit can be taken anywhere but I think such exploration is better to be pursued in another thread and stick to spitfire discussions here, right?

Cheers!

[BoogiemanX]

Daniel I still have that grin stuck on my face.
I hope it isn't permanent,  my cheeks hurt. Lol

[BoogiemanX]

Completely off topic here I apologize but I am overwhelmed at the amount of topics on this site. You guys here on the spitefire thread are the real deal and if anyone knows it's one of you.  much respect! Does anyone have a link to a good simple delay? Like the rebote or lofi. I can't seem to find a good detailed thread about this just trouble shoots and mods. Any help would be greatly apriciated.

[bluebunny]

You don't really say what you're looking for, Benji: "good detailed" could mean many things.  If you don't fancy any of the (many) existing threads, you could start your own?  Or else just download, for example, the Rebote project documentation from Tonepad and build it: it works out of the box.  But don't start talking delay in this Spitfire thread.  You'll only give Rob ideas...   

[stallik]

Rob already had those ideas. Check out the Abductor 2