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DIY Stompboxes => Building your own stompbox => Topic started by: Robertodue on June 10, 2017, 03:55:40 PM

Title: Crunch Box tone stack mod?
Post by: Robertodue on June 10, 2017, 03:55:40 PM
Hey guys, I had an idea to add a 3 knob tone stack to the crunch box....  I un-appologetically copied the Marshall tone stack and inserted it into the schematic (very crudely I might add)....  Before I actually build this thing I would like some input.... Is this going to work?  Problems you see?  Advice?  All constructive comments are welcome!
(https://s10.postimg.org/4ph956qo5/Crunch_box_V2_schematic_with_voltage_and_tone_st.jpg) (https://postimg.org/image/4ph956qo5/)
Title: Re: Crunch Box tone stack mod?
Post by: robthequiet on June 10, 2017, 06:14:11 PM
Worth trying on a breadboard at least. The question is does it have enough signal to punch through the tonestack? Options I would see would be placing the tonestack between the op amp stages, or possibly adding a FET recovery stage after the tonestack as you have it now. Plus tweaking cap values to get the best frequency response.
Title: Re: Crunch Box tone stack mod?
Post by: Plexi on June 10, 2017, 06:41:39 PM
I totally agree with quiets Rob
A recovery stage was the first thing I think when saw your schematic.
Try to breadboard the Rat Fet recovery stage, or maybe the more simple and always usefull, Big Muff one.
This last one, with a change of resistors, you get a LPB1 and a LOT of volumen  ;)
Title: Re: Crunch Box tone stack mod?
Post by: allesz on June 10, 2017, 06:50:59 PM
But the crunchbox has got tons of output, I think the tonestack will not make it too quiet.
Of course a gain recovery stage won't hurt, but you can add it later.
Title: Re: Crunch Box tone stack mod?
Post by: bool on June 11, 2017, 09:56:54 AM
Look at Marshall Guvnor and Shredmaster.
Title: Re: Crunch Box tone stack mod?
Post by: sominka on June 11, 2017, 10:49:54 AM
I tried something like this the other day and it worked really well on breadboard.
(https://s10.postimg.org/xxde7l3tx/Guvnor_variant_schem.jpg) (https://postimg.org/image/xxde7l3tx/)
Title: Re: Crunch Box tone stack mod?
Post by: robthequiet on June 11, 2017, 11:31:29 AM
^  ;)
Title: Re: Crunch Box tone stack mod?
Post by: sominka on June 11, 2017, 11:35:35 AM
Glad you liked my idea and want to try it out. It works really well. ;D

http://www.diystompboxes.com/smfforum/index.php?topic=117830.0
Title: Re: Crunch Box tone stack mod?
Post by: Plexi on June 11, 2017, 11:41:20 AM
Now I have to try...[emoji16]
Title: Re: Crunch Box tone stack mod?
Post by: sominka on June 11, 2017, 11:52:58 AM
Replace the clipping diodes with LEDS I used yellow.
Title: Re: Crunch Box tone stack mod?
Post by: Mark Hammer on June 11, 2017, 12:05:54 PM
When inserting a tonestack on the output of any sort of clipping pedal, the question to consider is how likely you will be to use settings less than full drive/gain.  There will generally be enough output for solos, when the user has the gain set high.  But tonestacks can often introduce enough passive loss that more modest drive settings, even with the pedal volume up full, may not provide enough output for solos or to simply push the amp the way you'd like.  IN those instances, a level-recovery gain-stage, like sominka shows, is helpful.

But again, the need will depend on how you expect to use the pedal, as well as the extent of passive loss the tonestack introduces.
Title: Re: Crunch Box tone stack mod?
Post by: Robertodue on June 11, 2017, 01:21:55 PM
Yeah....  I was concerned about loss of output, but the crunch box (as reported above) has a TON of output and should be OK.  However, adding a post-tone gain stage couldn't hurt... :icon_biggrin: