I have a bunch of gruntbox pcbs but I really wished they had the Mids control pots like the newer mudbunnys. Looking at the schem I realized its super easy but there's no value listed for the pot in the mudbunny pdf. Wondering what value you guys used?
While I'm at it, does this look correct to do a tone stack lift?
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That's where I put the last one I hacked.
What about a mids pot? 25Kb? 100Kb?
Hey, I am using a 25kB. Different values will change not only the mids, but the tonal response of the whol shebang, I think. Check out this site for an explanation: http://www.muzique.com/lab/tone3.htm
What about hacking it into the existing Mudbunny etchable layout?
I've been on a bit of a BMP kick lately and want to try a new twist.
Quote from: Bored on June 15, 2011, 11:24:16 AM
What about hacking it into the existing Mudbunny etchable layout?
I've been on a bit of a BMP kick lately and want to try a new twist.
Yes of course that's possible. It's gonna require 2 trace cuts on the board and soldering a few extra wires to the bottom of the board but nothing too hard or crazy. If you follow the schem I posted above, this is how you would do the tonestack lift. For the mids knob, I recommend changing R18 to something more like 3.3K. Your notice a way bigger sweep in the mids with that change! Also jumpering the first 3 transistors emitter resistors is adds a big bunch of gain to the circuit, but nothing unusable!
Here's an example for the single sided mudbunny tonestack lift.
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awesome thanks! I'll have to test it out on the Tonepad layouts as well... I've got a couple of those floating around as well.
Thanks again
Quote from: bigmufffuzzwizz on June 15, 2011, 03:25:27 PM
Quote from: Bored on June 15, 2011, 11:24:16 AM
What about hacking it into the existing Mudbunny etchable layout?
I've been on a bit of a BMP kick lately and want to try a new twist.
Yes of course that's possible. It's gonna require 2 trace cuts on the board and soldering a few extra wires to the bottom of the board but nothing too hard or crazy. If you follow the schem I posted above, this is how you would do the tonestack lift. For the mids knob, I recommend changing R18 to something more like 3.3K. Your notice a way bigger sweep in the mids with that change! Also jumpering the first 3 transistors emitter resistors is adds a big bunch of gain to the circuit, but nothing unusable!
Here's an example for the single sided mudbunny tonestack lift.
I'm wiring this up and had a question... what happens with lug 2 on the Tone pot? In your lift drawing you show it cut... so do I leave lug 2 on the tone pot empty?
Thanks!
Quote from: Bored on July 04, 2011, 02:47:36 AM
I'm wiring this up and had a question... what happens with lug 2 on the Tone pot? In your lift drawing you show it cut... so do I leave lug 2 on the tone pot empty?
Thanks!
I'm glad you looked it over cause I definitely made a mistake on that diagram. Only do the first trace cut next to lug 2/lug 1 going to the switch. If you do the second trace cut you won't get signal in regular mode when the tonestacks added.
So the cut before R19. Lug 1 goes to R19 pad, Lug 2 goes to any pad connected to Q3 collector/R15. Lug 3 of the switch goes to tone knob lug 2 or the pad of c12. I haven't tried this mod yet but I know others have.
I'm doing some more research to make sure mine matches the others examples out there. I noticed that without that second trace cut after tone knob lug 2, the tone stack won't be *completely* lifted.
I've found this schem --> http://www.generalguitargadgets.com/pdf/ggg_bmp_tbp_sc.pdf and it looks slightly different. With his tonestack lift he fully bypassed it and replaced it with a 150k resistor. To do this you would need a DPDT and you would do the 2 trace cuts like I posted before. IIRC, when Dcountry did his GBOM muff project, he stated if you do the tonestack lift the 150K will help keep the volume at a unity setting. He said to socket that resistor and experiment.
If your up for some adventuring in experimenting, then give my original suggestion a try(in the post before). If it doesn't work properly or sounds bad, then you know what to do. Cut the trace after lug 2 of tone pot and change switch for DPDT. I can make an easy wiring diagram w/ DPDT for you if you can't figure it out.
I highly recommend this addition to your muff. On the BYOC muff I built, the tonestack lift is the setting I leave it on. Tell me how it works for you. I gonna try both methods on the next muff I build, hopefully soon!
I dont know that I want to lift it... just wanted to add the mid control pot.
Not sure what layout your using, but you take the HPF resistor (R18 in the mudbunny/gruntbox) and connect that to a 25kb pot wired as a variable resistor, then to ground. You'll get a much better sweep if you change R18's value to somewhere 1k-3.3k range.