GGG its8 AMZ Fat Mod DPDT switch question

[heavy1011]

Hola,

New to guitar pedals and this forum, have a GGG its8 on the way
and have gone over the mods and have a question about the
AMZ fat mod and the way the circuit bypass C3 and DPDT switch
wiring.

I am looking to keep C3 stock .047 and use the bypass pads

http://www.generalguitargadgets.com/pdf/ggg_its8_mods.pdf

and use a DPDT On-off-On switch wired this way :



Will this allow me to use .047 stock cap when the switch is Off and .1/.22 as the other
two Bass settings for the corner frequency?

Thanks for any help
Much appreciated

[Philippe]

I considered this mod seven years ago when I purchased the ITS8 kit from JD. wrote to him via e-mail & he suggested against it as you will lose the natural sound of a tubescreamer. thus, I opted to bracket the tone caps with a switch & as it turned out, the original stock setting sounded best (to my ears). if you reference the analogman TS page, he will vouch for this as well. as far as the tubescreamer is concerned, asymetric vs symetric clipping is really all you need to consider & that option is provided in the kit. why mess with perfection when an EQ (or available amp/guitar tone controls) will accomplish the same fete.

[Mark Hammer]

1) Welcome.

2) The mod, as shown, will produce a slight "pop" when switching the larger cap into the circuit.  And if you want to use an on-off-on toggle for two different bass responses, both of those will pop.  If you switch in the extra cap when the pedal is in bypass, it's not a problem.  But if you flick the switch when the pedal is engaged, and your amp is turned up, the pop can be annoying.  Not dangerous, but annoying.

3) I am not so sure that differences in bass response will be all that noticeable.  Or rather, the difference between stock rolloff and added bass may be easy to hear, but degrees of added bass may be wasted effort.  If it were me, I would aim for a choice between the stock rolloff at 720hz, and one at roughly 150hz, by adding 150nf to the stock 47nf.

4) Prevention of popping is accomplished by never disconnecting one or both ends of a cap from the circuit.  In this case, you can try running a 470k-1M resistor in series with the added 150nf cap, and running that pair in parallel with the existing 47nf cap.  That will provide just the tiniest bit of bass boost - inaudible.  Use the toggle to bridge/bypass the extra resistor and your added cap is now in parallel with the stock 47nf cap...but without any pop.

[Elijah-Baley]

On my TS808 DIY I can choose as C3 47nF or 100nF. Bigger cap give me a more bass.

[heavy1011]

Thanks for the help everyone,

Really do love what a TS does and was looking to make it useful
for the Bass guitar as well.

Wish for the same 20 db bass cut for the bass too so it can work its
TS magic there as well. Might not be so pronounced on the bass
at 150hz

Think Marks answer would be best for this, switch in a 150 nf/470k in series to
add to 47 nf in parallel. Might not be so pronounced on the bass
at 150hz, maybe add another 47 nf to get to 330 hz?

Don't really think I'd use the added Bass when playing guitar, it seems to
be the consensus to leave it alone when using a guitar. Not just here
but most of what I've read say this Fat Mod is really only useful
for single coil pick ups.

Thanks for helping and not laughing me out of here with my
question.

[Tony Forestiere]

Thanks for helping and not laughing me out of here with my
question.

Welcome. Not a bad question at all, and I learned a bit myself. We laugh here, (mostly at each other), but a finer, experienced, knowledge-thirsting, well-rounded group of fellows cannot be found in cyberspace.

Mandatory reading: http://www.diystompboxes.com/smfforum/index.php?topic=76932.0  

*edit* Forgot tolerant. Very tolerant. They haven't kicked me out. Yet. 

[Elijah-Baley]

[...]
I've read say this Fat Mod is really only useful
for single coil pick ups.
[...]

I agree.

[simonbull]

hi  i am  trying to adapt this pedal so i can use it for blues harp

really need to be able to add 20 DB as a bass boost ( via fat switch ) any idea of the cap values i would need to say swith between 10 and 20 db

also value of input buffer to get it to 10 ohms resistance