MXR Noise Gate Tonepad Revisited Need Help

[duck_arse]

geeze, I just read the report, looked at the momentary switch, and thort 'I suppose'. it seemed to work as advertised on the breadboard.

@kipper (the real one) - in eagle, settings/misc, you should turn on "auto set junction" if the new version has it. it will dump spots where wires meet.

[Kipper4]

Thanks for the tip I didn't know it was an option in eagle.
I'll make the change for future schematics.
Rich (the real Kipper) as opposed to the imposter I've only just heard of Anti-kipper.
How very dare they?
@Duck Arse I've pm'ed you some ideas.

[MrStab]

haven't read the thread thoroughly, but re. the momentary switch:
i figure either way you're gonna need two footswitches if you want to both temporary disable and bypass the effect fast on stage, so it'd crossed my mind a few times to just have a regular true bypass setup with a momentary DPDT or 3PDT (instead of cutting the signal within the gate itself) but i don't know if that's too cheap a fix, with potential sudden tone change & popping risks etc.

or maybe you could wire up a complex toggle to go between "modes" on 1 footswitch, which would limit functionality somewhat but save space (and would probably necessitate electronic bypass)

[Kipper4]

I just figure if you want the gate off use true bypass switching
Keep it simple

[MrStab]

i think an issue with straight-up momentary TB is you're suddenly going from buffered to unbuffered and back again, which probably wouldn't be such an issue for most people as gates are usually later in the chain, but means the circuit would be dependent on what comes before it

[Mark Hammer]

haven't read the thread thoroughly, but re. the momentary switch:
i figure either way you're gonna need two footswitches if you want to both temporary disable and bypass the effect fast on stage, so it'd crossed my mind a few times to just have a regular true bypass setup with a momentary DPDT or 3PDT (instead of cutting the signal within the gate itself) but i don't know if that's too cheap a fix, with potential sudden tone change & popping risks etc.

or maybe you could wire up a complex toggle to go between "modes" on 1 footswitch, which would limit functionality somewhat but save space (and would probably necessitate electronic bypass)

If the attack time can be set so that the gate opens (turns "on") with any appreciable/noticeable delay, then it would be able to function much like the PAiA Gator pedal (which is essentially a noise gate adapted to provide a very long attack/rise time).  If that were possible, then a pair of paralleled SPST switches - one momentary, one latching - would be useful.  Closing the latching switch would leave the gate always on/open, while use of the momentary switch would allow the player to select when they did and didn't want the "swell" effect.

[Kipper4]

heres some food for thought

http://www.diystompboxes.com/smfforum/index.php?topic=64657.0

[MrStab]

so both latching and momentary SPSTs in the same place as suggested for just the momentary in the Tonepad schematic, Mark? surely that'd affect the purist demand for true bypass! lol.

my gate has Attack and Release controls, which i find invaluable. tweaking those is probably what made me forget about the momentary mod. i usually only play noisy stuff, though - i can imagine it'd be more useful when playing clean (but then i probably wouldn't need a noise gate!).

i was gonna put a key/trigger input a bit like that post you linked to suggests, Rich, but again the Attack/Release controls proved sufficient for my needs. i just have bog-standard DPDT true bypass.

[MrStab]

just built another one of these for my bassist and it doesn't work for s*** lol. only difference is BC549c's instead of 2n5088s and a 100nF input cap. still in the debug process, though. hope i don't have to change any of the transistors - finding a match was annoying.

[Kipper4]

i found the fet more troublesome than the bjts
I'll pm you my modded layout for callgate 1. no momentary switch mind you

[MrStab]

ill debug more comprehensively and get back to you. there's some weird kinda tremolo vibe going on a certain settings. i wonder if going that high with the input cap wasn't what the rest of the circuit expects, and how important the specs of the JFET are

[Kipper4]

tremelo
sounds like the gate is opening and shutting. stuttering
I'm no expert I promise you that.
which fet are you using?
im using 2n3904 for bjts (matched as near as i could IIRC)and
a j201 fet

[MrStab]

"When making noise gates, don't forget big-ass jumpers" -Confucius.

lol seems to work quite good now. i'm using a 2n5952 - probably criminal as they're obsolete, but i had no other FETs lying around.
need to test it a bit more and i don't know how it'll be on bass, but that may well be 2 successful ones i've built now.

so it's pretty much this: http://www.sabrotone.com/wp-content/uploads/2011/08/MXRNoiseGate.gif except R5 becomes 4.7K, C7 becomes 2.2uF and there's a 60pF (though this time i only had 100pF) between output & inverted input on the left half of the opamp. hope we can help standardise all this to limit the widespread problems with this build.

[duck_arse]

stop matching those transistors, people! they don't do anything needing a match.

it seems the worst part of this is the rectifier and its ripple. although some people think it fine. mr stab, do you want slow, fade gate or fast, slam gate? did you vary the 1M gate resistor from the 1uF//150k?

[MrStab]

i couldn't find anything definitive on the matching thing - even though it does seem a bit "off" when you usually only need to bother with JFET matching for phasers etc. - but i went with the "just in case" protocol! so i'm not a convert, i'm just paranoid. lol

iirc i just have the 150k (well, 147) and 1uF. quite a hard, fast gating. i like having a split second of noise before and after so there's not too much drain on attack, so i adjust to suit with the attack/release controls. it's not perfect but it does really tighten things up. no amount of cleanup will fix poor amp design, unfortunately, but for the most part it's cool.

my bassist basically gave me a Danelectro "Cool Cat Metal II" he never uses, with a free license to put whatever might be handy in there, and its main function will be a MOSFET Boost for solos (he does em well, not the usual tacky bass solo) so if the gate turns out to be problematic he'll be able to switch it off with a DPDT toggle. kinda funny that the secondary feature is at least twice as large & complex as the first and is causing space problems as he's a battery guy.

[Kipper4]

goddam I might just have to get some of those 2n5952s just to try them.
I hate paying silly money for parts.
Thanks guys

[duck_arse]

hold off on the spending there, kipper. I'm pretty sure we only need to get fets with a Vgs(off) {I think} lower than V/2, and then swing that much to the gate, and we're there. and that means all your beloved j201's and 2n5457 and bf245a and and and .... and probably even 2n5952.

[aswang05]

Hi guys... I maybe be a little late but I have some problems with the MXR noise gate that I built from tonepad. It's a ver.1 and it looks like its a mismatch to the digitech's grunge which i borrowed from a friend. I did change the resistor connected from Q1 since it looks like it does'nt have a gating when the settings of the Loud and Grunge level are on the 12 o clock position and beyond. Any suggestions? thanks.....

[Kipper4]

Which fet are you using?

[aswang05]

well, since i have a hard time finding the recommended FET, I used the 2n5485. Will it do any good if I change it to 2sk30A?