SOLVED Muzzle (Classic) not gating

[bass4130]

Hello world,

The muzzle I build recently doesn't seem to gate at all (the led is indicating changes just fine, but no attenuation at the output level).
I've spend several hours testing and debugging without success.

I'm suspecting the 4305 retro fit board. Some users had similar issues but so far I haven't seen a definitiv answer.
Any news/insights why some have issues with their chips?

Maybe I'm missing something obvious?

Here is a short video clip better illustrating the behaviour: http://perasmus.de/musikding/muzzle.MOV

 

[Paradox916]

Assuming you have double checked all your component values and orientations, There are a couple of things I would do next to verify everything is operating as it should,

1) I personally hate sip sockets there is no need for them in this build, and they can induce more problems than they are worth, I would definitely ether removed them or solder the Qs in and check that Q2 is operating properly,
2) have you tried operating the range switch? We can’t see what you have going on there it’s buried. The less aggressive setting can be relatively subtle especially between 7 and 12 o’clock
3)how is the module installed? Dip socket or soldered in place? Are there any solder bridges?

those are simple ones to chase first,
A couple things I don’t think are issues but they are deviations from the build docs and you never know.

1) the led isn’t a CCLED and R21 and R22 are bridged I assume? Can’t really see…

2) key jacks are normally grounded to the circuit chassis per the docs and you are using isolated jacks with a “pass through ground”?

 

[darwin999]

Yes, check those pass throughs

Muzzle kit (noise gate diy) , how to mount IC THAT 4305 DIP 20 ?

Hi there I first ordered the Muzzle kit and after few diy pedals with absolute satisfaction , the noise gate is the exception to not work . :( :unsure: I've checked with audio probe the signal circuit and the consequence is the THAT 4305 , which I strongly suppose I've put in the wrong side...

forum.pedalpcb.com

 

[bass4130]

Hey Guys, thanks for your replies!
Since I've been at a bbq and had some drinks I'll try to be brief ^^

@Paradox916
1) since I never had problems with those sockets I haven't paid too much attention. Will check/measure again next time I'm in the rehearsal room.
2) I tried the switch in both positions. Except of the sweep of the pot there was no real difference in behaviour. I hadn't mentioned before: if I turn the pot to the extremes the volume of the gated signal is lowered — yet still way louder than I'd expect after watching videos of the zuul/muzzle. But since the gate only opens at really loud peaks it is unusable to play guitar. I also tried adding a boost in front (since someone mentioned impedance issues), just using the two cable method and many more things.
3) Dip socket as well. No solder bridges as far as I can tell

I'll try to take some clearer pictures next time I'm at the rehearsal space.
1) since I didn't have a common cathode leds I used two leds and connected their cathodes to emulate a ccled.
2) key and passthrough jacks are isolated to avoid ground loops (which seems to be the problem for some Muzzle builds). The jacks pass a ground and tip connection. Ground currently isn't connected to the center pad on the pcb (I wanted to add a ground/lift switch someday — just like the Zuul+).

@darwin999
I tried several different setups including 2 and 4 cable method. Unfortunately no difference in behaviour.

As far as I can tell I think there might be something wrong between RMS (since the led reacts as expected) and VCA (since it doesn't seem to react to the rms signal as expected)

 

[bass4130]

PS: I once used an alligator clip to simulate a ground connection between key input/passthrough and pcb ground: no difference

 

[bass4130]

I'll give another retrofit module a try and see what happens. Fingers crossed.

 

[bass4130]

Partial success... or something.
I just received my second retrofit module. It was responding slightly different, but only slightly. Nevertheless I kept on testing and checking and found a somewhat usable solution. The key input seems to need A LOT of signal. After splitting my guitar signal one path leads into my pedals that need gating, the other into a fully dimed od808 into the key input. The signal is finally strong enough to have a somewhat usable noise-lessening effect. The noise/hiss is still present and louder than I'd prefer — as in: not really a gate, but rather a bottleneck.

Though I'm still not entirely convinced that this is the way it is supposed to be.
I might build some buffer/booster and see what will happen... or maybe I'll try to find an overpriced genuine that4301p...

After checking all the components again, tracing the schematic, swapping Q1, measuring voltages (VCC = 9V, »-9V« = -8.5V), I'm wondering what kind of mV the VCA wants to see and if there are ways other than blasting the key input to achieve that.

Maybe the opamps (IC2.2, IC2.3 -> N5532) on my retrofit modules are not providing the required kind of signal at VCA input EC+ compared to the those found in a that4301... I have no idea.

 

[bass4130]

Found an overpriced (hopefully) Orginal that4301. Will report back if this‘ll fix the problem.

How do I spell „sunken cost fallacy“ again?

 

[bass4130]

The original that4301 arrived and... drumroll... it works!
Though I didn't have much time to test it, it performed waaaaaaaaaay better. Even with just a passive splitter I was able to trigger the unit with my puny oldschool singlecoil signal and achieve way, way better gating than before.

I conclude that either: some retrofit modules are not working properly and I was unfortunate enough to receive two of those
or: some other mysterious combination of parts/equipment is not compatible with those retrofit modules.