That4305 issues

Keith

Member
Has anyone built the muzzle with the new that4305 adapter board? Ive built 2 and both have the same issue , only gate when the threshold is maxed out , the key isnt working and it cuts off notes.. I have built about 10 to 15 of the regular 4301s and smds without any issues and just cant figure out whats going on.. I will prob it next to see if all passes signal. Thanks in advance
 
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I just got mine put together and I am in the same boat with it not completely gating and just making the string noise and such a lot quieter when it gates. This is using the retrofit module in front of the amp only. I don't have the key jack wired up so I have a jumper running between the pads.

Guitar > Greengage OD > Front of amp.
 
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I'm going to have to get one of the defective modules back so I can see / hear what you're hearing.

I've just tried two more retrofit modules (randomly selected out of the parts bin), the original hand-assembled prototype, as well as an original THAT4301 IC. All four of these behave exactly the same.

I put a noisy fuzz cranked wide open in front of the gate then dialed up the threshold until the noise disappears. I can still hear string noise if I drag my finger across the strings or gently drag the string across the fretboard like the intro to "Foxey Lady" by Hendrix, but the buzz and noise from the fuzz is gone completely, and there is no reduction in volume when I start actually playing.

The Muzzle doesn't behave like a lot of gates, the Threshold knob controls the threshold where gating happens, but it does also affect how fast/hard the gate closes. It's not a matter of signal dropping below the threshold and the gate instantly clamps to dead silence, that's not exactly how it works. According to the Fortin Zuul owners manual: "The ZUUL's threshold knob also controls the dynamics of the gate circuit."

I'm not saying that you aren't experiencing abnormal behavior, but so far I have been unable to replicate anything out of the ordinary for the circuit.
 
I'm going to have to get one of the defective modules back so I can see / hear what you're hearing.

I've just tried two more retrofit modules (randomly selected out of the parts bin), the original hand-assembled prototype, as well as an original THAT4301 IC. All four of these behave exactly the same.

I put a noisy fuzz cranked wide open in front of the gate then dialed up the threshold until the noise disappears. I can still hear string noise if I drag my finger across the strings or gently drag the string across the fretboard like the intro to "Foxey Lady" by Hendrix, but the buzz and noise from the fuzz is gone completely, and there is no reduction in volume when I start actually playing.

The Muzzle doesn't behave like a lot of gates, the Threshold knob controls the threshold where gating happens, but it does also affect how fast/hard the gate closes. It's not a matter of signal dropping below the threshold and the gate instantly clamps to dead silence, that's not exactly how it works. According to the Fortin Zuul owners manual: "The ZUUL's threshold knob also controls the dynamics of the gate circuit."

I'm not saying that you aren't experiencing abnormal behavior, but so far I have been unable to replicate anything out of the ordinary for the circuit.
can confirm the one module I got operates almost identical to the 4301 and the muzzle/Zuul buy design is atypical in operation in regards to others noise gates… that’s just my limited experience
 
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I wish I knew someone with a Zuul to compare to. For me there's no balance between killing hum and not cutting off pinch harmonics early.

Before this, I was using my Axe FX Ultra (the old old one) with the gate block after my preamps in the loop, set to track the input (like the key input baically), and I never had any issues with it cutting off pinch harmonics or anything.
 
Pay attention to this clip of the original ZUUL at the 2:12 time stamp. You can see when the gate closes the signal is reduced (how much depends on the Threshold control setting), but it doesn't completely clamp to dead silence, you can still hear the guitar.

This is normal behavior.

 
Okay, so I think this might be working (sort of) as expected.

So, first things first, the side chain drastically reduces performance for a noisy setup, at least mine. So first thing to do is get rid of that.

Second thing, I was getting a lot of hum, so I had to turn the threshold knob up to be quite aggressive. Turns out there's an EMI vortex or something on my floor where I had the pedal sitting.

So how I have it set up right now, I have my splitter which goes to my 2 boosts in parallel, a TC Pre and a TS clone I had from years ago, think Deadweald Duality. They run to the same output jack, then goes to my preamp (VHT GP3), then the preamp out runs to the Muzzle, then out to my power amp.

Things I notice when using the key input: unless I turned it up a fair amount, say maybe 30% of the threshold knobs adjustment, it just was not gating. I could hear the hum be reduced that I was getting through my cab, but the LED was not changing color. This was okay, it's better than nothing, but didn't really get me the chuggy staccato like palm muting chugs. If I turned it up a lot more, it was great for that... but nothing else. I attempted to just adjust it to where the red light came on while not playing with the guitar's volume turned up, but it still wasn't performing good at all. All dynamics were gone. I know I've probably said "pinch harmonic" like 20 times in this thread, but it's just kind of a litmus test for me. If I hit one, it would ring out for maybe a second then die.

Removing the key input from it, and turning it up maybe half way so it's gating based on my preamp output now, I can set it with the guitar's strings muted so it's just barely gating, and it doesn't kill dynamics.

Maybe I'm just not a fan of one knob noise gates, I'm not sure as I've never used one before this. Performance is acceptable now, but it seems odd to me that the "key" feature (pun quite intended) reduces performance for me. This is the selling point in what has become the gold standard for noise gates. Like I don't think there's any errors on the board that I've made, it's technically working, it's just not what I was expecting. I have a friend that also got a Muzzle and it's working well for him but I'm guessing my setup is quite a bit noisier. He's going to come over when he gets a chance so we can compare, maybe I'll see if he'll let me bang a key input on his for testing (he has it jumpered at the moment) and see if it's the same deal.
 
I have zuul and muzzle. I have the same problem. I think the key input is an impedance issue. I plugged the buffered splitter after the guitar to improve sustain and performance. Next, I switched from a single coil(HS-3)guitar to a humbucker guitar and plugged it in. The sustain is better and this seems to be no problem. The slide switch is on the right. As a result, buffered splitters and powerful pickups, especially buffered splitters, seem to be the answer. Because they sell a buffered splitter called Fortin roach. I'm sorry for my poor English, do you understand? I would like to try 4301 instead of 4305 with zuul. I wish I could get good results with any guitar, without a buffered splitter.
 
There's only been one batch, but this is too many reports to be coincidence.

I'm waiting to receive one of the defects back so I can try to determine what is happening. I've tested several here and can't find one with a problem so it's puzzling.
Did you ever look over the chip I sent back? I oredered a new one from the second batch with the same results , no gating but when I put in a 4301 the circuit works fine. Im stumped with the new adapters.
 
There's only been one batch, but this is too many reports to be coincidence.

I'm waiting to receive one of the defects back so I can try to determine what is happening. I've tested several here and can't find one with a problem so it's puzzling.
I accidentally threw the old one in and thats the one that didnt work. The new one from the second batch works perfect. Sorry for the confusion.. thanks
 
Hello, I ordered the Muzzle in kit from Musikding. I built it some years ago, but this time I got the three SMD chip 4305 adapter PCB. That's new for me.
I have to start to populate the PCB, but I'm reading some issue with this adapter, and now I'm little bit worried. I'm not sure if I understand what is this issue... is the adapter? is the Muzzle PCB?
Can you confirm that everything is ok with the Muzzle PCB and this new replacement?
 
The 4305 module is a direct replacement for the discontinued THAT 4301.

The project has been built successfully hundreds of times with the Muzzle PCB and 4305 module.

Of course defects are possible with any components, but the module is fine.
 
For our purposes it's essentially a drop in replacement.

The notes in the transition guide are handled on the 4305 module. This is almost identical to how the Revv G8 works aside from it's added Hold and Release circuitry.

I personally can't distinguish any difference between the 4305 module and an original THAT4301 through-hole IC.

As far as the few reported issues, I have yet to receive a "defective" 4305 module that didn't work perfectly fine in my build. I can't explain what is happening, but so far I have been unable to reproduce the issue.
 
I've made 4305 adapter board from this project/schematic/layout. I'm using NE5532 opamps with THAT4305 chip from Mouser.
DIY Muzzle board + 4301 - ok, zero issues.
DIY Muzzle board + 4305 module - functional but some issues.

First of all - elevated hum and interference level with 4305. Also, when the potentiometer is set above 3/4 it starts cutting the ends of the notes.
Here's short clip.
00:00-00:16 with THAT4301
00:17-00:51 with THAT4305
 
I received the third 4305 module, and this time seemed work. I'm not sure if the pedal worked so fine like the first Muzzle with 4301 chip.
I tested it with different gear, but I wasn't so impressed like with the first pedal.
 
Sorry to hijack this thread. Until now I was just reading and just recently joined. I'm not sure whether to start a new thread or not.
The muzzle I build doesn't seem to gate at all (the led is indicating changes just fine, but no attenuation in output).
I've spend several hours testing and debugging without success. I'm suspecting the 4305 retro fit board. Any news/insights why some have issues with their chips?

I can post a short video clip if anyone is interested.
 
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