Will this noise gate do?

[stonerbox]

Alright, thought I post the final version in case others find it helpful in the future.

It works on the breadboard but it can't handle dampened strings very well and gates them in a strange fashion, It also sounds more choked than with the pickups going straight in to Q1 (far right on schem).

In Spice it does not close. I'm feeding it 50mV which is well enough to close the gate in reality.

In summary:

1. It sounds choked compare to pickups straight into Q1 (on the far right on the schematic). If I remove Q18 it sounds perfect and open. Which indicates the gate does not fully open up?
2. It chops off the negative part of the wave (sample taken after Q20). In Ltspice the negative part of the wave only gets cut off if the signal is strong, keep it below 110mV and all is good.
[Actual waveform post Q20]

3. In real life it does close and open but in Spice not so much, it stays permanently open.
4. Dampened bassy playing influences the gate to drop out the signal when it should not, could very well be due to the fact half the wave is not there.

[click to enlarge]

[antonis]

What's the actual value of VR..??

[stonerbox]

What's the actual value of VR..??

Look at the schematic again.

[antonis]

Sorry but I can't follow you..
You continually change schematics and item values..

[stonerbox]

Sorry but I can't follow you..
You continually change schematics and item values..

It is all sorted out now. No more changes coming up! Promise!!

[antonis]

What are Q19 Collector & Emitter voltages in Spice..??

[stonerbox]

What are Q19 Collector & Emitter voltages in Spice..??

Q19 (Spice)
C 5.676
B 3.352
E 2.276

Real World

Q19
C 7.19
B 1.98
E 1.38

Q5
C 8.98
B 2.55
E 2.04

Q14
C 8.92
B 3.74
E 0

Q17
C 7.39
B 0
E 0

Q18
C 0
B 0.562
E 0

Q20
C 8.91
B 3.31
E 2.89

Q1
C 7.61
B 0.562
E 0 to 0.111 (depending on 100k gain)

Video with Q18 in and then with Q18 removed.
https://i.imgur.com/gNBh8Qy.mp4

[stonerbox]

Edit: This bread board seems to be the culprit. Got Q18 going now from 188Ω (closed) to 34Meg (open). Finally!!

Small progress but not home yet. My brand new TRU Component (64 rows) board had a faulty ground. With that out of the way the gate no longer chops off the negative swing of the wave.

However I cannot for the life of me get it to open up.

The gate goes from 110Ω (closed) to 117Ω (open). If I increase R66 (Q17) from 100k to 1Meg the gate goes from 282Ω (closed) to 437Ω (open).


Funny thing is I can remove Q17 and nothing changes. The gate still responds. I guess to the input of the guitar at Q18's collector?


I need a lot of help.



I altered the design closer to Klipper's version, in a desperate try to get it to function.

Code Select Expand


(From the left)
Q19
C 6.30
B 2.61
E 2.13

Q5
C 8.98
B 2.33
E 1.80

Q14
C 2.68
B 0.645
E 0

Q17
C 3.585
B 0.010
E 0

Q18
C 0
B 0.599
E 0

Q20
C 8.95
B 3.31
E 2.83

Q1
C 7.09
B 0.560
E 0 to 0.110 (depending on 100k gain)