Hotamp Noise Gate

[Chris60601]

Was looking for a Maxon NG-9 but ran across this one.
Anyone care to take a stab at this please?

Cheers
Chris

[Silver Blues]

I'm actually quite curious to see if this works well, a friend of mine asked for a noise gate and I was tossing up the MXR gate and a bootstrapped twin-T notch filter; this seems much less complex than the MXR and perhaps a better choice than the notch. I'll tackle this one later today (seeing as it's 12:46 here already...)

[Alex]

Hi!
Haven't test it but it should match the schematic:

[Silver Blues]

Alright never mind  this is probably much nicer than I could have made it.

[Alex]

Sorry mate! I've drawn this for a friend.
Give it a go anyway.
At the end it's always good for practice and it might even come out better than mine.
There is still a standing resistor!

[Silver Blues]

Ah that's alright. I like yours anyway  And not necessarily, one could always put an 1/8W resistor there and have it lay flat, wouldn't make any kind of difference.

[Chris60601]

Wonderful! I'll build this on the weekend.
Thank you both! Muchly appreciated!

Cheers
Chris

[Chris60601]

SB - I built this (not boxed yet) and it appears to work!
While I'm unsure as to what the trim is supposed to do (since I have not found much else about this circuit).

To me, it sounds like a very subtle gate/suppressor. If or when you build this, would be curious on your thoughts.

I'm going to dig around to see what else I come up for this circuit but at least for now, it appears to be verifiable.

Cheers
Chris

[Silver Blues]

Great to hear it works! I think my friend will like this.

The circuit came from a guy on Techniguitare (a French guitar forum) and I had a read through the thread on it, and though my understanding of the language is pretty good, the crude colloquialisms kind of kicked my ass so the information I could glean from it was fairly limited (translation was essentially useless).

To that end I can't even remember what the trimmer was for... I can try and find it again if you'd like.

Also sorry for any formatting mistakes, I'm writing this on a new tablet that I'm still learning how to use

[Chris60601]

SB -

It would be great if you could. However, this may help (I'm sure you ran across this before)
These few images at least show some growth on this circuit but the last - "could be" what the trim is but the values don't line up.

I may replace the trim with 100k to see if there is more play or move it to a pot. I also wonder (and here's where m ignorance takes over) if the trim may tinker with the voltage on the emitter of both/either the MPSA18 and BC5447C ( 6.5 and 6.0 respectively).

Admitted, image 3 may not even be this circuit or may has evolved.

[Silver Blues]

Yeah I saw these. The first two are this circuit, and I believe that the second one is just the same circuit as the schematic you posted; in which case, Alex's layout is nicer. I don't think the third layout is the same circuit.

The schem you posted is the "evolved" version, it started off a little different (most notably, transistor spec was changed for less noise when engaged as people were complaining about noise... ironic).

[Synsound]

I finished this tonight. To me it just seemed like a hardly noticeable attenuation. I may have missed something neither pot did anything. I may come back to it but for now it is filed under scrap.

[Beaker]

I'm just posting this just in case anyone is unsure exactly WHAT a noise gate is SUPPOSED to do.

A good noise gate should be transparent - it should not affect the sound. All it should do is reject line noise. It is also not going to do anything  noticeable at bedroom volume levels.

To test if it really is working properly, plug it in at the end of your signal chain, after your noisiest, hissiest distortion or fuzz pedals.

Kick them all on and crank your amp until you get a mass of hissing and howling feedback. Smack a big powerchord.

Now  switch on the noise gate, adjust the controls so that you get the absolute minimum gating of your signal, but the maximum silence as the chord dies out.

[meffcio]

"To me, it sounds like a very subtle gate/suppressor."

" To me it just seemed like a hardly noticeable attenuation. "

Isn't this supposed to work kinda like MXR's smart gate?

[sharaynishi]

Sorry for the bump. You people claim it works, but kind of does nothing as the effects is very "minimal".
When moving the pots (trimpot included nothing happens)
I used 547B an 2n5089 subs, but I don't think this is the issue.

In my build I can take out all the transistors and the IC while the circuit is on and it makes no difference whatsoever, guitar signal goes thru.

How does it react for you?