13700 Noisegate/Expander

[DIMstompboxes]

I will buddy as soon as I get time I will put the DMM back on it and probe it too.
I briefly probed the input and found no signal on the q1 emitter .
Thanks for the encouragement DIM.
I'll get it sorted.
At the moment it's just gating to much when it does pass signal.
Btw I hadn't realised that d5 was an external led I put a red diffused 5mm led right there on the board. Doh
Later guys it's time for bed
Thanks

Be back on breakfast... I have kipper for ya

[Kipper4]

Mmmmm kippers

[Kipper4]

Guys after a couple of hours debugging its working
it turns out i missed off the node from R4 to TR1 lug 1
i'm using TL071 so thats confirmed as well
It's a beauty. I will mess with it later I got stuff to do now but i'll report back when i have it going better.
Thanks to Larry Dim and everyone who made this possible
great work guys
Rich

[DIMstompboxes]

Downward expander perform much better at the front chain...put all your dirt box after it.  Guitar--> tuner/wah -->expander noisegate -->dirt boxes -->modulation effect(delay/reverb)-->AMP
CONGRATULATION

[Kipper4]

Thanks dude
Are all those effects in the chain mandatory? 


Onwards and upwards.
I have a Deacy amp, treble boost, direct record to rewire first and the maxon noise gate to debugg first.
Then it's play time with the expander

[DIMstompboxes]

Thanks dude
Are all those effects in the chain mandatory? 


Onwards and upwards.
I have a Deacy amp, treble boost, direct record to rewire first and the maxon noise gate to debugg first.
Then it's play time with the expander

Nope... just as an example.
Great you have maxon noisegate to compare with.
You see many have no thought of reward using a noise gate at all, (nah I don't need one...all my built were ok..) In my experience, this come handy when you move your set up with different amp (not yours) most especially also in various VENUE. Expect the worst 
Cheerio,
Roger
 

[fendman]

I also built the noise gate/expander...Luckily I tested the boards' ic and transistor sockets without the components in them   as I had a dead short across the 9v rail I was also using my bench power supply which has a current limit circuit, so when that red led lit up yeh I thought Hmmm not good!!!

Anyway sorted that out the following morning and tested it on a couple of noisy fuzz pedals, I have used the TLO71, BC349C, and the rest as is the BOM.
The gating and threshold seem to work ok,  this guy has different views about noise gates http://www.ovnilab.com/articles/gate.shtml  

So I will play around with it a bit more. This is the first time I have used a noise gate  so I am still a bit in the dark.
Thanks to the guys on this thread who made it possible

Mike

[DIMstompboxes]

Hi mate,
Glad another one brave soul have tried, as I said if you're tired of using FET for noisegate, downward expander is one option.
quote and my thought from your link.
A gate (sometimes called "noise gate") is a downward expander with an extremely high ratio (and abrupt). When your signal level reaches the threshold, a gate goes from "closed" (no signal passes through) to "open" (all of your signal passes through). The threshold where you want to set your signal to be limit (including your noise floor), and above this limit it will open up and signal will passes through.
Threshold also is a common way of controlling noise and hum from high-gain distortions, single-coil pickups, and other noisy circumstances; when you pluck your note, the gate opens, and when the note dies down the gate closes, keeping quiet until the next note.

Tell us more later upon thorough testing your built buddy  

BTW, this is more effective in the front of the chain before any noisy pedals.
Guitar -> gate -> dirt pedals -> modulation pedals -> amp.
If only someone could add send/return feature on the existing schematic it would be a great so to isolate just the dirt pedals and not affecting the back modulation part somehow.
Guitar -> gate in - gate send -> dirt pedals -> gate return - gate out -> modulation(chorus/delay/reverb etc) - > amp
Anyway mine without this feature is already useful in my analog setup and simple to built and for me I would recommend this compare to FET gate which I also built before. YMMV

[armdnrdy]

I also built the noise gate/expander...
The gating and threshold seem to work ok

Mike,

Good to see that somebody built this.....
You have to dial in the controls to where the gating is least noticeable but performs the job it's supposed to do.
the gating should cut in at the end of sustained notes before the noise is noticeable.
You have to find a balance that works for you and your gear.

[DIMstompboxes]

Larry,
Can you try make this to have a send/return feature? I mean this is not just a simple routing.
Mate this is what's on my mind if possible. Using two OTA input and TL072  for
Guitar in  -  DEC send  one OTA input and threshold control
DEC return - Guitar out  one OTA input also with another threshold control knob using the half of the TL072
This way, the user may use the first threshold control knob to adjust the amount for guitar in - DEC send(out) defend on the level amount if you're using noisy pickup e.g Single coil
And the other threshold control knob to adjust the amount of level for DEC return(input) - (to) - Guitar out FOR dirt pedals amount and isolation before going out to modulation stuff.
This is sort of saying DIVIDE and CONQUER idea.
I'm not familiar with Decimator Gstring but this uses only one INTELLIGENT threshold control knob to sense both BUT my idea is manually two knob control for BOTH.
Later design is to make this more SMARTER like including attack/hold/decay control knobs but this is LATER 

Thanks buddy

   

[fendman]

Thanks Larry and Dim for your encouragement and help, I spent this afternoon between reading up on noise gates, ADSR circuits and noodling away with this circuit.

I came to the conclusion that the circuit perhaps lacks a smoother decay and at times a quicker release...it can stutter a little bit.. But hey, this is a circuit with only a Threshhold control.

which I might try some different values with.


Have just noticed Dim's new post, I  would also love to see this circuit get developed further.

Thanks
Mike

[DIMstompboxes]

perhaps lacks a smoother decay and at times a quicker release...it can stutter a little bit.. But hey, this is a circuit with only a Threshhold control.

which I might try some different values with.

Hi Mike, have you tried the said calibration.
Even my Boss NS2 Decay knob sometimes lack in smooth with some such amount of noise.
Regarding Threshold value, 1meg A is such a wide range to find the exact spot and sit where want. Logically, you can limit the range by putting 100k on both left/right of the threshold pot then use A500K, A250k or even A100k if you get what I mean. But as I said mine has serve me well even using single coil with such amount of drive too with acceptable decay.
I'm hoping Larry or someone who also has knowledgeable perspective with LM13700 will try to help add those smarter feature.

[fendman]

Hi Dim, Yeh I have tried the said calibration, using different pedals high gain, fuzz etc some are better than others, I am looking at changing

the pot like you were saying start with A100K see what happens. But like you said it really needs some smarter features, and someone with a lot

more knowledge of design than I have

Thanks
Mike

[DIMstompboxes]

Hi Dim, Yeh I have tried the said calibration, using different pedals high gain, fuzz etc some are better than others, I am looking at changing

the pot like you were saying start with A100K see what happens. But like you said it really needs some smarter features, and someone with a lot

more knowledge of design than I have

Thanks
Mike

Any progress Mike? Tried in the front of the chain? I find this best in the front before dirt boxes. What do you meant by "better than others"
I know its not superb noisegate but mine functioning well enough. But as I said it only need a send/return and I'm happy with it. I can use it without smart feature (decay/hold/attack)
I'm waiting for a friend to built his Gstring VCA not OTA.
Cheers


I

[fendman]

Hey Dim, I have been trying to finish old builds...and start the backlog of new ones...You know what its like, never ending

Anyway,after a lot of experimenting I have ended up useing  an  A100k pot, and have found it gives me no stutter... a better decay and quicker release. I am quite happy with it and will now use it as is..

I  saw you mentioned a Gstring VCA, saw this vid demo and liked the sounds this guy was getting, listen when he activates the switch on the pedal....noise gone.WOW!!!

http://www.youtube.com/watch?feature=player_detailpage&list=PLE8DB7FF3998B093B&v=glww9bJWndo

Enjoy
Mike

[DIMstompboxes]

Hey Dim, I have been trying to finish old builds...and start the backlog of new ones...You know what its like, never ending

Anyway,after a lot of experimenting I have ended up useing  an  A100k pot, and have found it gives me no stutter... a better decay and quicker release. I am quite happy with it and will now use it as is..

I  saw you mentioned a Gstring VCA, saw this vid demo and liked the sounds this guy was getting, listen when he activates the switch on the pedal....noise gone.WOW!!!

http://www.youtube.com/watch?feature=player_detailpage&list=PLE8DB7FF3998B093B&v=glww9bJWndo

Enjoy
Mike

Glad you also find it useful.. Decimator is also an expander using VCA voltage control amp unlike OTA expander is a current control amp but the same I think(maybe) in principle when it come to gating or noisegate using and design. Yet I sense OTA can be further design and develop to make it more smarter by those who are more knowledgable in OTA. I'm just a musician with low profile in electronic but hey I can build some.  Hope larry and brian will continue to look into it. I'm really tired of FET gate they are unpredictable even with the same value.
I found the Farnell store already my friend   
Maybe our quest for ultimate noisegate will come to an end ( you me and Kipper4). I believe that noisegate plays an important part of a chain even my Boss GT10 multiFX has two built-in noisegate as part of the FX chain.
Cheers,

[Kipper4]

+1

If you looked at the dod fx30 it might help you experiment where to put the side chain (line in ).

[DIMstompboxes]

+1

If you looked at the dod fx30 it might help you experiment where to put the side chain (line in ).

Hey Rich,
I read the dod fx30 at the other forum, its another FET gate design using J113 
Anyway, how long or days does UK first class post would arrive to received a package? My wife ordered 3pcs 4PDT at bitsbox yet never arrived in London. They sent email last FEB10(Monday) that the package was already dispatch. Until now its (Friday) FEB14 Valentine's day....I read on their site it takes only a day....
She already ordered 2 pcs THAT2181CL08-U, 5pcs MPS2222AG/2N5551 at Farnell yesterday.....with UK first class too....dude does it take that long?

No cheers,

[Kipper4]

Where are you based.
I'm in England and bits box only takes 3 to4 days max.

[DIMstompboxes]

Where are you based.
I'm in England and bits box only takes 3 to4 days max.

Uxbridge Road, london
She's looking for bitsbox phone number but to NO avail...no contact number on bitsbox site eek...My concern is one of her colleague schedule flight on FEB24 and shes the one would handed the items for me at the airport. IF ain't delivered before that date... she's gonna send box on APRIL and include those by then wahhah.
Including items that she ordered from Farnell for Gstring yesterday.....I'm keeping my fingers crossed