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Analogue Dub Siren

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tomizett

Active Member
Not too hard if you can solder (or want to learn) and are handy with your hands.
A quick google for "dub siren circuit" turned up what looked like some sensible results.
Maybe find a circuit you're interested in and post it here to see if people think it looks legitimate.

These people are even selling kits, which are often a good way to get started in electronics:
http://www.rdh-hifi.fr/en/electronics-equipment/diy/diy-kits
 

Rorut

Member
Not too hard if you can solder (or want to learn) and are handy with your hands.
A quick google for "dub siren circuit" turned up what looked like some sensible results.
Maybe find a circuit you're interested in and post it here to see if people think it looks legitimate.

These people are even selling kits, which are often a good way to get started in electronics:
http://www.rdh-hifi.fr/en/electronics-equipment/diy/diy-kits
Thank you for your answer!
I have no problem soldering. Thoose kits looks interesting.
 

atferrari

Well-Known Member
I thought at first, too much hardware just to get siren sounds but it seems they have an specific application for DJs.

Having built a dual NCO starting with code by Tom Napier I would develope the rest also with a micro.

In my case I have never built a kit. Sorry, it seems too much like painting by numbers.
 

Rorut

Member
Hi again!
I bought one DIY kit. But would like som help with a modification. There are three switches with four modes on each. The one to the right in the prebuilt kit by the seller has a potentiomer allowing to adjust the pitch instead of just four positions.

I asked before I bought the kit if they were the same and he told me so. Now he dont answer more about that question. Is it difficult to change (or just add, would be better, a potentimeter to the circuit) the one switch to the right with a potentiometer and how do I do it?
Appreciate all help a lot!

Here is some pics and links
DIY kit
https://www.rdhelectronics.fr/site/EN/cat-1/prod-63

Pre built with potentiometer to the right
https://www.rdhelectronics.fr/site/EN/cat-2/prod-47

Images on parts






 
Last edited:

audioguru

Well-Known Member
Most Helpful Member
To modify a circuit you need its schematic (it is probably not available) and an understanding of how it works. It might be simple or complicated to add a potentiometer to change the pitch. The demos have buttons, potentiometers and loud music so we do not know if the sounds are in the music or from the siren corcuit. I did not hear a sine wave, instead I heard a constant volume variable frequency buzzer.
 

dr pepper

Well-Known Member
Most Helpful Member
Looks like a fairly simple circuit, what you ask is most likely doable, however we'd need a schematic to tell you much more.
I noticed theres a fair bit of fx on the one being played in the vid, just the machine and an amp wont sound like the vid.
 

Rorut

Member
I think he is using an additional echo/delay in the video. Circuit is 100% analogue. How about replacing one of the "selected" resistors with a potentiometer with near value as possible?
I think circuit i based on this or very similiar
IMG_3213.PNG
 

dr pepper

Well-Known Member
Most Helpful Member
Ok then, yes you could replace the pitch switch with a 470k pot, but you'd need a dual or stereo pot, as there are 2 gangs on the switch 1 and 2.
Connect the wipers to the transistors bases and one of the outer track connections to the mode switch.
 

Rorut

Member
Circuit I attached may be faulty. Maybe we should not trust it to be exactly the same. (Behaviour should be same) Is your solution based on how that circuit works? Thank you dr pepper
 

dr pepper

Well-Known Member
Most Helpful Member
I just looked at the schem and saw that the switch just switches in a diferent resistor in each position, you can do the same thing with a pot but continuously adjust it.
One thing that might happen, if the resistance is adjusted towards the low side the oscillator might stop (or go supersonic, which some amps might not like), if thats undesirable you could put a resistor inline with the pot wiper, say 10k, you'd need to experiment.
If the resistor values on your board are the same then theres a good chance the oscillator will be the same too.
 

dr pepper

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Most Helpful Member
In that case trace out the connections going to the pitch switch and make a list of the resistors going to it.
Most likely they will be in decades, probably the 220k, 22k and 2k2.
 

Rorut

Member
In that case trace out the connections going to the pitch switch and make a list of the resistors going to it.
Most likely they will be in decades, probably the 220k, 22k and 2k2.
Got this answer from seller:
"NJD potentiometer : You can easily replace the rotary switch with variable potentiometer. Also you can just put a potentiometer instead of the resistors of the pitch (or speed) potentiometer of the NJD Siren. You have to buy a dual gang (two way) potentiometer of 250kohm value."

Like you said dr pepper. But I think I need i visualized to understand where to solder it.. maybe I can draw out numbers on the connections and add an image on dual gang pot with numbered legs and you can help me pair them? :) im such a noob
 

dr pepper

Well-Known Member
Most Helpful Member
Ok then I had to look at that a bit closer.

Heres what I think:

POT Switch
A -- (top side of R20)
B -- 1
E -- 3
F -- (top side of R21)

C&D on the pot do not need to be connected.
Looking at the second pic (the one of the bare board) I'm referring to 'top side' of R20 and R21, by 'top side' I mean the upper pad towards the top of the screen for those resistors..
 

spec

Well-Known Member
Most Helpful Member
Just a small point: make sure you get a linear pot not logarithmic like many dual gang potentiometers are.

spec
 

Rorut

Member
Hi again and thank you very much for your help. Just to be sure, is it correct in the picture? Earlier in the thread you talked about this
"One thing that might happen, if the resistance is adjusted towards the low side the oscillator might stop (or go supersonic, which some amps might not like), if thats undesirable you could put a resistor inline with the pot wiper, say 10k, you'd need to experiment."
Is that still something to think about?

front_new.jpg
 

spec

Well-Known Member
Most Helpful Member
Hi Rorut,

There are two maxims in electronics;
(1) If it is possible to go wrong, it will
(2) If it is impossible to go wrong, it will.

So any precautions you can take are wise.:D

spec
 

dr pepper

Well-Known Member
Most Helpful Member
Yes that looks good.
Yes put a resistor inline with the pot, doenst matter which leg of the pot.
Go for a 22k, as that is the smallest resistor inline with the original circuit when the switch is in the highest pitch position.
 
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