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Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers
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Author:  KrammeAcoustics [ 17 Aug 2010, 15:23 ]
Post subject:  Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

Hi forum

I've made a simple 12 V 3 sec. delay relay, coupled to the headphone output of my Rogers Gomez NP-100v12 Amp. Here are photos of my NP-100v12 - 12AU7 / IRF510 Headphone Amp with Turn-on Delay. It can also be used for speaker-outputs for a power amplifier. The Takamisawa 12v relay i've used is a two channel type, found in a scraped Onkyo power amplifier ( other brands can off course be used as well, just be sure it's a two channel type ).

I'll show everything as simple as possible, so even beginners of DIY can make this build.

First the simple schematics found on the internet:
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And here i've added some values and pinouts of the components:

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Pinout of the PNP transistor, base, collector and emitter ( other PNP types can be used ):
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Pinout of the diode, anode and cathode:
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A picture of my add-on delay relay:

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Author:  dtsup1 [ 17 Aug 2010, 20:41 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

Hi Kramme,

NIce n simple ! Is this a passive delay system requiring no external power ?

Can you show a rough connection diagram as to how it is connected to an amplifier and speakers ?

Thanks~

Author:  KrammeAcoustics [ 18 Aug 2010, 14:07 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

Hi Dinesh and others

No external power, it runs on the same battery that supplies the amp. But it's important to connect the circuit, so it always see + 12 V. A switch couples ground to the delay relay.

Note: An important information about this build, is that it won't delay the relay, if you turn it on and of, again and again. It will first have to empty the capacitor, for starting a new session. Simply wait for several seconds, before turning it on again. :exclaim:

I'm working on showing an usable pcb layout for this thread, but i'm not sure about the program shows it from top or bottom ...any ideas ? If the program i'm using would show only the printway circuit, it would be easy to find out, but it also present the components ...i guess it could bring frustration for beginners :worried:
( my own version is just point to point soldered ).

If any of you guys are good at working with pcb programs, you're more than welcome to add a "for real made" pcb to this thread. Sorry pcb's are not what i'm best at. Anyway here is a kind of layout 8-)

Note: BOTTOM VIEW.
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Author:  Gio [ 19 Aug 2010, 11:49 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

Awesome, this is great Kramme. Thanks for sharing as I know a few have asked about this.
Cheers

Author:  KrammeAcoustics [ 19 Aug 2010, 15:40 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

Hi Gio

You are welcome.

Actually i saw something likely was discussed, somewhere in a thread on this site :up:

Author:  CrazzyAbtTubes [ 19 Aug 2010, 22:17 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

That is a nice little circuit..... but I think those TO220 case transistors are a bit over kill for the application. :)

How is the shut off speed? I used a circuit with an 555 timer for my IRF640/12AU7 headamp and it only stops the ON pop, not quick enough to catch the OFF pop though and it is quite loud

Author:  Tfan [ 20 Aug 2010, 09:26 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

would it be possible to adapt it to a 6v tension? changing of course the relay?

Author:  KrammeAcoustics [ 20 Aug 2010, 15:11 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

CrazzyAbtTubes wrote:
That is a nice little circuit..... but I think those TO220 case transistors are a bit over kill for the application. :)

Hi Crazzy

It's not a secret that i distroyed a couple of BC557 and BC558's ( don't know why ) before i tried the BD's. My problem was the schematic, i found on the internet, it didn't tell which PNP transistors to use :?

It's not interesting that the transistor is fast or even easy to open ...it's more the opposite, to get this circuit functional.
CrazzyAbtTubes wrote:
How is the shut off speed? I used a circuit with an 555 timer for my IRF640/12AU7 headamp and it only stops the ON pop, not quick enough to catch the OFF pop though and it is quite loud

The delay i've made don't help the turn off problem, that i'll have to work on.

It would be great if you made a thread of that 555 circuit of yours, it could be a better solution than my circuit. 8-)

Author:  KrammeAcoustics [ 20 Aug 2010, 15:36 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

Tfan wrote:
would it be possible to adapt it to a 6v tension? changing of course the relay?

I guess so ( maybe by triming the 68k and the 470uF ). I've only tried voltages, between 8 ~ 15 VDC before mounting the circuit, so i can't promise anything.

The simple way this circuit works is that the transistors won't open, before the 470uF capacitor is near loaded. The 68k resistor and the capacitor works together in a kind of balancing act. During the capacitors "slow" loading through the resistor, it instead will be possible to lead the base of the first transistor, which draws the second transistor. When this happens the relay will be activated.

Maybe someone can explain it better, but that's the way i see it. :mrgreen:

Author:  KrammeAcoustics [ 20 Aug 2010, 16:20 ]
Post subject:  Re: Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers

CrazzyAbtTubes wrote:
I used a circuit with an 555 timer for my IRF640/12AU7 headamp and it only stops the ON pop, not quick enough to catch the OFF pop though and it is quite loud

A simple delay with the 555 circuit, even with a calculator: http://clarkson-uk.com/555-timer/operation/frames3.html

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