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PostPosted: 04 Jan 2009, 16:07 
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Joined: 03 Aug 2008, 20:22
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Location: Denver, Colorado
I have built simple turn on delay circuits before, Here is one designed by Nelson Pass. The only issue is in solid state amps there is a rush of current when the amp is turned off. In tube amps there is not so much of an issue as the tubes come up slowly and drain the caps at shutdown. I guess this circuit would work for the 6as7G amp, just vary the values.

AMB has a circuit that delays turn on and shut down http://www.amb.org/audio/epsilon12/ , might be an interesting build.


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PostPosted: 04 Jan 2009, 16:39 
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Hi there

Happy me, i made a ripple and humfree supply from a 12 V 900 mA wallwart ( found it in the junkbox ) and i'm also free of disconnecting the earphones ( no pop ), because the supply starts and stops quietly, try it for yourself :mrgreen:

I just added to resistors 10 and 22 ohm and two 4700 uF 35 v electrolyts.

Why i'm making a supply like this ( instead of battery ) is because my friend also are interrested in the hybrid like i was, so i'm building one for him to. :up:

First i tried it with a 7812 regulator, but as i had said before, it doesn't sound right, it's like the topfrequences dissapears. :down:

I want a delaycircuit with relay for my batteryversion, that's for sure.

Below is a diagram with a pop and humfree walwartsupply.

Regards from John Kramme :headphones:

Image


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PostPosted: 04 Jan 2009, 20:52 
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KrammeAcoustics wrote:
Happy me, i made a ripple and humfree supply from a 12 V 900 mA wallwart ( found it in the junkbox ) and i'm also free of disconnecting the earphones ( no pop ), because the supply starts and stops quietly, try it for yourself :mrgreen:

EDIT: Transformer = 16 V ...not 12 V !

LEI ( Leader Electronics Inc. ) Model no. 481609OOSE
230 V ~ 50 hz 150 mA 16 V -- 900 mA


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PostPosted: 05 Jan 2009, 16:26 
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Location: Dartmouth, Nova Scotia
KrammeAcoustics wrote:
Hi there

First i tried it with a 7812 regulator, but as i had said before, it doesn't sound right, it's like the topfrequences dissapears. :down:


hmmmm, sounds like a good experiment for me to try, I was thinking of using an LM317, and I could then vary the voltage and they provide more current and better regulation than the 7812.

But if what you say is even slightly true through my own listenings I will resort to your design since it uses fewer components.

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My Mini 12AU7 Tube Preamp, Pioneer SX-D7000, JVC XL-V221BK, JBL L80T, DCM TF700


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PostPosted: 05 Jan 2009, 17:57 
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CrazzyAbtTubes wrote:

hmmmm, sounds like a good experiment for me to try, I was thinking of using an LM317, and I could then vary the voltage and they provide more current and better regulation than the 7812.

But if what you say is even slightly true through my own listenings I will resort to your design since it uses fewer components.


Hi CrazzyAbtTubes

I found another walwart with the specs. 12 V 1 A, it measured 16 V output without load, but there was hum ...I solved it by adding one more 4700 uF electrolyt ( three instead of two ), mounted before the first resistor where 20 V was measured, after that it also was humfree. Try and try and it will work.

Note: It's important to use a wallwart with a good reserve, eks.1 A or more is good, where 500 mA offcourse in my first attempts, not was enough.

It's interresting what you'll experience. 8-)

Regards form John Kramme


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PostPosted: 06 Jan 2009, 18:41 
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I shall try it just by using parts on hand first, since wall warts can be inconvenient (large bulky, usually 2-3 outlets consumed, hence the name wall wart :)

Hmmm, I also wonder If this applies to using a regulated PS in a tube amp using mosfets or a CCS in the bias?

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PostPosted: 08 Jan 2009, 07:18 
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so, I'm probably stupid, that's not really a newsflash, but i gotta ask... what is C1 supposed to be in your schematic? "1m" ? is that 1000uf? 1000000uf? in your pics it looks like a chubby electrolytic.. so i'm guessing its 1000uf.. but every time i think i know what you people are talking about, I'm wrong.. (sorry, a little bitter today :) )

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PostPosted: 08 Jan 2009, 10:57 
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oak1780 wrote:
so, I'm probably stupid, that's not really a newsflash, but i gotta ask... what is C1 supposed to be in your schematic? "1m" ? is that 1000uf? 1000000uf? in your pics it looks like a chubby electrolytic.. so i'm guessing its 1000uf.. but every time i think i know what you people are talking about, I'm wrong.. (sorry, a little bitter today :) )

Hi oak

I don't think you are stupid at all .... :up:

An eksample, the way TINA TI describes it:
1u = 1uF
1m = 1000uF
1M = 1000000 uF ( Mega/Million ....1000000u is also the same as 1F = Farad )

C1 = 1u = 1 Micro Farad, C1 is a bipolar condensator -| |- ( non polar ), f.eks. an electrolytic is polar - -| |- +.

The program TINA TI add's "u" automaticaly when plotting 1 and "m" for "1000" and "M" for "1000000".

Sometimes you also could see these sizes which is smaller:
1p = ( p = pico )
1n = ( n = nano )

Regards from John Kramme :headphones:


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PostPosted: 08 Jan 2009, 11:39 
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Location: Denver, Colorado
Tina will convert 1000uF to 1m (lower case m)



Capacitors can be funky like that, I have two ceramics one is .01M and reads 10nF and I have a 5000M which reads 5nF or 5000 pF.

The best thing is to download Tina and play a little, it is such a time saver as you can see the output before you build the circuit. It will tell you if you have shorts or opens, also you can check what your current and voltage reading will be. There is even a wave generator and built in oscilloscope with a virtual probe.

As far as output caps 440uF will put you where you want to be, you can bypass it with a poly film 1uF (red drop or orange drop) for better frequency response. Basically solder it in parallel to the electrolytic.

Oh yeah, never a stupid question. I like this forum because a new builder can come and ask questions and there are no self sanctioned brainiacs making them feel ignorant.


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PostPosted: 08 Jan 2009, 11:56 
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roggom wrote:
Tina will convert 1000uF to 1m (lower case m)

I know ...i was trying to edit my answer :down:

I was writing "k" ....instead of little "m" ...sorry my mistake, but as i said i couldn't edit ( timelimited ). :bawling:

A bit irritating, i am standing in a bad light now. It looks like i don't know what i'm talking about. :mrgreen:

Maybe the forum administrator could help me, by editing "k" to "m" :?: (edits done, Gio 8 Jan 2009)

I understand if people are being confused about the little "m" vs. big "M".

Regards from John Kramme :headphones:


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