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Old 28th June 2013, 01:52 PM   #3781
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That'll be the same one that I found.
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Old 28th June 2013, 02:40 PM   #3782
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In yours?
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Old 28th June 2013, 03:19 PM   #3783
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But its funny anyeay, cause the guy from the other forum shows a pic where this
caps are also installed…

http://diyaudioprojects.com/Forum/do...4027&mode=view

But he didnt put in a pot...

Last edited by sangeet2; 28th June 2013 at 03:31 PM.
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Old 29th June 2013, 03:40 PM   #3784
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As I said before, try reverse engineering the board. I suspect that there is something wrong somewhere. It's a simple enough circuit to check. The problem that I had was that there an incorrect connection to the 0V top plane.
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Old 26th July 2013, 07:53 AM   #3785
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Hi, I have a 18 V, 5.0 W Zener Diode Voltage Regulator
I presume with just a simple circuit and this Diode i can have a nice steady 18v PSU.
Do i just attach the diode over the Rectifier outputs or ?

Ill search for some diagrams
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Old 26th July 2013, 12:20 PM   #3786
udailey is online now udailey  United States
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It needs a series resistor to limit current or it'll burn instantly.
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Old 2nd August 2013, 12:57 AM   #3787
Rixsta is offline Rixsta  United Kingdom
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aha thanks, well used an online calculator had a 400ohm resistor with the 18v Zener and worked for a while, power slowly rising on turn on up to 17v for the B1 then after a while i guess the Zeener just died as the voltage slowly dropped then nothing !
Hmmm back to the drawing board how to achieve 18v from 26vDC

I think i just fried a Zeener

Perhaps Ill just change the Caps in the B1 for higher voltage and run it from the 26v DC, If 26 is not too high for B1
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Last edited by Rixsta; 2nd August 2013 at 01:04 AM.
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Old 2nd August 2013, 03:24 AM   #3788
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Quote:
Originally Posted by Rixsta View Post
Hmmm back to the drawing board how to achieve 18v from 26vDC
LM7818 LM7818 PDF Datasheet 3-Terminal 1A Positive Voltage Regulator

LM317 http://www.google.com/url?sa=t&rct=j...,d.aWM&cad=rja
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Old 2nd August 2013, 05:02 AM   #3789
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400mW Zener at 18V should be capable of withstanding 22mA.

26 - 18 / 400 = 25mA, so 400 Ohms was slightly too low.

1K would be OK.

B1 will run on 26V anyway !!!!
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Old 2nd August 2013, 10:41 AM   #3790
Rixsta is offline Rixsta  United Kingdom
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Hey, Thankyou

Decisions Decisions upgrading the power caps to run the B1 from 26v seems easiest solution ill Probably go with that. yes Id had a 470ohm resistor.

Does anyone know of a good soft start circuit that wont take weeks to arrive in the Uk lol there's a turn on thump on the B1 which id prefer to get rid of!

im thinking Just get a soft start for the whole amp
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Last edited by Rixsta; 2nd August 2013 at 10:45 AM.
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