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 Post subject: Re: Grounding Techniques
PostPosted: 31 Dec 2016, 06:38 
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Joined: 29 Oct 2014, 12:32
Posts: 95
Location: Russia Komi republic
Hello! Much work on drawing, I love it!
One small remark. This is not a technical note. X2 capacitor 1 uF may be reduced to 0.1 or 0.15 uF. Just if you can save a dollar - should do it :)

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 Post subject: Re: Grounding Techniques
PostPosted: 31 Dec 2016, 08:28 
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Joined: 04 Jun 2008, 20:59
Posts: 4078
Location: Arizona, USA
Hi, I didn't check for that. My bad. I use a 0.1uf most of the time. I was just looking at the grounds and should have looked at the entire drawing. It is a great drawing, but I personally much prefer a schematic. They are easy to draw using the pre made circuit elements from the web (there are lots of them) and a simple program like MS Paint.

Good listening
Bruce

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 Post subject: Re: Grounding Techniques
PostPosted: 31 Dec 2016, 12:27 
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Joined: 14 Nov 2016, 21:03
Posts: 8
Hi Guys.

I did redraw the schematic I'm using also but don't want to post here as it would be off topic. Thanks for catching the .1uf error. That was a typo as the cap I drew in has the correct dimensions for the .1uF X2 cap I'm using.

So my final grounding questions are where should I terminate the ground from:

a) The ground from the secondaries on the Output Transformers (I understand this is good safety practice just in case there is a break down between the primary and secondary of the OPT.

b)The internal shield between primary and secondary of my torrid power transformer.

c)I'll be attaching the Hammond 5H choke under the chassis to the wood sides. Should I ground the case of the choke to the metal top? If so I assume this could go to the same point as the internal shield between primary and secondary of my torrid power transformer (b)

THANKS AGAIN for all the help!


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 Post subject: Re: Grounding Techniques
PostPosted: 01 Jan 2017, 13:19 
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Joined: 29 Oct 2014, 12:32
Posts: 95
Location: Russia Komi republic
"a) The ground from the secondaries on the Output Transformers (I understand this is good safety practice just in case there is a break down between the primary and secondary of the OPT."
I have not seen the scheme. Without it, I can not answer.
"b)The internal shield between primary and secondary of my torrid power transformer. "
Chassis.
"c)I'll be attaching the Hammond 5H choke under the chassis to the wood sides. Should I ground the case of the choke to the metal top? If so I assume this could go to the same point as the internal shield between primary and secondary of my torrid power transformer (b)"
This is not nessesary, in my opinion. You already have the chassis, as a screen.
By the way, I like copper foil adhesive. If you glue it on the wooden side panels, will screen at the sides. Essential that the foil is in contact with the cover plate.

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 Post subject: Re: Grounding Techniques
PostPosted: 03 Jan 2017, 15:47 
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Joined: 14 Nov 2016, 21:03
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zyu wrote:
"a) The ground from the secondaries on the Output Transformers (I understand this is good safety practice just in case there is a break down between the primary and secondary of the OPT."
I have not seen the scheme. Without it, I can not answer.
"b)The internal shield between primary and secondary of my torrid power transformer. "
Chassis.
"c)I'll be attaching the Hammond 5H choke under the chassis to the wood sides. Should I ground the case of the choke to the metal top? If so I assume this could go to the same point as the internal shield between primary and secondary of my torrid power transformer (b)"
This is not nessesary, in my opinion. You already have the chassis, as a screen.
By the way, I like copper foil adhesive. If you glue it on the wooden side panels, will screen at the sides. Essential that the foil is in contact with the cover plate.



thanks for the tip on the copper sides..

Here's the schematic. I need to figure out where I should be grounding the secondary of the OPT. THANKS!

Image


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 Post subject: Re: Grounding Techniques
PostPosted: 03 Jan 2017, 16:05 
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Joined: 06 Apr 2009, 10:08
Posts: 1605
Location: US Pacific Northwest
Can I ask a question?

Why the gain reduction on the driver tube? it only looks to be in neighborhood of 1/2 a dB. On a driver stage with around 22dBv of gain, I'm not sure I understand the point.

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 Post subject: Re: Grounding Techniques
PostPosted: 03 Jan 2017, 17:13 
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Joined: 29 Oct 2014, 12:32
Posts: 95
Location: Russia Komi republic
looking at the a scheme, I would have brought this point to the ground star.

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 Post subject: Re: Grounding Techniques
PostPosted: 04 Jan 2017, 14:17 
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Joined: 04 Jun 2008, 20:59
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Location: Arizona, USA
+1 on the star ground.

Good listening
Bruce

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 Post subject: Re: Grounding Techniques
PostPosted: 04 Jan 2017, 21:03 
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Joined: 14 Nov 2016, 21:03
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Suncalc wrote:
Can I ask a question?

Why the gain reduction on the driver tube? it only looks to be in neighborhood of 1/2 a dB. On a driver stage with around 22dBv of gain, I'm not sure I understand the point.


Hi Suncalc! I'm assuming you mean the 100 ohm R7 and R8? To tell you the truth I have no idea why they are being used. This is a design from a PCB that is no longer being sold. I redrew the schematic since the original in the PDF was separated by board connections. The original docs can be found here:

http://www.diytube.com/phpBB2/viewtopic.php?t=4893

The good news is with my turret board layout those resistors can be left out easily if need be.


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 Post subject: Re: Grounding Techniques
PostPosted: 18 Mar 2019, 11:45 
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Joined: 19 Oct 2018, 15:30
Posts: 132
Location: Montréal, Québec
Could somebody explain how a safety capacitor can be certified X2 AND Y2 at the same time ? How can it be made to fail open and short at the same time ? I’ve read elsewhere that they can be used in both situations, but I just can’t figure out how it’s possible. Is it safe to use this kind of cap as bruce indicates in his article ?

Thanks !


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