work around connections
If you have a speakon speaker side and optical spdif on source side internal I need grounding to the PE signal GND ?
Or only one Law is valid ?
If you have a speakon speaker side and optical spdif on source side internal I need grounding to the PE signal GND ?
Or only one Law is valid ?
The 15 Ohms is in series with the source signal. It will not make any practical difference Andrew
Here's the link to Daniel Joffe's paper for those interested - it's a good write up and some more input to help build knowledge on this issue
http://www.updatemydynaco.com/documents/GroundingProblemsRev1p4.pdf
http://www.updatemydynaco.com/documents/GroundingProblemsRev1p4.pdf
Hi guys,
I just had a look at this pdf and noticed in the "wiring diagram" that the fuse is shown on the blue wire. Can someone confirm this is correct? I always thought that you should put the fuse on the active wire (brown).
regards
Just my choice of bad colors - I will update it.
The correct line to fuse is the HOT (USA convention) or LIVE (UK/AUS/SA convention).
Thanks for pointing this out - could be confusing.
I am in the process of moving, so it will have to wait for a week or so.
The equipment chassis is only ONE ACCESSIBLE PART which can become HAZARDIOUS LIFE, the RCA connector and cable is another...
(and Hifi crowd love golden shiny metal parts..)
There are worse things than the Ground Lifter and it can do its job,
BUT in the normal domestic installation a Ground Lifter has nothing to do.
in my humble opionion, a case of overengineering (or not to see the wood for the trees)..
It think, the ground lifter CAN be built to adhere to the Class-I regulations.
BUT, this is not trivial, and many DIY'er (and Pros) are not able to do it right.
You must think of a lot of exceptional cases (lightning stroke, partial transformer breakthrough, defective or 40 year old connected gear...) AND you must test every single unit (with protocol, just in case).
If you need a Ground lifter, you should think about your general installation.
If you still need a Ground lift, you should go to a solid Class-II design.
Or better: build a Class-I design, where parts adhere to Class-II. This is simple,
you basically need a Class-II approved transformer, and voila, you can get rid of the clumsy Ground Lift...
Anyway companies selling millions of amps do not use the ground lifter...
Even if it is build safe, it is very expensive to justifiy its use in court as it is not covered in the Class-I standard. And the laywers are imaginative, especiall in USA.
Your cirucit in the PDF is a good inspiration,
but especially with the ground lifter a second fuse
(in the Life and Neutral wire) is a good idea.
With the second fuse you are independent of the main fuse
(and could in theory reduce the current rating of the ground lifter bridge rectifier).
Also a second fuse is a necessary when changing a defect fuse is possibe, while the main connector is still inserted (there have been bad accidents).
Life stage is the last place where ground lifters are extensivly used (and not every ground switch is as elaborate as the bridge version):
https://www.gearslutz.com/board/live-sound/873609-how-can-guy-get-electrocuted-stage.html
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Udok, you can build my recommended layout without the ground lifter. If you have no external ground loops, it will work perfectly. However the ground lifter brings added benefits in reducing noise.
I am not building amplifiers in high volume for commercial purposes. I build amplifiers for myself.
I am not building amplifiers in high volume for commercial purposes. I build amplifiers for myself.
if you have no exposed conductive parts then it is very easy to comply with the second requirement.If you have a speakon speaker side and optical spdif on source side internal I need grounding to the PE signal GND ?
Or only one Law is valid ?
That leaves the first requirement as the one that must be met.
But remember those two are what I as an informed "amateur" consider the most important.
For instance: to enable the Chassis to PE connection to be effective for operator SAFETY, one MUST FIT an appropriate fuse between supply and equipment
AND
the PE connection MUST be low impedance all the way back to the supply distribution board.
There will be dozens of other requirements, the two most important to our building ClassI projects are as I have stated as my opinion.
By my understanding of the subject of interference currents, I see the location of the added resistor does make a difference.
If the signal voltage is modulated by interference current passing through the added resistor, then we have chosen the wrong location for the interference current reducing resistor.
D.Joffe shows the added resistor "outside" the audio/signal current route.
This first post is wrong. It leads to a dangerous situation AFTER the fuse has blown.
Even worse: Fault Current flowing from Live/Hot to PE might not blow the fuse in the Neutral line.
This second post is correct.
AJT,
can you arrange to have your dangerous post removed from the Forum?
But the current will be flowing through all resistances in the input signal loop in that case surely?
No AndrewT, many posts will show that I do take advice, and I'm grateful for it.
But not from you. Because you wrongly present your debatable opinions as fact, which makes your advice--to call it that--worthless.
However, I'm glad you said something because it reminded me. I've been meaning to check with you about your post #9 here: http://www.diyaudio.com/forums/chip-amps/259494-tda2030-amp-issue-help.html
For your convenience I excerpt your post below:
The "post6" amplifier you refer to I re-post below, again for your convenience. "Who designed this amplifier" is the engineering staff at SG, of course. The highlighting is added by me, but otherwise the circuit is a screenshot, there are no changes. Here's the data sheet: https://www.futurlec.com/Philips/TDA2030a.shtml
I wanted to check with you on whether you'd heard back from the engineers at SG? Have they made the changes you require, is all that taken care of?
.
Attachments
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OK I think I see my mistake. Some of my mistakes. One of them.
I asked an open-ended question, which obviously is an invitation to chaos. Sure enough chaos ensued, unrelated pet theories and projects lined up at the door shouting hey looka me, I'm important.
But it's not important unless it relates in some visible way to the circuit I posted. For the following reason.
Contrary to the opinions of those who enjoy making things hard, it's not. Grounding is not arcane or mysterious. Not in the chip amp world.
For proof of this, bang together any single-stage NE5532 circuit. For crying out loud there are three--count 'em--connections to the zero-volt ground point. Run all three grounds to that one point.
How many times have you done exactly this when breadboarding a circuit? Notice anything? Oh yes, son of a gun, it worked!
Of course it worked. Many engineers, and many thousands of dollars spent on research and testing, say it has to work. With these little black chips the only hard thing is making it not work.
Er...usually, that is. There are pitfalls, yes. But to a newbie there are only two pitfalls that really matter: 1. He doesn't know where to start, and: 2. He doesn't know what not to do.
Hence my li'l compendium circuit. To give the poor guy a starting point, a plan of attack. One that will: 1. Work, and: 2. Keep him away from pitfalls unnamed.
It would also be awfully nice if it were: 3. Simple enough not to scare a newbie half to death. The compendium started out pretty simple, but due to valid advices received (ahem) it keeps getting more complicated. Well, I'm working on re-simplifying.
All of which considered, again I post. But this time, hoping to stick more closely to the subject, I include some of the references I've consulted. On the references I've added my own circled A, and red circled B, to illustrate the "common denominator" I'm looking for. Posted below are:
1. My circuit, illustrating, in very broad terms, the bus-star argument.
2. My circuit, the one under consideration, showing my understanding of the references that follow here:
3. Circuit by Bob Cordell, "Designing Audio Power Amplifiers."
4. Circuit by Douglas Self, "Self on Audio."
5. Circuit by Douglas Self, "Audio Power Amplifier Design."
6. Circuit by Bruce Trump, "Grounding Principles," writing for Texas instruments. The complete article is here: Grounding Principles - The Signal - Archives - TI E2E Community
7. Not an individual circuit, but reference is made to Texas Instruments, almost any data sheet, the section on Stability. For example page 7 of the LM1875 data sheet here: http://www.ti.com/lit/gpn/lm1875
The attempt is to gather these and other almost-the-same circuits into a single practical reference circuit, which is intended to be circuit #2 above. Comments and/or corrections that actually do apply to circuit #2 are implored.
.
OK I think I see my mistake. Some of my mistakes. One of them.
I asked an open-ended question, which obviously is an invitation to chaos. Sure enough chaos ensued, unrelated pet theories and projects lined up at the door shouting hey looka me, I'm important.
But it's not important unless it relates in some visible way to the circuit I posted. For the following reason.
Contrary to the opinions of those who enjoy making things hard, it's not. Grounding is not arcane or mysterious. Not in the chip amp world.
For proof of this, bang together any single-stage NE5532 circuit. For crying out loud there are three--count 'em--connections to the zero-volt ground point. Run all three grounds to that one point.
How many times have you done exactly this when breadboarding a circuit? Notice anything? Oh yes, son of a gun, it worked!
Of course it worked. Many engineers, and many thousands of dollars spent on research and testing, say it has to work. With these little black chips the only hard thing is making it not work.
Er...usually, that is. There are pitfalls, yes. But to a newbie there are only two pitfalls that really matter: 1. He doesn't know where to start, and: 2. He doesn't know what not to do.
Hence my li'l compendium circuit. To give the poor guy a starting point, a plan of attack. One that will: 1. Work, and: 2. Keep him away from pitfalls unnamed.
It would also be awfully nice if it were: 3. Simple enough not to scare a newbie half to death. The compendium started out pretty simple, but due to valid advices received (ahem) it keeps getting more complicated. Well, I'm working on re-simplifying.
All of which considered, again I post. But this time, hoping to stick more closely to the subject, I include some of the references I've consulted. On the references I've added my own circled A, and red circled B, to illustrate the "common denominator" I'm looking for. Posted below are:
1. My circuit, illustrating, in very broad terms, the bus-star argument.
2. My circuit, the one under consideration, showing my understanding of the references that follow here:
3. Circuit by Bob Cordell, "Designing Audio Power Amplifiers."
4. Circuit by Douglas Self, "Self on Audio."
5. Circuit by Douglas Self, "Audio Power Amplifier Design."
6. Circuit by Bruce Trump, "Grounding Principles," writing for Texas instruments. The complete article is here: Grounding Principles - The Signal - Archives - TI E2E Community
7. Not an individual circuit, but reference is made to Texas Instruments, almost any data sheet, the section on Stability. For example page 7 of the LM1875 data sheet here: http://www.ti.com/lit/gpn/lm1875
The attempt is to gather these and other almost-the-same circuits into a single practical reference circuit, which is intended to be circuit #2 above. Comments and/or corrections that actually do apply to circuit #2 are implored.
.
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