.
<< I also looked on internet for PCB layouts or amp layouts of D. Self designs and could not find one that used a star ground in the way described by bentsnake. >>
Causing me to again wonder whether anybody reads these threads, as opposed to just looking at the pictures. Because I've given my references at least once, and I'm pretty sure twice.
But since this has become The Thread That Never Dies, what the heck, Ill give them yet again.
For the benefit of latecomers, the key to the present you're-wrong contest is post #31, on page 4 of this thread. There I posted a couple of circuits, saying, "...this is my understanding of the references cited (many times checked). If I've misinterpreted or misunderstood anybody I'd be very happy to be corrected by them."
I don't think anybody ever did actually comment on the circuits I posted, but immediately there were explanations all about how star grounds can't possibly be any good, and only by using a ground bus can you ensure that your firstborn will be male. The usual screaming match ensued, and continues to this very day.
Those references:
Douglas Self, "Audio Power Amplifier Design Handbook"
Douglas Self, "Self on Audio"
Texas Instruments: Grounding Principles - The Signal - Archives - TI E2E Community
.
<< I also looked on internet for PCB layouts or amp layouts of D. Self designs and could not find one that used a star ground in the way described by bentsnake. >>
Causing me to again wonder whether anybody reads these threads, as opposed to just looking at the pictures. Because I've given my references at least once, and I'm pretty sure twice.
But since this has become The Thread That Never Dies, what the heck, Ill give them yet again.
For the benefit of latecomers, the key to the present you're-wrong contest is post #31, on page 4 of this thread. There I posted a couple of circuits, saying, "...this is my understanding of the references cited (many times checked). If I've misinterpreted or misunderstood anybody I'd be very happy to be corrected by them."
I don't think anybody ever did actually comment on the circuits I posted, but immediately there were explanations all about how star grounds can't possibly be any good, and only by using a ground bus can you ensure that your firstborn will be male. The usual screaming match ensued, and continues to this very day.
Those references:
Douglas Self, "Audio Power Amplifier Design Handbook"
Douglas Self, "Self on Audio"
Texas Instruments: Grounding Principles - The Signal - Archives - TI E2E Community
.
.
<< only a perception >>
There's nothing only about perception. As a person perceives, so is their reality. An insane person might perceive a monster biting their head off. Nobody else sees a monster, but the insane person still dies.
The basic rule is right lives, wrong dies. If I'm perceived by somebody as making them right, then I'm assisting their survival and I'm a friend. If I'm perceived by somebody as making them wrong, then I'm hindering their survival and I'm an enemy.
Upon perception, and this alone, doth the world turn. Which explains a lot, huh?
.
<< only a perception >>
There's nothing only about perception. As a person perceives, so is their reality. An insane person might perceive a monster biting their head off. Nobody else sees a monster, but the insane person still dies.
The basic rule is right lives, wrong dies. If I'm perceived by somebody as making them right, then I'm assisting their survival and I'm a friend. If I'm perceived by somebody as making them wrong, then I'm hindering their survival and I'm an enemy.
Upon perception, and this alone, doth the world turn. Which explains a lot, huh?
.
First thing in amplifier design is selection of parts.. then its PCB design then the power supply, enclosure and the last thing is wiring. If your components are mainsteam and PCB isnt 100% pure gold with some extreme design then why the hell would you wire it with silver or gold? Same with connectors... Thats all retarded stuff I think. Theres almost no difference between gold plated and bare copper PC board. Most of the audiophiles are silly fools who want your money... But even I use gold plated connectors because they dont rot and conduct a little better.. But all the cables and such remain cheap but good stuff. I could be wrong but thats what I think and you dont have to take it too seriously. If you have seen some of those ebay amplifiers.. Well the component layout looks great but really its full of ****.
Once I wanted to build cheap and fine amplifier from stuff off ebay but I searched for hours and found nothing useful.
Once I wanted to build cheap and fine amplifier from stuff off ebay but I searched for hours and found nothing useful.
Last edited:
I have already told people 'how to be right': use a ground bus in the PSU, with careful distinction made between the dirty end (rectifier/secondary) and the clean end (supply DC to amp circuit). You appeared to dispute that. I and others have explained why this is a good way to do it, as it keeps charging pulses and signal apart in the way that a star does not.bentsnake said:
If you don't like it, don't use it, but those who have tried it usually find a significant improvement in hum/buzz which had previously proved impossible to eliminate.
I commented, hence this discussion. I pointed out that naive star grounds can be unhelpful in a PSU. I did not mention procreation. I am not screaming.
Last edited:
<<For the benefit of latecomers, the key to the present you're-wrong contest is post #31, on page 4 of this thread. There I posted a couple of circuits, saying, "...this is my understanding of the references cited (many times checked). If I've misinterpreted or misunderstood anybody I'd be very happy to be corrected by them.">>
By "them" I understood the list of references and that you would not accept corrections/arguments from anyone else but those references. Was I wrong?
By "them" I understood the list of references and that you would not accept corrections/arguments from anyone else but those references. Was I wrong?
.
<< By "them" I understood the list of references and that you would not accept corrections/arguments from anyone else but those references. Was I wrong? >>
You're 99% right. People around here tend to proclaim their opinions as fact, then get upset when they're questioned. Caps Lock is endemic. I added the disclaimer (to call it that) hoping to avoid useless confrontations (see note 1).
But if I've made a mistake in my circuits, or if I have misunderstood something, then I'm not only delighted, but eager to learn of it. Adding that it's only a fact when the math can be shown, or a plausible reference is given. Otherwise it's an opinion, and one is as good as another.
note 1: Not that I claim to be innocent when it comes to screaming matches. I'm as guilty as anybody, more so than some.
Edit: That's if the math can be shown, not that it has to be. With some of this stuff showing the math would take up another 7 pages. and I don't think this forum would reproduce the symbols anyway.
.
<< By "them" I understood the list of references and that you would not accept corrections/arguments from anyone else but those references. Was I wrong? >>
You're 99% right. People around here tend to proclaim their opinions as fact, then get upset when they're questioned. Caps Lock is endemic. I added the disclaimer (to call it that) hoping to avoid useless confrontations (see note 1).
But if I've made a mistake in my circuits, or if I have misunderstood something, then I'm not only delighted, but eager to learn of it. Adding that it's only a fact when the math can be shown, or a plausible reference is given. Otherwise it's an opinion, and one is as good as another.
note 1: Not that I claim to be innocent when it comes to screaming matches. I'm as guilty as anybody, more so than some.
Edit: That's if the math can be shown, not that it has to be. With some of this stuff showing the math would take up another 7 pages. and I don't think this forum would reproduce the symbols anyway.
.
Last edited:
I suppose I'm a terrible person because I run a bus between multiple stars...
Yes, the order is critical. Yes, the charging current loop needs to have its own star (the last one on the bus). Yes, each stage gets its own star and the bus is run starting from the lowest level (input) to the highest level (power supply). And yes, the cherry on the parfait is the use of Kelvin connection caps at the power supply output.
Yes, the order is critical. Yes, the charging current loop needs to have its own star (the last one on the bus). Yes, each stage gets its own star and the bus is run starting from the lowest level (input) to the highest level (power supply). And yes, the cherry on the parfait is the use of Kelvin connection caps at the power supply output.
.
A moment for perspective.
Once upon a time the subject was grounding. It was being discussed for the benefit of the original poster, Pjotter (who hasn't been heard from lately, and who can blame him for that).
I posted two circuits as part of that discussion. Not circuits of my own, as I made clear, but circuits created by recognized authorities in the field of audio electronics. I took care to reference those authorities.
I took care also to explain that the circuits were "my understanding," not something I represented as factual. I invited correction in case I had made an error.
The result is there for anyone to see, including the present descent into surliness and oblique name calling. I'm sure it's all lots of fun--depending on what you call fun--but I don't think it helps anybody, which in my understanding is the purpose of this forum. So I'm going to just withdraw and leave the slapfighting to those who enjoy it.
That is...until next time, when the whole thing starts all over again. But then, c'est la mode de ce lieu.
.
A moment for perspective.
Once upon a time the subject was grounding. It was being discussed for the benefit of the original poster, Pjotter (who hasn't been heard from lately, and who can blame him for that).
I posted two circuits as part of that discussion. Not circuits of my own, as I made clear, but circuits created by recognized authorities in the field of audio electronics. I took care to reference those authorities.
I took care also to explain that the circuits were "my understanding," not something I represented as factual. I invited correction in case I had made an error.
The result is there for anyone to see, including the present descent into surliness and oblique name calling. I'm sure it's all lots of fun--depending on what you call fun--but I don't think it helps anybody, which in my understanding is the purpose of this forum. So I'm going to just withdraw and leave the slapfighting to those who enjoy it.
That is...until next time, when the whole thing starts all over again. But then, c'est la mode de ce lieu.
.
This was one of your earliest posts:
So, A moment for perspective ....
If you think that was a good example of a neutral response, then I think you have a severe attitude problem!
Arguments about use-flux-don't are meaningless. The only guy who knows anything is the guy holding the soldering iron.
If you have soldering skills, then yay you. But to your amazement, not everybody is as good as you. Some people need a little help. In fact, judging by the "it doesn't work" questions you see on forums, a whole lot of people need help.
That help comes in the form of a little dab of flux. This little bit of extra cleans the joint, and makes all the difference when you're first starting out. The difference between success and, "Aw, I just can't do it."
So you don't need it, so you're that good, more yay you. But if you want to withhold help from somebody just starting out, then maybe you'd want to rethink exactly what you're doing, and why.
If you have soldering skills, then yay you. But to your amazement, not everybody is as good as you. Some people need a little help. In fact, judging by the "it doesn't work" questions you see on forums, a whole lot of people need help.
That help comes in the form of a little dab of flux. This little bit of extra cleans the joint, and makes all the difference when you're first starting out. The difference between success and, "Aw, I just can't do it."
So you don't need it, so you're that good, more yay you. But if you want to withhold help from somebody just starting out, then maybe you'd want to rethink exactly what you're doing, and why.
So, A moment for perspective ....
If you think that was a good example of a neutral response, then I think you have a severe attitude problem!
Member
Joined 2009
Paid Member
Now that I think about it, this is what I do too. However, I just never felt comfortable thinking about multiple star grounds. So I tend not to call them all star grounds- rather I 'award' that name to just one, associated with the signal ground (and speaker return).
For the charging pulses I like to isolate them to the first cap after the rectifier by using rail resistors after these caps in a CRC configuration (or chokes) and the centre point of the rectifier-rail caps is of course a kind of local 'star ground' as you point out, which I connect to my main 'star ground'.
And of course I pay attention to the grounds on the pcb itself, looking at where local decoupling capacitor return currents flow, where the output zobel current flows and where the feedback shunt currents flow. So I guess there are one or two local 'star grounds' on my pcb but I don't call them that, I call them 'layered grounds' or 'good pcb layout practices'.
But if you look at the wiring in my chassis it will appear to have one clear physical 'star ground' where 'all the black wires go'.
I'm not terrible though
Last edited:
Most DIY amps have a local ground per channel which consists of all the returns of that channel, it could be a ground plane or a star. All the local grounds and PSU ground are connected to a main ground. Main ground is normally placed at the PSU. The speaker returns are connected to local or main ground.
What bentsnake is suggesting is to connect the local bypass caps to main ground leaving the local grounds free of any PSU components. (Please correct me if I am wrong)
The (bentsnake) amp would consists of local audio grounds with a single power star ground.
Perhaps all the confusion about multi channel grounding is that there is very little information in the data sheets or reference books on multichannel grounding.
All the methods discussed so far do not deviate from the original TI schematic!!!
What bentsnake is suggesting is to connect the local bypass caps to main ground leaving the local grounds free of any PSU components. (Please correct me if I am wrong)
The (bentsnake) amp would consists of local audio grounds with a single power star ground.
Perhaps all the confusion about multi channel grounding is that there is very little information in the data sheets or reference books on multichannel grounding.
All the methods discussed so far do not deviate from the original TI schematic!!!
It may help newbies get their grounding right. In any case, I was responding to your accusation that I had not told people how to get it right. If you don't want a response, don't make unfounded accusations.bentsnake said:
The maths is just Ohm's Law and knowledge of PSUs. Charging pulses generate a voltage across any conductors they flow though. Therefore you need to ensure that this voltage is not added to the signal. A bus ensures this; a star may not. There, it doesn't need 7 pages.
You received correction, as requested, but then seemed to take exception to this.
I assume you must mean comments like this:
Exactly who is being 'surly'?bentsnake said:
OK. We can go back to discussing grounding methods in a civilised fashion.bentsnake said:
Last edited:
Yes, thick copper wire preferably one that is at least 98% purity. I am scared of crystalline rectification caused by less pure copper
For signal wiring silver is actually quite nasty. I find it difficult to solder and it is very brittle in the thin formats required for small signal. Good quality annealed silver wire made by Cardas is quite good, and there may be others.
Since I cannot afford any of that stuff I use a local silversmith who gets metals in guaranteed pure grades and alloys them as per my specified numbers, then draws the wire by hand. I favour a specific mix of silver and copper that seems to yield the best balance between conductivity and malleability/strength. I then twist pairs after jacketing them in cotton, teflon or PVC and shield them when required with copper braid.
Most 'copper' wire sold in my city is either colored aluminum, or iron with copper plating - one of the benefits of being the first port of call from China. Even electrical wire is not pure enough, a chemical analysis performed by a friend showed copper purity down at ~75% with significant quantities of zinc, iron, phosphorous, lead and aluminum.
Therefore we chose to make our own small signal cable. For large signal we tend to oversize 3-4x the required gauge to prevent nasties (and pray hard), and for the good projects we import wire or buy from an 'audio' label. Even the most basic speaker wire sold by audio brands is 10x better than the nonsense that passes for wire over here.
Is any of this audible? I guess that is questionable, but at least I put in the best I could.
Member
Joined 2009
Paid Member
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.