Ah, I'm beginning to understand why you're so vocal in your claims that ground corruption doesn't occur.
If you look closely at that document, you'll see the following description of the ground connection:'LARGE AREA GROUND PLANE' = (ground symbol)
In general, DIY audio isn't done with grounds as large area ground planes - those are reserved for custom PCBs. The ground connection for a large area ground plane is much lower impedance at HF and so much harder to corrupt. Its not a universal panacea for audio because for the best quality we really need to have control over where our ground currents are flowing to minimise noise. If you look at the PCBs for well engineered DACs for example, they'll use multiple island planes rather than a single universal plane which is the norm for high frequency analog.
Is not that even. The loop of the HF is much smaller when you have the caps to the ground. If you put just one cap between rails, only THEN the HF noise needs to travel thru the rails all the way to the PS in order to be shorted by that cap.
This is because the OpAmp output load it is connected always to the ground, and only one of the output transistors is active at a certain time.
In the proper way, there is nothing "pushed" in to the ground. The way a decoupling cap is working, the HF it is actually "short-circuited" on the pins, before it reaches the ground.
This is because the OpAmp output load it is connected always to the ground, and only one of the output transistors is active at a certain time.
In the proper way, there is nothing "pushed" in to the ground. The way a decoupling cap is working, the HF it is actually "short-circuited" on the pins, before it reaches the ground.
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Always connected to ground? Always? I'm at present designing a bridged chip amp. Plenty of others are bridging amps - how is the load always connected to ground?
I've done this in more than one commercial product and I didn't use a 'single rail PS'. A colleague also did it under my supervision in another product, he did not use a single rail PS either. In none of these products did we 'go crossed between the pins' - its simply impractical, requiring two capacitors where one bigger one is quite sufficient. What a load of hogwash
The fact that you THINK that you have used a dual rail in a bridge amp doesn't mean that really happend. What you have there is a single rail PS with a reference 1/2 voltage that YOU called ground. The fact that you can replace that "ground" with two 10kohm resistors should give you a hint that that is not a POWER ground that needs decoupling.
The "ground" in the above discution for a dual PS is the one that the load is connected to, that carries higher currents that the input polarization.
The only time when you see cap between rails is for a fed-forward amp. But even then you will have a cap to the ground (that is power ground).
You can bicker or you can try to read some papers about decoupling.
The "ground" in the above discution for a dual PS is the one that the load is connected to, that carries higher currents that the input polarization.
The only time when you see cap between rails is for a fed-forward amp. But even then you will have a cap to the ground (that is power ground).
You can bicker or you can try to read some papers about decoupling.
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Doesn't matter what I call it - I could call it 'Rosemary' for all the difference it'd make.
That would be a 'fact' that you manufactured.
No, the load is only connected to the outputs of two chipamps.
Hi I'd like to upgrade the JRC NE5532D on my inexpensive Asus Xonar DS card.
Although I know my way around building computers from components, I'm a total beginner at modifying a card.
Apparently the opamp on this card is designed to be user-upgraded ... some people describe it as 'socketed'.
After research on various forums, it looks like some candidates would be:
LME49720, LME49723 and LME49725.
I need to understand which packaging I need. Can I use the 'narrow SOIC' 49720MA, 49723MA and 49725MA? I'm really not sure whether the NE5532D on my card is an SOIC-Narrow or an MDIP like LME49720NA.
I'm not up to any soldering, so is this just a drop-in replacement? Do I need any kind of adapter?
I may also want to consider an LT1358. If this is also a compatible part, can you please tell me which order part # is the right one?
Thanks a lot for helping a beginner! I tried to research this independently but I just don't have the necessary background.
Although I know my way around building computers from components, I'm a total beginner at modifying a card.
Apparently the opamp on this card is designed to be user-upgraded ... some people describe it as 'socketed'.
After research on various forums, it looks like some candidates would be:
LME49720, LME49723 and LME49725.
I need to understand which packaging I need. Can I use the 'narrow SOIC' 49720MA, 49723MA and 49725MA? I'm really not sure whether the NE5532D on my card is an SOIC-Narrow or an MDIP like LME49720NA.
I'm not up to any soldering, so is this just a drop-in replacement? Do I need any kind of adapter?
I may also want to consider an LT1358. If this is also a compatible part, can you please tell me which order part # is the right one?
Thanks a lot for helping a beginner! I tried to research this independently but I just don't have the necessary background.
The following bit of mostly wild speculation is actually a request for more information.
Nobody mentions JRC4580 and 4560 (stronger).
JRC has just released the Muse 02 and 02 type duals
specifically for audiophile applications.
Exactly my sentiments about your postings here
There's no firm dividing line between an opamp and a chipamp. Chipamps are just bigger, more powerful opamps, so principles of opamp decoupling apply just as well to them, only they have greater output current but in general lower GBW. So I brought the bridged chipamps into the discussion because you said 'always' the load goes to ground. This example is but one where the load does not go to ground, there are others, and I have already mentioned one other.
The simple reason that you don't get it is because you're not seeing the bigger picture, you're just assuming that the chipamp (X2 for bridged) is all there is to the application. Well no, that's not the case - this instance I'm referring to (a commercial product I designed) had more to it than just those bridged chipamps. There were other chips in that product that were using the ground, but still running from the same power supply. So the application wasn't just a single supply as you've been trying to maintain it was. Yes, the speaker load wasn't to ground, but other loads were. I can only suggest that you ask more questions rather than jumping to conclusions.
I'm not going to show you the schematics as I long ago left the company and they belong to the company, not to me. I no longer have access to them even though I could probably re-create them from memory.
Please explain as I can't follow your argument here. In particular, why if I don't cross connect the caps the current loop goes all the way back to the power supply? I know that wasn't the case with the product I'm speaking of as the power supply could be up to 100m distant.
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Dude, I don't care how many stages you where feeding with that supply! The discussion is about decoupling of just one OpAmp, why do you bring in the discution the preamp and whatnot you have there?
For the scope of this discussion - DECOUPLING OF OpAMP'S - the bridged chips are fed from a single supply (since their load is not connected to the middle zero potential) and you should decouple them as per SE power supply!
This was not what I was talking about and not what I said. I don't care to talk about straw man!
PS: I grew in a communist country too and I am well "educated" in this kind of derailments of an argument!
For the scope of this discussion - DECOUPLING OF OpAMP'S - the bridged chips are fed from a single supply (since their load is not connected to the middle zero potential) and you should decouple them as per SE power supply!
This was not what I was talking about and not what I said. I don't care to talk about straw man!
PS: I grew in a communist country too and I am well "educated" in this kind of derailments of an argument!
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All along in my perception decoupling's been a system thing not just about decoupling one opamp. And as for the alleged topic being just about one opamp - since when? Straw man.
Oh, at last we agree. Actually that was my point earlier on - that opamp decoupling should be dependent on the loading and where those load currents are going. It shouldn't be 'always two caps, each rail to ground'. So at last, some progress.
That "education" is evident from your postings - straw men and misunderstandings of other people's arguments all over the place. I'm used to dealing with them from online discussion so I have no problem torching them.
My statement in that particular post was about the OpAmps fed from dual PS (implying that the load is to the ground)! That was all.
You brought the bridged power amp in discussion and SE power supply - is that not straw man tactics?
PS: I know that red China is no different from other former red countries... don't need to show off. At least we are FORMER red.
You brought the bridged power amp in discussion and SE power supply - is that not straw man tactics?
PS: I know that red China is no different from other former red countries... don't need to show off. At least we are FORMER red.
That's the rub. You may have thought that having a dual PS implied that the load is to ground. Maybe you still even think so, but its clearly not the case.
Since you're asking, the answer is "no, that is not straw man tactics". A straw man is when a person makes a caricature of the other person's position - that caricature is called a 'straw man'. Your position appears to be that dual PS opamps must always be decoupled to ground. You maintain that a bridged opamp/chipamp is not really a dual supply at all. My position is 'it depends where the load current is going and whether a dual or single PS is in use isn't particularly relevant'.
Your claim above is partly true, but partly false. I did indeed bring in the bridge power amp, just as a counter example to your claim of 'always the load current goes to ground'. I have never introduced 'SE power supply' - that notion has come from you. So your introduction of 'SE power supply' here looks to be a red herring.
Your so called 'knowledge' here is both false and irrelevant. It is true that there have been many political tie-ups at various levels between the former USSR and China, but that doesn't make China 'no different' from those countries. However I've only lived in China for 5 years, I'm not native to this country. As for 'showing off' - where have I done that? I'm not concerned at all whether you pay any attention to my writings, I write purely for my own amusement here - that's why I don't care that you continue to disagree with my eminently reasonable position.
The terms of Dual Power Supply or Single Power Supply are (as for ALL the sources in the electric industry) in strict connection with the LOAD that they supply. That's the link - SUPPLY-CONSUMER.
What other small loads you choose to do supply with the power is not relevant.
So - a load that has a pin to a median voltage (called ground in most of the schematics, but it is not relevant) and the other fed alternative from two rails via your circuit (usually equal voltages above and below the median) means that the load it is fed by a DUAL power supply.
Easy to remember - THREE voltages feeding the load (alternatively of course) means dual PS.
A load that that has a pin to one of the PS (negative or positive one) and the other pin fed from the other rail (via your circuit) means that the load it is fed by a SINGLE power supply. TWO voltages means single PS.
A load that has the pins connected alternative to two rails (bridged circuit) means that that load is fed by a SINGLE power supply. The fact that you have a middle connection that does something else in the circuit doesn't matter. The way the LOAD is fed is from a Single Supply uses only TWO voltages - so it is single PS.
The load doesn't "see" the other median voltage that you insist to call "ground" and insist to count as a supply for that load.
What need to be bypassed with capacitors are exactly those supply circuits. So... a dual voltage PS needs TWO capacitors (one for each alternate rail, to the middle one, called usually ground).
A single voltage PS needs just ONE capacitor between that single voltage rails (one is usually called ground, but when, like in the case of bridged amps, other voltage is called ground, it doesn't change anything).
PS: The "ground" term it is confusing you. It is just a convention, people used to call positive terminal "ground", then negative one, then the 1/2 voltage... It doesn't have relevance for the relation supply-load.
What other small loads you choose to do supply with the power is not relevant.
So - a load that has a pin to a median voltage (called ground in most of the schematics, but it is not relevant) and the other fed alternative from two rails via your circuit (usually equal voltages above and below the median) means that the load it is fed by a DUAL power supply.
Easy to remember - THREE voltages feeding the load (alternatively of course) means dual PS.
A load that that has a pin to one of the PS (negative or positive one) and the other pin fed from the other rail (via your circuit) means that the load it is fed by a SINGLE power supply. TWO voltages means single PS.
A load that has the pins connected alternative to two rails (bridged circuit) means that that load is fed by a SINGLE power supply. The fact that you have a middle connection that does something else in the circuit doesn't matter. The way the LOAD is fed is from a Single Supply uses only TWO voltages - so it is single PS.
The load doesn't "see" the other median voltage that you insist to call "ground" and insist to count as a supply for that load.
What need to be bypassed with capacitors are exactly those supply circuits. So... a dual voltage PS needs TWO capacitors (one for each alternate rail, to the middle one, called usually ground).
A single voltage PS needs just ONE capacitor between that single voltage rails (one is usually called ground, but when, like in the case of bridged amps, other voltage is called ground, it doesn't change anything).
PS: The "ground" term it is confusing you. It is just a convention, people used to call positive terminal "ground", then negative one, then the 1/2 voltage... It doesn't have relevance for the relation supply-load.
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Couldn't really follow you there, but never mind.
Nope, the supplies don't need the bypass caps, the opamps do. That's a fundamental error in the way you're thinking. The supplies will already have caps in them - if they come from the mains via a transformer or an SMPSU.
It doesn't matter how many times a false statement is repeated, it remains false every time.
No confusion here, its just your imagination
Personally I have two papers that say that I understand OK the electrical circuits. There are called "electrical engineering diploma" and there are from two different countries.
And I guess that also all those engineers that wrote the papers that I linked above are stupid too, showing the decopling from each rail to the ground.
PS: Supply circuits is not equal with power supply. It is clear that you have a major problem in understanding those circuits, so I let you be.
And I guess that also all those engineers that wrote the papers that I linked above are stupid too, showing the decopling from each rail to the ground.
PS: Supply circuits is not equal with power supply. It is clear that you have a major problem in understanding those circuits, so I let you be.
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Do you mean 'exam certificates' ? They don't say that you 'understand OK' they just say that you satisfied the examiners with your answers to selected questions on particular days in the past. Significant difference.
Your guess would be based on false premises. I think I'd already read the paper by Brokaw you recently cited, he's by no means a stupid guy. As far as I recall those papers were not concerned with high-end audio, they were giving examples for high speed analog. But we've been here before, you didn't listen last time....
What's clear here is you conflate opinion with observation. If you were able to see clearly enough to observe my misunderstanding, why wouldn't you explain carefully where my understanding was broken? I shan't be 'leaving you be' in your misunderstandings - if I see them and can correct them I will. Its entirely possible that one day you'll be ready to listen
In the meantime others may be able to avoid your mistakes.