What the audio and instrumentation world needs is a ground post made of matter from a black hole.
MikeBettinger said:
There is only one reference, Mike. A middle point between capacitors. The same potential has a middle point between windings. If you connect this points together there will be still only one reference point: right in the middle of the wire between capacitors.
5 milli-Henries? Do you use inductors intended for speaker crossover networks? How do you keep the external field from coupling to, well, pretty much everything? Do you add resistive damping to minimize the inevitable resonances from such a physically large coil?
How about powdered iron core toroidal inductors for this application?
Whew - that's more questions that even my third grade teacher would allow at one time...
PMA said:
Exactly. The plain physics: wires have inductance and resistance. Even short and thick wired do have. The lower pulsations of a voltage you get on your 1'st filtering cap, the higher are charging peaks, the higher are diode discharging peaks. The higher will be voltage drop on the peace of wire through which the charging current flows. But the middle point between caps will be always a middle point, so if you take it for the null it will be a null. Zero. When you lower ripples either by additional LC or RC filtering, this point connected to the point of the second pair of capacitors no logger is a reference point. The point between last filter capacitors is the null, thee zero, the Earth now. This point should be grounded, and in respect to this point power supply rails have thi minimal dynamic resistance and the minimal level of ripples. Now, from this point, start your "Star Ground".
Also, if a wire through which charging current flows is close and parallel to another one, it will act as a transformer.
Wavebourn said:
Technically we're saying the same thing so I won't belabor this. My point was that the loop for the charging currents and filtering started and ended at the individual secondary winding that was being utilized during the phase of the ac waveform that forward biased the rectifier.
Mike
The bridge is the bridge; in both cases the same charging current flows through both capacitors connected in series. If capacitors are equal, both halves of the secondary are identical, there will be no difference if the middle point of the transformer secondary grounded or not; but as soon as there are some variations the current flows through it: the bigger are differences between halves of secondary and between capacitors, the higher will be currents between both centers.
However, when I need a bi-polar source, I connect the center tap.
However, when I need a bi-polar source, I connect the center tap.
Wavebourn said:
I'm going to stop now because I find this to be different and my current probe concurs, your understand is valid and works for you. Which way is better sonically and stabilitywise is more in question.
I will say one last thing (feel free as well). What messes up some attempts to measure this is placing the current probe around the single center-tap wire coming out of a transformer as opposed to measuring the individual secondary returns. This paints a different picture.
Both approaches are functional so let's leave it at that.
Mike.
I've haven't figured out how to edit a post.
I am only talking about bypolar supplies. I mentioned that in one of my responses to John and this only makes sense in that framework.
Mike.
MikeBettinger said:
Sure. Because in the first case you measure the whole current, the second time you measure the differences only.
MikeBettinger said:
Me too, about a bipolar supply. But when idle, no different currents drawn. Like, physicists say, "Let's start to review this horse related problem from the ball-shaped horse in the vacuum". However, when different currents are drawn from rails (and they are), the picture will be more complex, and different load currents will cause different current spikes on the center tap that goes to the ground. So, if it is connected to the wrong place, of course there will be a voltage drop on that peace of conductor between the center tap and the ground.
Has anyone actually seen or heard one of these blowtorch pre-amps ??
How do we know it's any good apart from the claims made by its designer ??
How do we know it's any good apart from the claims made by its designer ??
john curl said:
Yes I agree to this reasoning, but let's try to take it a step at the time. The only thing we as designers of our equipment have under control is this grounding stuff in our piece of electronics. And I do believe that proper ground routing and implementation can make it a non-issue in the local area of a single equipment, using topologies as shown by Mike above.
I always found it much easier to comprehend these things by drawing the supply circuit, for example, and replacing all direct wires with impedances. Great eye-opener!
Then to interconnect different pieces of equipment there's no better alternative than balanced lines of course. I just found out that Neutrik came out with an RF-supression XLR (the 'EMC-XLR') which has internally in the shell supression caps and a some other stuff to avoid even the very small ground loops inside the connector shell that are significant for RF injection.
Sorry for the tangent; as I said, let's tackle one issue at the time. Even one thread a day will give you a complete shirt after a few months 😉
Jan Didden
Re: Re: Re: Ouput Trannies
(Second reply)
Hi Arthur,
According to Scott the MAT02 trannies are far too large.
(see: http://www.diyaudio.com/forums/showthread.php?postid=1821653#post1821653)
In the mean time I've replaced them with smaller ones (partly derived from the MAT04). Now the AC behavior is more in line with ADI's own model.
I'll send you a MicroCap .mac file for all the details.
Regards,
Edmond.
PHEONIX said:
(Second reply)
Hi Arthur,
According to Scott the MAT02 trannies are far too large.
(see: http://www.diyaudio.com/forums/showthread.php?postid=1821653#post1821653)
In the mean time I've replaced them with smaller ones (partly derived from the MAT04). Now the AC behavior is more in line with ADI's own model.
I'll send you a MicroCap .mac file for all the details.
Regards,
Edmond.
That's the problem with models!
Still, they can be useful, but I don't count on them, since I have solderless breadboards that can tell me about as much, with about the same amount of effort.
With regards to the comment about the Blowtorch. Most here will never hear a Blowtorch, nor should it be necessary for them to do so. Only 40 or so were ever made, and are spread throughout the world, usually owned by very wealthy people, who can also afford the same quality added components necessary for useful listening quality.
I have never driven a Porsche 959, but I can well imagine what it might drive like. I don't ever have to see one to understand its conception and performance.
Still, they can be useful, but I don't count on them, since I have solderless breadboards that can tell me about as much, with about the same amount of effort. With regards to the comment about the Blowtorch. Most here will never hear a Blowtorch, nor should it be necessary for them to do so. Only 40 or so were ever made, and are spread throughout the world, usually owned by very wealthy people, who can also afford the same quality added components necessary for useful listening quality.
I have never driven a Porsche 959, but I can well imagine what it might drive like. I don't ever have to see one to understand its conception and performance.
john curl said:That's the problem with models!
You're right. The way I did it was rather time consuming and it's not very accurate either. Why don't ADI give us better models, i.e. on the device level? But I can't afford (and don't like) any mistakes. To be on the safe side, I first do a simulation before going through the whole process of PCB artwork, building, testing etc.
/OT
A Porsche 959... very impressive. Do you dare to drive such a car? Handling 450HP without special training isn't that easy, not to say dangerous.
BTW, the 959 wasn't street-legal in the U.S.
Cheers,
Edmond.
I'm pretty sure that I could handle a 759, if I had the chance to drive one, but so what? I don't deny the quality of the execution of the design and its results, yet I have never driven one. It is the same with the BLOWTORCH. It has been owned and reviewed by enough people to know what it does, compared to other products, and some other products are just as good, I would presume.
959
Please, don't misunderstand me. I'm not saying you can't drive a 595, I'm only frightened by 450HP.
Please, don't misunderstand me. I'm not saying you can't drive a 595, I'm only frightened by 450HP.
My friend Jack Bybee drives a car with 651 HP, but it is well behaved on the streets. I hope to drive it, one of these days.
john curl said:
I am totally satisfied by a half of this power.
8 pots, 5.6l total.
FlyBTR registration number (Flying Armored Troop Carrier, Russian vehicle called BTR). However, it was made by Samurais.
I was offered the opportunity to drive a Porsche Carrera GT. I was interested, but with the owner next to me, knowing that the belly pan was $25K and that my last similar drive was a Ferrari Dino 20 years earlier, I passed on it (a risk-reward ratio calculation). Fortunately he was driving when he scraped that $20K pan on a driveway. Quite the experience to ride but not something i want to drive right now.
Optimizing the grounding in a component can really only be done in the context of the rest of the system. E.G., ideal grounding of the circuit to the shield should be at the lowest level point in the system. That would be at the phono cartridge in a phono preamp. However its not possible in any phono environment I know of, its not supported in the tonearms and may have hum problems if the shield doesn't include a shield between primary and secondary on the power transformers. You must look beyond your box to the environment its in.
Optimizing the grounding in a component can really only be done in the context of the rest of the system. E.G., ideal grounding of the circuit to the shield should be at the lowest level point in the system. That would be at the phono cartridge in a phono preamp. However its not possible in any phono environment I know of, its not supported in the tonearms and may have hum problems if the shield doesn't include a shield between primary and secondary on the power transformers. You must look beyond your box to the environment its in.
- Status
- Not open for further replies.