The Black Hole......

I would like to give some personal experience relating to mains pollution.
I have two Class A Monoblock's, each consuming 500Watt.
The mains lines have some circuitry to block DC from the Transformers, see figure 1 below.
Figure 2 shows the Mains voltage in red and the voltage over this circuit in blue.
And as can be seen, the mains is no longer sinus shaped but has a flat top, giving the huge secondary caps a bit more time to get charged.
Figure 3 shows the terrible spectrum of the voltage over the circuit in figure 1, all odd harmonics.

Every cycle the caps are getting charged, a voltage is induced in the power cord's PE line, causing that the PE on the Amp chassis differs in voltage from the mains socket.
Figure 4 shows how large this difference can be when switching on a remote lamp having a Triac dimmer in it's line chord polluting the mains, in this case as much as 400mV over the Amp's power chord's PE line can be measured, which gave a loud click from my speakers. Bill Whitlock even patented a power chord giving much less induction in the power chord's PE line.

In connection to my preamp over a balanced in connection, the induced voltage over the Main amp's power chord causes a a current to the preamp's chassis and over it's power chord to the PE's mains socket.
Looking at the preamps power supply, I got the spectrum in figure 5.
However when disconnecting pin 1 on the receiver side, thereby creating a OneEndOnly or OEO connection, complete cleaned the power supply as can be seen in figure 6 and the click when switching on the lamp was no longer there.

After having changed all my equipment to OEO, I borrowed an expensive Shunyata power conditioner in combination with very expensive powercords to connect to my audio gear.
Result ? I could not hear the slightest difference in sound on my ELS63's.

That's why I favour balanced OEO connections wherever possible, making suppression of mains pollution and whatever cause a thing of the past.

Hans
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When I neglect my HP35, in a certain way my first computer was
a Telefunken TR4. It had a previous live @ the army and operators
from 9 to 5. In the remaining time, some trusted EE students were
allowed to run it as they liked. I wrote a macro cross assembler for 8080
and my really first own computer was an 8080 on Eurocards.
Then I studied CS on top of EE, built a Z80, ported CP/M to it
and then designed a 16 bit stack machine in HP's full custom
dynamic n-MOS. Stack machines like UCSD or Tanenbaum's
Experimental Machine were a big thing at that time.

I also tried to port Fortran Spice 2G6 to my 10 MHz 286 running
Interactive Unix. It quickly showed that f2c was not up to that task.
-----

< TR-4 inhalt >

Gerhard
 
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Yes, "difference" and "audible difference" are exactly the same.
To you perhaps. There are measurable differences, visual differences, interface differences... etc. Like I explained, your problem is the language barrier.

Otherwise you should write
Just to suit your taste? There is a possibility that I may consider it if you use the magic word, "please".
 
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Anyone else here ever used a vacuum tube computer?

Bendix G-15

Later a CDC 6600 (all discrete and tunnel diodes).

Then working in a vertically integrated company that had semi ovens in the basement, PCB, Chassis and Monitor assembly on the main floor and cutting rubylith on the top floor. Building computers that looked a lot like early versions of a PC.

Then I escaped that really boring world for Audio. Maybe I should have stayed. Some of my compatriots went on to early stage Apple. They did much better financially.
 
To you perhaps. There are measurable differences, visual differences, interface differences... etc. Like I explained, your problem is the language barrier.


Just to suit your taste? There is a possibility that I may consider it if you use the magic word, "please".

I am not English mother tongue but I am not stupid either.

When you write "double blind listening test" and "audible difference" you are referring to what we ear and not to what we see.
There is no "audible difference" in measurements, visual aspects and interface.

Are you confused about how the senses work?
 
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Hans,

Thank you for that, I found it interesting. Waiting to see if there is any other reaction from thread participants.


Whitlock proposes something similar, but with a capacitor at the remote end. The Neutrik EMC range effectively implement this albeit with pin 1 via an inductor.



JN will be along in a minute to tell us how they do it when measuring femtovolts in the presence of kA flowing around.
 
Bendix G-15

Later a CDC 6600 (all discrete and tunnel diodes).

Then working in a vertically integrated company that had semi ovens in the basement, PCB, Chassis and Monitor assembly on the main floor and cutting rubylith on the top floor. Building computers that looked a lot like early versions of a PC.

Then I escaped that really boring world for Audio. Maybe I should have stayed. Some of my compatriots went on to early stage Apple. They did much better financially.

In my opinion you did the right choice, money isn't everything.

The IT world is depressing, I have just restarted my Windows machine because the OS did freeze.
In Redmond they still haven't been able to handle a keyboard interrupt and to isolate the processes (especially the GUI thread).
I would advise them to ask the Rochester folks.
 
Moreover, maybe they have read the ASR review of the MSB DAC and the measurements are not so spectacular.

Although I have never listened to the MSB digital chain I'm confident it sounds very well.

What review? I searched the archives twice and found nothing but a copy of Stereophile's graphs.

The second comment is hilarious, sort of like "It's class A with no feedback so I'm sure it sounds better." I don't even have to listen to determine that.
 
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You probably did not collide with FORTH.

I'm a C/C++ guy. Used to do a bit of assembler (Z80/8080 and a bit on some of the ST micros) but have gone over completely to ARM now using the mbed platform which I really recommend. The jump from 8 bit to 32 bit machines is fantastic. I understand why folks like the Arduino, but on the ARM devices, just about any pin can be set as an interrupt, you have some seriously good peripheral integrated onto the devices (BT, Ethernet, 12 bit A-D & DAC's etc).

My youngest has gone down the Python route . . . hopefully he will find work since the area he was in has ground to a halt since the pandemic struck.
 
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One of the problems of making excellent line regenerators is: audiophiles connect audio power amplifiers to them!

Audio power amplifiers usually have a large power transformer, some rectifier diodes, and a capacitor bank.

To minimize voltage ripple on the DC power supplies, audiophile power amplifiers employ a LARGE capacitor bank having many many microfarads of capacitance.

UNfortunately, with large capacitance and low ripple, the power transformer and the rectifiers must supply ALL of the necessary coulombs of electrical charge, in a very brief & very narrow pulse. Some books talk about the narrowness of this current pulse using the terminology "conduction angle".

To supply the necessary load current in a narrower and narrower pulse of current, you gotta make that pulse taller and taller. Where do these super tall current pulses come from? From the rectifiers, and from the power transformer secondary. Which means there are identical current pulses (multiplied by the transformer turns-ratio) flowing in the transformer primary. Which means there are identical current pulses sucked out of the line regenerator. Fifty or a hundred amps tall. Ouch!!

Hook up an enormous macho power amplifier with 200,000 microfarads of filter capacitance, to a line regenerator, and then play it at maximum volume. It's a torture test of the regenerator.

I never understood why folks connected these huge cap banks to the output of the transformer rectifier. If you design for say 1V ripple at full load and let the amp PSRR do its job, you have a better design balance. I did a dealer show about 3 yrs ago and one of the brands (Swiss based) boasted about 500 000uF cap bank on a 140 Watt per channel amp. The thing was the size of a large microwave.
 
What review? I searched the archives twice and found nothing but a copy of Stereophile's graphs.

The second comment is hilarious, sort of like "It's class A with no feedback so I'm sure it sounds better." I don't even have to listen to determine that.

Yes, it's a copy of the "Impressively unpossible" Stereophile measurements.

The second comments is based on MSB's design choices I have listed.
Since we are following similar architecture for our DAC design I think there are the conditions for it to sound fine.
We don't know what performance we will achieve, however some choices had to be made before starting the project. So we agree on most of MSB's design choices, while we don't like PWM DAC designs.

Obviously a listening session would provide the feedback to see if I was too confident.

Finally, even more hilarious, I would add single ended to class A with no feedback.
 
Why do you keep calling them PWM?

I saw that picture of the MSB board, lots of 8-legs in there. I hope they know the LT1115 is the same die as the LT1028 but at a lower price (for the audiophiles of course).

Because I like to call PWM all noise generators, however from now on I will call them delta sigma even if the result does not change.

What picture are you pointing out, can you provide a link?
 
Then ask other forum members who are English mother tongue if "difference" and "audible difference" are exactly the same when comparing DACs. Go ahead, ask via private message or openly and see what they say.

Since you listen to a DAC rather than watch it the only possible difference is the "audible" one.
So when I write "difference" by definition I mean "audible difference".

But since you keep climbing on mirrors I quote again your claim: "Every level matched double blind listening test I've read about show no audible difference between expensive and cheap contemporary DACs".

This means that you can buy indifferently a 47 Euro DAC or a 100k USD DAC because the sonic result is the same ("no audible difference between").

I wonder if you have ever listened to a dac or if you spend your life reading the measurement graphs so you have no more time for listening.
 
Whitlock proposes something similar, but with a capacitor at the remote end. The Neutrik EMC range effectively implement this albeit with pin 1 via an inductor.

Yes Bill, but this means that you will have to modify your cabling.
When I'm correct, Neutrik and Whitlock had the same goal in mind to isolate DC and LF, just as with OEO preventing ground loops, but to have a HF connection from shield and pin1 to mains gnd on the receiving side.
When you are not living next to an extremely powerful radio station, I see no benefit.

That's why I have successfully connected my equipment as in the figure below.

Hans
 

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JN will be along in a minute to tell us how they do it when measuring femtovolts in the presence of kA flowing around.
Nah, he won't.

Han's measurements are interesting. 400 mV of haversine on the PE, it is certainly dependent on the measurement loop arrangement, and the other devices will of course see similar loop coupling.. I assume that there is no neutral current on the PE and it is all magnetic coupling. I have seen in the past some house wiring where a subpanel had PE and neutral tied together such that neutral currents flowed on the PE. Against code of course, but many DIYers do not know that the neutral to PE bond must be disconnected on a sub panel.

When troubleshooting a system for current induced signals, it must be remembered that line haversine current coupling on the primary side is odd order harmonics, whereas everything on the secondary side is even order harmonics.

Some line cords are not designed to zero the hot/neutral induction to the PE, some are, some by accident.

Oh, ps...don't forget, these haversine currents are modulated by the audio signal power draw, some systems will be quiet with no music, yet will couple odd harmonics of 60 hz when playing loud. Class A excepted, it would see the odds all the time and annoy the listener during quiet passages.

jn
 
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