Yes, I have brought up mode conversion before. The usual response is to use balanced interconnects, often implemented with op amps at both ends. Unfortunately op amps are not without their own complications. No free lunch.
Same as what I usually think when they do that, which is that they don't know everything about what can go wrong with people. They know what they memorized from medical school. It covers a lot of ground, but not everything possible. Also, doctors tend to be reluctant to say "I don't know." Most of them would rather say almost anything else, even if they know very well they are not being honest with the patient. Many of them also believe that if standard measurements look good, then any complaints must be all in the patients head. ...Hey, that reminds me of some other professionals I can think of too!
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And, balanced interconnects don't help with mode conversion from common mode to differential mode. The damage is already done. Plus, what is the CMRR of most balanced systems anyway, especially above the audio band?
Side note - It's funny how a drawing of all the current paths in a system can show how you can get into trouble pretty quickly. But, who ever even does that?
Side note - It's funny how a drawing of all the current paths in a system can show how you can get into trouble pretty quickly. But, who ever even does that?
Hi CG good to hear from you again! Thanks for posting the link to the General Semi doc that references my article in The Audio Amateur, I had forgotten about that GS doc. GS is only interested in showing data about their diodes, not how they interact with transformers, while it is important to include transformers and what they do with diodes for our equipment to have low RFI. Thanks too for posting the information on the current probes.
There is a reason that Walt Jung, John Curl, Richard Marsh and other no longer post information on this site like they once did, and the reason is the personal attacks to them. You would think that members here would want to learn from them, but some of them are more interesting in attacking them. When a small guy gets drunk in a bar and wants to get prove himself to the crowd, who does he pick a fight with, the biggest guy in the room.
It is s breath of fresh air to read your posts CG, but be prepared, an attack could be coming!
JmFahey, you have challenged me that I was not a real DIY member and you wanted to see information that proved I had contributed knowledge to advance audio equipment design. You should see by now that I am real and I have contributed. Because of your rude and inappropriate behavior along with your personal attacks to myself and others I will no longer be responding to any comment or post you make. You will be totally ignored by me from this point on. Goodbye.
Those two guys I know. Regarding most or all of what JC would like to pass onto others is contained in a compilation of writings John posted over the years. The collection was compiled by Dímitri Danyuk. Its about 150 pages long. If anyone would like a copy, I could post it somewhere.
Measurement of "stuff" on the lines is dangerous...and we have all blown the ground clip off an oscilloscope probe at one time or another!
How to measure power line impedance shows a safe method using isolated probe and current injector : https://www.omicron-lab.com/fileadm...Impedance/AppNote_PowerLineImpedance_V1.1.pdf
I’d be thrilled if that was all there was to it…
Cable design can affect sound on an enclosureless device with no connections to safety ground internally. On a device with a very lossy transformer, very low noise diodes, etc, plugged into a socket with a quality CMC on it. It can be a head scratcher.
The people that say “just use balanced” don’t do the financials, enclosure design, or tech support for a business, in an industry where a huge portion of the “balanced” connections are actually not. You have to account for that issue, and consider what it does. Lazy circuit designers for things like TV’s with headphone outputs presume too much since they are use to HDMI receiver chips that have essentially perfect CMNR for the application that’s digital, so when something that isn’t Class II is plugged in it dumps everything from the whole house right through it. In fact they’ve eliminated the output all together at this point. If you don’t think that can happen in a stereo with a phono stage despite using all XLR cables, you’re delusional/welcome to high end audio.
You don't need any help in explaining this, but I thought I'd add in a nice visual aid so that people can see what you're talking about.
Ott on Ground Loops
Figure 3-22 shows how common mode currents pass between pieces of an audio system. With direct coupling - not electromagnetic field coupling - the current always passes through a loop. Very basic stuff. I you want to stop that current, you need to break the loop. There's a couple suggestions in figures 3-23 and 3-24. But, you can also break the loop elsewhere, like right in the AC mains connections.
Of course it is not 'all there was to it'. But it is a mayor cause for hum, noise and perceived sound changes with power cables exchange, and for ground loops as a part of the same problem. Methods for breaking ground loops are well known, and most of DIY folks are using them.
I use ground loop breaker circuits in all my builds and that is a reason there was no noise increase, past internal audio components noise floors, with my measurements at post #107. I don't use any balanced connections.
I hope you are not mentioning some mystical sound change that can be only perceived by listening, but nothing can be measured with any instrument and method known to humanity. Coincidentally, in another thread with the same 'suspects' (me included 🙂), respectable research of Olive & Toole was mentioned:
"Have a look at the works of Olive & Toole. Not all differences in perceived sound quality are related to the stimulus that reached the ears of the participants in their studies. Hence my comments about psychology earlier.
For example: In sighted trials better looking equipment is judged to sound better. More expensive equipment is judged to sound better if the prices are known by the participants. Harman Kardon gear was perceived to sound better by Harman employees in sighted trials. Etc., etc. Harman used to make this research public, but removed it from their website some 10 years back, so you'll have to dig through the AES papers or Sean Olive's blog for the results."
I do listen very carefully to my audio equipment. However, I never forget that all we hear is conjured spatial illusion made up by our brain as an interpreter (‘Lost in translation’ movie comes to my mind).
So, for me to bring up any perceived change in sound as real, it must be solid and repeatable. If I hear something only here and there, my rule is to dismiss that as something I can claim is there, although I continue to suspect and search.
Funny to assume what I might think on something never mentioned by me and classify me as delusional. 😉
Nah, we were already there with magical power cables.
Listening to fine music while typing.
I came late to this thread after seeing the latest post on the front page of the web site, which I rarely visit. I hadn't read the entire thread thread until this morning, which is my bad.
Earlier on, there were some comments about rectification effects in amplifiers. I remembered some analysis on this subject performed by Analog Devices on their own parts several years ago, that they documented in some tech notes. Here they are:
RFI Rectification Concepts
In-Amp Input RFI Protection
If you want to believe what they wrote, fine. If not, fine, too.
Earlier on, there were some comments about rectification effects in amplifiers. I remembered some analysis on this subject performed by Analog Devices on their own parts several years ago, that they documented in some tech notes. Here they are:
RFI Rectification Concepts
In-Amp Input RFI Protection
If you want to believe what they wrote, fine. If not, fine, too.
That was a good post except maybe it would have been a little better without the words, delusional, and magical. (...know you didn't use delusional first).Funny to assume what I might think on something never mentioned by me and classify me as delusional. 😉
Nah, we were already there with magical power cables.
Listening to fine music while typing.
Other than that, several good points.
Curious though about your system. Maybe in a sense it is high end, better than standard off-the-shelf consumer stuff? At least it sounds like you fixed the ground loops...
Nothing was addressed to you, except this one post. Jeez.
It is just a very good system. No budget for Hi-end.
DAC – Gustard X-16
Preamplifier – Salas DCG3 with matched SK170 at input, dual mono Salas UBib shunt regulators and Muses 72323 volume control. BTW, it can direct drive 4 Ohm loudspeakers to listenable level. Initial build without Muses:
https://www.diyaudio.com/community/threads/salas-dcg3-preamp-line-headphone.296406/post-6324276
Amplifier – LuDEF with my own design of super regulators for power supply and my own input buffer for driving amplifier VAS transformer and OS. Initial build: https://www.diyaudio.com/community/threads/ludef.369990/post-6823298
Fyne Audio F501 loudspeakers + KEF KC62 subwoofer.
https://www.theabsolutesound.com/articles/fyne-audio-f501-loudspeaker/
It is not much but reproduction I get is simply amazing in details and soundstage. Loudspeakers don’t exist at all. Sound emanates only from positions on wide and deep stage that stretches behind loudspeakers and room walls.
This is off topic so we should stop at my post. 🙂
I believe that some people can hear un-measureable differences in things and other people cannot. Hundreds of years ago there was no test and measurement equipment, yet some people could tell if a musical note was sharp or flat. Later when audio frequency was able to be measured it was proven that the note was off frequency. Yet some people could hear this, they had an ability that most other people did not. I feel that people that must see a measured result to something that other people hear are simple unable to hear what others do. It seem that most of the people on this site are not able to hear differences, and they must see measurement to believe it. I do not have perfect pitch, but I can hear the differences in power cords. 🙂I hope you are not mentioning some mystical sound change that can be only perceived by listening, but nothing can be measured with any instrument and method known to humanity
Here is the problem: All physical differences should in-principle be 'measurable.' Thus, 'unmeasurable' is probably not the best way to describe it. "Typically not measured," or "as yet unmeasured, at least to my knowledge," etc., probably less likely to attract responses with the word 'magical' in them (which would be to imply non-physical characteristics have been claimed). Its that words like magical and delusional tend to promote increased polarization, something not necessarily helpful to a discussion.
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I agree with you Markw4, at least in this web site. I like "as of yet unmeasured". Like pitch was hundreds of years ago.
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