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Review and Measurements of Totaldac d1-six DAC

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amirm

amirm

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It doesn't need to be a special one, like for medical purpose. If you buy from Radioshark, find one where primary and secondary windings have separate spools, or at least there is a shield between windings.
No. All of the transformers sold for this purpose have the safety ground on the input tied to the output. This is for UL/safety reasons. As such, none of them provide isolation as you are imagining, including those that say "medical." You would have to get one and modify it to provide true isolation and with it, loose protection of safety ground.

There was a reason I asked you the question ;). So please don't keep saying to use one of these transformers. It would do nothing to change this situation.
 
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I was only just hoping you'd say you could control the variables well enough we could reliably draw conclusions from your data about these effects. Too bad we can't. That would have been nice.
That is 100% the case. In the case of unbalanced interconnects where such ground loops are likely, then I try a number of techniques to reduce their impact. And report on the same in the review as to whether it made a difference or not. I do this with full instrumentation and therefor with high confidence. The AP by the way, has floating RCA inputs so often actually grounding things makes the situation worse.

When mains leakage is high, I examine to see if it is impacting SINAD for example. Or SNR. And again, comment as such when this is the case.

See this example:

The dac1421 has an internal switching power supply fed by a two-pronged cord. The case as such is "floating." Teardown will come in a future article. The issue and one that is not unique to the dac1421 is that its case can start to float up causing ground differentials. This shows up in the spike that you see at 60 Hz. There is a 50 ohm resistor between the chassis and signal ground. When I bypassed this with a jumper, it made a significant reduction in mains leakage. Søren says he is not seeing any of this in his testing. Unfortunately the vagaries of unbalanced audio interconnects and grounding in consumer audio is that it is perfectly possible for the two scenarios to exist. Søren is considering lowering the value of that resistor.

So when I don't comment on this situation, it absolutely means that it is not a concern in the rest of the measurements. That is the case for this review.

So to summarize:

1. Mains leakage for a number of reasons can show up in FFT spectrum display.

2. If it is significant and impacts other measurements, I note it. And take measures to minimize it.

3. If I don't make a big deal out of it, then it is not a big deal.

4. My testing is quite standardized and consists of same cables, same instrument, same test project file, etc. They have been refined after some 200 reviews. They absolutely convey an apples to apples comparisons of one product versus another. If they do not, I invite manufacturers to provide their own measurements to the contrary. None have so far.

5. I am not the QA or certification shop for any equipment. My work is not about extensive, 100 point tests. I test enough until a clear picture of the equipment's performance materializes.
 

KMN

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That is 100% the case. In the case of unbalanced interconnects where such ground loops are likely, then I try a number of techniques to reduce their impact. And report on the same in the review as to whether it made a difference or not. I do this with full instrumentation and therefor with high confidence. The AP by the way, has floating RCA inputs so often actually grounding things makes the situation worse.

When mains leakage is high, I examine to see if it is impacting SINAD for example. Or SNR. And again, comment as such when this is the case.

See this example:



So when I don't comment on this situation, it absolutely means that it is not a concern in the rest of the measurements. That is the case for this review.

So to summarize:

1. Mains leakage for a number of reasons can show up in FFT spectrum display.

2. If it is significant and impacts other measurements, I note it. And take measures to minimize it.

3. If I don't make a big deal out of it, then it is not a big deal.

4. My testing is quite standardized and consists of same cables, same instrument, same test project file, etc. They have been refined after some 200 reviews. They absolutely convey an apples to apples comparisons of one product versus another. If they do not, I invite manufacturers to provide their own measurements to the contrary. None have so far.

5. I am not the QA or certification shop for any equipment. My work is not about extensive, 100 point tests. I test enough until a clear picture of the equipment's performance materializes.

Thank you for explaining. It helps me understand more clearly how much thought you have put into it. Again apologies for being overcritical if that's how I'm coming across. In reality I'm in awe about this site and haven't been able to get enough since I discovered it...and bro you do phono preamp testing. I have this weird and irrational soft spot for these things. Thank you for all of it and taking the time to be cool and explain to a noob and best regards.
 

solderdude

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I do appreciate the safety ratings and whatnot, but personally I would find plots of the scans , of my gear, from the sorts of equipment generally required to perform that sort of testing, fascinating if that data were made available to me. Not a requirement or anything but I'd certainly look it over. Why not?

Well some manufacturers actually can supply EMC test data on request. Especially the larger companies that also sell professional equipment that
are fearing ending up in court over something as simple as emission.
You would have to be pretty into these measurements to make heads or tails from these plots and their consequences.
You would have to have handbooks present of norms used to understand what the the test conditions actually were.

Designing to pass for EMC immunity and emission and ESD immunity requires special ways of layout on PCB's, screening and requiring well screened cables and filtering. Sometimes usage of 'non audiophile' components in audiopaths if you want to adhere to the stricktest rules.
Having those tests done is very expensive. The more physical inputs and outputs one has the more time consuming and expensive those tests are.

I have to design that way and test it (to stricter rules as home equipment) and know what challenges and pitfalls lie ahead. When a designer is experienced in these matters it isn't that difficult to make something that passes on the first test.
I seriously doubt that many of the 'high-end' and esotreric stuff would ever pass such testing.
 
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sajunky

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No. All of the transformers sold for this purpose have the safety ground on the input tied to the output. This is for UL/safety reasons. As such, none of them provide isolation as you are imagining, including those that say "medical." You would have to get one and modify it to provide true isolation and with it, loose protection of safety ground.

There was a reason I asked you the question ;). So please don't keep saying to use one of these transformers. It would do nothing to change this situation.
So, they are not isolating at all and UL prevents from doing that? Interesting. We have perhaps better safety regulation or Wikipedia is wrong. If I were nasty, I would ask for a proof, but I leave alone, as it is not my business.
 
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amirm

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So, they are not isolating at all and UL prevents from doing that? Interesting. We have perhaps better safety regulation or Wikipedia is wrong. If I were nasty, I would ask for a proof, but I leave alone, as it is not my business.
It is a "trap for young players" as my favorite electronics blogger, Dave Jones would say. :) Read the reviews of these isolation transformers on Amazon and you invariably find someone pointing this out. There are a number of excellent videos online on this issue and dangers within.

Best of them is from my favorite electronics repairman from Canada, "Mr. Carlson's Lab:"


Watch from 1:30. It only takes him 3 minutes to explain this.

You can modify them to not have this grounding but then you are taking chances with the case energizing and not being grounded anymore.
 

sajunky

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You can modify them to not have this grounding but then you are taking chances with the case energizing and not being grounded anymore.
You are definitely missing a point of windings on separate spools or shielding in isolation transformers, as you are trying to shift discussion to other things like grounding.

You obviously don't need such ground, as in every system you should have a single ground, but it is a separate issue from isolation. As it looks like from the tone you are entering entertaining stage, aiming to prove that there are no isolation transformers, I will leave you alone. Speak to yourself.
 

Thomas savage

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Sassy-Queen-With-Crown-Filled-Machine-Embroidery-Design-Digitized-Pattern-700x700.jpg
 
OP
amirm

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You are definitely missing a point of windings on separate spools or shielding in isolation transformers, as you are trying to shift discussion to other things like grounding.
You either didn't watch that video, or didn't understand his explanation.

You obviously don't need such ground, as in every system you should have a single ground, but it is a separate issue from isolation. As it looks like from the tone you are entering entertaining stage, aiming to prove that there are no isolation transformers, I will leave you alone. Speak to yourself.
I don't think you know a (safety) ground from fertilizer with that comment.

There are isolation transformers. But what you thought you can go and buy from Radio Shack doesn't exist. Actually Radio Shack doesn't exist anymore but that is beside the point. :D

As to your final jab, I bid you goodbye. Find another forum where you can be disrespectful to the host this way.
 

Thomas savage

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You either didn't watch that video, or didn't understand his explanation.


I don't think you know a (safety) ground from fertilizer with that comment.

There are isolation transformers. But what you thought you can go and buy from Radio Shack doesn't exist. Actually Radio Shack doesn't exist anymore but that is beside the point. :D

As to your final jab, I bid you goodbye. Find another forum where you can be disrespectful to the host this way.
 

solderdude

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solderdude

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Yes, it is wonderful isn't it ?
There are no words to describe this beauty of a square-wave.
It sounds marvelous too and can hear all harmonics nicely spread over the entire audible range.
The undoubtably very high SINAD value, I can read from this plot, will put it right up there in the SINAD chart.

As Lavorgna so beautifully worded: (some words may have been altered somewhat)

"The totaldac D1-seven offers an uncanny ability to convey the squarewave’s most intimate details in a total package of stunning realism. In other words, squarewaves sound like they sound in real life—all rich, glorious, intimate, and stunning. What’s more, music unfolds into a sound image that is Barn-filling, of course this is recording-dependent, in such a way as to invite us into the performance, outside space and time (that’s a big deal)." Michael Lavorgna, twitteringmachines.com

"Here are my first impressions: Wow
The d1-seven is by far one of the most stunning DACs I've had the pleasure to hear my squarewaves through.
The totaldac d1-seven excels at reproducing squarewaves's life, energy, and delicate nuance.
Once seated, there's a lock-in into the space and time of the recording that is at once addictive and entrancing.
Every aspect of a squarewave, risetime, texture, color, meaning- are conveyed with an uncanny realness.
Come to think of it, rightness may be the better word.
If you want to hear your file-based squarewave at its best, at the peak of its acoustic power, I recommend the totaldac d1-seven as your guide." Michael Lavorgna, AUDIOSTREAM
 

graz_lag

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I would have no problem to become a fan of Matej Isak, Publisher-Editor in Chief-Founder-Owner, of Mono&Stereo.com - if he just would go thru some kind of deep plastic surgery and sex change from this:

Matej Isak.jpg


To this:

Naomi_Campbell_1997.jpg
 

Dialectic

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After this review was posted, now-former audio reviewer Michael Lavorgna, who had been a major proponent of TotalDac products, posted a number of "jokes" on YouTube and Instagram that clearly targeted this forum. Soon thereafter, those jokes disappeared from those platforms, and Mr. Lavorgna announced that he was retiring from audio.

While I thought it likely that he retired for a typical reason, such as family commitments or health issues, I wondered whether he retired because of this forum. Here is a post by a friend of his that all but confirms that he left the high-end scene because of this forum--probably this very thread.
 
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JJB70

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If ASR contributed to Michael Lavorgna throwing in the towel I will need to donate more to the site :p:D
Seriously, how anyone can blame measurement and objective opinions of a sh*t product for being villains rather than a shill reviewer encouraging the gullible and deluded to spend over 10,000 euros on said sh*t just beggars belief.
 

Dialectic

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If ASR contributed to Michael Lavorgna throwing in the towel I will need to donate more to the site :p:D
Seriously, how anyone can blame measurement and objective opinions of a sh*t product for being villains rather than a shill reviewer encouraging the gullible and deluded to spend over 10,000 euros on said sh*t just beggars belief.
Not sure how I feel about his "quitting" audio. I think it would be better if the information here convinced the hardcore subjectivists to take a more rational approach to the hobby.

But I'm glad he's not out there continuing to misguide others with his reviews.
 
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