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Safety And Design of DIY originated Audio Products

Thomas savage

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I do appreciate the support but he's not here to defend himself so let's all move on. Personally I take any sanctioning action I have to take as a defeat.

I apologise to you all ( including mike) for allowing things to reach that point but I'm done protecting people from themselves.
 
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amirm

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There was something earlier on about lots of pots needing to be set or some such, but no discussion of why this circuit needs such a seemingly problematic setup; whether these settings are stable with temperature, etc.
Mike doesn't know what those pots do. He is buying those modules from Weiss which likely calibrates each module prior to release. They explain what the trimp pots do in their datasheet: http://www.weiss.ch/files/downloads/op1-bp/OP1-BP-Datasheet-R1.pdf

"6.4 DC Precision

There are three amplifier parameters which influence its DC precision at a given temperature: offset voltage, input bias current and input offset current. The offset voltage of the OP1-BP is trimmed to a very low value of typically ±10 µV with the amplifier fully warmed up. As the offset and drift contribution of the second amplifier stage have been kept low zeroing the amplifier offset voltage will also lead to very low offset voltage drift. As there is hence no need for further offst voltage trimming the according trimmer is sealed after adjustment to prevent inadverted readjustment."​

And

"Bias is factory set such that for output currents up to ±30 mA class A operation is ensured; the user can adjust the class A output current to values from about ±10 mA to ±50 mA by means of a trimmer (see section 6.3)."​

So seems like the first one does not need adjustment but the second one can be trimmed to trade off distortion and heat generated/current consumption.
 

NorthSky

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I just googled this morning: Intempéries, to track the situation of rain across the world.
In some parts rain is desperately needed (forest fires burning @ record levels), in other parts they have erosions, mountains' sides collapsing, volcanoes extinguished, Ireland is under rain, Sussex, England was under a chlorine cloud of some origin, Texas is under Harvey dropping intermittently buckets over buckets of water that you need a boat to drive around the streets in Houston. Houses are getting destroyed, picture albums, souvenirs, or by fires or by water...intempéries.

But the entry number nine brought me right here, @ ASR in this very thread, how come. It's not raining around the west coast, it's not raining in the Okanagan valley, it's more forest fires that people are fighting against. And it's rain that is much needed.

We live sometimes in an unbalanced world, and there is not much we can do about it...the natural elements, the emotional stress syndrome, the syndicate of audio laws. We can only defend and protect ourselves against too many fires burning and too much rain falling by playing safe. ...Building products that are on higher grounds, underground electrical wires, wireless communication systems using satellites and not earth towers, building walls between cities and forests...or fireguards, and by being preventive. If we don't invest in training, we will be experiencing casualties. It's a figure of speech, an important one.

It's rare that a product catch fire; it happened with some Onkyo receivers in the past, and with some Samsung androids in planes above 30,000 feet.
Just imagine a plane going down with all the passengers aboard because of a cell phone! Or a house burning down with all its occupants, including children, because of a poorly designed receiver. It's very rare, but it can happen and we all have read true stories (no fake news here) of poor safety designs.

Where do they make Samsung androids and tablets? And who was convicted recently to five years in jail?
Where do they make Onkyo products, and who bought them to join their ranks?

Those are only two brands here, and covering only a short period time about specific circumstances.
But, I can enumerate many other brands over the years with poor safety designs and malpractices, or deceptive tactics.
Do you want the names of those companies...like Sony, Lexicon, Panasonic, and on and on and on.
Where are those products made; America, China, Canada, UK, Japan, Korea, Phillipines, ...where and by who and in what working conditions and with what kind of business plan?

Intempéries are deadly for electronics. ...Dust too, air pollution, heat. Batteries can explode, capacitors can explode, fast processing chips can heat so fast that without heatsinks or fans they are vulnerable to the elements of unsafe protection; failures.

Be good with each other because in some other parts of the world it is much worst on how women and children are exploited by men of destruction/violence and unsafe practices. It leads nowhere but down, like hell, like billion flames of fire, like a downpour rain inundating everything in its path; destroying all electronics, electrical grids, insurance claims, warranty protections, basic food services, 911 support, human lives.

Yes, rain brought me right here in this very thread...strange isn't it. But it's raining over there too...in Texas, in Ireland, in the heart of children, men and women all across the four corners of our globe. People are crying everywhere, inside their heart and out. Making safe babies by designing them with care and love is the way to build better products in a better world. ...Taking care of people's health first is taking care of the air we breathe, the water we drink, the food we eat, the smoke we produce, ...the planet we all live in.

A balance of the natural elements is part of the human agenda in the year 2017 and beyond. ...In and out.
 

RayDunzl

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NorthSky

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Exactly (Koyaanisqatsi, with two "a"); a must see. It's in my Blu documentary library, of course:


Click on it ↑ for more info on this excellent Blu-ray trilogy from the Criterion Collection.
 
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amirm

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Earlier I was telling Mike about his mains wiring must not be so close to signal wiring. He kept saying his wiring is twisted and all is well.

As it turns out, I had to induce mains into a twisted-pair Ethernet cable and all I had to do was wrapping the mains wiring around the Ethernet cable to get this: http://www.audiosciencereview.com/f...o-en-60kds-ethernet-isolator.1869/#post-48753

index.php


The twisted cable in Ethernet is far better than the "hand job" that Mike has done here:

index.php


In the test I am running, I am trying to induce leakage through a DAC. In Mike's case, the induction will occur directly into analog output of the DAC -- a much easier situation.

Anyway, keep your AC lines away from signal lines if you are building such things.
 

Sal1950

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Wayne

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Build great products and you get my respect. Look at how my nearly 20 year old DAC (Mark Levinson No 36S) and how it rejects jitter compared to its modern counterparts in AVRs:

i-bs5DqCC.png

Found this to be most informative. Thanks
 

fitero

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Like many, I've been a lurker for quite some time. I decided to join the forum for this specific thread.
Just to add some perspective; the photos you have posted are not nearly as egregious as what I received from his company. I was one of the first customers to purchase a product from him. Though in the end, the DAC worked as described, I have never forgiven him for the shoddy, dangerous work that was sold to me. I rewired the whole thing prior to placing the DAC in service.

This is what I found upon opening the case up;
 

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Wombat

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Like many, I've been a lurker for quite some time. I decided to join the forum for this specific thread.
Just to add some perspective; the photos you have posted are not nearly as egregious as what I received from his company. I was one of the first customers to purchase a product from him. Though in the end, the DAC worked as described, I have never forgiven him for the shoddy, dangerous work that was sold to me. I rewired the whole thing prior to placing the DAC in service.

This is what I found upon opening the case up;

Welcome aboard.

The pics are a good summary.
 

Sal1950

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This is what I found upon opening the case up;
Soldering reminds me of the first Knight Kit I assembled back around 1960 or 61.
It also worked but had issues. :eek:
 
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amirm

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Let me add my welcome also Fitero. It is one thing when electronics engineers decide to freelance and build such gear. It is another matter when a person who has not been one tries to learn on the job.
 

Thomas savage

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Like many, I've been a lurker for quite some time. I decided to join the forum for this specific thread.
Just to add some perspective; the photos you have posted are not nearly as egregious as what I received from his company. I was one of the first customers to purchase a product from him. Though in the end, the DAC worked as described, I have never forgiven him for the shoddy, dangerous work that was sold to me. I rewired the whole thing prior to placing the DAC in service.

This is what I found upon opening the case up;
Jesus Christ :eek::eek::eek:
 

fitero

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Thank you for the kind welcome.

When the unit ultimately failed, I contacted him asking for support so that I could replace the malfunctioning board. I was met with another sales pitch, urging me to buy the much superior new product at a special low price, just for me, since I had been one of the first clients and all that. Yuck!

I didn't mention the drama related to the purchase; such as unprofessional delays, always blaming somebody else and never assuming responsibility, the lack of single-ended outputs as per email agreement, or the small things such as not powering up the led lighting circuit of the power switch.

He's now flogging his wares to a new set of gullible dopes such as myself on another forum. I hope that they are wiser than I, and can see through the dense barrage of dubious chatter this individual displays and buys elsewhere.
 

Thomas savage

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Thank you for the kind welcome.

When the unit ultimately failed, I contacted him asking for support so that I could replace the malfunctioning board. I was met with another sales pitch, urging me to buy the much superior new product at a special low price, just for me, since I had been one of the first clients and all that. Yuck!

I didn't mention the drama related to the purchase; such as unprofessional delays, always blaming somebody else and never assuming responsibility, the lack of single-ended outputs as per email agreement, or the small things such as not powering up the led lighting circuit of the power switch.

He's now flogging his wares to a new set of gullible dopes such as myself on another forum. I hope that they are wiser than I, and can see through the dense barrage of dubious chatter this individual displays and buys elsewhere.
 
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