Safety And Design of DIY originated Audio Products

[Mivera]

We figured that much so far.

Do those numbers look as good or worse than the numbers you listed for the parts?

The numbers on the parts are what contribute to the excellence in the sound department. However the outdated gear you have will only tell you it's an excellent design, not the superb design that it is.

 

[Mivera]

Well I thought they valued helping your credibility. Seems like they don't value that either.

No my products have already verified my credibility.

 

[Mivera]

While you're on a roll, here's some more pictures you can bash:

 

[March Audio]

No because anyone who has enough knowledge to know what matters, will understand the build is excellent. I like knowledgable people, just not forum educated numbers mongers. So my products are for music listeners, or professionals only.

...mmmm...

So you will like all the questions posed here by knowledgeable professionals who know what matters.

 

[Mivera]

...mmmm...

So you will like all the questions posed here by knowledgeable professionals who know what matters.

Sorry seems those are few and far between around here. Where's Daniel Weiss, Nelson Pass, Dustin Foreman etc?

 

[March Audio]

Hey Mike, What are all the pots for trimming on those boards?

 

[Cosmik]

I built a soft start circuit into a power amp I once built that used a large toroidal transformer. People may not know just how high tech (not) such a thing is: when you apply mains power using a soft start circuit, it reaches the toroidal transformer through some power resistors, limiting the inrush current. After a delay, the device shorts out the resistors with a relay. It works, but it is only necessary for high power applications based on larger toroidal transformers that would otherwise keep popping circuit breakers or fuses.

By the look of it, the soft start module used here has its own small linear power supply based on yet another transformer - so by using it, you are placing one of those in the middle of the box. If it's not necessary, why introduce all that extra magnetic flux leakage, etc. into the box?

I have seen series inductive mains filters send an SMPS into self-destructive oscillation (and everything attached to it). So I wouldn't mess about with stuff on the input to an SMPS.

Me, I'd use an external wall-wart and with filtering and linear regulation in the box. Playing about with mains power supplies turns a nice hobby or potential cottage industry into a nightmare of regulations, hum loops and sleepless nights (if you have any imagination regarding what could go wrong).

 

[Mivera]

Hey Mike, What are all the pots for trimming on those boards?

They're for idle current and DC trimming.

 

[Mivera]

I built a soft start circuit into a power amp I once built that used a large toroidal transformer. People may not know just how high tech (not) such a thing is: when you apply mains power using a soft start circuit, it reaches the toroidal transformer through some power resistors, limiting the inrush current. After a delay, the device shorts out the resistors with a relay. It works, but it is only necessary for high power applications based on larger toroidal transformers that would otherwise keep popping circuit breakers or fuses.

By the look of it, the soft start module used here has its own small linear power supply based on yet another transformer - so by using it, you are placing one of those in the middle of the box. If it's not necessary, why introduce all that extra magnetic flux leakage, etc. into the box?

I have seen series inductive mains filters send an SMPS into self-destructive oscillation (and everything attached to it). So I wouldn't mess about with stuff on the input to an SMPS.

Me, I'd use an external wall-wart and with filtering and linear regulation in the box. Playing about with mains power supplies turns a nice hobby or potential cottage industry into a nightmare of regulations, hum loops and sleepless nights (if you have any imagination regarding what could go wrong).

The EMI from that tiny transformer is so low it's a non issue. 1000x less than any Toroidal transformer you find in the DAC's Amir shared as examples of excellence. That's a very well made softstart, and uses a very high quality gold plated silver contact relay. It's a better way to switch power on and off than a mechanical switch.

All of the caveats you describe aren't an issue with the Purestream. I have a client who has massive horns that are 109dB/1W efficiency. Combined with my Preamp, he can turn to max and put his ear in the horn and it sounds like it's off.

Once we get better than 120dB SNR, I don't think noise is an issue anymore.

 

[Blumlein 88]

No because anyone who has enough knowledge to know what matters, will understand the build is excellent. I like knowledgable people, just not forum educated numbers mongers. So my products are for music listeners, or professionals only.

This series of replies is simply retarded on your part. You put component numbers for pros who know the difference, but not to mislead those who don't because you want only customers who listen, and won't put actual finished output measures because it would confuse people. Bollocks!.

 

[Mivera]

This series of replies is simply retarded on your part. You put component numbers for pros who know the difference, but not to mislead those who don't because you want only customers who listen, and won't put actual finished output measures because it would confuse people. Bollocks!.

You see my main business is OEM. Mivera Audio was only a gift to music lovers who have good ears, and appreciate phenomenal sound. I'm selling all of this gear for less than BOMx2!! Industry average is BOMx6!

Of course all of my OEM clients get all the numbers they desire, and more. Then they can choose if they want to use them for marketing purposes or not. These well established OEM's already have professional marketeers who know the market well. So they know best how to advertise their gear.

 

[March Audio]

They're for idle current and DC trimming.

...mmmmmmm....thermal drift.........

The EMI from that tiny transformer is so low it's a non issue. 1000x less than any Toroidal transformer you find in the DAC's Amir shared as examples of excellence. That's a very well made softstart, and uses a very high quality gold plated silver contact relay. It's a better way to switch power on and off than a mechanical switch.

All of the caveats you describe aren't an issue with the Purestream. I have a client who has massive horns that are 109dB/1W efficiency. Combined with my Preamp, he can turn to max and put his ear in the horn and it sounds like it's off.

Once we get better than 120dB SNR, I don't think noise is an issue anymore.

How do you know? Did you measure it? I thought you werent concerned about the measured output of the DAC, only the specs of the components you put in it

If nothing below -120dB is of issue, why are you so concerned about the phase noise of your femidom clock?

 

[Cosmik]

For me, the general point is that boutique audio is a minefield of ways to lose large sums of money, burn your house down or kill your loved ones! And this applies even without the horrors that lurk within the amateurish boxes we have been looking at.

Take the conventional practice of using a vastly over-powered amp to drive smaller speakers. This is like attaching a large power supply without any current limiting to a low power, un-fused device housed in a flammable box. I really don't know what the characteristics of average speaker drivers are when it comes to blasting high current DC through them - in one of the common failure modes of power amps (particularly 'boutique' ones). Will they spit burning wreckage all over the carpet?

 

[March Audio]

You see my main business is OEM. Mivera Audio was only a gift to music lovers who have good ears, and appreciate phenomenal sound. I'm selling all of this gear for less than BOMx2!! Industry average is BOMx6!

Of course all of my OEM clients get all the numbers they desire, and more. Then they can choose if they want to use them for marketing purposes or not. These well established OEM's already have professional marketeers who know the market well. So they know best how to advertise their gear.

So who are these mysterious OEM clients? Searg.....no, Rosemary the telephone operator, no......Henry the mild mannered janitor..?

Mike, you make me laugh, it's all Hong Kong Phooey

 

[Mivera]

...mmmmmmm....thermal drift.........




How do you know? Did you measure it? I thought you werent concerned about the measured output of the DAC, only the specs of the components you put in it

If nothing below -120dB is of issue, why are you so concerned about the phase noise of your femidom clock?

Each one is custom calibrated for the operation temp of the Purestream by Daniel Weiss in Switzerland. They only drift until warmed up, then are rock solid. Which is why they're calibrated warm.

Your second question is only a great demonstration of how little you know about oscillator phase noise.

 

[Mivera]

For me, the general point is that boutique audio is a minefield of ways to lose large sums of money, burn your house down or kill your loved ones! And this applies even without the horrors that lurk within the amateurish boxes we have been looking at.

Take the conventional practice of using a vastly over-powered amp to drive smaller speakers. This is like attaching a large power supply without any current limiting to a low power, un-fused device housed in a flammable box. I really don't know what the characteristics of average speaker drivers are when it comes to blasting high current DC through them - in one of the common failure modes of power amps (particularly 'boutique' ones). Will they spit burning wreckage all over the carpet?

This fear mongering certainly isn't going to slow down my sales. As I mentioned before, All of my Mivera Audio products have been discontinued other than custom projects. Folks who order my custom gear only do so because they already know how good my stuff is. They don't come to ASR for education. If they want some worthwhile education, I'll introduce them to some real engineers.

 

[Mivera]

So who are these mysterious OEM clients? Searg.....no, Rosemary the telephone operator, no......Henry the mild mannered janitor..?

Mike, you make me laugh, it's all Hong Kong Phooey

How did you know!

 

[Blumlein 88]

For me, the general point is that boutique audio is a minefield of ways to lose large sums of money, burn your house down or kill your loved ones! And this applies even without the horrors that lurk within the amateurish boxes we have been looking at.

Take the conventional practice of using a vastly over-powered amp to drive smaller speakers. This is like attaching a large power supply without any current limiting to a low power, un-fused device housed in a flammable box. I really don't know what the characteristics of average speaker drivers are when it comes to blasting high current DC through them - in one of the common failure modes of power amps (particularly 'boutique' ones). Will they spit burning wreckage all over the carpet?

No they won't do that.

 

[March Audio]

Each one is custom calibrated for the operation temp of the Purestream by Daniel Weiss in Switzerland. They only drift until warmed up, then are rock solid. Which is why they're calibrated warm.

Your second question is only a great demonstration of how little you know about oscillator phase noise.

Interesting, so you think that the internal case temperature stays the same? No effect from ambient temperature? I don't like circuits that need to be trimmed by pots, whoever has designed them. Its an inherent weakness that will drift over time.

I know plenty about phase noise Mikey and I do have the kit to measure it. It simply amuses me how you are selective about what you worry about. You cant get the basics right with the designs we have seen photos of here, but you shit your pants over phase noise you cant even measure and use "plug in" clock boards to try and improve it - without any verification its doing anything beneficial.

The fact is that you are unable to demonstrate and measure the effect of your femidom clock and are just playing a "numbers game" with component specs. It works on the technically ignorant audiophile punter, but not round here.

 

[Thomas savage]