DIY Purifi Amp builds

[PaulD]

SIY, are you able to follow a reasoning?

The main problem with the amplifier is to amplify a signal with the less possible deformation, the least amount of distortion.

What creates the distortion? It is the passage of the audio signal through the various circuits and components. Less the signal passes through circuits / components, less it is damaged.

Why there is differents buffer stage, Sonic and others? Because each one has different performances which more or less deteriorates the signal at differents levels.

Why the Sinad noise level measurement is better on the Purifi without the input buffer? Because although it is very good, it degrades performance, like any electronic circuit.

Why want to take the signal and get it over the input buffer which for the majority of us is not useful ?

I ask the question again: why do you think Purifi spent time and money making a circuit where you can bypass the input buffer ? Just for measurement performance…?

The aim of their product range is to transcribe a recording as purely as possible, if they have left this possibility ... it should not be only to make measurement scores

So you who position yourself here as a Master, do the test, measure a sinusoidal signal at 100Hz, 1 kHz, 10kHz, at different level, or what you want to measure if YOU're be able to do this ..... measure it, at least to be critical, measure the impossible and come and give us the result …

I understand that here the measurement predominates, but for once please, if you cannot measure the immeasurable, be logical…

Wow, SIY provides evidence and reasoning and you IGNORE it to prefer your biases? That is the very definition of ignorance.

There is plenty more evidence of how casual listening is simply full of biases. Try Sean Olive's blog on The Dishonesty of Sighted Listening for a start https://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html

Here is an excerpt from Olive's piece: "The psychological biases in the sighted tests were sufficiently strong that listeners were largely unresponsive to real changes in sound quality caused by acoustical interactions between the loudspeaker, its position in the room, and the program material. In other words, if you want to obtain an accurate and reliable measure of how the audio product truly sounds, the listening test must be done blind."

Everything that can be heard can be measured. We can measure to better resolution than our ears are capable of.

 

[Thomas savage]

SIY, are you able to follow a reasoning?

The main problem with the amplifier is to amplify a signal with the less possible deformation, the least amount of distortion.

What creates the distortion? It is the passage of the audio signal through the various circuits and components. Less the signal passes through circuits / components, less it is damaged.

Why there is differents buffer stage, Sonic and others? Because each one has different performances which more or less deteriorates the signal at differents levels.

Why the Sinad noise level measurement is better on the Purifi without the input buffer? Because although it is very good, it degrades performance, like any electronic circuit.

Why want to take the signal and get it over the input buffer which for the majority of us is not useful ?

I ask the question again: why do you think Purifi spent time and money making a circuit where you can bypass the input buffer ? Just for measurement performance…?

The aim of their product range is to transcribe a recording as purely as possible, if they have left this possibility ... it should not be only to make measurement scores

So you who position yourself here as a Master, do the test, measure a sinusoidal signal at 100Hz, 1 kHz, 10kHz, at different level, or what you want to measure if YOU're be able to do this ..... measure it, at least to be critical, measure the impossible and come and give us the result …

I understand that here the measurement predominates, but for once please, if you cannot measure the immeasurable, be logical…

You can cut out the rude tone thanks.

 

[Thomas savage]

It might be there just to allow a certain amount of customisation, DIY individuals can play about and companies using these modules can claim some sort of USP .

Makes sense to me if you want to increase market potential, it's not good business sense to exclude people from your product especially when your already dealing with something of a niche.

 

[Dbfr]

You can cut out the rude tone thanks.

Rude tone ! sorry it was not my goal...
I try to be logical, and just offer reasoning
if someone can measure it, it would get things done.

 

[boXem]

What creates the distortion? It is the passage of the audio signal through the various circuits and components. Less the signal passes through circuits / components, less it is damaged.

No. In example, an active filter will have better performance than a passive one while using a lot more components.

Why there is differents buffer stage, Sonic and others?

Product differentiation, marketing, audiophile myths,....

Why the Sinad noise level measurement is better on the Purifi without the input buffer?

Because noise is lower, mainly due to lower gain.

Because although it is very good, it degrades performance, like any electronic circuit.

When using the buffer, CMRR increases, input impedance increases,... These are improvements.

I ask the question again: why do you think Purifi spent time and money making a circuit where you can bypass the input buffer ? Just for measurement performance…?

It's an evaluation board, bypassing the buffer allows to measure the module performance by itself. So not for measurement performance, just for measurement.

 

[SIY]

I understand that here the measurement predominates, but for once please, if you cannot measure the immeasurable, be logical…

Since I was talking about listening tests in the context of you wanting to claim sonic differences, I'm having difficulty following the prose that leads up to this.

Everything audible is measurable, but not everything measurable is audible. And demonstrating audibility requires basic controls.

 

[Dbfr]

No. In example, an active filter will have better performance than a passive one while using a lot more components.

I do not necessarily agree, yes a passive filter by its components deteriorates the signal, but an active filter can also deteriorate it, by its sampling frequency and other logical processes ...

 

[Dbfr]

What I see is that a moderator tells me to change my tone, while some say I am ignorant and others show bad faith.
The dialogue only goes in one direction, the other is obstructed

So I really do not see what I am doing on this forum, I clearly have no place here.
I will therefore request to close my account

 

[McFly]

Off topic but I love how when people want to go out in a blaze of glory they demand their account be closed. Couldn't you just - I dunno - log out and never come back?

 

[PaulD]

but an active filter can also deteriorate it, by its sampling frequency and other logical processes ...

Provably untrue when properly implemented, from the several AES studies already published.

Opinions do not equal substantiated facts.

 

[PaulD]

What I see is that a moderator tells me to change my tone, while some say I am ignorant and others show bad faith.
The dialogue only goes in one direction, the other is obstructed

So I really do not see what I am doing on this forum, I clearly have no place here.
I will therefore request to close my account

Not letting a random internet commentator deny established facts with hearsay and casual opinion is the responsibility of everyone who cares about the truth and science. That is why you get pushback in this forum. It's titled Audio SCIENCE Review.

 

[Wombat]

I have asked about it in other forums and I still do not have convincing answers. I know more about audio than you think.

And less than you think.

 

[boXem]

I do not necessarily agree, yes a passive filter by its components deteriorates the signal, but an active filter can also deteriorate it, by its sampling frequency and other logical processes ...

An active filter can be analog or digital. I was thinking analog, i.e. with active components like transistors, diodes, ...
The bad reasoning is when you consider that adding a component systematically degrades the signal. Let's take another example. The Purifi stuff has brilliant performance because the guys at Purifi were able to get a stable amplifier with tons of feedback. This was done by adding components to the feedback circuit. Without these additional components, the 1ET400 would not be called Eigentakt but UcD since their base principle (self oscillating circuit) is exactly the same.
This reasoning of lower component count = better music was introduced by some snake oil specialists who found a solution to sell at high price poorly designed circuits costing nothing to produce. I agree that at a first glance, this is seductive and sounds like plain logic, but sadly, the facts are what they are .

 

[Count Arthur]

I'm guessing that the correct number of components, is somewhere between 0, in which case you won't hear anything, and infinity, in which case you wouldn't be able to power them.

 

[barrows]

You can cut out the rude tone thanks.

I suggest that SIY's tone is equally rude, as a "moderator" please apply your standards equally. Also, it is clear that English is not DBfr's first language, and given that some leeway might be allowed.

 

[barrows]

Not letting a random internet commentator deny established facts with hearsay and casual opinion is the responsibility of everyone who cares about the truth and science. That is why you get pushback in this forum. It's titled Audio SCIENCE Review.

Umm... I have to admit seeing what I would consider a problem here though. Observation is part of the scientific method, and should not be ridiculed. When members on this site ridicule observation, it is science denial. Indeed, observation is only part of the scientific method, but it is a valid part. Jumping all over someone who all reports his observations, no matter how subjective they may be, does not do a service to anything, or anyone: there would be no science without observation. Often I find members at this forum not able to acknowledge anyone's observations, this is closed minded, and being closed minded is also not very scientific. Indeed, observations should be verified through empirical means as a next step, but this does not make observations invalid.
If this site really wants to make a valuable contribution to the hobby, and industry, of audio playback, I would suggest a more open attitude to observation would help, not hinder, that possible contribution. Additionally, instead of ridiculing an observation, why not then respect an observation, and then follow the scientific method and attempt to either prove or disprove that observation with empirical methods? As a science based forum, this site has a unique opportunity to advance the understanding of audio performance, but the constant attitude of "we already know all there is to know" about audio performance is holding this site back, and is also un-scientific. Being open minded and aware of the possibility that there may exist more aspects of audio performance to find appropriate measures to understand could actually contribute something new.

Indeed, i view measurements as very important to the understanding and evaluation of audio components, but I also find the "standard set" of audio measures lacking in describing all aspects of audio performance. I think Amir's publishing of multi-tone tests a step in the right direction (as does Audio Precision themselves) of finding, perhaps deeper, understanding of a component's performance under different signal conditions (these measurements often show distortions at levels not seen in single tone testing of the same component). While I do believe we have the ability to measure all aspects of an audio component's performance, I do not believe the "standard set" of measures accounts for this, yet.

 

[SIY]

"Observation" requires controls to be valid.

Really, it's not complicated.

 

[JimB]

Sooo..... Anyone done any DIY with Purifi modules, lately?

I heard from Ghent that they are making slow progress due to the impact of COVID on efficiency, but also because they are creating a new case form for these amps (250mm wide, instead of 200 or 300). A new extrusion die is needed and they are still optimizing it (as I understand). It will likely be about 2 more months before we see any completed cases.

 

[beren777]

Sooo..... Anyone done any DIY with Purifi modules,lately?

Getting started, but more in an "assemble it yourself" context.

I just received an EVAL1 kit yesterday for a DIY stereo amp build. I still haven't finished my TPA3251 build but I won't be able to start the Purifi build anyway until the Hypex power supply ships. They're currently backordered.

Eventually I want to swap out the banana connectors for speakON but I'm dragging my heels to see what case Ghent releases later this summer. Until then I'll probably throw it into a temporary box.

I'd like to add a music sense power trigger. I plan to use it with a DAC like the M300 mk2 which I don't think has a 12V trigger out on it.

 

[starfly]

Sooo..... Anyone done any DIY with Purifi modules,lately?

I heard from Ghent that they are making slow progress due to the impact of COVID on efficiency, but also because they are creating a new case form for these amps (250mm wide, instead of 200 or 300). A new extrusion die is needed and they are still optimizing it (as I understand). It will likely be about 2 more months before we see any completed cases.

My 2 Purifi modules should arrive tomorrow, and my Neurochrome buffers maybe next week. Though it might take a few more weeks for my power supply to arrive, apparently the SMPS1200A400 is out of stock everywhere.

Haven't ordered my case yet, but will probably do that next week. Will get one of those Hifi2000 cases with custom cutouts in the back for a 3 channel setup in mind, though I'm starting off with only 2 channels.