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Amir have shown measurements that bypassing the pre gain buffer provides better performances, isn'it ?
https://www.audiosciencereview.com/...easurements-of-purifi-1et400a-amplifier.7984/
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DIY Purifi Amp builds
- Thread starter JimB
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https://www.audiosciencereview.com/...easurements-of-purifi-1et400a-amplifier.7984/
Since this measurement is noise dominated for all cases, we can't conclude anything on distortion.Amir have shown measurements that bypassing the pre gain buffer provides better performances, isn'it ?
https://www.audiosciencereview.com/...easurements-of-purifi-1et400a-amplifier.7984/
Noise is lower when bypassing the buffer, which makes sense since the buffer noise is no more amplified.
So, from this particular measurement, the only thing that can be concluded is that if something is to be heard, it's lower noise.
IMD of multitone could highlight potential differences other than noise.
In any case, I don't want to enter the debate on the audibility of all this, I am just an engineer.
At those levels, audibility is... questionable. If you have very efficient speakers (say 100dBSPL/2.83V/m), the noise level will be under 0 dBSPL at a meter. Good luck hearing that!
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Noise floor just tell us an idea of the level of the amplifier
It’s appear to be logical, the signal goes through fewer components
It seems (at my ears) that without the buffer stage, it’s sound better on all the listening sessions that’ll do at different level with différents songs, it’s more magical, more depth that i have listen with the buffer wired
But it’s not a measure and here it seems that you only listen with laboratory instrument
Do you really think that Purifi would have spent time and money to leave this possibility if it did not bring something to the ear?
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More magical, more depth? Really? Come on...
You didn't use your ears, you peeked. So please stop making these unsupported claims. They're nonsense and you clearly don't trust your own ears or you would put in basic controls. Not to mention the tiresome "you only listen with laboratory instrument" lie.
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400W/4ohm might seem like a lot, but if you deduce a few dBs for digital EQ this drops pretty quickly.
This is especially true in an active crossover setup where you have to shape the response of the driver.
This is especially true in an active crossover setup where you have to shape the response of the driver.
OP
- Thread Starter
- #1,089
At high output power, where heat matters most, the efficiency of the NC400 and the 1ET400A are quite comparable, so your statement about one needing more cooling than the other is interesting. Can you describe what you showed in that post in more detail? You say it was with the top cover removed, but I don't understand some of the patterns. Also, you say the "top board of the cabinet" was cooler. Was the amp run with the top on, then removed? Or just run with it off? Or always on? @elberoth showed temperatures on the little vertical boards of the 1ET400A at ~50C with the cover off. Top covers increase internal temperatures.
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soccermommy
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Can you share the DXF file you provided to Modushop ? I'm in the process of ordering the same case. Thanks.
It was after a long comparative session of the two (several hours) where the two amps were placed one next to the other without top cover.
After closing the amp and putting it in the cabinet where the ncore was, after several weeks, it becomes clear that the top board of the cabinet appears fresher than when I had the ncore in the same place in the same type and size of case
But ... it's not a scientifical measure...
After closing the amp and putting it in the cabinet where the ncore was, after several weeks, it becomes clear that the top board of the cabinet appears fresher than when I had the ncore in the same place in the same type and size of case
But ... it's not a scientifical measure...
maty
Major Contributor
Do not pay much attention to him and continue also in the ASR forums. Not everything is measurable in audio today. There are things that are still inexplicable, at least to me.
Just because you don't understand something doesn't mean that it is not understood.
maty
Major Contributor
I have asked about it in other forums and I still do not have convincing answers. I know more about audio than you think.
no, sorry
I'm tired of having to justify myself constantly, some are too obtuse, I deleted all my posts,
audio can be measured, at least some things, but closing your eyes and take a lot of pleasure is not measurable
No, it's not, at least not easily, but sonically evaluating two amplifiers properly is straightforward. Playing make-believe by peeking is as well, but has no value.
I never got why insisting on very basic and well-established controls gets some people riled up enough to toss the toys out of the pram. But hey, if faith is more important than truth, have at it.
what I notice is you criticize again and again, without even knowing peoples, their systems, their pasts, their experiences, without ever proposing on your side things to advance the others, if this is the basis of ASR then it will be without me
you are constantly expecting ...
all your posts on different subjects, not only the purifi are only critics ...
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Sensory science doesn't care about "peoples, their systems, their pasts, their experiences"- not yours, not mine. The methods were developed to control for the non-auditory stimuli, leaving ears as the sole arbiter. And we ALL need to do this for our subjective impressions of sound to have validity. No-one is immune to various kinds of non-sonic bias, and anyone who claims that he is immune by virtue of experience or knowledge or whatever is full of shit.
If you like, you can read a casual review of methods and motivations here. I hope you do and that you find it educational.
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…
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…
