BrokenEnglishGuy
Major Contributor
- Joined
- Jul 19, 2020
- Messages
- 1,936
- Likes
- 1,158
waiting for VTV Purifi eval-1 
hope comment soon as possible
hope comment soon as possible
-
WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Review and Measurements of Purifi 1ET400A Amplifier
- Thread starter amirm
- Start date
BrokenEnglishGuy
Major Contributor
- Joined
- Jul 19, 2020
- Messages
- 1,936
- Likes
- 1,158
New Purifi owner, what a badass amplifier! My room it's only 2.8x3x3 with weird form
First impressions: Very transparent and also the bass wake up in comparason with my nad c355, very powerfull i feel how the bass kick my chest
First impressions: Very transparent and also the bass wake up in comparason with my nad c355, very powerfull i feel how the bass kick my chest
If possible try to separate the KEFs more so that they form roughly an equilateral triangle, and point them to you. Nice speakers, had them for a while, as well as the Burson CV2+.
BrokenEnglishGuy
Major Contributor
- Joined
- Jul 19, 2020
- Messages
- 1,936
- Likes
- 1,158
The photo have a lot of optical distortion, the monitor is 27 '' but look pretty small
In reality look different, im already in a equilateral triangle
My room have a pretty weird form, this is the best position, if i put more distance between them, one side will point to the door and sound really ugly, i tryed a lot of position, definily if i separete more the speakers sound worse
This is how the speakers are set in my room, the height is different the right height is 70cm above than the left side
The purifi sound a lot different than NAD, i changed the EQ from APO EQ because of that
Last edited:
Sorry for any misunderstandings, but where is the exact measurements for the nc502mp.
yes there is the nord nc500 measured at sinad 96 here on this forum.
but according to nord themselves, the nc502 is 85-90% of the nc500.
then there is the variance in the company who builds its design.
NC502MP measurements are from the datasheet, as the spreadsheet column Source indicates.
Nord's percentages are his subjective opinions, not SINAD measurements.
this still would mean that the nord nc500 input buffer implementation has room for improvement, and hence a higher sinad score.
it has been rated 96 here, and you are saying that the data sheet for nc502 is 96db too.
On an off topic, orchard audio is offering its amp modules for use as higher output on sale right now.
the data sheet claims sinad of 110db, I think.
https://orchardaudio.com/shop/ols/products/strk-ltr-mdl
the data sheet claims sinad of 110db, I think.
https://orchardaudio.com/shop/ols/products/strk-ltr-mdl
What listening rooms (or recordings) have a SINAD of 96 db?
Can that even be evaluated. I don’t know.
as a newbie I thought I would ask it.
maybe a speaker that amir or someone else has already reviewed.
as for the room, leave that to last as room correction.
maybe provides some logic this way round.
SINAD is basically the ratio (in dB) of signal vs. noise+distortion. The SINAD of your listening room is pretty much the difference between the loudest you (can) play vs. the background noise (traffic, AC etc. - and even you moving and breathing). A very quiet room has a noise level of maybe 30 dB SPL. Your system is unlikely to produce more than 110 dB SPL (and you are unlikely to want to listen louder), so the SNR of your room is 80 dB. The only way your speaker affects SNR is by how loud it can go. It does add distortion - orders of magnitude more than any amp or digital source.
Room correction corrects frequency (and possibly time) response, it does not affect noise or distortion.
Then we have the source material...
Anyway, SINAD is not a be-all number to stare at. It is a basic indicator of the design (a bad SINAD is a sign of a bad design), but you very quickly reach a point where other things dominate.
Bartender1981
New Member
- Joined
- Feb 22, 2021
- Messages
- 3
- Likes
- 0
I have bluethoot Ldac into gustard x16.
If I buy an amp like this what's the best method to change the volume? Currently I use the volume of my smartphone, my dac have volume but how it degrade the quality?
If I buy an amp like this what's the best method to change the volume? Currently I use the volume of my smartphone, my dac have volume but how it degrade the quality?
it will not degrade quality, just make sure you don't clip the amp by raising the volume on the DAC too high.
Adding here, the noise level will matter most when using high efficiency speakers, and/or low music levels. This is when the noise might be noticed - when you are far from using full power.
This is a review and detailed measurements of the Purifi 1ET400A Class-D amplifier module. Company was kind enough to send me a complete, assembled kit consisting of two modules, power supply and case, ready to go. They have not disclosed the cost of the unit. Modules will be available to DIY channel in Q4 of 2019.
As cases go, the prototype unit came in an attractive one:
A touch of color on the lid goes a long way to break the monotony of DIY aluminum cases. Someone should take this case, put two giant VU meters in the front and make me happy!
Here is a quick teardown:
A single Hypex SMPS1200 is used to power both channels. That feeds two 1ET400A amplifier modules.
A single "Amp Connector Board" feeds both channels using balanced input through an optional gain stage of 13 dB. Here is more detail from documentation on the features of this EVM board:
View attachment 28849
I was pleased to see high-quality Rubycon capacitors used in the amplifier modules:
View attachment 28850
The power supply seems like the stock Hypex SMPS1200:
View attachment 28851
It is remarkable that a high-performance amplifier could be built in such a small enclosure with so few subcomponents.
In use, the evaluation unit would barely get warmer above room temperature. Heat dissipation is simply not an issue here. You could easily put these amps in an enclosed cabinet and not worry.
Note that the main offering here is the 1ET400A. The Amp Connector board is offered as convenience. In that regard, I tested the amplifier with and without the extra gain that the connector board provides. Alas, I wish there was something in between. You get full power with as little as 1.5 volt with the extra gain but need 11+ volts without it. I like to see manufacturers build a gain stage that produces full power at 4 volt which we routinely get out of source products (e.g. DACs).
Amplifier Audio Measurements
As provided, the extra gain stage was active producing this dashboard view at 4 ohm producing 5 watts:
View attachment 28852
Focusing on FFT spectrum of a 1 kHz tone, we see stunningly low distortion product. 2nd Harmonic is barely visible which may actually be the contributions from my source signal. The third harmonic hovers around -130 dB which again, is almost at the limit of what we can measure. Given the ear's 116 dB or so dynamic range, you are assured zero audibility of these distortion products.
THD+N and hence SINAD (signal over noise and distortion) is substantially lower though at 104 dB. Since THD+N is sum of distortion products and noise (+N), the latter is the culprit here. We can see this reflected in SNR measurements:
View attachment 28853
As you see on the left, our noise contributions is essentially what we see for SINAD. Fortunately at full power (right), performance shoots way up to fantastic level of 123 dB.
We can do better though by disabling the pre-gain stage:
View attachment 28854
We gain 4 dB in SINAD resulting this summary ranking:
View attachment 28857
The Benchmark in its low gain mode maintains the championship status still but the 1ET400A gives it serious competition here.
SNR naturally improves with lower gain:
View attachment 28858
Drilling into the distortion (with pre-gain active) we see the vanishing harmonic distortion more plainly:
View attachment 28859
Power is everything in amplifiers so let's see how we do with 4 ohm load:
View attachment 28862
The tables are turned and the 1ET400A produces 257 watts of exceptionally clean power. More could be had if I had run this test with finer resolution and/or allowed the distortion to climb more.
We see the effect of lower gain with reduction of noise at lower power levels although even with the extra grain stage, we are talking very quiet here.
Switching to 8 ohm, the results are similar:
View attachment 28863
Notice the big difference between a commercial amplifier (QSC DAC2422). They have more brute-force power but nowhere as clean as the 1ET400A amplifier module.
Intermodulation distortion versus power gives us another shot at analyzing distortion, this time what is in audio band:
View attachment 28864
The Benchmark AHB2 maintains its less noisy baseline but as we reach full power, the 1ET400A catches up to it and keeps going with more power.
Distortion+noise versus power and frequency yields this (with pre-gain stage on):
View attachment 28865
I was surprised to see the rise in distortion with frequency. I had hoped that the super high gain-bandwidth of the 1ET400A would do away with this. Not an audible concern though as the distortion products here are all in ultrasonic range.
I ran this test multiple times, tuning the input voltage. This eventually upset the amp and caused it to shut down when producing 274 watts into 4 ohm before our sweep completed (in green). Documentation clearly states that extra cooling is needed for continuous power.
The Benchmark AHB2 does a lot better since it has much cleaner ultrasonic spectrum:
Frequency response is exceptionally flat for a class-d amplifier:
View attachment 28866
The output filters in class-d amps can cause variations as we get close to 20 kHz but we see none of that here. Response smoothly rolls off. At 50 kHz, we are down 1 dB.
Crosstalk using my non-optimal setup is still exceptional:
View attachment 28867
I had to pull up the graph to show its crosstalk at 1 kHz. The 1ET400A is that good!
EDIT: here is the broadband spectrum of a 1 kHz tone:
View attachment 28895
We have our switching frequency around 500 Khz and its harmonic at 1 Megahertz. Otherwise pretty clean.
Conclusions
It was just a few years ago that people scuffed at class-D amps not being very clean or good for audiophile use. How the situation has changed. First with Hypex modules and now with the Purifi 1ET400A. Audiophile myths are shattered with use of large amount of feedback and high bandwidth to produce an amplifier which brings transparency to anything you throw at it.
Importantly, the 1ET400A does all of this while producing a ton of power and staying cool and efficient to boot.
There is a subjective aspect to measurements that doesn't come across in the graphs. When I run these tests with switching amplifiers, I often watch the analyzer struggle to get reliable reading, or there are jumps and glitches in measurements. None of that was here. The amplifier basically acted like a traditional class AB amplifier. Indeed, I measured it with and without my AES-17 40 kHz filter and the analyzer was happy both ways. This is when I know there is quality engineering that has gone into design of this amplifier.
Overall, it is my pleasure to strongly recommend the Purifi 1ET400A to DIY and OEM manufacturers.
-------------
As always, questions, comments, recommendations, etc. are welcome.
The pink panthers can be pretty lazy at times. I asked them to help clean up the lab and they rolled their eyes and went back to sleep! So I need to hire a housekeeper to keep the walk way clean to my test station. Please donate generously as the hourly rate can be high for such work:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
Hi.
I have tried to copy your project.
The problem is just that it doesn't seems to work for me.
I can hear a click when the power is turned on, maybe that's from the power supply.
Mine is without connector J2. Is it needed or is it just for an extra button on/off?
This is a review and detailed measurements of the Purifi 1ET400A Class-D amplifier module. Company was kind enough to send me a complete, assembled kit consisting of two modules, power supply and case, ready to go. They have not disclosed the cost of the unit. Modules will be available to DIY channel in Q4 of 2019.
As cases go, the prototype unit came in an attractive one:
A touch of color on the lid goes a long way to break the monotony of DIY aluminum cases. Someone should take this case, put two giant VU meters in the front and make me happy!
Here is a quick teardown:
A single Hypex SMPS1200 is used to power both channels. That feeds two 1ET400A amplifier modules.
A single "Amp Connector Board" feeds both channels using balanced input through an optional gain stage of 13 dB. Here is more detail from documentation on the features of this EVM board:
View attachment 28849
I was pleased to see high-quality Rubycon capacitors used in the amplifier modules:
View attachment 28850
The power supply seems like the stock Hypex SMPS1200:
View attachment 28851
It is remarkable that a high-performance amplifier could be built in such a small enclosure with so few subcomponents.
In use, the evaluation unit would barely get warmer above room temperature. Heat dissipation is simply not an issue here. You could easily put these amps in an enclosed cabinet and not worry.
Note that the main offering here is the 1ET400A. The Amp Connector board is offered as convenience. In that regard, I tested the amplifier with and without the extra gain that the connector board provides. Alas, I wish there was something in between. You get full power with as little as 1.5 volt with the extra gain but need 11+ volts without it. I like to see manufacturers build a gain stage that produces full power at 4 volt which we routinely get out of source products (e.g. DACs).
Amplifier Audio Measurements
As provided, the extra gain stage was active producing this dashboard view at 4 ohm producing 5 watts:
View attachment 28852
Focusing on FFT spectrum of a 1 kHz tone, we see stunningly low distortion product. 2nd Harmonic is barely visible which may actually be the contributions from my source signal. The third harmonic hovers around -130 dB which again, is almost at the limit of what we can measure. Given the ear's 116 dB or so dynamic range, you are assured zero audibility of these distortion products.
THD+N and hence SINAD (signal over noise and distortion) is substantially lower though at 104 dB. Since THD+N is sum of distortion products and noise (+N), the latter is the culprit here. We can see this reflected in SNR measurements:
View attachment 28853
As you see on the left, our noise contributions is essentially what we see for SINAD. Fortunately at full power (right), performance shoots way up to fantastic level of 123 dB.
We can do better though by disabling the pre-gain stage:
View attachment 28854
We gain 4 dB in SINAD resulting this summary ranking:
View attachment 28857
The Benchmark in its low gain mode maintains the championship status still but the 1ET400A gives it serious competition here.
SNR naturally improves with lower gain:
View attachment 28858
Drilling into the distortion (with pre-gain active) we see the vanishing harmonic distortion more plainly:
View attachment 28859
Power is everything in amplifiers so let's see how we do with 4 ohm load:
View attachment 28862
The tables are turned and the 1ET400A produces 257 watts of exceptionally clean power. More could be had if I had run this test with finer resolution and/or allowed the distortion to climb more.
We see the effect of lower gain with reduction of noise at lower power levels although even with the extra grain stage, we are talking very quiet here.
Switching to 8 ohm, the results are similar:
View attachment 28863
Notice the big difference between a commercial amplifier (QSC DAC2422). They have more brute-force power but nowhere as clean as the 1ET400A amplifier module.
Intermodulation distortion versus power gives us another shot at analyzing distortion, this time what is in audio band:
View attachment 28864
The Benchmark AHB2 maintains its less noisy baseline but as we reach full power, the 1ET400A catches up to it and keeps going with more power.
Distortion+noise versus power and frequency yields this (with pre-gain stage on):
View attachment 28865
I was surprised to see the rise in distortion with frequency. I had hoped that the super high gain-bandwidth of the 1ET400A would do away with this. Not an audible concern though as the distortion products here are all in ultrasonic range.
I ran this test multiple times, tuning the input voltage. This eventually upset the amp and caused it to shut down when producing 274 watts into 4 ohm before our sweep completed (in green). Documentation clearly states that extra cooling is needed for continuous power.
The Benchmark AHB2 does a lot better since it has much cleaner ultrasonic spectrum:
Frequency response is exceptionally flat for a class-d amplifier:
View attachment 28866
The output filters in class-d amps can cause variations as we get close to 20 kHz but we see none of that here. Response smoothly rolls off. At 50 kHz, we are down 1 dB.
Crosstalk using my non-optimal setup is still exceptional:
View attachment 28867
I had to pull up the graph to show its crosstalk at 1 kHz. The 1ET400A is that good!
EDIT: here is the broadband spectrum of a 1 kHz tone:
View attachment 28895
We have our switching frequency around 500 Khz and its harmonic at 1 Megahertz. Otherwise pretty clean.
Conclusions
It was just a few years ago that people scuffed at class-D amps not being very clean or good for audiophile use. How the situation has changed. First with Hypex modules and now with the Purifi 1ET400A. Audiophile myths are shattered with use of large amount of feedback and high bandwidth to produce an amplifier which brings transparency to anything you throw at it.
Importantly, the 1ET400A does all of this while producing a ton of power and staying cool and efficient to boot.
There is a subjective aspect to measurements that doesn't come across in the graphs. When I run these tests with switching amplifiers, I often watch the analyzer struggle to get reliable reading, or there are jumps and glitches in measurements. None of that was here. The amplifier basically acted like a traditional class AB amplifier. Indeed, I measured it with and without my AES-17 40 kHz filter and the analyzer was happy both ways. This is when I know there is quality engineering that has gone into design of this amplifier.
Overall, it is my pleasure to strongly recommend the Purifi 1ET400A to DIY and OEM manufacturers.
-------------
As always, questions, comments, recommendations, etc. are welcome.
The pink panthers can be pretty lazy at times. I asked them to help clean up the lab and they rolled their eyes and went back to sleep! So I need to hire a housekeeper to keep the walk way clean to my test station. Please donate generously as the hourly rate can be high for such work:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
Hi.
I have tried to copy your setup (Purifi EVA1 and Hypex SMPS1200.
Mine doesn't works. It really sucks.
The purifi module is without I2C, J2. Is it needed or is it just for an extra switch on/off?
The AUX J3 (Purifi) have I connected to J5.3, J5.5 and J5.7(Hypex). But on the picture it looks like that you have connected it to J4 (Hypex). Why and which pins?
When switched on I don't see any LED lights up on Purifi board.
With the cable kit from Purif there was 2 extra cable. What are they needed for?
Can you post pictures of your build?
Amir was testing a completely pre-built, working prototype amp that Purifi sends to reviewers.
For questions concerning building your own Purifi amp, look at this thread:
https://www.audiosciencereview.com/forum/index.php?threads/diy-purifi-amp-builds.10478/
On the Vera P150/600 amplifier we use our own buffer design. The gain is adjusted in 3dB steps using a rotaty switch and have 0,01dB accuracy. The implementation has virtually no noise penalty at higher gains (other than that the source noise of course also will be amplified).
Our buffer has a consistant high CMRR of at least 94dB when using a balanced source (and cables).
Similar threads
- Poll
