Purifi 1ET400A Measurements

Audio Science Review has posted measurements of a (pre-production?) sample of Purifi's upcoming 1ET400A kit. According to the site, DIY modules should be available in Q4 2019.

Looks like marginal improvements over NCore, more interesting talk on exact model prediction, technological modeling using Matlab compared to brute force calculations, furious amount of marketing :p.

At what price point will this come at, I wonder.
 
Looks like marginal improvements over NCore, more interesting talk on exact model prediction, technological modeling using Matlab compared to brute force calculations, furious amount of marketing :p.

At what price point will this come at, I wonder.


There is another product on the market, but the person who developed it as a developer of marine military radars and audio amplifiers for special orders, so not many people know about him. However last years car on his SO amplifiers beta version 2.1 has gotten 4th place in EMMA sound competition. (subjectively marked down because car was from Russia :rolleyes: )

Any way, first time since developing from 2014 now he finally decided to go public and develops V3, it is almost complete now, I'm waiting for pre orders to start. He said that pre-order platforms and website will be ready in few weeks.

His 2.1 beta version was already much better speced than any of Hypex and still better than Purifi. While price was about 180 euro. V3 is based on no compromise components policy, so will be more expensive - looking at 280 euro with Balance or Digital input. :cool:

That about as much as I know about his Indra Amps v3
 
There is another product on the market, but the person who developed it as a developer of marine military radars and audio amplifiers for special orders, so not many people know about him. However last years car on his SO amplifiers beta version 2.1 has gotten 4th place in EMMA sound competition. (subjectively marked down because car was from Russia :rolleyes: )

Any way, first time since developing from 2014 now he finally decided to go public and develops V3, it is almost complete now, I'm waiting for pre orders to start. He said that pre-order platforms and website will be ready in few weeks.

His 2.1 beta version was already much better speced than any of Hypex and still better than Purifi. While price was about 180 euro. V3 is based on no compromise components policy, so will be more expensive - looking at 280 euro with Balance or Digital input. :cool:

That about as much as I know about his Indra Amps v3

I can believe, (even the subjectively marked point you make) its pretty clear vast amounts of esoteric of control theory influence lies in Russia its not the first time I hear this.Would be interested to hear where Putzeys gets he's research from.
 
I would not wish to be misinterpreted if I stepped in and gave a shout for Putzeys but 'wondering where he gets his research from' makes it sound like he is ripping someone else off. I often rip off ohms law but sometimes have to be slightly more insightful when I combine it with other stuff.

As for 'esoteric control theory originating from Russia' and the unknown designer working on marine military radars I'm sure the marine mammal fraternity think he is a bit of a dick and ISTR the original designer at NuForce worked on Tomohawk Missiles and managed to produce something that was unhappy with certain loads.

Having said as much it might be better to properly link to a product rather than leaving us to guess. Perhaps yoodog can consolidate his cherry with his second post to the forum.
 
here is the thread. Old version of those amps got 1st place on all car audio competitions in Russia in top class SQ and came 3rd on final of EMMA CarAudio. New version is on the verge and is now being built on no compromise ideology.

?????????? ????????????????? ????????? (soAmp) Oriel Indra - ???????? 11

Guy who developed those is navy defence radar developed who sells his product to China and some other countries for costal defence :eek:

he never has time so I'm trying to make it interesting fort him to complete it asap. Can't wait for those beasts to be complete
 
Purifi Patents. EP Register might be more useful but the following might not be complete.

About this file - European Patent Register
About this file - European Patent Register
About this file - European Patent Register

The "All Documents" list may be of further interest. My read is that these patents are going to fail due to prior art, lack of inventive step and more importantly consideration of how someone 'skilled in the art' would approach the 'problem to be solved'. That seems to be a general theme in the written opinions.

Perhaps something might be salvaged but I would be slightly upset if someone gained a patent on a generalised compensation scheme and a cookbook of circuit limiters.

Mr Putzeys seems to have already voiced such an opinion in respect of patents and their general utility and of course you have to recognise that he has the analytical recipe to make an edible meal.
 

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I would not wish to be misinterpreted if I stepped in and gave a shout for Putzeys but 'wondering where he gets his research from' makes it sound like he is ripping someone else off. I often rip off ohms law but sometimes have to be slightly more insightful when I combine it with other stuff.

As for 'esoteric control theory originating from Russia' and the unknown designer working on marine military radars I'm sure the marine mammal fraternity think he is a bit of a dick and ISTR the original designer at NuForce worked on Tomohawk Missiles and managed to produce something that was unhappy with certain loads.

Having said as much it might be better to properly link to a product rather than leaving us to guess. Perhaps yoodog can consolidate his cherry with his second post to the forum.


I’m in contact with the developer and with person who has installed his first gen amps and got first or second places basically in every single or car audio competition in Russia and nearby on them - to be fair SQ is extremely popular in Russian car audio, there are at 4 different international formats that take place in and around Russia (Ukraine, Kazakhstan and some east Eu countries even) + he participated in the only big EU car audio competition Emma and got great results on his system when it was not even fully set.

About developer background. I just shared what his background is, because his head working is something I have not seen in my life - if you ever saw passion and professionalism working together than you know what I mean. I have been waiting for 6 a while for him to complete his v3 now and it seems like he did it finally :)

I will be happy to share more info once avaible, but that is all I have for now. Oh new amp name is Indra v3.0 as far as I know
 
Purifi Patents. EP Register might be more useful but the following might not be complete.

About this file - European Patent Register
About this file - European Patent Register
About this file - European Patent Register

The "All Documents" list may be of further interest. My read is that these patents are going to fail due to prior art, lack of inventive step and more importantly consideration of how someone 'skilled in the art' would approach the 'problem to be solved'. That seems to be a general theme in the written opinions.

Perhaps something might be salvaged but I would be slightly upset if someone gained a patent on a generalised compensation scheme and a cookbook of circuit limiters.

Mr Putzeys seems to have already voiced such an opinion in respect of patents and their general utility and of course you have to recognise that he has the analytical recipe to make an edible meal.

Figure 18: Is that a conceptional sample and hold circuit (used as an example analog to digital converter using the switched capacitor technique)
 
Figure 18: Is that a conceptional sample and hold circuit (used as an example analog to digital converter using the switched capacitor technique)

More like an integrate and hold. Figure 16) looks like the limiter Sous has used in their implementation. You would have to read through the applications, claims and reports to see whether any of them are suggested or accepted as being novel.
 
I'm not so sure its worth the effort to seek depth into this (maybe for research yes), improvements of this modulator has reached ceiling level THD improvements, settling with an NCore modulator design is satisfactory.

For true technological advancement in this day and age, effort should be spent on other aspects like amplifier resiliency, Example: using a micro-controller to provide sophisticated features like monitoring of the attached speaker's voice coil, health profiling, protocol design i.e sending command frames to do fancy things like lower gain vs temperature, measure amplifier abuse, monitor deterioration of fets and activate early warning alarms ..

IMO its still a missing must have feature in commercial and diy audio that's aims for reliability.
 
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Has anybody deciphered those claims? How are the compensator network, gain stage and primary amplifier actually connected?

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Then there is an 'operating mode' with the gain stage disconnected??

Jan

I'll be bold and suggest that other than causing your head to implode in an effort to decipher the bulk of it it really is just a cookbook of RC pole/zero networks wrapped around a bunch of amplifiers incorporating various limiters and bypasses dependent and independent of circuit operating modes.

There may be a rhyme and/or reason as to why any particular combination is chosen but it is ultimately just doodling with standard component building blocks. Look at something like average current mode control where switch current is sampled/controlled.

For slope matching the sensed current needs to be integrated. The sensed current comes from the inductor which integrates the switched voltage. You have two integrators, one from the power stage and one from the compensator, which, if both were active at crossover, would result in an unstable system. You introduce a phase bump, RC zero/pole around crossover to the compensator to gain 45 degrees phase margin.

Take any/many SMPS control ICs. You will see that the error amplifiers are designed to saturate/limit just above/below the ramp valley/peak. It's an effort to aid speed of recovery. If you were rolling your own you would start slapping in diodes, zener diodes, transistors around the local error amplifier to achieve the same function.

All these things are known. Practical implementation may/will cause other headaches. According to words elsewhere and indeed in these patents the 'secret sauce' is in the implementation. The loop is apparently third order at some point in its characteristic due to the addition of an extra integrator. Even a second order loop is going to be unhappy if it loses the plot and does not find it again.

As per the white paper elsewhere the circuit with the additional integrator has, unstable, solutions if the loop gain decides to tank which it will when approaching clip. It would appear that is largely down to the modulator gain falling with output level. The chosen solution is to 'knock the integrator out'.

Figure 16) as used by Sous is a limit. Whilst the integration is gone the amplifier is still active in as much as signal is passing through it. Mention is made of transconductance which is the mode in which this limit is acting. It's not a hard, zener/diode clamp so the stage still has a voltage gain. Roll your own version of 16)

Reactance mention Figure 19) which is an integrate and hold. In this case the integrator is taken entirely out of the circuit. It could be bypassed via another route but consider the case when the amplifier is about to or has entered clip/instability.

The integrator output was as a level commensurate with that condition. If you place it in hold then the amplifier will sit just before or at clip. When it comes out of clip the lower frequency, unstable solution, is not present, no integrator. When the amplifier starts operating again, switching above the wrong solution, the integrator is taken out of hold at the, previous, right output level and things carry on.

I am uncertain as to how EPO defines Novel and Inventive Step and it would appear that all 13 claims qualify as Novel. However all 13 claims do not involve an Inventive Step. Novel may be application of known solutions to supposedly new situations but if you are using known solutions there are no Inventive Steps.
 

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More wordy stuff. It is sort of relevant to inventiveness.

We 'know' the amplifier has at least two solutions. One low frequency/unstable and one high frequency/stable. They are valid over a range of frequencies.

Trigger a monostable off the switching frequency. Whilst it is being held in reset, timeout longer than a minimum switching period, the integrator is allowed to operate. If the switching frequency drops below some minimum the monostable is set and places the integrator in hold with the amplifier continuing to operate at a, stable, minimum frequency at or close to clip.

When the switching frequency increases, the amplifier is coming out of clip, the monostable is taken out and the integrator taken out of hold. First order thinking/solution that is almost but not quite there. Probably needs an FPGA to tweak things.

Just random thoughts but it is in the realms of 'someone skilled in the art' from someone who is probably not.