Review and Measurements of Purifi 1ET400A Amplifier

[g29]

Any update on when these will be available in the DIY wild ?

 

[headshake]

You need glasses if you do not see the big one, the more obvious.

more kapton tape?

SN380 is interesting. Did they scrap a few runs?

 

[maty]

European, PCB001a, BIG coil: 1ET400A02A

Asian, PCB002b, BIG coil: 1ET400A02B

It is evident that they are different.


Why? Maybe not only just increase the loop gain.

https://www.audiosciencereview.com/...-of-purifi-1et400a-amplifier.7984/post-254975

-> Purifi Audio - A Straight Wire to the Soul of Music, October 23 2019
https://www.audioxpress.com/article/purifi-audio-a-straight-wire-to-the-soul-of-music

[ So there is an element of hysteresis, memory if you like, which causes strong nonlinearity. Although the feedback loop decreases all nonlinearities it encloses, if the error is large enough it can make itself heard in the output signal. This also suggests the solution: just increase the loop gain (that is, the amount of feedback)!

The crux for increased feedback is a tailored compensation loop, but to be able to design that you need to be able to model how the amplifier (and its output filter with the output coil) varies in gain and phase at any load and any level within its working envelope, and adapt the feedback/compensation loop accordingly... ]

 

[Hayabusa]

European, PCB001a, BIG coil: 1ET400A02A

View attachment 37447


Asian, PCB002b, BIG coil: 1ET400A02B

]

This also shows different soldering quality of the top-right two coils. The soldering-through is not done (well) in the lower picture.

 

[maty]

They have to assess the quality of the Asians. If not -> to change the manufacturer, I say.

That said, it is better not to be among the first if there is no need, regardless of the type of product. If it also causes it to pay a minimum of $ 200 x2 + assembler margin more...

If we have a good sound now we should not be in a hurry. There are others who have it to sell. Compulsive purchase is not a good practice to us, my two cents.

 

[Audiocrusader]

European, PCB001a, BIG coil: 1ET400A02A

View attachment 37447


Asian, PCB002b, BIG coil: 1ET400A02B

It is evident that they are different.


Why? Maybe not only just increase the loop gain.

https://www.audiosciencereview.com/...-of-purifi-1et400a-amplifier.7984/post-254975

-> Purifi Audio - A Straight Wire to the Soul of Music, October 23 2019
https://www.audioxpress.com/article/purifi-audio-a-straight-wire-to-the-soul-of-music

[ So there is an element of hysteresis, memory if you like, which causes strong nonlinearity. Although the feedback loop decreases all nonlinearities it encloses, if the error is large enough it can make itself heard in the output signal. This also suggests the solution: just increase the loop gain (that is, the amount of feedback)!

The crux for increased feedback is a tailored compensation loop, but to be able to design that you need to be able to model how the amplifier (and its output filter with the output coil) varies in gain and phase at any load and any level within its working envelope, and adapt the feedback/compensation loop accordingly... ]

So you're saying the sticker on the coil will affect the sound, or just the text on the sticker? The sticker has the model number of the amplifier on it. It's only on the coil because it was a good place to stick it. If there's any changes to a PCB at all there's slight changes to the model numbers as well. The coils are identical coils from the same supplier.

 

[Audiocrusader]

They have to assess the quality of the Asians. If not -> to change the manufacturer, I say.

That said, it is better not to be among the first if there is no need, regardless of the type of product. If it also causes it to pay a minimum of $ 200 x2 + assembler margin more...

If we have a good sound now we should not be in a hurry. There are others who have it to sell. Compulsive purchase is not a good practice to us, my two cents.

Where's your source for the module cost? Sounds like another thing you completely made up.

 

[Audiocrusader]

Reply from Purifi on the board differences:

"No difference in audio or other functions. The first PCB had options for a bigger output inductor, those holes are removed on the latest PCB layout.

 

[MethHead]

So, get yer teeth into this lot! I just joined ASR specifically to enter this thread. As did Breaking Wind, I mean @BreakingBad, when he deliberately lifted closed forum comments from Mivera's forum, onto page 33 of this thread, to cause trouble. Understandably pissed, Mike closed the forum except to those of us who are buying from him. Now BB just did it again, copying over the picture of the local and Asian purifi boards. As with most of Mike's posts on his excellent and entertaining forum, the photo was purely for info, not to induce any subversive, racist or other perjorative reactions from his members, unlike BBs seeming intent in joining ASR. So a well and truly fed-up Mike has closed the forum completely. Thanks a lot BB, on behalf of all of us Mivera forum fanboys. The irony is that BB is a Mivera customer too, as only peeps waiting for a Purifi amp have retained forum access, since BB first stirred the pot.

Yes, all's fair in love, war and business etc etc, but, really , BB? Obviously NOT a mate of Mike's, as you first referred to yourself, and more obviously associated with a competitor, I do hope when your amp arrives it explodes and burns your house down. Except it won't as Mike seems to know what he's doing.

BTW I'm not Mike, before anyone chimes in. He replies to customer emails promptly and will continue to take care of us, but I'm super hacked off that @BreakingBad has ruined a great forum for us. At least Mike will have more time to just build his amps and get them out to us.

BB, your chosen name doesn't surprise me. You apparently share the same moral structure as your favourite protagonist.
Otherwise, some very interesting threads here. Let the fun begin.

 

[Thomas savage]

So, get yer teeth into this lot! I just joined ASR specifically to enter this thread. As did Breaking Wind, I mean @BreakingBad, when he deliberately lifted closed forum comments from Mivera's forum, onto page 33 of this thread, to cause trouble. Understandably pissed, Mike closed the forum except to those of us who are buying from him. Now BB just did it again, copying over the picture of the local and Asian purifi boards. As with most of Mike's posts on his excellent and entertaining forum, the photo was purely for info, not to induce any subversive, racist or other perjorative reactions from his members, unlike BBs seeming intent in joining ASR. So a well and truly fed-up Mike has closed the forum completely. Thanks a lot BB, on behalf of all of us Mivera forum fanboys. The irony is that BB is a Mivera customer too, as only peeps waiting for a Purifi amp have retained forum access, since BB first stirred the pot.

Yes, all's fair in love, war and business etc etc, but, really , BB? Obviously NOT a mate of Mike's, as you first referred to yourself, and more obviously associated with a competitor, I do hope when your amp arrives it explodes and burns your house down. Except it won't as Mike seems to know what he's doing.

BTW I'm not Mike, before anyone chimes in. He replies to customer emails promptly and will continue to take care of us, but I'm super hacked off that @BreakingBad has ruined a great forum for us. At least Mike will have more time to just build his amps and get them out to us.

BB, your chosen name doesn't surprise me. You apparently share the same moral structure as your favourite protagonist.
Otherwise, some very interesting threads here. Let the fun begin.

Banned , clearly only wants to bring a beef from other places .

Explicitly says so, only interest in this thread and doing just that.

Proxy battles will not be tolerated.

 

[BreakingBad]

So, get yer teeth into this lot! I just joined ASR specifically to enter this thread. As did Breaking Wind, I mean @BreakingBad, when he deliberately lifted closed forum comments from Mivera's forum, onto page 33 of this thread, to cause trouble. Understandably pissed, Mike closed the forum except to those of us who are buying from him. Now BB just did it again, copying over the picture of the local and Asian purifi boards. As with most of Mike's posts on his excellent and entertaining forum, the photo was purely for info, not to induce any subversive, racist or other perjorative reactions from his members, unlike BBs seeming intent in joining ASR. So a well and truly fed-up Mike has closed the forum completely. Thanks a lot BB, on behalf of all of us Mivera forum fanboys. The irony is that BB is a Mivera customer too, as only peeps waiting for a Purifi amp have retained forum access, since BB first stirred the pot.

Yes, all's fair in love, war and business etc etc, but, really , BB? Obviously NOT a mate of Mike's, as you first referred to yourself, and more obviously associated with a competitor, I do hope when your amp arrives it explodes and burns your house down. Except it won't as Mike seems to know what he's doing.

BTW I'm not Mike, before anyone chimes in. He replies to customer emails promptly and will continue to take care of us, but I'm super hacked off that @BreakingBad has ruined a great forum for us. At least Mike will have more time to just build his amps and get them out to us.

BB, your chosen name doesn't surprise me. You apparently share the same moral structure as your favourite protagonist.
Otherwise, some very interesting threads here. Let the fun begin.

My post comprised of only a picture indicating Make location of each version, with intent of getting feedback from ASR as the two boards seemed not identical. Meant no harm to Mike, so I will stop posting any Mivera related data from now on.

 

[Audiocrusader]

My post comprised of only a picture indicating Make location of each version, with intent of getting feedback from ASR as the two boards seemed not identical. Meant no harm to Mike, so I will stop posting any Mivera related data from now on.

Adam Schiff is that you??

 

[BDWoody]

My post comprised of only a picture indicating Make location of each version, with intent of getting feedback from ASR as the two boards seemed not identical. Meant no harm to Mike, so I will stop posting any Mivera related data from now on.

Edited and corrected for being wrong.
Cheers

 

[Hayabusa]

No, it included a narrative that was certainly not very complimentary. If that's how you treat your 'friends'...?

BDWoody: what narrative do you mean? I have looked back into BB posts and I can not find it.

 

[BDWoody]

BDWoody: what narrative do you mean? I have looked back into BB posts and I can not find it.

Absolutely correct. Totally missed that one.
Thanks for the correction, and apologies to @BreakingBad

My bad.

 

[Jamn]

My post comprised of only a picture indicating Make location of each version, with intent of getting feedback from ASR as the two boards seemed not identical. Meant no harm to Mike, so I will stop posting any Mivera related data from now on.

 

[yodog]

So where can I purchase an insanely good measuring amp or DIY amp kit from...?

 

[gab]

So where can I purchase an insanely good measuring amp or DIY amp kit from...?

https://neurochrome.com/collections/power-amplifiers/products/modulus-286-kit-limited-edition

only 2 left!

 

[tensor9]

Is the 1ET400 a little under spec'ed (EDIT: manufacturer was overly conservative with the listed spec) into 2 Ohms? Do they only claim 450W into 2 Ohms because it just can't officially sustain that current for prolonged periods of time?

 

[ahofer]

Is the 1ET400 a little under spec'ed into 2 Ohms? Do they only claim 450W into 2 Ohms because it just can't officially sustain that current for prolonged periods of time?

I think @March Audio posted a video of the NC going full power for 6 minutes and barely heating up. I haven’t tested it, but I think the “Class D can’t do low impedance” is a canard.