Review and Measurements of Purifi 1ET400A Amplifier

[JimB]

Amir tested 1 NC400 channel running off of a 600watt PS and it still did not produce the manufacturer's specs.

My point only being that the NC400 does not need 240VAC mains to achieve its rated output.

 

[g29]

My point only being that the NC400 does not need 240VAC mains to achieve its rated output.

Read the NC400 thread to find information to the contrary.

 

[Matias]

From the SMPS600 datasheet.

 

[DonH56]

A believe they can only charge the caps during the times the mains is a bit above the required output voltage (assumes they do not up-convert). For a 64V output, I'd estimate that to be about 1.5mS at 115 VAC, 60 Hz, full wave rectified, and about 1.0mS if 230VAC, 50 Hz, full wave rectified.

As I said, hand-waving... I didn't feel it worthwhile to get into phase angles for charge/discharge and all that jazz. For the level the OP was asking, order-of magnitude seemed good enough to get across the concept. I.e. charge 100x faster, get away with 1/100 the capacitor value, for equivalent current flow.

 

[JimB]

As I said, hand-waving... I didn't feel it worthwhile to get into phase angles for charge/discharge and all that jazz. For the level the OP was asking, order-of magnitude seemed good enough to get across the concept. I.e. charge 100x faster, get away with 1/100 the capacitor value, for equivalent current flow.

You are certainly right that the time that the caps in a conventional linear supply needs to hold between recharges is much more. I did not mean to dispute that. Depending how one designs, the rails run at close to peak voltage, so the caps do have to carry the load 8-10 times longer, while sagging/rippling the whole way.

 

[JimB]

From the SMPS600 datasheet.

View attachment 42350

So, with two NC400s, there's higher output with this particular power supply, at 120VAC. I expect that is likely due to 60 vs 50 Hz.

 

[g29]

From the SMPS600 datasheet.

View attachment 42350

It also says this on Page 10, section 8.1:

- 1x400 @ 4Ohm @ 240VAC @ 1%THD+N @ 1kHz when connected to NC400
- 1x300 @ 4Ohm @ 120VAC @ 1%THD+N @ 1kHz when connected to NC400

https://doc.soundimports.nl/pdf/brands/Hypex/SMPS600N400/pdf_Hypex_SMPS600N400_1.pdf

 

[Dion_Sinewave]

I am tri-amping my front speakers and needed 6 channels of NC400. I concluded that 2x stereo boxes with 1x SMPS1200 and 2x NC400 for mid/high range for each speaker plus monoblock for bass each side was the best option in terms of current deliver.

 

[NTomokawa]

I am tri-amping my front speakers

What speakers are those!? How much power are you feeding them!?

 

[Killingbeans]

I'm guessing: What ever they ask for!

 

[Dion_Sinewave]

Slightly modified VAF i93 MK2 Signatures. Probably unknown outside of Australia. Forgive my poor photos but my room is so dark and has a lot of acoustic curtain (theatre black) so it’s very hard to get decent photos in there.

 

[Dion_Sinewave]

All of my amps are 240V too

 

[Dion_Sinewave]

The measurements I get from the NC400 and VAFs are astonishing

 

[Dion_Sinewave]

I definitely don’t want to hijack this very valuable thread about the Purify amps, so I’ll create another in ‘my system‘ or something.

 

[g29]

All of my amps are 240V too

240VAC has its advantages with the SMPS1200.

 

[Dion_Sinewave]

240VAC has its advantages with the SMPS1200.

Yes I studied those specs, and I believe that my stereo amps with SMPS1200s can draw a maximum of 1500 watts each from the wall, so I had a 32 Amp circuit installed with two 16 amp lines to the front of my room. Currently (pun intended) I’m using one 16A circuit per amp, and four normal 240 wall outlets for my (many) other power amps to avoid any possible current limiting. This may be overkill.

 

[dkinric]

This may be overkill.

Is there really such a thing in this hobby? It's more a matter of degree... Nice setup

 

[JimB]

Does anyone know if the DIY Purifi Amp kits are going to see the light of day yet this year ?

As of today, I heard "Yes, it's a bit delayed, but quite soon!" I still understand that the initial DIY offering will be the OEM evaluation kit, which is two modules, an audio interface board and maybe an interconnect cable or two. Essentially, the guts of what Amir tested in this topic, but without a power supply or case. Note that there could be a couple differences in details from the package tested here, such as on-board banana sockets and a mode switch - like in the third picture in Amir's first post.

SO! If you could buy it today, what would you do with it? Have a case lined up? Any other implementation plans?

 

[dwkdnvr]

Someone on the HTGuide diy forum has indicated that if you email Purifi directly you can get pricing for the amp boards. He appears to have purchased a set of boards that look to be the same as what was measured by Amir.

 

[JimB]

Someone on the HTGuide diy forum has indicated that if you email Purifi directly you can get pricing for the amp boards. He appears to have purchased a set of boards that look to be the same as what was measured by Amir.

I am trying to order a kit for evaluation. Buying might be easier in the future once they have a DIY shop set up.