HypeX/PuriFi amplifier products available in the USA?

[echopraxia]

Thank you for your reply and I am awaiting your findings echopraxia. I do not understand the practical differences between the two designs (purifi vs hypex) The hypex amp from March Audio being more ‘powerful’ compared to the purifi unit seems to have more ability to drive low sensitivity speakers. OTOH, more watts does not always mean more available current at a given instant in a musical/theatrical passage. And of course there are other factors to consider, how ‘quiet’ the amp is, how fast the circuitry can adapt to changing input voltages,etc.

Yeah it will be interesting, since these are both exceptionally good amps. So, the question will be whether the remaining difference is audible. I just will need to figure out a good way to switch quickly between amps, wait for my March Audio P701’s to arrive (in my posts above you’ll see why that’s happening vs the prior NC1200 build I had), and then I’ll be able to test this.

 

[EB1000]

The 1ET400A only comes with a stereo interface board, which is a deal-breaker for me. I'm still waiting for a monoblock 1ET400A DIY kit.

 

[CDMC]

Are those built on Hypex or Purifi modules? Just not sure how that relates to this topic here. But anyways, personally I can’t see myself ever paying $10k on a pair of amps ever, let alone on ones with no measurements. There’s just so many better things you can do with that much money.

In any case, I’d bet Hypex NC2K would outperform it at a fraction of the cost.

They are AB with two power supplies that vary the rail voltage. Sort of Class G/H but different due to the use of tow power supplies.

 

[CDMC]

OTOH, more watts does not always mean more available current at a given instant in a musical/theatrical passage. And of course there are other factors to consider, how ‘quiet’ the amp is, how fast the circuitry can adapt to changing input voltages,etc.

Be careful falling into this trap, an amplifier only supplies as much current as necessary to maintain the voltage it is supplying. Take for example 100 watts into 8 ohms. This is 28.28v at 3.53 amps. It doesn't matter whether your amp can supply 5 amps of current or 100 amps of current, it will only supply 3.53 amps. If it can't supply 3.53, current becomes the limiter and voltage will sag, decreasing wattage. (I am ignoring phase angle which can change this a bit).

So looking at the hypex and purifi amps, the NC1200 and 1et400 both have plenty of current capability to maintain their power into any reasonable load. In the case of the NC1200 it has 38a of current capability. Running it's power calculations we come up with:

8 ohm @ 400 watts = 56.5v and 7.07 amps;
4ohm @ 700 watts = 52.9 v and 13.22 amps;
2 ohm @ 1200 watts= 49 v and 24.5 amps.

You are not running out of current even into a two ohm load. You will see that voltage sags a bit, a perfect amplifier would not, but there are very few, if any amplifiers that don't have some voltage sag at the rails into lower impedances.

Taking the Purufi 1et400 module, it is capable of 25 amps and notes that the "amplifier is stable into loads <2 ohms. Output power into impedances <3.2 ohms may be limited by the Over Current Protection system." Taking the numbers:

8 ohm @ 227 watts = 42.6 v and 5.32 amps
4 ohm @ 425 watts = 41.2v and 10.3 amps
2 ohm @ 450 watts = 30v and 15 amps.

So with the Purifi we see that when we get down to 2 ohms, it did what the manufacture said, it limited the current to 15 amp and the voltage dropped. If we calculate output at 3.2 amps, assuming we are still at a 41v rail voltage, we get 12.8 amps of current and 525 watts.

So here is the really important thing, these numbers only apply with the amps are right up against their clipping point. At anything less voltage and in turn amp requirements drop a great deal.

As far as how quiet both amps are, they are both well below the level you will ever hear, at least 110db. The only difference is that one amp will give you an additional 3-4db of sound output capability over the other.

 

[skypickle]

@CDMC thank you for that explanation. Yes, in the graphs where the THD is graphed against power output, I see the number getting lower and lower until some magical point where it explodes upwards. Yet two manufacturers that use the same NC1200 module (March audio P701 and Apollon PNC2k) have different power measurements. And the Apollon stateS 48 amps of current capability. Clearly I am not knowledgeable about the other components that might be boosting the 38 amp number to 48 amps.

@EB1000 Some purifi based amps using the 1ET400 A are monoblocks (MarchAudio P451) so I do not understand your statement About them being stereo.

 

[CDMC]

@CDMC thank you for that explanation. Yes, in the graphs where the THD is graphed against power output, I see the number getting lower and lower until some magical point where it explodes upwards. Yet two manufacturers that use the same NC1200 module (March audio P701 and Apollon PNC2k) have different power measurements. And the Apollon stateS 48 amps of current capability. Clearly I am not knowledgeable about the other components that might be boosting the 38 amp number to 48 amps.

@EB1000 Some purifi based amps using the 1ET400 A are monoblocks (MarchAudio P451) so I do not understand your statement About them being stereo.

The max the Nc1200 is capable of is 38 amps. Apollon likely has a typo on their website.

 

[Soundstage]

The current Purifi offering should be more than enough power for the Salon2 2 speakers. From the Stereophile measurements:

"My estimate of the Revel Ultima Salon2's voltage sensitivity was 86dB(B)/2.83V/m. This is slightly lower than the specified 86.4dB but within experimental error of that figure. The speaker's impedance (fig.1) drops to between 3 and 5 ohms between 17Hz and 600Hz, but as the electrical phase angle is generally low in this region, the Salon2 should not be hard for the partnering amplifier to drive."

Running that through the home theater calculator (which Floyd Toole says underestimates volume) I come up with 107 db at a 12 foot listening distance (105 db at 15 feet) with the 450 watts available from the Purifi into 4 ohms. This comfortably exceeds the very loud THX/Dolby specifications for home theater (105db for very large rooms). Even if Purifi comes out with a new amp that is double the power, you would only be picking up 3db that is highly unlikely you would ever get close to using.

What about the 45 degree phase angle? Wouldn’t that double the power needed into 4 ohms?

 

[echopraxia]

@CDMC thank you for that explanation. Yes, in the graphs where the THD is graphed against power output, I see the number getting lower and lower until some magical point where it explodes upwards. Yet two manufacturers that use the same NC1200 module (March audio P701 and Apollon PNC2k) have different power measurements. And the Apollon stateS 48 amps of current capability. Clearly I am not knowledgeable about the other components that might be boosting the 38 amp number to 48 amps.

@EB1000 Some purifi based amps using the 1ET400 A are monoblocks (MarchAudio P451) so I do not understand your statement About them being stereo.

The Apollon PNC2K uses the much higher powered Hypex NC2K modules.

 

[Rick Sykora]

What about the 45 degree phase angle? Wouldn’t that double the power needed into 4 ohms?

In general, yes. For the Salon 2, it barely gets to 45 degrees around 700 Hz and the impedance there is about 6 ohms. Would not appear to be a major issue for any amp that can handle 4 ohm loads.

 

[kukocz]

The 1ET400A only comes with a stereo interface board, which is a deal-breaker for me. I'm still waiting for a monoblock 1ET400A DIY kit.

Ask Purify directly (I asked them about that over a month ago but I ended up with a stereo kit). Two mono kits will be more expensive than eval1.