HypeX/PuriFi amplifier products available in the USA?

[CDMC]

Not sure, but in general when bridging an amplifier, it will see 1/2 the impedance as a non bridged amplifier. In this case, it would mean the bridged Purifi modules would be seeing as low as 1.5 ohms, which is quiet low. Hopefully someone here can confirm if this is correct and if so, if it would be an issue.

 

[echopraxia]

Not sure, but in general when bridging an amplifier, it will see 1/2 the impedance as a non bridged amplifier. In this case, it would mean the bridged Purifi modules would be seeing as low as 1.5 ohms, which is quiet low. Hopefully someone here can confirm if this is correct and if so, if it would be an issue.

What sort of issues would that cause? Pardon my ignorance; I'm kind of rushing to research amps to buy a good one to hopefully arrive in a similar time-frame as the new Salon 2's

 

[CDMC]

What sort of issues would that cause?

The power supply will not be able to maintain sufficient voltage resulting in output dropping. Keep in mind an amplifier should act as a perfect voltage source. The amperage required at any voltage is a function of impedance. Half the impedance and double the ampage requirement for a set voltage. It is Ohm's law. The way that most engineers think about it is not to think in watts, but volts. So for the Purufi, it puts out about 42.5 volts. If it had unlimited current capability, it would put out the following outputs:

8 ohms- 225 watts
4 ohms- 450 watts
2 ohms- 900 watts
1 ohm- 1800 watts

Current at these levels would be:

8 ohms- 5.3 amps
4 ohms- 10.6 amps
2 ohms- 21.2 amps
1 ohm- 42.4 amps

The thing is that the Purifi doesn't have unlimited current capability, NO AMPLIFIER DOES. Purifi rates their amplifier to less than 2 ohms with the caveat that "[t]he amplifier is stable into loads <2 ohms. Output power may be limited by the Over Current Protection system." At 2 ohms they also provide that the amp puts out 450 watts "as limited by thermal system". If you take their rated output spec at 2 ohms, it suggests the maximum current the amplifier can supply is 15 amps. At 450 watts into 2 ohms (Purifi's rated output), voltage has dropped to 30 volts. At 1.5 ohms, this means maximum voltage will drop to 22.5 volts and 337.5 watts output.

Now lets bridge two channels. Voltage doubles, impedance seen by the amplifier is 1/2, and current capability is the sum of the two amplifiers (so 30 amps) (correction, I said before voltage was the same, it doubles). So now with a 85 volt maximum voltage and unlimited current the numbers are:

8 ohms (4 ohms seen by the amplifier)- 900 watts
4 ohms (2 ohms seen by the amplifier)- 1800 watts
2 ohms (1 ohms seen by the amplifier)- 3600 watts
1 ohm (.5 ohms seen by the amplifier)- 7200 watts

Current at these levels would be:

8 ohms (4 ohms seen by the amplifier)- 21.2 amps
4 ohms (2 ohms seen by the amplifier)- 42.4 amps
2 ohms (1 ohms seen by the amplifier)- 84.8 amps
1 ohm (.5 ohms seen by the amplifier) - 169.6 amps

But we don't have unlimited current capability. We have 30 amps and that is subject to heat dissipation ability. So bridged the Purifi numbers look like:

8 ohms (4 ohms seen by the amplifier)- 900 watts
4 ohms (2 ohms seen by the amplifier)- 1700 watts
2 ohms (1 ohms seen by the amplifier)- 1800 watts (current limited)
1 ohm (.5 ohms seen by the amplifier)- 900 watts (current limited)

Current at these levels would be:

8 ohms (4 ohms seen by the amplifier)- 10.6 amps
4 ohms (2 ohms seen by the amplifier)- 21.2 amps
2 ohms (1 ohms seen by the amplifier)- 30.0 amps
1 ohm (.5 ohms seen by the amplifier) - 30.0 amps

Because of the limited heat dissipation, when bridging, you will be running closer to the thermal limits and maximum capability of the amplifier more often. It is likely the maximum output at low impedance will be less than my calculations. Bridging also normally doubles distortion and in general amplifiers generate more distortion at lower impedance. THIS IS NOT UNIQUE TO PURIFI, IT APPLIES TO ALL AMPLIFIERS. Given the foregoing, it is generally not the best idea to run bridged amplifiers into low impedance loads and why amplifiers that are rated into 4 ohms loads are rated only down to 8 ohms when bridged.

It is important to note, this is my understanding based on my limited knowledge. I may well be wrong and encourage anyone with more knowledge to correct any mistakes.

https://en.wikipedia.org/wiki/Bridg...nected between,most often used for subwoofers.

 

[echopraxia]

Thanks for the summary and calculations! The ATI seems to cite only 4 ohm loads, so like you say, it's probably not rated for <4 ohm loads.

Given the impedance chart of the Salon 2 drops below 4 ohms at times, I can definitely see why this amplifier is probably not best suited for it. If I assume ATI does high quality engineering and mitigates the stress as much as possible (dealing with heat, etc. as much as possible) perhaps it performs well under its operating specs, but even then yes you'd have to consider the extra distortion which isn't so great for a product at this price.

 

[CDMC]

Note, I modified the prior post to make corrections.

 

[boXem]

Bridging the Purifis is not recommended.

 

[echopraxia]

Bridging the Purifis is not recommended.

To clarify, ATI bridged HypeX modules, not PuriFi modules. Still, I'm sure there are similar problems either way?

 

[boXem]

Ah, missed this. I don't know for the NC500, but I suspect it's the same problem since they share the same connection scheme with the Purifi. The best would be to ask ATI and Hypex.

 

[CDMC]

There is zero point in running bridged Hypex modules. Hypex offers the NC1200 which puts out 400 watts into 8 ohms, 700 into 4 ohms, and 1200 into 2 ohms. Need more, the NC2000 is 1600 watts into 8 ohms, 2500 into 4, and 2000 into 2 ohms. If you need more than that Lincoln makes excellent arc welders.

I would get the Purifi, which should have plenty of power for the Salon 2s. If there is a question of enough power, step it up to the NC1200 and get another 2.5 db of headroom. The only question that needs to be asked is if you want them in a stereo case with long speaker wires, or monoblocks using long XLR and short speaker wires. The simple fact is that at this point in time, there appears nothing to be gained by spending more than what is needed to buy a good Class D amp, unless you have just some whacky insane load.

It may be worth noting, the NC500, while rated into 2 ohms, loses power from 4 ohms (700 watts) to 2 ohms (550 watts). The NC400 is not rated into 2 ohms.

 

[Matias]

Bridging the Purifis is not recommended.

...and yet this:
https://www.audiosciencereview.com/...io-class-d-amp-build-quality.9895/post-438649

 

[boXem]

...and yet this:
https://www.audiosciencereview.com/...io-class-d-amp-build-quality.9895/post-438649

I know about it. They have a trick, it's not a "basic" bridge.

 

[March Audio]

Not sure, but in general when bridging an amplifier, it will see 1/2 the impedance as a non bridged amplifier. In this case, it would mean the bridged Purifi modules would be seeing as low as 1.5 ohms, which is quiet low. Hopefully someone here can confirm if this is correct and if so, if it would be an issue.

Correct. Amps can start to current limit as a result. If you look at the Hypex documentation it specifically mentions this and their modules when used in bridged mode minimum recommended (note its more about current limiting than a specific impedance limitation) impedance rises from 2 to 4 ohms.

 

[echopraxia]

Correct. Amps can start to current limit as a result. If you look at the Hypex documentation it specifically mentions this and their modules when used in bridged mode minimum recommended (note its more about current limiting than a specific impedance limitation) impedance rises from 2 to 4 ohms.

Hi, I was going to PM you but maybe this question will help others too: I really want to buy a stereo setup of your March Audio P451 Purifi monoblock amps, but am having a hard time convincing myself to buy those for $2500 USD versus the Audiophonics option which in addition to having bigger (at least visible) heat sinks and multiple gain switch settings, costs 1500 euros shipped to the US which is roughly $1700 USD.

What would you say to people like me facing this choice? My bias is for March Audio due to all the great support and comments and info you post here

If the cost difference is just due to the dual mono block nature of things, are there any upcoming stereo Purifi units we may look forward to from you?

 

[CDMC]

Hi, I was going to PM you but maybe this question will help others too: I really want to buy a stereo setup of your March Audio P451 Purifi monoblock amps, but am having a hard time convincing myself to buy those for $2500 USD versus the Audiophonics option which in addition to having bigger (at least visible) heat sinks and multiple gain switch settings, costs 1500 euros shipped to the US which is roughly $1700 USD.

What would you say to people like me facing this choice? My bias is for March Audio due to all the great support and comments and info you post here

If the cost difference is just due to the dual mono block nature of things, are there any upcoming stereo Purifi units we may look forward to from you?

I will give my two cents. When you buy a VTV or Audiophonics amplifier, you are buying the economy version of the amplifier. Chinese made cases assembled by people that are likely not technicians. Performance should be good, but due to way the amplifiers are wired, soldering quality, and grounding, may or may not meet the amplifier module's specifications. I own a VTV and am happy with the quality and would gladly purchase another. I also am comfortable soldering if I need to fix anything.

When you pay more for Nord or March you are paying for 1) better quality cases, usually Japanese or Italian, 2) assembly by a tech with experience and skill, 3) careful wiring layout, and 4) better small parts quality (power switch, connectors). With Nord you also have an option of different gain stages for many amps, but the best measuring ones are the factory Hypex and Purifi.

In the case of March, you are also paying for a manufacture that has a full lab with test equipment that is used to confirm the performance of their layout and components. (Nord probably has the same). Finally, the owner of March appears to be very detail oriented, so everything is carefully checked and confirmed.

Also keep in mind, anytime you go from a stereo amp to monoblocks the cost will be higher, you are paying for a second case, power switch, assembly and some small parts. This is apparent when you look at the VTV Purifi amplifiers, the monoblock starts at $689 or $1,378 for the pair, the stereo $959.

 

[echopraxia]

I will give my two cents. When you buy a VTV or Audiophonics amplifier, you are buying the economy version of the amplifier. Chinese made cases assembled by people that are likely not technicians. Performance should be good, but due to way the amplifiers are wired, soldering quality, and grounding, may or may not meet the amplifier module's specifications. I own a VTV and am happy with the quality and would gladly purchase another. I also am comfortable soldering if I need to fix anything.

When you pay more for Nord or March you are paying for 1) better quality cases, usually Japanese or Italian, 2) assembly by a tech with experience and skill, 3) careful wiring layout, and 4) better small parts quality (power switch, connectors). With Nord you also have an option of different gain stages for many amps, but the best measuring ones are the factory Hypex and Purifi.

In the case of March, you are also paying for a manufacture that has a full lab with test equipment that is used to confirm the performance of their layout and components. (Nord probably has the same). Finally, the owner of March appears to be very detail oriented, so everything is carefully checked and confirmed.

Also keep in mind, anytime you go from a stereo amp to monoblocks the cost will be higher, you are paying for a second case, power switch, assembly and some small parts. This is apparent when you look at the VTV Purifi amplifiers, the monoblock starts at $689 or $1,378 for the pair, the stereo $959.

Thanks. I definitely agree with what you’re saying about March Audio and so far thats why I’m leaning towards them (though the price difference of their PuriFi monoblocks seems even larger, so it’s harder to justify than their other products). However I am a bit confused about what you’re saying about Audiophonics and Nord:

• I had thought Audiophonics was fairly well regarded for assembly quality. Is this not true?
• Nord isn’t really any more expensive than Audiophonics and VTV, so I’m not sure why you said “you pay more for March Audio and Nord”. For example, Nord’s PuriFi monoblock is 625 euros, which is only marginally more expensive than VTV.

Lastly, my impression is that Nord is more on par with VTV quality than March Audio. For example, didn’t the Nord One reviewed here on ASR have the polarity of one of the channels reversed? Or was that ever explained away somehow?

 

[JKJ]

I have the bridged ATI AT542NC amplifer, purchased before the NC1200 was available at the more reasonable prices it commands today. I can say that in real world usage driving my Focal Sopra No3 speakers (~2.75 ohms minimum per Stereophile's measurement, so the amp could be seeing as low as 1.375), they have exhibited no "bad behavior". Still, I'm looking closely at the NC1200 just to have some breathing room when running at higher volumes.

By the way, I haven't seen an obvious benefit or drawback from ATI's use of a linear power supply instead of a SMPS. I suspect that's because I don't typically run things hard enough to tax the supply since the Sopras are reasonably efficient. There may be some power supply noise evident if hooked up to an evaluation rig like Amir's, but in practice I hear nothing of the kind from the speakers in use, or with the amp cranked to max with no input signal. I have not evaluated a similar amp with a SMPS in any kind of double blind test. I'm comfortable with the fact that I likely paid more for a linear power supply and the ATI name on the case simply for the sake of a heavier box and a label with some history to fall back upon than for any measurable benefit.

 

[March Audio]

Hi, I was going to PM you but maybe this question will help others too: I really want to buy a stereo setup of your March Audio P451 Purifi monoblock amps, but am having a hard time convincing myself to buy those for $2500 USD versus the Audiophonics option which in addition to having bigger (at least visible) heat sinks and multiple gain switch settings, costs 1500 euros shipped to the US which is roughly $1700 USD.

What would you say to people like me facing this choice? My bias is for March Audio due to all the great support and comments and info you post here

If the cost difference is just due to the dual mono block nature of things, are there any upcoming stereo Purifi units we may look forward to from you?

Hi. So what @CDMC says above covers lot of it. We pride ourselves with attention to technical detail (signal input RF filters as an example) and engagement and support of customers. All the products are run through a suite of technical tests after build to confirm they are wired correctly and perform as they should. Plus a 24 soak test to catch any infant mortality. Thats why we are happy to offer a 3 year warranty which is AFAIK longer than other manufacturers.

Without mentioning names, there is a relatively low bar to clear to start banging out amps and some of the efforts seen on this forum are frankly at amateur DIY level, some aspects even dangerous, which makes me question technical competence and quality control. Our customers dont have to get a soldering iron out to rectify incorrect builds.

We have a satisfaction guarantee. No-one has returned an amp yet

I think a final comment is that we have no intention of trying to compete on price. A race to the bottom only ends up with companies going out of business because they cut corners leading to poor quality and customer satisfaction, plus ultimately they cant cover their costs.

 

[echopraxia]

Hi. So what @CDMC says above covers lot of it. We pride ourselves with attention to technical detail (signal input RF filters as an example) and engagement and support of customers. All the products are run through a suite of technical tests after build to confirm they are wired correctly and perform as they should. Plus a 24 soak test to catch any infant mortality. Thats why we are happy to offer a 3 year warranty which is AFAIK longer than other manufacturers.

Without mentioning names, there is a relatively low bar to clear to start banging out amps and some of the efforts seen on this forum are frankly at amateur DIY level, some aspects even dangerous. Our customers dont have to get a soldering iron out to rectify incorrect builds.

I think a final comment is that we have no intention of trying to compete on price. A race to the bottom only ends up with companies going out of business because they cant cover their costs.

Thanks. This definitely makes sense. The individual testing you do is a huge plus, and currently (from my research so far) one of the biggest things that sets March Audio at the top of my list currently.

It appears that virtually every other budget brand has embarrassingly bad mistakes pop up on people’s units around here (on buyers units who didn’t even realize it), which doesn’t bode well for their overall quality control.

I certainly don’t want to have to open up and do QA myself on a brand new amp costing somewhere around $2000. If I’m going to do that, I might as well DIY it myself.

 

[March Audio]

Oh one more thing, we have become so convinced regarding the products high reliability that we are now covering return shipping costs in the very unlikely event of any problems.

 

[oneforward]

Oh one more thing, we have become so convinced regarding the products high reliability that we are now covering return shipping costs in the very unlikely event of any problems.

Have you shipped to Canada, without issues? Thanks.