Buckeye Purifi Eigentakt 1ET9040BA monoblock power amplifier Stereophile Measurements

[David_M]

@MicroAudio, is it safe to say that if your power supply is used (please state which one) instead of the Hypex ones, then the 9040BA will meet its rated specs? Thanks!

 

[David_M]

Can't you just read that off their website?

Buckeye Amps

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

I did and they seemed to be straight from Purifi's datasheet, like many vendors do. Its not clear if these were AP measured or not... and I seem to recall him saying they no longer have access to the AP audio measurement system anymore. Hence the need for a clarification.

 

[KSTR]

1. Nowhere in the 1ET9040BA datasheet is the power supply module used for the datasheet specs listed.. For all we know, they could have used an industrial beefed up lab bench power supply for their tests! But no Hypex PS listed anywhere in the datasheet. This is a serious and glaring oversight imho. It could explain why no vendor is able to get the datasheet spec'd 1% THD 1400W of power in 2 ohms using the recommended Hypex PS.

Using a lab supply is the only correct way to spec a module, engineering-wise. You want to have clean reproducible conditions, and such conditions as not to degrade performance. You want to know want the module is capable of, best-case. Same strategy why eg DAC measurements are made under idealized lab conditions.

For the same reasons, power supplies themselves are specified using a mains synthesizer.

@Buckeye Amps , can you please help put this conflict to rest? How much power is available from the 1ET9040BA using the recommended Hypex A180 power supply at 2 ohms with 1% THD. Thanks!

Please note that the Hypex supplies are unregulated in that the output scales with mains voltage, which may not be nominal to begin with and may also sag under load (notably in 115V range countries).
And remember that output power goes with output voltage (or current) squared, so when your mains is 10% off, output power will be like 20% off.
Therefore, unless you have a mains synthesizer at hand, output power values can vary quite a bit. Ideally, one should also measure/log rail voltages during the test.

 

[David_M]

Using a lab supply is the only correct way to spec a module, engineering-wise. You want to have clean reproducible conditions, and such conditions as not to degrade performance. You want to know want the module is capable of, best-case. Same strategy why eg DAC measurements are made under idealized lab conditions.

For the same reasons, power supplies themselves are specified using a mains synthesizer.


Please note that the Hypex supplies are unregulated in that the output scales with mains voltage, which may not be nominal to begin with and may also sag under load (notably in 115V range countries).
And remember that output power goes with output voltage (or current) squared, so when your mains is 10% off, output power will be like 20% off.
Therefore, unless you have a mains synthesizer at hand, output power values can vary quite a bit. Ideally, one should also measure/log rail voltages during the test.

Ok, you've made a very fine point...But doesn't the Hypex PS produce a constant output AC voltage, regardless of the AC variations on its inputs?

Purifi should state these test conditions precisely in their datasheets or even let the user know how fungible their power ratings can be based on line voltage conditions.

 

[KSTR]

But doesn't the Hypex PS produce a constant output AC DC voltage, regardless of the AC variations on its inputs?

No:

 

[KSTR]

Purifi should state these test conditions precisely in their datasheets or even let the user know how fungible their power ratings can be based on line voltage conditions.

They did, that's why datasheets have the "Typical" column, as the frame of reference:

EDIT: As a general note, engineering datasheets are written in a condensed fashion for engineers who can figure out the consequences of different conditions themselves.
"Noob info", if available at all, is usually contained in user/application manuals.

 

[David_M]

No:

View attachment 418894

Thanks for the correction ... its a pity they rated only for 240Vac supplies and not 120VAC knowing that the majority of their end users will be North American based.

 

[David_M]

They did, that's why datasheets have the "Typical" column, as the frame of reference:
View attachment 418896

View attachment 418895

Cool ... btw, is it possible to design a mains invariant power supply that produces a constant VDC output? The VP+ delta and VP- delta are simply too wide for comfort, imho.

 

[KSTR]

Thanks for the correction ... its a pity they rated only for 240Vac supplies and not 120VAC knowing that the majority of their end users will be North American based.

Not correct again, the module is fully rated for 115V and 230V operation and the corresponding min and max values. In the footnote to be applied they only referred to the 230V range of voltages to keep the information compact.

 

[SIY]

I wasn’t familiar with that place. I spent 10 minutes reading, and I won’t spend another one.
This particular thread is a tough read:

Spoiler: The lone warrior

Pseudoscience in audio - Milind N. Kunchur

audiophilestyle.com

Why Paul engages with a stunningly dishonest guy like Frank eludes me. How many forums has Frank been banned from now...?

 

[KSTR]

Cool ... btw, is it possible to design a mains invariant power supply that produces a constant VDC output? The VP+ delta and VP- delta are simply too wide for comfort, imho.

Yes, and some manufacturers do that, offering fully regulated supplies.
The line voltage dependency of the Hypex supplies is indeed not optimal and a source of confusion. It could even be dangerous, running a Purifi module above maximum voltage when line voltage is high.

 

[Sal1950]

Why Paul engages with a stunningly dishonest guy like Frank eludes me. How many forums has Frank been banned from now...?

A few that I know of, including here.
He seems to live to troll sites and wind people up.

 

[David_M]

Yes, and some manufacturers do that, offering fully regulated supplies.
The line voltage dependency of the Hypex supplies is indeed not optimal and a source of confusion. It could even be dangerous, running a Purifi module above maximum voltage when line voltage is high.

Then I say its best to precede these Hypex/Purifi amps with AVRs (automatic voltage regulators) that will not limit the line current from the wall but produce a constant 120VAC or 240VAC output to the Hypex inputs.

 

[Sokel]

I hope no one complains about PSU demands,I did my best to make Purifi built one so this thing work,next step is to learn the team's dirty secrets and blackmail them

Seriously now,the gap is abysmal,is not only about power,is about the premium and quality feeling a Purifi PSU will bring,let alone peace of mind.

 

[MicroAudio]

I hope no one complains about PSU demands,I did my best to make Purifi built one so this thing work,next step is to learn the team's dirty secrets and blackmail them

Seriously now,the gap is abysmal,is not only about power,is about the premium and quality feeling a Purifi PSU will bring,let alone peace of mind.

 

[Salt]

25 minutes to reply ...Respect

 

[tmtomh]

I wasn’t familiar with that place. I spent 10 minutes reading, and I won’t spend another one.
This particular thread is a tough read:

Spoiler: The lone warrior

Pseudoscience in audio - Milind N. Kunchur

audiophilestyle.com

Yes, and thanks for finding and linking to that old thread there! It's a great example of what happened when the "Objective-Fi" subforum was created. The Orwellian abuse of scientific concepts there is just - well, I won't say it's surprising, but it's striking nonetheless.

 

[MicroAudio]

@MicroAudio, is it safe to say that if your power supply is used (please state which one) instead of the Hypex ones, then the 9040BA will meet its rated specs? Thanks!

Hi David,

With the SMPS1K-SN I pulled 1200W at 2 Ohms.

The SMPS output voltage in idle was +-47VDC and +-45VDC with the 1ET9040 module loaded 1200W.

Sadly, a screwdriver slipped underneath the 1ET9040 module and destroyed it during my test.

Now I am waiting for a new 1ET9040 module from Purifi to be shipped soon.

The SMPS1K-SN has active power factor corrector and the output voltage will remain the same at any AC input voltage range 120~260VAC

Thanks

 

[Salt]

DAC/DSP is done, amplification is done, next shootout goes to power supply ...

 

[Buckeye Amps]

My question would be what would an SMPS race consist of?

What is missing from a high quality offering like Micro Audio that would somehow further advance performance?