Buckeye Amps: 2nd Generation Purifi EIGENTAKT 1ET9040BA Amplifier

[Buckeye Amps]

Want to emphasize "quick and dirty" again. Will be following up with a more dialed in IMD and power sweep measurements after tweaking our rig a little more. Can at least confirm the amps do not shut down at half power....for instance 4ohms reaches over 700w under 1% as expected.

Quick point was just to show that, yes, the original review unit had a defective module.

 

[jruser]

Want to emphasize "quick and dirty" again. Will be following up with a more dialed in IMD and power sweep measurements after tweaking our rig a little more. Can at least confirm the amps do not shut down at half power....for instance 4ohms reaches over 700w under 1% as expected.

Quick point was just to show that, yes, the original review unit had a defective module.

Stereophile said he operated the amp at 30 minutes at moderate power before testing. Any chance you could do similar before a power sweep?

 

[Buckeye Amps]

Stereophile said he operated the amp at 30 minutes at moderate power before testing. Any chance you could do similar before a power sweep?

Absolutely

 

[tmtomh]

Stereophile said he operated the amp at 30 minutes at moderate power before testing. Any chance you could do similar before a power sweep?

Why ask Dylan to do a rather randomly selected test that's only done by one publication and is most notably not the specific test some of our more... insistent members here have been requesting anyway?

 

[Buckeye Amps]

Why ask Dylan to do a rather randomly selected test that's only done by one publication and is most notably not the specific test some of our more... insistent members here have been requesting anyway?

I think in this case it is to cover all bases in case Stereophile runs into the amp shutting down at half power again (which it has not done on our end). This way we can at least say "Well, using your specific circumstances we did not run into that issue".

 

[pma]

It will pass the 30 minute preconditioning without problem.

 

[jruser]

I think in this case it is to cover all bases in case Stereophile runs into the amp shutting down at half power again (which it has not done on our end). This way we can at least say "Well, using your specific circumstances we did not run into that issue".

Yeah, this was basically my thought. Double check that heat soak wasn’t causing the protection on the 8-ohm sweep, etc.

 

[Old_School_Brad]

Why ask Dylan to do a rather randomly selected test that's only done by one publication and is most notably not the specific test some of our more... insistent members here have been requesting anyway?

It’s not a randomly chosen test because:

A) It’s the method Stereophile uses and plans to continue using, and
B) It loosely aligns with the FTC’s 30-minute test rule, which is also why Stereophile adopts it.

You could also view it as a form of quality control for your product and brand, ensuring, as much as possible, that no issues arise -especially given what happened the first time. I would replicate the test 1:1 before shipping it to testing. It seems like the logical thing to do.

 

[tmtomh]

It’s not a randomly chosen test because:

A) It’s the method Stereophile uses and plans to continue using, and
B) It loosely aligns with the FTC’s 30-minute test rule, which is also why Stereophile adopts it.

You could also view it as a form of quality control for your product and brand, ensuring, as much as possible, that no issues arise -especially given what happened the first time. I would replicate the test 1:1 before shipping it to testing. It seems like the logical thing to do.

(A) is a good point - I hadn’t considered that, but as someone noted above, it would provide a proactive check just in case Stereophile were to come up with a strange result. So I agree with you on that.

As for (B) we’re going to have to continue to agree to disagree - me entire point was that any number of different test procedures can be said to conform to the insufficiently precise terms of 2024 FTC; and when one widens the net to “loosely aligns” and shifts from a 5-minute test to a different 30-minute one, then we’re back to a wide range of different tests, which is the opposite of a standard.

 

[Old_School_Brad]

(A) is a good point - I hadn’t considered that, but as someone noted above, it would provide a proactive check just in case Stereophile were to come up with a strange result. So I agree with you on that.

As for (B) we’re going to have to continue to agree to disagree - me entire point was that any number of different test procedures can be said to conform to the insufficiently precise terms of 2024 FTC; and when one widens the net to “loosely aligns” and shifts from a 5-minute test to a different 30-minute one, then we’re back to a wide range of different tests, which is the opposite of a standard.

I think you might be confusing the 5-minute full-power test with the 30-minute preconditioning test.

The standard is what it is, and I applaud Stereophile for attempting to interpret and implement it. In my opinion, that’s better than doing nothing, which would also go against the regulation. This seems to be a transitional phase where regulations are still being interpreted, and things are a bit unsettled until a common approach is agreed upon. It’s possible an addendum will be issued with specific clarifications, or, as is typical in the EU with standards and norms, a guideline might eventually be published.

 

[Neuropsychology]

Want to emphasize "quick and dirty" again. Will be following up with a more dialed in IMD and power sweep measurements after tweaking our rig a little more. Can at least confirm the amps do not shut down at half power....for instance 4ohms reaches over 700w under 1% as expected.

Quick point was just to show that, yes, the original review unit had a defective module.

by tweaking the rig you mean your measurement instruments not the amp right? I actually ordered from you (2ch 2nd gen purifi) about a week ago hoping everything goes smoothly with mine!

 

[Buckeye Amps]

by tweaking the rig you mean your measurement instruments not the amp right? I actually ordered from you (2ch 2nd gen purifi) about a week ago hoping everything goes smoothly with mine!

Measurement setup, yes.

 

[JustJones]

Where did the idea that a 5 minute test is a method Stereophile is going to continue to use? Quick perusal of their amplifer reviews in December last year I only found 1 they did a 5 minute test on , Buckeye amp, and 2 they didn't, Moon 861 December 4, . The most recent December 27 review of the Gryphon Diablo 333 I didn't see a 5 minute test maybe I overlooked it.

 

[restorer-john]

Where did the idea that a 5 minute test is a method Stereophile is going to continue to use? Quick perusal of their amplifer reviews in December last year I only found 1 they did a 5 minute test on , Buckeye amp, and 2 they didn't, Moon 861 December 4, . The most recent December 27 review of the Gryphon Diablo 333 I didn't see a 5 minute test maybe I overlooked it.

Perhaps the items in question were submitted/organized for Stereophile's review before the latest amendments to the rule came into play? The Buckeye product is likely new, post rule amendment.

You'd have to ask @John Atkinson, but I expect there would be a transition period for review samples in the queue or in the subjective reviewers' hands.

 

[David_M]

Dylan:

1. Did you receive the faulty amp back from Stereophile and validate their IMD measurements? I hope you returned the faulty module back to Purifi for replacement.

2. Have you generated Power vs Frequency curves to verify whether the 9040 delivers the same power at 20Hz, 1kHz and 20kHz into 2,4, and 8 ohms? Inadequate storage capacitance has capped low frequency power performance of many class D amps. Easy to deliver rated power at 1kHz but not so much at 20Hz for the rated distortion level.

 

[Buckeye Amps]

Dylan:

1. Did you receive the faulty amp back from Stereophile and validate their IMD measurements? I hope you returned the faulty module back to Purifi for replacement.

2. Have you generated Power vs Frequency curves to verify whether the 9040 delivers the same power at 20Hz, 1kHz and 20kHz into 2,4, and 8 ohms? Inadequate storage capacitance has capped low frequency power performance of many class D amps. Easy to deliver rated power at 1kHz but not so much at 20Hz for the rated distortion level.

1) Yes, the review amps were sent back well before the article was published
2) No

 

[David_M]

1) Yes, the review amps were sent back well before the article was published
2) No

On the 2nd item, can you let us know whether the amps meet their rated power specs at 20Hz?

 

[Buckeye Amps]

On the 2nd item, can you let us know whether the amps meet their rated power specs at 20Hz?

I'll certianly let you know the 1kHz power sweep as planned.

 

[RickS]

…Have you generated Power vs Frequency curves to verify whether the 9040 delivers the same power at 20Hz, 1kHz and 20kHz into 2,4, and 8 ohms? Inadequate storage capacitance has capped low frequency power performance of many class D amps. Easy to deliver rated power at 1kHz but not so much at 20Hz for the rated distortion level.

Which Class D amps are capped at 20 Hz? Have not seen this issue on Hypex or Purifi amps or are you comparing them to inexpensive Class D chip amps? Even the Purifi data sheets do not include measurements at 20 Hz. However, if you look at Amir’s review of the Hypex NCx500, it does well with a comparable Hypex SMPS1200 supply…

Btw, there are other ASR threads where power performance has already been discussed by Amir and other experts.

 

[mdunjic]

or you could buy a new Buckeye amp every year for 25 years.

Exactly … pretty much … but I don’t believe one even needs to … I am sure Buckeye would be happy to fix or replace it … I am happy with my 2-ch power amp based on ‘smaller’ Purifi 1ET400A module. Works like a charm so far.