Buckeye Amps: 2nd Generation Purifi EIGENTAKT 1ET9040BA Amplifier

[yys310]

For clarity, this is not one of our customers as far as I am aware

Thanks, but isn't the protection provided by the module itself?
Is there difference in protection between yours 1ET9040BA module amps vs other amps?
Or is it that your amp won't have such problem as he mentioned?
Thanks!

 

[Buckeye Amps]

Thanks, but isn't the protection provided by the module itself?
Is there difference in protection between yours 1ET9040BA module amps vs other amps?
Or is it that your amp won't have such problem as he mentioned?
Thanks!

The module has protection, yes.

More that I cannot comment on the problem he encountered because I don't know his exact setup (such as referencing to "his power supply")

 

[Sokel]

What the f... their short circuit protection, overload protection did not protect this condition?
That's surprising...

Short-circuit and overload is one thing,grounding the (balanced) output of a bridged amp is another.
There has to be a specific protection about it and also stated specifically (and a bold warning also) .

 

[yys310]

Short-circuit and overload is one thing,grounding the (balanced) output of a bridged amp is another.
There has to be a specific protection about it and also stated specifically (and a bold warning also) .

1ET9040BA - Data Sheet (1.10)

 

[Sokel]

View attachment 397047
1ET9040BA - Data Sheet (1.10)

Yes,that's the proper way.
Which makes it odd for the damage that happened.
Without knowing the conditions though we can only speculate.

 

[Full Zhou]

What the f... their short circuit protection, overload protection did not protect this condition?
That's surprising...

It should be protected, but my actual situation did happen, and it happened twice. Both times, the MOSFET burned out. Of course, it happened when I tested with a sine wave. Maybe the music was not a problem. My 9040 module was purchased from the official store of purifi. Due to poor insulation between my terminal post and the chassis shell, when the signal was increased, the terminal post and the chassis leaked and arced, and the cause was found only after the second damage. It has now been repaired and sold.
If I'm not mistaken, the protection threshold of the bridge amplifier is to monitor the sum of the two output currents. When only one side is connected to GND, the current on one side needs to be doubled to activate protection, which should exceed the current that MOSFET can withstand. There should be no problem with a short circuit between OUT+ and OUT-.
Those who have samples can try this operation, maybe it's just this one that has a problem. I dare not do 2OHM sine wave full power test, but those who are brave can try it.

 

[Sokel]

It should be protected, but my actual situation did happen, and it happened twice. Both times, the MOSFET burned out. Of course, it happened when I tested with a sine wave. Maybe the music was not a problem. My 9040 module was purchased from the official store of purifi. Due to poor insulation between my terminal post and the chassis shell, when the signal was increased, the terminal post and the chassis leaked and arced, and the cause was found only after the second damage. It has now been repaired and sold.
If I'm not mistaken, the protection threshold of the bridge amplifier is to monitor the sum of the two output currents. When only one side is connected to GND, the current on one side needs to be doubled to activate protection, which should exceed the current that MOSFET can withstand. There should be no problem with a short circuit between OUT+ and OUT-.
Those who have samples can try this operation, maybe it's just this one that has a problem. I dare not do 2OHM sine wave full power test, but those who are brave can try it.

Conditions matter and matter a lot.
Here's a similar failure running NC502MP BTL at 4 Ohm to torture conditions.
Protections did kicked in but amp was destroyed:

Power amps: continuous output power measurements

Are you measuring built in sub amps or using some sort of external amp for passive sub use? Mostly I wouldn't worry about an amp suited to the powered sub, but would worry more about if you're trying something with a "passive" sub and another amp....

www.audiosciencereview.com

 

[atomek]

Very few, almost no people will use the low gain setting. Most people will need to use the medium or high gain settings to match their source equipment. 4 volt xlr or 2 volt rca. These are the gains where amps should be compared as its most relevant to most users. Otherwise just bypass the input buffer and just claim the Purifi module performance.

Could you tell more about this, I plan to buy this amplifier to power Dynaudio S25 (200W 4ohm) spekars. I calculated required gain: Vout = sqrt(200 * 4) = 28.3 Vrms, Gain = Vout/Vin = 28.3 / 5.2 (my DAC have 5.2 Vrms) = 5.44, so 14.7 dB which is below "low gain" settings of 15.5 dB (which according to calculations could power 240W 4ohm at 100% DAC volume output). Should I use medium gain anyway? Or can I use low gain and maybe even bypass gain?

 

[welwynnick]

Could you tell more about this, I plan to buy this amplifier to power Dynaudio S25 (200W 4ohm) spekars. I calculated required gain: Vout = sqrt(200 * 4) = 28.3 Vrms, Gain = Vout/Vin = 28.3 / 5.2 (my DAC have 5.2 Vrms) = 5.44, so 14.7 dB which is below "low gain" settings of 15.5 dB (which according to calculations could power 240W 4ohm at 100% DAC volume output). Should I use medium gain anyway? Or can I use low gain and maybe even bypass gain?

All your calculations are correct, on the condition that you only want 240W into a 4 ohm load, which would be under-utilising a very capable amplifier.

I wouldn't over-think it. You can change the gain and see for yourself. Set the gain to low and see if it goes loud enough for you. They're quite efficient speakers, so it probably will.

 

[quattro98]

There's a review of the Buckeye Purifi 9040 amp in Stereophile by Kal Rubinson. I saw it via an Apple News+ subscription, so I posted the link below. I assume it will show up on the Stereophile website (and be in the print issue). I couldn't see all of the measurement figures via Apple News+. Not sure why. Perfect for driving your Estelon X Diamond Mk II reviewed in the same issue.

Buckeye PURIFI EIGENTAKT 1ET9040BA1 — Stereophile

Cover

apple.news

 

[Matias]

This will be fun. Can't wait to show up on the Stereophile website.

 

[Kal Rubinson]

This will be fun. Can't wait to show up on the Stereophile website.

Me, too.

 

[Buckeye Amps]

Let me just say, when I first started Buckeye Amps, never ever did I think it would be on the audio radar large enough to be noticed by a publication like Stereophile.

Thanks everyone!

 

[jacktracks707]

Purify Gen 2 three channel just arrived and hooked up. Sounds great for the LCR of Kef R11 metas and R6 Metas. Part of a 9.4.4 system. Denon 6800 is the main brain.

 

[yys310]

Let me just say, when I first started Buckeye Amps, never ever did I think it would be on the audio radar large enough to be noticed by a publication like Stereophile.

Thanks everyone!

Hi,
For this review I subscribed the stereophile for 3mo.
Is the 19kHz+20kHz-IMD measurement result within your exception?

Edit: CCIF --> 19kHz+20kHz

 

[Buckeye Amps]

Hi,
For this review I subscribed the stereophile for 3mo.
Is the 19kHz+20kHz-IMD measurement result within your exception?

Edit: CCIF --> 19kHz+20kHz

Let me look into this further

 

[Sal1950]

Me, too.

Good review Kal !
I got my copy of the Jan 2025 issue last week but just stated reading my way thru it.
Nice honest presentation of the amps great virtues, S-P needs more like this.

Dylan, Better gear up for some increased sales.
Sal