Buckeye Purifi Eigentakt 1ET9040BA monoblock power amplifier Stereophile Measurements

[Julf]

No, I can't. I am not computer literate enough to do so, I don't stream. I use analog sources (Reel to Reel, cassette decks, Turntables, CD, DVD, Blu Ray & 4K.

Just have to point out that CD, DVD and Blu-ray are all digital sources.

(Population: 140 people per square kilometer) and slowly going up. Another few years & it might be time to move further out.

Pretty nice! I know a bunch of that kind of places in my native Finland, not much chance of that here in the Netherlands (with a rather different population density).

 

[antcollinet]

No, I can't. I am not computer literate enough to do so, I don't stream. I use analog sources (Reel to Reel, cassette decks, Turntables, CD, DVD, Blu Ray & 4K.
My system does not have either a computer or TV (although there is a 32" monitor for my videos). It is not hooked to the internet in anyway & is not in the same room as my communications desktop that I am on now.
While I know what information that you are talking about, I have no idea of how to go about getting that information.
I do know that if music/singing doesn't have great level changes (dynamic range 12 or above according to some computer internet site that I have seen), I am probably not listening to it. Unless it is some of my 78's from the 1920's.
I do not do general social media with either my computer or my phone. (I would have to stand on my deck within a 1/3 meter zone to have a phone conversation or I loose the signal. (It keeps conversations short & sweet). And I don't get a decent enough signal where I live to do any of those things, anyway.
I can literally fish of my deck & I see many kayakers a day & ZERO cars other than my own unless I leave my place to go somewhere.
Grocery shopping is about a 50 kilometer drive each way.
(Population: 140 people per square kilometer) and slowly going up. Another few years & it might be time to move further out.

Old school - love it.

Just have to point out that CD, DVD and Blu-ray are all digital sources.

I'm going to guess - not when it comes out of the player it isn't

 

[EJ3]

Just have to point out that CD, DVD and Blu-ray are all digital sources.

Pretty nice! I know a bunch of that kind of places in my native Finland, not much chance of that here in the Netherlands (with a rather different population density).

I did not think that I needed to point that out to others.
Obviously, you understood that those are not my analog sources, I figured that most people are at least as smart as us & would also know that. (without a notation being required).

 

[EJ3]

Pretty nice! I know a bunch of that kind of places in my native Finland, not much chance of that here in the Netherlands (with a rather different population density).

I think that there are some places in my born country of Austria (Salzburg) that are that way, too.
But, I am not sure, as I have not been there since 1990.

 

[EJ3]

Just have to point out that CD, DVD and Blu-ray are all digital sources.

Pretty nice! I know a bunch of that kind of places in my native Finland, not much chance of that here in the Netherlands (with a rather different population density).

I guess that I should have put and (or &), sometimes I get lazy, I guess.

 

[Julf]

I think that there are some places in my born country of Austria (Salzburg) that are that way, too.

And in Salzburg there are hills. That is something I miss here in the Netherlands (called that for a reason).

 

[pma]

And in Salzburg there are hills. That is something I miss here in the Netherlands (called that for a reason).

I spend one holiday week every year in Austria, not far from Salzburg. Hills are good, both in the countryside and in music.

 

[EJ3]

And in Salzburg there are hills. That is something I miss here in the Netherlands (called that for a reason).

Hills at my home from 2003-2018: Saipan (never goes below 20 C or above 33 C) and at the bottom of the hills

 

[David_M]

Its nice (and a bit odd) seeing someone reacting to my English posts in French, a language I do not speak nor know anything about. Hope the translation was perfect!

 

[Fidji]

According to Crowns on-line calculator, one gets 85 dB SPL with 20 dB headroom at 2,5 meters listening distance with 2x50W (at 8 ohm) amplifier and 8 ohm speakers with 88 dB/1W/1m sensitivity (assuming typical 3dB room gain and normal stereo two speaker set up).

Imho, this is easily enough for any sane person in home audio set up. Speakers with 88 dB sensitivity are nothing special, and someone who is after high SPL is hardly using small low sensitivity bookshelf speakers anyway.

Sure, for insanely high volumes, big spaces and long listening distances, the the power requirement raises logarithmically i.e. very sharply, but I'm quite confident that most of us don't have to worry about that.

More quality watts - good. More Amperes - good.

1et65020 good, 1et9040 gooder

(can not write it more simply).

 

[David_M]

More quality watts - good. More Amperes - good.

1et65020 good, 1et9040 gooder

(can not write it more simply).

You wanna know something funny? The 1et6525, measures better than its higher powered 1et7040 though. Its noise specs are closer to the 9040 than the 7040 amp. In terms of power 6532 < 7040 < 9040.

 

[Salt]

 

[antcollinet]

According to Crowns on-line calculator, one gets 85 dB SPL with 20 dB headroom at 2,5 meters listening distance with 2x50W (at 8 ohm) amplifier and 8 ohm speakers with 88 dB/1W/1m sensitivity (assuming typical 3dB room gain and normal stereo two speaker set up).

Imho, this is easily enough for any sane person in home audio set up. Speakers with 88 dB sensitivity are nothing special, and someone who is after high SPL is hardly using small low sensitivity bookshelf speakers anyway.

Sure, for insanely high volumes, big spaces and long listening distances, the the power requirement raises logarithmically i.e. very sharply, but I'm quite confident that most of us don't have to worry about that.

Are you sure about that - in crowns calculator I've found and plugged in those figures, you need 2x80W (the calculator seems to have no inputs for room gain or two speakers, so I've subtracted 3dB for each from the headroom to compensate)

But now perhaps your speakers only have 85dB sensitivity - so you need 2x160W. And if your listening distance is actually 3m (only 50cm further) - now you need 225W

Finally, what happens if every now and then when the family is out and you like to really crank it to 95dB - now you are looking at 2250W.

And we haven't had to go to anything insane for that. Individual cases need to be considered individually.

 

[Salt]

Game of numbers ...
Two and a half men Kilowatts are good to fry any Coil within a second .... and at only 95 dB?
We are talking about micro impulses, not?

 

[Sokel]

Game of numbers ...
Two and a half men Kilowatts are good to fry any Coil within a second .... and at only 95 dB?
We are talking about micro impulses, not?

Everything at this range are probably ms.Bear in mind though but the VC mentioned can may be true for a tweeter of or mid.
A nice woofer's 3" (or bigger) VC on the other hand can take a lot more and that's where the power is needed.

And all the above at sane practices.If we take for example this new (wrong) trend of filling dips down low to get this nice,straight line we see at the charts power demands can skyrocket.
Imagine filling a 10dB dip at 50's for example,or couple of them as it's usually the case down low.2kW may be not enough
A little clipping led is a life-savior sometimes.

 

[antcollinet]

Game of numbers ...
Two and a half men Kilowatts are good to fry any Coil within a second .... and at only 95 dB?
We are talking about micro impulses, not?

Sure - sub 50ms transients perhaps that you don't want to clip.

But my point is not that everyone needs to go out and buy multi kW amps, just that the 50W-is-plenty only applies in some applications. I think more typical is going to be in the illustration above somewhere between step 2 and 3 (so in the 100W to 250W region)

I have 2x100W on tap, am at only 2m distance, in a small room and speakers at 87dB sensitivity. Sometimes (on those family out of the house occasions), I'd like a little more oomph.

 

[Salt]

Everything at this range are probably ms.Bear in mind though but the VC mentioned can may be true for a tweeter of or mid.
A nice woofer's 3" (or bigger) VC on the other hand can take a lot more and that's where the power is needed.

And all the above at sane practices.If we take for example this new (wrong) trend of filling dips down low to get this nice,straight line we see at the charts power demands can skyrocket.
Imagine filling a 10dB dip at 50's for example,or couple of them as it's usually the case down low.2kW may be not enough
A little clipping led is a life-savior sometimes.

Well, there are woofers that are confirmed reliable to stand 1 kW and more, but that is PA stuff mostly.
I've seen 1,5 mm coil's isolation melting with 2+ Ampere current for producing Backlack coils at Mundorf: it did not take 2 seconds an it was finished (baked).
Now imagine these tiny strips of coil windings .....
I don't say there is no field to inject high power, but in home hifi needs ....

 

[Sokel]

I don't say there is no field to inject high power, but in home hifi needs ....

I won't speak for myself as my setup is unusual and my listening room big.
But as a known example,lets not go far,see Amir's set-up for example at a big room.He has stated time and time again that he manages to clip his kW amps.
Or Erin in a similar fashion,though with a lot less power on tap.

It's user-depended all the way,there's no norm to it.

 

[David_M]

It bears to say that the limiting factor with these new Purifi amps will be the buffer board. The excellent datasheet specs of the 9040BA for example where sourced by a truly reference source, the AP measurement system which is ultra noise free and superb in every way. Costs more than $50K plus options.

Our usual OP1612 or Weiss OP base buffer or Sparkos, etc are not AP quality, ofcourse, so they will be the great limiting factor. The Purifi module has a THD+N less than -130dB or better per its datasheet. With these buffer boards, based on their design, layout and shielding, expect that spec to drop by more than 10dB to -110 or worse as a realistic spec.

This does not take into account the style of wiring inside the amp case. Are the high current/high voltage/high slew rate wires just casually passing over the sensitive buffer board? If so, expect a significant noise penalty. Are these wires twisted or not? If not, looking at you VTV amplifiers, radiated EMI bleeds into the audio buffer to raise distortion even further. Let's not forget radiated emissions from an unshielded and/or poorly placed switch mode power supply.

Lastly, the 9040BA has a rated 4.5uV noise floor and a 14.4dB gain. A buffer's output noise scales with its gain, so to get the typical 26dB total gain, like analog amplifiers, the buffers gain stage will gain up its output noise by 12dB, not including the voltage and current noise contribution of its gain resistors and the opamp itself, etc

Anyways, by the time you figure out all these things, the final noise penalty will be severe. March Audio specs a THD+N or -115dB (0.00017%) to -119dB (0.00012%), depending on output power level for their P801 9040 based mono amp. It has an SNR of -136dB (!) per the website verses the -140dB of the 9040BA module . This is excellent and superb and probably the best out there.

Even specs from another 9040 amp from Cymax, amp with crazy shielding has a -106dB THD+N spec (0.0005%) and an SNR of 118dB, despite having an ultra low noise Weiss OP opamp (see last page of user attached datasheet).

Lesser capable vendors amplifiers will produce worse specifications than March Audio. We should demand vendors to publish measured specs of their amplifiers as a complete system and not claim those of the Purifi modules alone.

 

[Buckeye Amps]

Here is a quick and dirty IMD 19+20kHz measurement of the monoblocks shipping out to JA (Stereophile) on Wednesday.