Buckeye Amps: 2nd Generation Purifi EIGENTAKT 1ET9040BA Amplifier

[shion_ca]

Monarchy SM-70 pro.
Not really. If I could describe it in one word it would be better presence. Maybe grip as others have said. The Buckeye monos are very nice, very happy.
Contrary to many who believe they don't need a break in period, I believe it. I've just left them on for past week + and they "seem" to have gotten better out of the box.

Now they're all going to demand you arrange a proper blind A/B test involving time travel! God help me if they ever see the cones I have my setup on

 

[CLT]

Now they're all going to demand you arrange a proper blind A/B test involving time travel! God help me if they ever see the cones I have my setup on

No worries, I'm armed with silence.

Show us the cones!!

 

[shion_ca]

No worries, I'm armed with silence.

Show us the cones!!

Once Dylan ships me the mono’s I will put giant power cables, cones, and every audiophile cringe thing I can think of on them and post pics

 

[Julf]

Now they're all going to demand you arrange a proper blind A/B test involving time travel! God help me if they ever see the cones I have my setup on

No, we simply disregard the subjective, personal perceptions that don't correlate with objective reality.

 

[goryu]

Once Dylan ships me the mono’s I will put giant power cables, cones, and every audiophile cringe thing I can think of on them and post pics

someone beat you to it...

 

[Buckeye Amps]

Hey @Buckeye Amps. Can I ask about the gain settings? Will it get to full power with a RCA source? 25dB seems low.

View attachment 386324

Full power output with High gain requires 2.9V
So it depends on what the source is capable of outputting over its RCA preouts.

 

[Buckeye Amps]

Thanks. Aren't most rca 2 volt?
Is the amp design finalised? Your measurements show only 104dB sinad with high 2nd and 60Hz

Design is finalized and listed on the site, yes.

 

[Sokel]

Thanks. Aren't most rca 2 volt?
Is the amp design finalised? Your measurements show only 104dB sinad with high 2nd and 60Hz
k

???
High H2 at -120dB?Given the fact we can't hear it even at -60dB?
I think ASR has spoiled us!

 

[yys310]

???
High H2 at -120dB?Given the fact we can't hear it even at -60dB?
I think ASR has spoiled us!

That's not how people here response when they see machine with 80dB or 90dB SINAD.

 

[Buckeye Amps]

FWIW, our AP unit (baseline) has an inherently higher H2 then would be expected from an AP unit.

 

[Sokel]

That's not how people here response when they see machine with 80dB or 90dB SINAD.

Maybe for DACs or line-level signal devices,yes,that would show poor engineering.
For amps on the other hand depends on power,most importantly gain,etc.

I would be very happy with an amp of 90dB SINAD all over 20Hz-20Khz and with a good SNR at the same range with a healthy 25-28dB gain which also delivers good amounts of power.

 

[RickS]

Ha. Your point is taken, but isn't this module supposed to have better noise distortion than the 1et400? The results are worse. Big 60hz also suggests something is wrong.

What @Buckeye Amps mentions as analyzer distortion is more likely in the test rig. Unlikely it is the new design but at -120 dB is minutiae. My analyzer is good to about -120 dB and so these “peaks” are not even visible as they are buried in the noise floor. While good to be thorough, you can chase inaudible artifacts exhaustively but be out of business as you never ship.

Buckeye’s designer is an electrical engineer and has significant professional experience. I have served as a black box quality check for most of the designs. While not perfect, it is certainly a better development process than for a typical hobbyist box. As for comparison to 1ET400A, at these levels, needs to be done on the same test rig and same conditions for an accurate comparison.

P.S. As I missed earlier, will point the analyzer distortion issue does show in Buckeye's posted loopback. The 60 Hz spike may be a slight grounding issue, but as I mentioned, was not significant in my measurements. Could be a test setup issue. They are still debugging the test system.

 

[Buckeye Amps]

Ha. Your point is taken, but isn't this module supposed to have better noise distortion than the 1et400? The results are worse. Big 60hz also suggests something is wrong.

Your original post quoted the High gain measurement. If you compare apples to apples (gain to gain) it does have better noise distortion.

 

[Buckeye Amps]

Not really

In any case, the 9040 must have higher gain to reach full power output. If it's all down to the analyser, let's wait and see what Amirs measurements are.

That is measurements of the 1ET7040SA model from Boxem (the model number in the chart is mislabeled.
Either way, from the same review you can see that switching to Low gain on that amp, the SINAD barely changes (stays around 106dB). Whereas Low gain on the 9040 goes down to 110dB.

 

[Buckeye Amps]

The reference 1ET400A Amir reviewed a few years ago got 108dB with no gain stage...bypassing gain stage on the 9040 you get 114dB.

 

[goryu]

perhaps that is not the point for some...

And you will never be able to hear the difference between 104 and 114dB SINAD.

 

[restorer-john]

FWIW, our AP unit (baseline) has an inherently higher H2 then would be expected from an AP unit.

Is it within guaranteed spec?

 

[Buckeye Amps]

Is it within guaranteed spec?

That is their stance, yes. But loopback/baseline H2 is higher than other AP rig measurements like Amir's.

 

[restorer-john]

That is their stance, yes. But loopback/baseline H2 is higher than other AP rig measurements like Amir's.

That's the thing with analyzers. You can be lucky and get one way better than spec, or not. But at the price of the AP, I wouldn't be happy.

Is it down to one channel being better than the other, the A/Ds itself/themselves or the high performance sine gen with the H2 issue? If it's the gen, you may be able to better it from a modern SOTA D/A converter.

 

[Buckeye Amps]

I will wait for Amirs tests

Sounds good