Purifi 1ET9040BA vs AGD GAN vs Class A/AB

[vipersg]

I am looking to power Sonus Faber Amati speakers and found Class D power amplifiers to be a very interesting proposition.

I initially found AGD Duet’s reviews on YouTube to be super compelling, with AGD GAN’s 800kHz switching frequency powered by audio-specific GAN transistors to be a unique selling point of sounding smooth, full-bodied and yet detailed, albeit at a very high price point of US$11k for a pair of monoblocks.

With Purifi’s first 2nd generation Eigentakt power amp module 1ET9040BA, the flat frequency response being load invariant across 2-8ohm, and delivering power at 0.0001%THD rated 700W/4ohm or 900W/2ohm.

The Amati dips below 2ohm below 110Hz and above 10Khz, with the lowest peak impedance being 0.86ohm at 75Hz. So I suspect the Purifi 1ET9040BA will do well driving power with super low distortion into sub 2ohm.

Since the Purifi 9040 can be configured with different input boards, I found that the most compelling configurations are:

Option 1: Apollon Audio Purifi 1ET9040BA Eigentakt Premium Monoblock Amplifier PET1200M

Purifi 1ET9040BA Eigentakt Premium Monoblock Amplifier PET1200 M

Elevate your audio experience with the Purifi 1ET9040BA amplifier, featuring Weiss OP2-BP Op Amps and a custom-designed power supply for impeccable sound clarity.

apollonaudio.com

- Weiss OP2-BP input board powered by Linear Power Supply
- ⁠Excellent chassis design, proper shielding

Option 2: VTV Monoblock Amplifier with Purifi 1ET-9040-BA module and Tube Buffer

Monoblock VTV Amplifier with Purifi 1ET-9040-BA module and Tube Buffer | VTV Amplifier

- Gold Lion 6922 tube buffer and Weiss OP2-BP input board powered by Hypex SMPS
- ⁠Decent chassis design, no internal shielding

Option 3: VTV Monoblock Amplifier with Purifi 1ET-9040-BA module

Monoblock VTV Amplifier with Purifi 1ET9040-BA module | VTV Amplifier

- Weiss OP2-BP input board powered by Hypex SMPS
- ⁠Decent chassis design, no internal shielding

However, one concern is - what is the sound signature of the 9040? Will it sound cold and lack musicality compared to AGD GAN, Class A or Class AB amps?

VTV’s Weiss input sounds very compelling but there were comments about power supply noise being a disappointing occurrence. https://www.audiosciencereview.com/...ifi-amplifier-review-with-weiss-buffer.24887/

There are many other brands in the market using the Purifi 1ET9040BA module, but i generally divide them into 2 groups one that use LPS and one that use SMPS for the input board. Then of these, I further split into those that offer different Op-amp input boards for price and personal preference. But end of the day, is the Purifi 9040 able to compete with far more expensive power amplifiers and provide the body, musicality, dynamics and clarity to make it a really good choice?

 

[vipersg]

VTV Power Amp

Apollon Power Amp

Cymax Power Amp

 

[Matias]

You are not going to get subjective opinions on these amps on this forum.

What I suggest is that you check the return policies of the 9040 manufacturers, buy and test them in your system to evaluate how you like them yourself.

VTV has usually subpar build quality but you can't go wrong with Apollon, boXem, March, Nord, etc.

 

[staticV3]

However, one concern is - what is the sound signature of the 9040?

There is no sound signature. Purifi Amps are wires with gain.

 

[VintageFlanker]

Welcome!

But end of the day, is the Purifi 9040 able to compete with far more expensive power amplifiers and provide the body, musicality, dynamics and clarity to make it a really good choice?

Let me ask the other way : why wouldn't it be able to compete against far more expensive power amplifiers ?

Musicality doesn't exist with audio gears. It's music related and has no clear definition whatsoever.

Body and dynamics are more related to your speakers, assuming these are properly drived to begin with. From what I see, the Amati (Homage ? Tradition?) does have acceptably high sensitivity, with up to 500W power handling (don't know about the impedance curve, tho). I have few doubt that the 9040 will push them to their limits without clipping.

You buying criterias should be based on design, eventual features, assembly and so on. Also, be sure that the 9040 is not underpowered (wich means either one SMPS1200 per channel, or one SMPS3K for both).

 

[Matias]

There is no sound signature. Purifi Amps are wires with gain.

I usually think the opposite: a "no sound signature" IS a sound signature for people used to colored amps.

 

[Koeitje]

Which version of the Amati do you have? You are probably better off with better loudspeakers than an amplifier upgrade over whatever you are using now. For the same money you can get an absolute state of the art loudspeaker in the form of the Blade 1.

 

[vipersg]

Thanks for the inputs.

I have the Amati G5. From

Sonus faber Homage Amati G5 Loudspeaker Drive Hard

Drive Hard Sonus faber's 're-tuning' of the Amati's bass performance has been achieved by combining its latest 220mm woofers, boasting increased magnetic field strength and improved suspension, with the new Stealth Ultraflex slot loading. The hybrid crossover – a mix of the 'semi-balanced'...

www.hifinews.com

the G5's minimum impedance is 2.36ohm/93Hz [black trace, inset Graph] following aggressive +43°/–74° swings in phase angle [blue trace] that deliver a super-tough EPDR [red trace] of 0.86ohm/75Hz. In practice the Amati G5 tasks its partnering amplifier with a sub-2ohm EPDR from 55Hz-110Hz and sub-3.3ohm from 52Hz right up to the 2.2kHz crossover. Above 10kHz it falls below 2ohm again.

 

[DVDdoug]

Normally, I look at performance, features, and price (and maybe appearance, etc.) and I don't worry about what's inside.

Option 2: VTV Monoblock Amplifier with Purifi 1ET-9040-BA module and Tube Buffer

It's 2024. Tubes are "dumb". They've been outdated for about half a century and there are no audio advantages. When it comes to tube power amps (tube output-stages) you need an output transformer and that tends to be a disadvantage. (It can be overcome with careful design and enough money.) Tubes also have heaters which make them energy inefficient.

Class-A is also "dumb". It's not class-A because it's the best, it's class-A because it was the first. It was also cheaper in the old days because class A/B required an additional tube. Now an additional transistor or MOSFET costs almost nothing and class A/B is usually more cost effective, especially when you want higher power.

I assume in the future almost everything will be class-D because that's now the most economical.

Will it sound cold and lack musicality

With audio electronics there are ONLY 3 "sound quality" characteristics - Noise, distortion, and frequency response. Frequency response and distortion are almost always better than human hearing unless an amplifier is over-driven into clipping. Sometimes noise can be audible but that also depends on the sensitivity of your speakers, how close you are to the speaker, and the other noise in the room. See Audiophoolery.

 

[pogo]

900W/2ohm

Correct to 1400W
Btw., the EPDR value does not play a role in class-D.

 

[quattro98]

ASR is quite different from the usual audiophile media. A change in perspective is often required.

Message to golden-eared audiophiles posting at ASR for the first time...

Hello friend. Hey, listen...we know how it is. Believe me, most of us have been there too. You've spent years toiling in the muck of audiophilia. You read ALL the reviews. You watched ALL the youtube videos. You visited ALL the other forums where everything always makes a difference. You...

www.audiosciencereview.com

 

[EdW]

View attachment 393346

Thanks for the inputs.

I have the Amati G5. From

Sonus faber Homage Amati G5 Loudspeaker Drive Hard

Drive Hard Sonus faber's 're-tuning' of the Amati's bass performance has been achieved by combining its latest 220mm woofers, boasting increased magnetic field strength and improved suspension, with the new Stealth Ultraflex slot loading. The hybrid crossover – a mix of the 'semi-balanced'...

www.hifinews.com

the G5's minimum impedance is 2.36ohm/93Hz [black trace, inset Graph] following aggressive +43°/–74° swings in phase angle [blue trace] that deliver a super-tough EPDR [red trace] of 0.86ohm/75Hz. In practice the Amati G5 tasks its partnering amplifier with a sub-2ohm EPDR from 55Hz-110Hz and sub-3.3ohm from 52Hz right up to the 2.2kHz crossover. Above 10kHz it falls below 2ohm again.

EPDR only really applies to non switching designs - not class D. EPDR is a measure of the real impedance effect of the speaker as regards heating in a non switching amplifier.
A class D amp works differently and won’t heat up in the same way. In fact the heating of amp + its power supply
in a largely reactive load could be lower than into a resistive load - very different from a non switching design. The black impedance curve gives an indication of peak currents and may give you a better guide to the drive capability of any class D design you might consider

 

[Koeitje]

View attachment 393346

Thanks for the inputs.

I have the Amati G5. From

Sonus faber Homage Amati G5 Loudspeaker Drive Hard

Drive Hard Sonus faber's 're-tuning' of the Amati's bass performance has been achieved by combining its latest 220mm woofers, boasting increased magnetic field strength and improved suspension, with the new Stealth Ultraflex slot loading. The hybrid crossover – a mix of the 'semi-balanced'...

www.hifinews.com

the G5's minimum impedance is 2.36ohm/93Hz [black trace, inset Graph] following aggressive +43°/–74° swings in phase angle [blue trace] that deliver a super-tough EPDR [red trace] of 0.86ohm/75Hz. In practice the Amati G5 tasks its partnering amplifier with a sub-2ohm EPDR from 55Hz-110Hz and sub-3.3ohm from 52Hz right up to the 2.2kHz crossover. Above 10kHz it falls below 2ohm again.

This is simply unacceptable for a speaker at this price point:

Seriously, don't bother with a new amplifier if you are using it to drive a speaker that performs like this. There is a huge dip in the midrange, so I can understand your want for a "full-bodied" sound, but an amplifier won't provide that. I'd look at something like the KEF One Meta if you want a "smooth, full-bodied and yet detailed" sound.

If you do want to stick with these speakers, I'd look at a DSP to apply some EQ. The radiation pattern of your speaker is probably not very good for equalizing, but it might solve the issues you are having.

For reference, this is a KEF Blade One Meta, see how even it is across the entire hearing range from up to 20kHz. That is how you get that sound you seem to be looking for. Also notice how the red and teal line match perfectly with the black line? That means directivity is perfectly controlled and could even be equalized to your needs with perfect accuracy (but you wont need to because its already as good as it gets for a passive speaker).

Anyway that is the difference between a loudspeaker designed by people who can make beautiful wooden loudspeakers but lack engineering prowess when it comes to actual audio reproduction, and a loudspeaker designed by engineers who try to push the envelope of what is possible with modern knowledge and state of the art materials (no surprise KEF's VP of technology is also a member here).

 

[terryforsythe]

There is no sound signature. Purifi Amps are wires with gain.

I agree, except maybe not this one:

Option 2: VTV Monoblock Amplifier with Purifi 1ET-9040-BA module and Tube Buffer

(Emphasis added).

I don't know whether a tube buffer makes much of a difference. But, I have a tube phono stage - I never use it and it sits in the garage collecting dust. The phono stage on my Adcom GFP-565 (sold) sounded much better, and had much, much better bass response.

 

[vipersg]

This is simply unacceptable for a speaker at this price point:
View attachment 393407

Seriously, don't bother with a new amplifier if you are using it to drive a speaker that performs like this. There is a huge dip in the midrange, so I can understand your want for a "full-bodied" sound, but an amplifier won't provide that. I'd look at something like the KEF One Meta if you want a "smooth, full-bodied and yet detailed" sound.

If you do want to stick with these speakers, I'd look at a DSP to apply some EQ. The radiation pattern of your speaker is probably not very good for equalizing, but it might solve the issues you are having.

For reference, this is a KEF Blade One Meta, see how even it is across the entire hearing range from up to 20kHz. That is how you get that sound you seem to be looking for. Also notice how the red and teal line match perfectly with the black line? That means directivity is perfectly controlled and could even be equalized to your needs with perfect accuracy (but you wont need to because its already as good as it gets for a passive speaker).
View attachment 393412

Anyway that is the difference between a loudspeaker designed by people who can make beautiful wooden loudspeakers but lack engineering prowess when it comes to actual audio reproduction, and a loudspeaker designed by engineers who try to push the envelope of what is possible with modern knowledge and state of the art materials (no surprise KEF's VP of technology is also a member here).

Thanks for your inputs. I measured my Amati speakers with REW in my room (untreated). It’s 83cm from the front wall with 7.5 deg toe-in so there is room boundary interference. These are using Parasound A31 power amplifier. I ordered a Purifi 9040 amp from Cymax and will test it out in a few weeks.

 

[Koeitje]

Thanks for your inputs. I measured my Amati speakers with REW in my room (untreated). It’s 83cm from the front wall with 7.5 deg toe-in so there is room boundary interference. These are using Parasound A31 power amplifier. I ordered a Purifi 9040 amp from Cymax and will test it out in a few weeks.


View attachment 393598

Your current amplifier is more than sufficient. If you do not like the sound a new amplifier isn't go to do much (or anything at all). You could try equalizing down after 4kHz, there is a bump there that you normally don't want.

 

[vipersg]

Your current amplifier is more than sufficient. If you do not like the sound a new amplifier isn't go to do much (or anything at all).

Actually the sound of Parasound is good but the amp is now faulty, and I am looking to change it.

 

[vipersg]

EPDR only really applies to non switching designs - not class D. EPDR is a measure of the real impedance effect of the speaker as regards heating in a non switching amplifier.
A class D amp works differently and won’t heat up in the same way. In fact the heating of amp + its power supply
in a largely reactive load could be lower than into a resistive load - very different from a non switching design. The black impedance curve gives an indication of peak currents and may give you a better guide to the drive capability of any class D design you might consider

Thanks, I didn’t know EPDR didn’t apply to Class D. I like that the 9040 seems to handle wide variations of impedance with ease since the frequency response is flat regardless of impedance. Do other Class D like NcoreX, GAN, etc behave like this?

 

[Koeitje]

Actually the sound of Parasound is good but the amp is now faulty, and I am looking to change it.

Ok, then pick the cheapest of your options, there won't be any difference between them and spend the extra money on a DSP.

 

[terryforsythe]

Thanks for your inputs. I measured my Amati speakers with REW in my room (untreated). It’s 83cm from the front wall with 7.5 deg toe-in so there is room boundary interference. These are using Parasound A31 power amplifier. I ordered a Purifi 9040 amp from Cymax and will test it out in a few weeks.

If you do want to stick with these speakers, I'd look at a DSP to apply some EQ.

I concur with the suggestion by Koetje for looking into DSP. I use DSP in two of my systems, and it is a game changer.