Cymax Purifi 1ET9040BA with Weiss OP2-BP Dual-Mono Power Amplifier

[vipersg]

I was hunting around for a Purifi 1ET9040BA implementation that I really like. I found this power amplifier from Cymax and wanted to share some photos of its design, which has been very thoughtful and high in its quality of implementation and design.

It has dual XLR inputs which enables me to connect my Network Streamer and LR channel of my AV Processor to the Cymax power amp, and have the inputs and gain easily selectable from the front with its rotary dial with LCD display. I love the shielded power supplies and that it uses a linear power supply for the input op-amp boards, keeping the Hypex SMPS1200A180 to power the Purifi 1ET9040BA amp module in dual mono configuration.

Their website allows configuring for various options so I have spec several upgrades

Black shielding for Hypex SMPS1200A180 (Dual Mono)
Blue shielding for Linear Power Supply for input buffer and power management

View attachment 402318
Rotary dial features a LCD display with user selectable XLR input 1 and 2, and user selectable Gain 1 (21.4dB) and Gain 2 (28.4dB)

View attachment 402314View attachment 402317

Equipped with Furutech FI-06 Rhodium NCF IEC socket.

Input 1 - Furutech XLR Rhodium socket
Input 2 - Neutrik XLR Gold socket
Output - WBT 0703 Silver

Weiss OP2-BP input buffer board fed by linear power supply. Neotech UP-OCC copper wiring, nicely implemented.

It’s running in now on Sonus Faber Amati G5 speakers. First impressions are effortless dynamics, detailed (especially instruments and voice), neutral, bass is punchy (a little less weighty than my Parasound) but seem more textured.

 

[pogo]

At least all four possible connections are used in this version. I haven't seen this with any other implementation so far (I'm leaving Marantz out of the equation). Only two more speaker outputs are missing.

The output impedance of 1ET9040BA is significantly lower than the resistance of even a single high quality output binding post. To derive the greatest benefit of the ultra-low output impedance, 1ET9040BA is fitted with a four-pole output connector which permits bi-wiring. This prevents load dependent currents from e.g. the bass section of a speaker from impacting the mid/tweeter section. 1ET9040BA’s ultra-low output impedance offers a degree of isolation that can otherwise only be matched by full bi-amping. <-- datasheet

Btw, with these PSUs it is unlikely to reach the possible 1400W@2ohms per channel.

 

[pogo]

The linear power supply would perhaps be better located in the middle and the input buffer section could also have been shielded.

 

[Old_School_Brad]

Looks like a quality implementation. First I thought I was missing a gain selection but it seems like it's built in.

 

[Mnyb]

The good things finally gain selection on the front . Nice implementation. Nice box finally looks like proper product.

The bad a bit to much flirting with audiophile nonsense , furutech and wbt would just make it more expensive.

 

[vipersg]

@pogo, Agree, these are all good ideas. I suspect Cymax wanted to put the LPS next to the rotary power and multifunction dial switch. I wonder if it hits 1000-1100W into 2ohm instead of rated 1200W, can it still do so with clean power?. I wonder if anyone has measured the noise and voltage/power performance Hypex SMPS1200?

 

[Matias]

Wow, great amp. Congrats!

 

[Ted B]

@pogo, Agree, these are all good ideas. I suspect Cymax wanted to put the LPS next to the rotary power and multifunction dial switch. I wonder if it hits 1000-1100W into 2ohm instead of rated 1200W, can it still do so with clean power?. I wonder if anyone has measured the noise and voltage/power performance Hypex SMPS1200?

Thanks for posting this writeup and photos. How is this amp working out for you one month later? It seems that Cymax is a Canadian company with production in Hong Kong. The overall design and build quality looks solid. The small LCD and selectable gain is a nice touch, as are the user-defined build options. Their dual monoblock Hypex NC-500 dedicated subwoofer amp has my attention as well.

 

[d3l]

Also super interested. This amp has pretty much everything going that Im looking for in a purifi build.

 

[vipersg]

@Ted B and @d3l, I have since sent my unit back to Cymax for upgrading the internal shield and partition from aluminum to nickel plated red copper, which has better EMI shielding performance. This is now offered as an option on the order page. This includes separating the input buffer boards from the Purifi 9040 modules. I have also asked them to replace my Rhodium XLR sockets to both being Neutrik Gold as my personal preference after listening to both as the Neutrik Gold was smoother sounding. This power amplifier resolves details well so you can use neutral to warm sounding components.

 

[pma]

I have also asked them to replace my Rhodium XLR sockets to both being Neutrik Gold as my personal preference after listening to both as the Neutrik Gold was smoother sounding

You must have very good ears - my admiration.

 

[Ted B]

@Ted B and @d3l, I have since sent my unit back to Cymax for upgrading the internal shield and partition from aluminum to nickel plated red copper, which has better EMI shielding performance. This is now offered as an option on the order page. This includes separating the input buffer boards from the Purifi 9040 modules. I have also asked them to replace my Rhodium XLR sockets to both being Neutrik Gold as my personal preference after listening to both as the Neutrik Gold was smoother sounding. This power amplifier resolves details well so you can use neutral to warm sounding components.

Good to know, thank you for the update. I have reservations about rhodium or silver plated conductors or connectors in the audio path and would avoid them in general. The Neutrik gold plated connectors I would choose by default given these are what I use for all of my (DIY) XLR connections, having found them to be neutral, transparent, and predictable. As for the EMI shielding, if this theoretical upgrade from aluminum to copper translates into any perceptible improvement in noise performance in this application, you would be the first to know, but the proximity of those large switching power supplies makes the most effective containment practical seem like a logical step.

I should note that I am on the same exact path that you outlined in the OP of your earlier discussion: Purifi 1ET9040BA vs AGD GAN vs Class A/AB. I am similarly dealing with a large, low impedance load, and my first experiment in class D was with a Crown XLS-2502 following its review here (Crown XLS2502 Stereo Amplifier Review), which impressed me given its resolution, soundstage, and transparency at that price point. In the quest to take a step up within the realm of class D, I have arrived at the same crossroads as you back in September, 2024 concerning builder and buffer options for the 1ET9040BA. I've also decided on monoblocks using the Weiss op amps over tubes. As you are presently a step ahead with this Cymax amp, your experience and continued feedback with it are much appreciated.

 

[VintageFlanker]

I have also asked them to replace my Rhodium XLR sockets to both being Neutrik Gold as my personal preference after listening to both as the Neutrik Gold was smoother sounding.

Listening to some XLR socket really is a new concept to me.

 

[vipersg]

The AB comparison between the socket types is easy to do on the Cymax because the input selector is on the front panel and it is extremely rare for a power amplifier to have dual XLR inputs. The common configuration of many power amps is a choice of XLR and RCA inputs with the selector switch at the back. Once I am able to easily AB test between the different sockets, it was really different in sound, like listening to different amplifiers. I was honestly hoping the Rhodium would win, but no, the Neutrik Gold was clearly a better match for my system.

@Ted B, thanks for sharing your journey. I spoke to a local shop that deals with MBL systems. MBL has a power amplifier that is also class D based. The very knowledgeable owner shared with me that for Class-D, he strongly recommends thicker copper based power cords as that is better matched for Class D current characteristics. I suspect the reason is class D does not have huge banks of capacitor for instantaneous current. I’ll get my amp back next week and will share more.

 

[RandomEar]

Thanks for the pictures. Apart from a couple of small details, it looks like a competent implementation. I like the minimal UI "in" the knob. Using an anodized screw on an anodized panel for connecting the safety ground isn't the best solution. Also, the incoming mains wires are routed very close to the fat inductors on that purify module - that may inject 50 / 60 Hz noise into the output. Should be easy to rectify. Otherwise a clean build.

The copper EMI shields sound a bit pointless if they are also open at both ends. The black aluminium plate is still the main separator between the PSUs and the buffer & amp section. If anything, that should be copper, right?

The AB comparison between the socket types is easy to do on the Cymax because the input selector is on the front panel and it is extremely rare for a power amplifier to have dual XLR inputs. The common configuration of many power amps is a choice of XLR and RCA inputs with the selector switch at the back. Once I am able to easily AB test between the different sockets, it was really different in sound, like listening to different amplifiers. I was honestly hoping the Rhodium would win, but no, the Neutrik Gold was clearly a better match for my system.

Sighted testing. I recommend reading up on bias.

 

[Matias]

The AB comparison between the socket types is easy to do on the Cymax because the input selector is on the front panel and it is extremely rare for a power amplifier to have dual XLR inputs. The common configuration of many power amps is a choice of XLR and RCA inputs with the selector switch at the back. Once I am able to easily AB test between the different sockets, it was really different in sound, like listening to different amplifiers. I was honestly hoping the Rhodium would win, but no, the Neutrik Gold was clearly a better match for my system.

@Ted B, thanks for sharing your journey. I spoke to a local shop that deals with MBL systems. MBL has a power amplifier that is also class D based. The very knowledgeable owner shared with me that for Class-D, he strongly recommends thicker copper based power cords as that is better matched for Class D current characteristics. I suspect the reason is class D does not have huge banks of capacitor for instantaneous current. I’ll get my amp back next week and will share more.

A friendly tip: ASR is an objective forum and describing subjective impressions of connector metal and power cords in sounds is sure to create heated discussions here.

 

[vipersg]

Thanks for the pictures. Apart from a couple of small details, it looks like a competent implementation. I like the minimal UI "in" the knob. Using an anodized screw on an anodized panel for connecting the safety ground isn't the best solution. Also, the incoming mains wires are routed very close to the fat inductors on that purify module - that may inject 50 / 60 Hz noise into the output. Should be easy to rectify. Otherwise a clean build.

The copper EMI shields sound a bit pointless if they are also open at both ends. The black aluminium plate is still the main separator between the PSUs and the buffer & amp section. If anything, that should be copper, right?


Sighted testing. I recommend reading up on bias.

Thanks for the analysis. Good point on the proximity. I’ll ask them to check on that.

The black partition plate is also replaced by nickel plated copper.

 

[Ted B]

@Ted B, thanks for sharing your journey. I spoke to a local shop that deals with MBL systems. MBL has a power amplifier that is also class D based. The very knowledgeable owner shared with me that for Class-D, he strongly recommends thicker copper based power cords as that is better matched for Class D current characteristics. I suspect the reason is class D does not have huge banks of capacitor for instantaneous current. I’ll get my amp back next week and will share more.

I agree and have already been down that road. I can recommend Viborg shielded power cables and connectors as a high quality brand that can be ordered finished in any length from multiple vendors at reasonable cost. I presently use VP1501 for digital and line level devices and will use either VP1008 or VP1707 (both 600V/30A) for the new amps. Given the power demands on the nearest circuit, I will run a dedicated 10AWG (30A) line from the panel with Leviton 8300-LIG (20A) hospital grade outlets for the amps.

 

[atomek]

Are there any european manufacturers of amplifiers on 1ET9040BA modules? I'm looking for good quality dual-mono or monoblocks. I'm bit lost with opamps - which one is the "safest" bet in terms of audio quality? Or if they are "same" - which one measures best?

 

[Matias]

Are there any european manufacturers of amplifiers on 1ET9040BA modules? I'm looking for good quality dual-mono or monoblocks. I'm bit lost with opamps - which one is the "safest" bet in terms of audio quality? Or if they are "same" - which one measures best?

Apollon has both stereo and mono

One moment, please...

BoXem mono only

boXem - Arthur 5523/E1

1 channel HiFi power amplifier, Purifi second gen. Eigentakt technology. Designed and proudly built in Luxembourg.

boxem-audio.eu

Nord

Nord Acoustics | 1ET9040BA

1ET9040BA with its powerful BTL power stage, 90V voltage swing, and 40A output current, delivers exceptional audio performance.

nordacoustics.co.uk