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

[David_M]

Very good comparative analysis, I also have some doubts in choosing 7040SA and 6525SA, after all, 7040SA has more output current and lower output impedance, but the difference in output power is not too much, and 6525SA hav the second 2nd generation Eigentakt While I'm not particularly aware of the second generation advantages，so can you help me analyze and compare these two products.

1. The 7040SA is NOT a 2nd generation but a 1st generation Eigentakt. The 6525SA is a 2nd generation Eigentakt. One of the main differences is the bandwidth (see option 3).
From the frequency response curve shapes, it is a beefed-up 1st gen 1ET400A, with more power.

2. The 7040SA is noisier (THD+N wise) than the 6525SA by about 10dB or more.

3. The 7040SA has lower bandwidth (60kHz) than the 6525SA (80kHz).

4. The 7040SA has a higher output impedance (< 0.65mOhms) than the 6525SA (0.35mOhms) form 20Hz to 20kHz. Not that it matters here. These amps have very high damping factors with an 8 load (8/0.35mOhm = 22,857 minimum and 8/0.65mOhms = 12,308 minimum). These numbers are excellent.

5. The 7040SA is MORE powerful than the 6525SA.

These are what I could find so far on short notice. There may be other advantages of one amp over the other. If I were to choose between these two amps, my choice would be the 6526SA amp as my preference, especially with lower-impedance speakers.

 

[vipersg]

1. The 7040SA is NOT a 2nd generation but a 1st generation Eigentakt. The 6525SA is a 2nd generation Eigentakt. One of the main differences is the bandwidth (see option 3).
From the frequency response curve shapes, it is a beefed-up 1st gen 1ET400A, with more power.

2. The 7040SA is noisier (THD+N wise) than the 6525SA by about 10dB or more.

3. The 7040SA has lower bandwidth (60kHz) than the 6525SA (80kHz).

4. The 7040SA has a higher output impedance (< 0.65mOhms) than the 6525SA (0.35mOhms) form 20Hz to 20kHz. Not that it matters here. These amps have very high damping factors with an 8 load (8/0.35mOhm = 22,857 minimum and 8/0.65mOhms = 12,308 minimum). These numbers are excellent.

5. The 7040SA is MORE powerful than the 6525SA.

These are what I could find so far on short notice. There may be other advantages of one amp over the other. If I were to choose between these two amps, my choice would be the 6526SA amp as my preference, especially with lower-impedance speakers.

1. The 7040SA is NOT a 2nd generation but a 1st generation Eigentakt. The 6525SA is a 2nd generation Eigentakt. One of the main differences is the bandwidth (see option 3).
From the frequency response curve shapes, it is a beefed-up 1st gen 1ET400A, with more power.

2. The 7040SA is noisier (THD+N wise) than the 6525SA by about 10dB or more.

3. The 7040SA has lower bandwidth (60kHz) than the 6525SA (80kHz).

4. The 7040SA has a higher output impedance (< 0.65mOhms) than the 6525SA (0.35mOhms) form 20Hz to 20kHz. Not that it matters here. These amps have very high damping factors with an 8 load (8/0.35mOhm = 22,857 minimum and 8/0.65mOhms = 12,308 minimum). These numbers are excellent.

5. The 7040SA is MORE powerful than the 6525SA.

These are what I could find so far on short notice. There may be other advantages of one amp over the other. If I were to choose between these two amps, my choice would be the 6526SA amp as my preference, especially with lower-impedance speakers.

Great comparison

I’ll add another point:

6. The 6525SA has higher switching frequency 550 kHz vs 515 kHz of 7040SA. I find that the higher the switching frequency, the higher the ability to reproduce a square wave signal with less overshoot and undershoot, resulting in less waveform distortion. It also moves the high frequency distortion further from the audible band. The result sounds smoother and more relaxed as compared to earlier class D generations which had low distortion, high power, etc but sounded harsher on the treble.

 

[boXem]

These modules switching frequency is not fixed but signal dependant. And has always been around 500 kHz since UcD, 30 years ago...

 

[David_M]

These modules switching frequency is not fixed but signal dependant. And has always been around 500 kHz since UcD, 30 years ago...

Yeah, the larger the input signal, the lower the switching frequency becomes. The highest switching frequency occurs at idle.

 

[David_M]

Great comparison

I’ll add another point:

6. The 6525SA has higher switching frequency 550 kHz vs 515 kHz of 7040SA. I find that the higher the switching frequency, the higher the ability to reproduce a square wave signal with less overshoot and undershoot, resulting in less waveform distortion. It also moves the high frequency distortion further from the audible band. The result sounds smoother and more relaxed as compared to earlier class D generations which had low distortion, high power, etc but sounded harsher on the treble.

Probably they had much lower SF and at high amplitudes, the SF lowered itself into the audio band, probably the root cause of the harshness.

 

[boXem]

"Class D harshness" is due to interaction between the output filter and the speaker causing a bump on the FR, something that doesn't affect self oscillating amps with post filter feedback.

 

[darcman]

I would like to know more about this amp. I do not want to know about covid. I do not want to hear about what makes a test a test. I do not want to know why all components sound the same. I do not want to know why certain parts cant make a difference. I do not want to hear from people using tea leaves to tell me how this amp sounds.

I was hoping to hear more from people that actually bought this amp and maybe their impressions on different op amps, build, reliability.

Like others have said the Cymax is one of the nicest builds, the Opollon looks good too but is considerably more money...plus it sounds like it takes forever to get one

I was kinda intrigued by the Maroon amp. I actually emailed Maroon and I could get the weiss version for the same price (even slightly cheaper) than the Cymax bare bones version. I zoomed in on the Maroon and it appears to use a cheaper metal case. Where the top on the Maroon screws down looks like they have standoffs, so its not a thick aluminum case. Another thing I wondered about with the Maroon, the board thats flipped over to me that looks like some sort of custom double purifi 9040 module or am I wrong.

With the Maroon I guess it doesnt have to have a really nice case to sound good. When you look at the IEC it doesnt appear to have fuse, so I guess that must be internal. One more thing with the Maroon there doesnt seem to be an easy switch to select gain, maybe thats done internally with jumpers.

I hope I didnt come off as an ahole. I am seriously considering a 9040 build and I really wanted to hear more from real owners of the Cymax or Maroon. I just didnt want to hear a bunch of arguing about stuff that I dont want to hear about or really isnt going to help.

 

[David_M]

Currently, this seems to be the best implementation of the 1ET9040BA next to the Marantz Model 10.

Why do you claim so? Those high SINAD numbers are acquired at 1V but need to scaled down substantially to compare fairly to the 5W specs typically done at ASR.

 

[pogo]

Additional linear PSU, shielding measures and see here: Link

 

[David_M]

Additional linear PSU, shielding measures and see here: Link

Not sure what the purpose of that link was, but the remeasured SINAD specs were done at 1V input into the amp, which is several hundred output watts into 4 ohms. If it takes 4 Vrms (XLR) to reach 750W into 4 ohms @0.1THD, then 1Vrms will produce around 200W. A far cry from the 5W ASR test spec where the SINAD will fall from 118dB to under 110dB. Still good but may other amps such as March Audio or @boXem meet these specs easily.

 

[vipersg]

I would like to know more about this amp. I do not want to know about covid. I do not want to hear about what makes a test a test. I do not want to know why all components sound the same. I do not want to know why certain parts cant make a difference. I do not want to hear from people using tea leaves to tell me how this amp sounds.

I was hoping to hear more from people that actually bought this amp and maybe their impressions on different op amps, build, reliability.

Like others have said the Cymax is one of the nicest builds, the Opollon looks good too but is considerably more money...plus it sounds like it takes forever to get one

I was kinda intrigued by the Maroon amp. I actually emailed Maroon and I could get the weiss version for the same price (even slightly cheaper) than the Cymax bare bones version. I zoomed in on the Maroon and it appears to use a cheaper metal case. Where the top on the Maroon screws down looks like they have standoffs, so its not a thick aluminum case. Another thing I wondered about with the Maroon, the board thats flipped over to me that looks like some sort of custom double purifi 9040 module or am I wrong.

With the Maroon I guess it doesnt have to have a really nice case to sound good. When you look at the IEC it doesnt appear to have fuse, so I guess that must be internal. One more thing with the Maroon there doesnt seem to be an easy switch to select gain, maybe thats done internally with jumpers.

I hope I didnt come off as an ahole. I am seriously considering a 9040 build and I really wanted to hear more from real owners of the Cymax or Maroon. I just didnt want to hear a bunch of arguing about stuff that I dont want to hear about or really isnt going to help.

An update is coming for Cymax to have improved layout for straight and shortest path wiring.

 

[darcman]

An update is coming for Cymax to have improved layout for straight and shortest path wiring.

Thats good to know. Any idea on when this will happen? I still think the Cymax is one of the nicest builds with the case etc for the money.

The Maroon looks pretty good too, but the case doesnt look quite as nice as the Cymax. I am kinda leaning towards the Cymax as it looks like a more nicer simpler straight forward build. Say if something did go wrong the Maroon with that flipped over board might leave you with non existant repair parts...maybe it wouldnt ever be an issue. The Buckeyes ok, but the case is fairly basic and I was thinking of a stereo version. I have some quite nice AB monos, but I am thinking of scaling back a bit. I have always liked the Apollon premium builds, but they are like almost double the price of the Cymax.

 

[David_M]

Thats good to know. Any idea on when this will happen? I still think the Cymax is one of the nicest builds with the case etc for the money.

The Maroon looks pretty good too, but the case doesnt look quite as nice as the Cymax. I am kinda leaning towards the Cymax as it looks like a more nicer simpler straight forward build. Say if something did go wrong the Maroon with that flipped over board might leave you with non existant repair parts...maybe it wouldnt ever be an issue. The Buckeyes ok, but the case is fairly basic and I was thinking of a stereo version. I have some quite nice AB monos, but I am thinking of scaling back a bit. I have always liked the Apollon premium builds, but they are like almost double the price of the Cymax.

You may also consider mono and stereo amps from March Audio. They look great and also measure the best. MA is the only manufacturer who lists true specs of the amps and not Purifi datasheets as others do. Its the preceding buffer that determines the distortion and noise levels of an amplifier, degrading by 10dB or more. When other list their specs, they list the Purifi module specs and not buffer+purifi module specs.

Again, the gating factor of your amp performance will be the buffer. The 5W THD+N of the 9040BA module spec is roughly -116dB at 4R. Add a generic buffer and that spec will decrease to much less than -110 dB (worser at higher gains). The better buffers will have minimal impact on the noise and almost pass the signal through to the purifi module unmolested.

 

[vipersg]

Thats good to know. Any idea on when this will happen? I still think the Cymax is one of the nicest builds with the case etc for the money.

The Maroon looks pretty good too, but the case doesnt look quite as nice as the Cymax. I am kinda leaning towards the Cymax as it looks like a more nicer simpler straight forward build. Say if something did go wrong the Maroon with that flipped over board might leave you with non existant repair parts...maybe it wouldnt ever be an issue. The Buckeyes ok, but the case is fairly basic and I was thinking of a stereo version. I have some quite nice AB monos, but I am thinking of scaling back a bit. I have always liked the Apollon premium builds, but they are like almost double the price of the Cymax.

March 2025. I should be able to share a pic in 2-3 weeks.

 

[darcman]

March 2025. I should be able to share a pic in 2-3 weeks.

Thats nice to see that Cymax isnt just content sitting on the layout, but is improving the design to bring us a better amp. To me I find that telling when a company like Cymax strives to improve designs. Do you know if this is going to add to the cost of the amp or is it a no cost evolution?

 

[vipersg]

Thats nice to see that Cymax isnt just content sitting on the layout, but is improving the design to bring us a better amp. To me I find that telling when a company like Cymax strives to improve designs. Do you know if this is going to add to the cost of the amp or is it a no cost evolution?

I believe it’s a no cost evolution but best to check with their website next month. Yes they are fast with design improvements!

 

[d3l]

Is there a vendor expect apollon in Europe that offers similar build to Cymax? I would not need the screen but would prefer to have Linear PSU feeding the op-amps.

 

[Doodski]

would prefer to have Linear PSU feeding the op-amps.

Why?

 

[vipersg]

Here's an update to the Cymax power amp for 2025. Now with the LPS mounted in the middle and the center partition replaced with nickel plated copper instead of aluminium. The copper shielding between the power supplies and audio modules are more thorough in coverage. This also results in wiring being much neater and a more direct path from the power supplies to the Purifi 9040 modules and Weiss OP2-BP input buffer modules. The final change I did was the WBT 0703 Speaker Binding Post was changed from Silver to Copper (gold plated). The 0703 CU sounded to me a little warmer, more weight in bass, and a presentation that sounds a bit more romantic. The 0703 AG sounded to me being more revealing, more micro-detail, open and airy. The one you pick should be based on your personal preference and system matching. Now that the amp has all nickel plated copper shields internally, it has also become substantially heavier as well.

Weiss OP2-BP Input Buffer.

Linear Power Supply with Elna capacitors.

Dual XLR Inputs enable me to connect my AV Processor (Marantz AV10) and Network Music Streamer (Lumin P1) to the Cymax and select Input 1 or Input 2 per channel from the front rotary LCD Dial.

@darcman @David_M

 

[pogo]

The ribbon cables in particular should be protected from the edges of the sheet metal.