Class D Purifi Eigentakt / Mark Levinson 333 / Benchmark AHB2 - Listening & Conclusion

5.  
There needs to additional scientific measurements that can explain why the benchmark AHB2 sounds better than Purifi Eigentakt in my environment and why the Levinson sounds more dynamic and detailed on loud classical music. Traditional SINAD, THD , IMD measurement using sinewave do not have the musical waverform complexity and can not explain the contrast of what we heard among these amplifiers in our environment. What we heard can not be explained with just THD measurement as they all sound good (not distorted) but different. As below certain THD, the delta is not audible.

Well those amps are driving complex loads if they are driving an actual speaker.

One could capture what is being presented at the speaker in terms of voltage, and then overlaying the three plots in time domain or frequency domain.

If they sound different, then they should be driving the speaker differently.

How we know which one is “more right” than the others is another thing.

lastly, with a different speaker, and a different complex load, does the choice of “which amp is better” then flip?

I too tried exactly one pair of Class D amplifiers and I have concluded without a doubt that my preconceived notion was correct that Class D is not ready because the tonal balance of this amp was not what the balance of my other amplifiers.

 

So, you are absolutely right, Class D is not ready!

I upgraded my 105 several years ago, replacing the IEC, 110/220 jumper and linear power supply terrific upgrades, all to improve my SACD playback. I use WireWorld series 8 XLRs into a Audio Alchemy DDP-1 + PS 5, a $800 power cord and Nob Sound springs. I also have the Stereophile, XLO, and Isotec burn in discs

 

My speakers are Emerald Physic 3.4s using Wire World jumpers and series 7 speaker cables  a Core Power 1800 power conditioner

 

I tried Emerald Physics 100.2 SEs with upgraded fuses> PS Audio M700s, EVS 1200, each move was positive, but it wasn't until I got a LSA GaN 350 that my system started sounding believable. The biggest difference IMO is switching speed

 

hth 

Also recently tried NAD and PS Audio Class D amp.

They sound fine when they are not being compared to the Levinson.  When playing high dynamic classical music or high quality master and SACD reproduction , these Class D amps do not compete well with high-end , good design Class AB amp.

I was thinking I could go cheap (less than $10k) to get sonic improvement over my existing setup. I am now inclined to get the newer Mark Levinson No 536 or the big Pass Labs XA200 amplifier for appreciable sound quality improvement.

Class D amplifiers have improved a lot of the years but Class D Amps are still no match to good design Class AB Amp.in term of sound quality and dynamic handling

This is not a conclusion you can draw due to the small sample size of 'one'. Its only a conclusion you can draw with the amps in your current setup.

@georgehifi
You clearly prefer vertical biamping AHB2 than bridging monos. My Soundlab Esl has only one pair of terminals. What do I do in this case?
Also, someone told me that since these speakers can go down to 1-2 ohm at high frequency, AHB2 may not be able to handle it. What do you think?
thanks, Jay

Hi Jay sorry was away for a while when you PM’d
Not just vertical bi-amping https://ibb.co/jfnTwTc if both amps are the same.
But horizonal https://ibb.co/VMSks36 also if both amps are not the same.

But you have a problem that can’t be fixed by either of these because they are full range with no xover to be able to be split for biamping.

And as for bridging the AHB2’s into that kind of load 1-2ohm, that’s a no from me also.
You only have one option really, that is to look at other amps for those magnificent beast of a speaker to drive them properly.

I suggest to stay with linear solid state, and suggest looking for high current high Class-A bias linear Bi-Polar (BJT) output stage amps, such as Gryphon poweramp/s or a cheaper alternative Parasound JC1 Halo monoblocks, both which a have a high/low class-A bias switching, for seriouse listening (high bias) or for dinner/background/party time listening low Class-A bias listening.
Others are Boulder, D'Agostino, etc etc 

Cheers George

@georgehifi
You clearly prefer vertical biamping AHB2 than bridging monos. My Soundlab Esl has only one pair of terminals. What do I do in this case? Also, someone told me that since these speakers can go down to 1-2 ohm at high frequency, AHB2 may not be able to handle it. What do you think?

thanks, Jay

Nice write up. 
I have not heard these exact amps but your thoughts align with mine having owned A/B, class D, and benchmark equipment in the past. I currently am using big power AB and don’t see myself changing for a long time. 

You seem to be drawing a lot of conclusions about the Purifi module from the absolute cheapest implementation.  There are many Purifi implementations that have a much better power supply and much better input buffer that are admittedly more expensive, but then so are the amps you are comparing. 

I have been pretty impressed with the Purifi modules in my own DIY amp. It doesn't quite match my Pass XA60.8s but holds it's own very well with less expensive class A/B amps including the Parasound JC5 that I owned for a while. 

I haven't directly compared my Purifi amps to the other amps you have, but I used to own the ML 333 and I think a good Purifi implementation could easily give it a run for it's money, and would likely surpass it in many areas (IMHO).  Of course, it all depends on system synergy. 

Thanks for taking time to both do the comparison and detail it here!

Not in the bass I believe, as the 802's EPDR impedance is too low for a bridged amp.

You are correct if that graph indicates a lot of 2 Ohm action. Then the single AHB2 in stereo is better. I speak from experience with Thiel CS3.7 and AHB2's.

Nevertheless the AHB2 is my favorite amp. Just love that clear smooth sound

Great A/B/C subjective review of the three amps, would have I believe been my choice.
50-150hz that’s where the 802’s nasties lay, low EPDR, (low impedance with high negative phase angle), "should?" have suited the ML333 and ABH2 better as well. https://www.stereophile.com/images/616BW802fig1.jpg

Your speakers seem perfectly suited for the AHB2 in mono.

Not in the bass I believe, as the 802's EPDR impedance is too low for a bridged amp.


Cheers George

Great info. I was thinking of getting the VTV and getting it modded by tweakaudio. 

If you used 2 AHB2's in mono the dynamic aspect of the AHB2 would likely be closer to the ML. Your speakers seem perfectly suited for the AHB2 in mono.