The Next Step in my Audio Journey — When System Synergy Trumped Individual Components

The Next Step in my Audio Journey 

— When System Synergy Trumped Individual Components

Rajiv Arora

For the last couple of years, the main components in my system have remained unchanged, because I was so happy with the sound quality I was experiencing. Yes, there were minor tweaks ongoing, but I don’t count those. Until recently, that is. Since this is the system which forms the baseline for my reviews, I thought I’d share the recent fairly drastic changes, and the rationale for them. 

To set the stage for those of you who haven’t seen my posts and articles chronicling my audio journey, I am first and foremost a headphone listener. I am not for one second asserting that headphone listening trumps speakers — it doesn’t — but it made sense for me and my situation. My current system is the result of many years of refinement to deliver the best headphone sound quality I could afford. Second, I love experimentation and tweaking, so my system reflects choices that you may find, well, weird! 

Until the beginning of 2022, my system continued to look like the picture below:

This was anchored by the Taiko SGM Extreme server and the Chord DAVE DAC, powered by the Sean Jacobs DC3 external PSU (power supply unit). My current reference headphones comprise the Meze Elite, Sennheiser HD800 (SD mod) and Abyss AB-1266 Phi CC. I got the best SQ driving the Elite and the HD800 directly from the 6.3mm output of the DAVE, while the Abyss sounded best driven through my external Cavalli Liquid Gold headphone amp.

The Catalyst for Change

The obvious next step I was contemplating was the upgrade of the Sean Jacobs DC3 PSU to either the DC4 ARC6 PSU — which I informally reviewed here — or continue the forlorn, interminable wait for my Paul Hynes SR-7 DR custom DAVE PSU. But something was nagging @romaz, @ray-dude, @Nenon, @Zaphod Beeblebrox and me. Emile at Taiko Audio, whose ears we all trust, had a DAVE/DC4 ARC6/SRCDX setup in one of his listening setups, playing 24/16FS PGGB files, but despite all our improvements to the DAVE in place, it still did not engage him as much as his flagship DAC setup at Taiko HQ. We considered three possible reasons for this: differences in personal preference, the importance of the USB interface, which benefits hugely from the Taiko USB driver optimizations, and the analog stage, which in Emile’s experience is where the truly great DACs shine.

This struck a, ahem, chord with me, as I have experienced the same in my DAC explorations. Even in my recent review of the Ayre QX-5 Twenty USB2 Board Upgrade, I talked about how the SQ of a DAC is the sum of all aspects of a DAC’s design, not just the digital filters and D/A converter. In particular, I know how important a role the USB interface, the analog output stage and the preamp play. Perhaps it was time to zoom out a bit and explore the analog domain in my own audio journey.

The other great equalizer in determining the next direction for me was PGGB upsampling. In my experience, the extremely long windowed Sinc filters of PGGB deliver outstanding transparency, layering, and transient response on my DAVE, replacing the WTA1 stage of the DAC, or the hardware M-Scaler. Perhaps it was time to consider other DACs that were amenable to the benefits of PGGB, while possessing more robust analog stages. 

Finally, I have been wanting to explore more powerful, and possibly better, speaker amps to drive my headphones. This was another factor in deciding my next steps.

Approach

How did I narrow down the list of candidate DAC/amps? Here are some criteria:

• Uses a USB controller with the XMOS2 chipset to exploit the Taiko USB driver
• Likely to benefit from and exploit PGGB
  • Support at least 16FS (705.6/768 kHz) sample rates
  • Support OSF bypass:
    • Either explicitly via a “NOS” switch, 
    • Or implicitly at max sample rate
• Excellent analog output stage
• Tight integration
  • Excellent preamp stage
  • Excellent headphone/speaker amp.

Of course, the criteria above are specific to my use case, where I use the DAVE as an integrated DAC/HP amp. Those who own bespoke pre- and power amps that they love will have different criteria.

I must give a huge amount of credit to Roy ( @romaz ) for identifying and trying several DAC/pre’s, which I won't name, since I only want to write about gear that I’ve tried myself. None, in his estimation, exceeded the high bar set by the DAVE/DC4 ARC6/SRCDX. None, that is, until the Vinnie Rossi L2 DAC, which is a modular add-on to the L2 and L2i SE integrated amps, as well as the L2 Signature Pre. The L2 DAC/L2i SE combo had checked a lot of boxes for us:

1. Based on Vinnie's reputation, as well as posted comments and reviews, expected to have outstanding analog performance from the L2 DAC's dual mono class A JFET output stage, the Pre (JFET/DHT (directly heated triode)), and the amp (MOSFET)
2. Uses the JLSounds XMOS2 controller, which should benefit from the Taiko USB driver
3. Use AKM AK4497EQ DAC chip  — Emile and Vinnie sing the praises of AKM DACs having great SQ
4. Has selectable NOS — more correctly, OSF (oversampling filter) bypass — mode, which is necessary to benefit from PGGB
5. Supports 16FS sample rates — again, should benefit from PGGB.

Roy's initial reports to us after trying the VR L2 DAC/L2i SE were so promising that I had to hear this for myself. In Roy’s application, he used the L2i SE as a DAC/pre, replacing his DAVE/DC4 ARC6/SRCDX and existing D’Agostino preamp. 

Luckily, I got a chance to audition and compare the L2 DAC/L2i SE integrated amp with a DAVE/DC4 ARC6/SRCDX in @Zaphod Beeblebrox setup. ZB is also a headphone user like myself, so we were able to use the L2i SE’s amp stage to drive our headphones.

System Changes

Based on this audition, I went ahead and procured a VR L2i SE integrated amp for myself, and my reference system now looks like this:

What changed and why?

Goodbye, Cavalli Liquid Gold Headphone Amp

I have been wanting to evaluate a high-end speaker amp driving headphones, but had not done so until now.

In the evaluation at ZB’s house, we used the DAVE/DC4 ARC6/SRCDX as the source, and compared the Cavalli and VR L2i SE as headphone amps. The L2i SE's speaker terminals have an output impedance of a low 0.02Ω, so it can easily drive our various headphones, ranging in impedance from 10Ω to 300Ω. To adapt the L2i SE speaker terminals, we used a non-ideal, but convenient, "banana plugs to female XLR" adapter from eBay, connecting to the Transparent Audio Ultra headphone cable system we both like. In this comparison, we were not using tubes, running the L2i SE in DHT bypass (JFET) mode. Tubes did enter the picture, but at a later stage.

The results of this comparison were unambiguous. The L2i SE is a much better amp than the Cavalli. The soundscape created by the L2i SE was bigger in all three dimensions, more real, and more dynamic than the Cavalli. This should not have been surprising, considering that the L2i SE as an integrated amp has an MSRP many times the Cavalli.

I have really enjoyed the Cavalli for over 5 years, so it was with bittersweet feelings that I found it a new home, using the proceeds to offset the purchase of the L2i SE.

Added Transparent Audio Banana Plugs-to-XLR Adapter

As you've seen in all my recent reviews, I'm a huge fan of the Transparent Ultra headphone cable system. Not only is the SQ of these cables outstanding, I just love the modularity of their design. The main cable (in my case, 3m) stays unchanged, and you just change adapters on both ends as you vary headphones, or amps. For the VR L2i SE, I initially used a "banana plugs to female XLR" adapter from eBay, but Transparent Audio built me a far more robust Ultra adapter, which was notably superior sounding to the flimsy eBay one, and interfaced perfectly with the rest of the Ultra cable.

The L2 DAC/L2i SE replaced the Chord DAVE/DC3/SRCDX

This is the biggest change in my system. I arrived at this outcome by evaluating three different configurations on ZB’s setup:

• DAVE Direct
  • Server > SRCDX > DAVE/DC4 ARC6 > headphones
• DAVE driving L2i SE amp
  • Server > SRCDX > DAVE/DC4 ARC6 > VR L2i SE > headphones
• L2 DAC/L2i SE Direct
  • Server > VR L2 DAC/L2i SE > headphones

This was indeed revelatory. Using 24/16FS PGGBed content, my listening confirmed a few things:

• Comparing 1) to 2), the latter sounded much better. The DAVE Direct path is noted for its outstanding transparency, and indeed there was a slight loss of transparency adding the L2i SE amp in the path. But the L2i SE more than made up for it in other areas. Similar to the Cavalli comparison, the L2i SE rendered a bigger and more realistic image. Instruments were denser, more visceral and more dynamic. This confirmed that the addition of the L2i SE was a big improvement in the system’s SQ. But the L2i SE is an expensive amp, so this is a pretty spendy option, purely as a headphone amp.
• Enter the L2 DAC module. Comparing configuration 3) to 1), I was really impressed by how well 3) did, despite the fact that the L2 DAC is priced at a fraction of the DAVE combo. In fact, it outperformed 1) quite comfortably in areas related to tonal richness, realism, dynamics, and density. Music simply sounded more real and more emotionally engaging. But this wasn’t a slam dunk. The transparency, layering, and transient accuracy of the DAVE was still evident, and superior, but this was now a tradeoff between many attributes.
• Was 3) better than 2)? Perhaps surprisingly, yes! This wasn’t a night and day difference, but I found the L2 DAC path to have crisper transients, along with more muscularity and density, even though both paths shared the L2i SE amp. Was this because of the L2 DAC’s output stage? Or the JLSounds XMOS2 USB interface? Or the interconnects we used between the DAVE and the L2i SE? We tried a couple of different ICs, and they made a notable difference. Was it the benefit of PGGB, that freed the L2 DAC from OSF duties? I suspect all of the above.

Whatever the reason, what I was hearing with the L2 DAC/L2i SE combo driving my headphones directly, was a new balance of strengths, a new synergy, that took my system’s SQ a quantum step forward.

Upgraded DHT Tubes to Takatsuki TA-300B

I initially wasn’t a big fan of the stock DHT’s in the L2i SE, and assumed I would stick to the solid-state JFET mode of the preamp. But then I was persuaded to try the Takatsuki TA-300B tubes — who knew I’d start tube rolling! — and my world was rocked. The Taks improve SQ even further, and quite substantially over the stock tubes. Once I had them, I could never return to the JFET DHT-bypass mode. I’ve never been a tube guy, but this particular application is just magical.

Fewer Cables!

The beauty of this new setup is that I no longer need:

• analog interconnects for an outboard amp, since the VR's amp is integrated.
• dual BNC cables from SRCDX to the DAC.

Software Changes

Taiko OS update

Emile introduced a cumulative update in Jan/Feb 2022 that delivered:

• A slew of OS and network driver optimizations, and
• An improved Taiko USB driver, incorporating elements of the Taiko Audio Server (TAS).

With these new tunings, Emile asserted very emphatically that the network should stay connected using copper Ethernet, not fiber, and to revert to using Roon as the music server. This was quite a departure from my previous operating point, which was to run:

• With local PGGBed content
• With network disconnected after hitting Play
• Using TAS (Taiko Audio Server).

I did not just follow this advice blindly, but also was not surprised when his recommendations were borne out in my listening tests. So this led to additional software changes.

But first, the improvement brought about with this OS and USB driver update was really profound. I’ve heard the benefit of software improvements on a music server before, but I did not expect this magnitude of a change on an already highly-optimized server.

One advantage of having switched over to the L2 DAC was that its JLSounds XMOS2 USB controller fully benefited from the Taiko USB driver update, and this too was not a small subtle change. I remain amazed at how much more Emile is able to squeeze out of the USB driver!

Switch from TAS back to Roon

I had never expected to go back to Roon, and Taiko’s plan is to eventually deliver their new XDMS player, that will supersede TAS and become the recommended option for the future. Still, consistent with Emile’s claims, I was flabbergasted to find Roon sounding excellent, and as promised, outperforming both TAS and HQPlayer, that I also use occasionally as a music player. Quite remarkable.

Network Changes

Connected outperforms Unconnected?!

I am still scratching my head over this one, but I cannot argue with the difference I’m hearing. For the last almost 2 years since I bought the Extreme server, I’ve gotten off the network switch optimization game. Over time, Emile’s Ethernet driver tuning had gotten me to the point that the switch chain upstream of the Extreme was doing very little harm. Still, for best SQ, using local files and a non-chatty player like TAS or HQPlayer, I would hit play and disconnect the network for the best and most consistent SQ. While my system diagram still showed a chain of 3 switches, honestly, it’s just a carryover from my switch optimization days.

So when Emile asserted that Roon was the best sounding player software with his new update, it meant that I could no longer use the disconnected mode, since Roon does not function for long periods when disconnected. But then Emile also insisted that with his latest fixes, the SQ is actually better with the Extreme attached to the network via Ethernet, than disconnected. He has his hypotheses why this is the case, but I just wanted to test the assertion.

Roon will still play back for a short duration (under a minute in my case) with the network disconnected, so I compared the connected vs. the disconnected case. While it wasn’t night and day, I certainly heard what appeared to be a small improvement with the network connected. Honestly, I would have been happy even with a no-degradation result, as this allows me to explore streaming again.

Simplified switch chain

With the network back in play, I felt compelled to revisit my switch chain to find the best sounding operating point, with the gear I already had. As it turned out, I shortened the switch chain to:

• router > copper > etherRegen > fiber > SOtM > copper > Extreme.

Emile and Taiko have plans to deliver their own Ethernet PCI NIC, upstream switch, and even a router, so I don’t plan to do any more network tuning until I’ve tried these products.

Caveats

• The VR L2i SE is a discontinued product, so I am not for a second advocating this as a path for others to necessarily follow. The availability of this amp in the used market is very spotty. That said, there is a good chance that some subset of current L2i SE users will upgrade to Vinnie's new, much pricier Brama amp, in which case Vinnie should have some trade-in units for sale.
• The AKM AK4497EQ DAC chip in the L2 DAC is no longer available, and with the recent fire at AKM's facility, AKM chips are generally in short supply. Vinnie has said he has no spare L2 DAC modules in stock, so any units that require repair may be out of luck, even if you are still under the original warranty, or whatever warranty Vinnie offers for the trade-in units he sells.
• When using the Taks, there is a very faint background hum when no music is playing. It is most noticeable with lower-impedance headphones like the Elite, and almost non-existent on the 300 ohm HD800. I found this to be a non-issue during playback.

Final Thoughts

When exploring improvements to one’s audio system, it is natural to apply focus to specific parts of the audio chain at any given time. Over the last few years, I’ve explored and enjoyed tweaking the network chain and the music server architecture, and trying various DACs and headphones. For the last couple of years, it just happened that my focus narrowed to finding ways to make the Chord DAVE even better sounding than it already is in its stock form. Between upgrading the PSU to the Sean Jacobs DC3 and DC4 ARC6, bypassing the Amanero USB interface with the Audiowise SRC-DX, PGGB upsampling, and exploring various dual-SPDIF cables, this was a fertile and satisfying exploration.

Still, there comes a point where it makes sense to step back and look at the bigger picture. Everything in the audio chain matters, and the analog portion is no less important. It was this act of stock-taking, as well as the invaluable fellowship of audio friends willing to experiment, that led to this latest round of updates. The tipping point for me, that caused me to act, was the incredible synergy and simplicity of the L2 DAC/L2i SE.

Do I think any less of the DAVE/DC4 ARC6/SRCDX/PGGB combo? Heck no!! I am still in awe of how good this combination sounds. For people running this combo with a pre/power/integrated amp they love, move along, there’s nothing to see here. 🙂 To underscore the point: I still own a stock DAVE that now lives in my office system. It’s not going anywhere!

Is the L2 DAC/L2i SE my end game setup? I know better than to make any such claim. Change will come eventually – it always does! Until then, I am incredibly pleased with the sound quality of my system, and that is ultimately what it’s all about!

System Pictures

If you’ve actually read this far, then here, by way of thanks, are some pictures of my system!

My audio system actually lives in my home theater, where I’m using the length (left to right) of the room for A/V use, and back to front for my listening.

Mine is a headphone system, and this is where they hang, when not in use.

The Vinne Rossi L2i SE integrated amp, with Takatsuki TA-300B tubes.

The Transparent Ultra banana plugs-to-female 4-pin XLR adapter, that allows this speaker amp to drive headphones.

The Sound Application TT-7 Reference power conditioner (bottom), SOtM sNH-10G switch (top shelf).

The Taiko SGM Extreme Server.

The rest of the switch stack and the Paul Hynes SR7MR3DRXLFC10 custom PSU.

Since I rewire things so often for my reviews, you’ll notice a theme of components with a side orientation. This spares my poor back immensely, even though it’s ugly!

Reference System Details

Music Computer:          Taiko Audio SGM Extreme Music Server, Taiko USB upgrade

DAC:                               Vinnie Rossi L2 DAC module

Amp:                               Vinnie Rossi L2i SE integrated speaker amp

Headphones:                 Meze Elite, Abyss AB-1266 Phi CC, Sennheiser HD800 (SD mod)

Ethernet Switches:        SOtM sNH-10G, Uptone EtherREGEN, Buffalo BS-GS2016 (modded for LPS)

Power supplies:             Paul Hynes SR7MR3DRXL (dual regulation, 3-rail)  for switches

Power Details:               Dedicated 30A 6AWG AC circuit

                                        Sound Application TT-7 Reference Power Conditioner

Power Cables:                Sablon King (wall to TT-7), Sablon Prince (Extreme),

                                        Cardas Clear Beyond (L2i SE, SR-7),

                                        Cardas Clear for all other components

USB cable:                     Sablon Evo 2022 USB

Ethernet cables:             Sablon 2020, Supra Cat 8

DC cables:                     Paul Hynes fine silver (SR-7)

Headphone cables:       Transparent Ultra cable system

Accessories:                  Synergistic Research Tranquility Base XL UEF. Galileo MPC

                                       Synergistic Research MiG 2.0 footers

                                       Taiko Audio Daiza Isolation Platforms

                                       High Fidelity Cables Trinity Helix Headphone Module.

Acknowledgments

Many thanks to the following companies for supplying cables and accessories to aid in this evaluation:

Cardas Audio, for a full loom of Cardas Clear cables.

Transparent Audio, for the Transparent Ultra headphone cable with a full complement of headphones leads and source terminators.

About the Author

Rajiv Arora — a.k.a. @austinpop — is both a computer geek and a lifelong audiophile. He doesn’t work much, but when he does, it’s as a consultant in the computer industry. Having retired from a corporate career as a researcher, technologist and executive, he now combines his passion for music and audio gear with his computer skills and his love of writing to author reviews and articles about high-end audio.

He  has "a special set of skills" that help him bring technical perspective to the audio hobby. No, they do not involve kicking criminal ass in exotic foreign locales! Starting with his Ph.D. research on computer networks, and extending over his professional career, his area of expertise is the performance and scalability of distributed computing systems. Tuning and optimization are in his blood. He is guided by the scientific method and robust experimental design. That said, he trusts his ears, and how a system or component sounds is always the final determinant in his findings. He does not need every audio effect to be measurable, as long as it is consistently audible.

Finally, he believes in integrity, honesty, civility and community, and this is what he strives to bring to every interaction, both as an author and as a forum contributor.