SFAF Phono Stage Shoot Out Event Review
PART ONE: What’s in an Event?
This was a mini marathon event. We had six different phono preamplifiers and to cover enough audio and musical tastes we listened to six short tracks on each. Time was the essence and therefore the main instrument in the system was the large atomic LCD clock. With all the good intentions, we went over the planned 90 minutes time by a big margin, probably an hour or so extra.
Would I change the format? Not really. We included interesting gear, each for its own features, and interesting mostly acoustic tracks. Cutting down the number of preamps or tracks would subtract from the total experience.
But there are more lessons to learn. This is the second time we organize an event in a venue that was very generously made available on the ZAG company premises (thanks Jim Hunton!) and being a work office we could not set up a few days in advance. Last minute setups are hectic and are sometimes imperfect. For example, we ran the event with the covers on the drivers of the magnificent Perlisten S7t speakers, not realizing that these are magnetically attached and super easy to remove. The sound improved when we removed them at the end.
The RM-10 mk 1 amplifier for the event was chosen because it’s a landmark design that is nearing re-introduction by Music Reference (i.e. our own Tony Chipelo, as he continues to run the late Roger Modjeski’s company). You don’t find an EL-84 amp producing 30WPC every day, and a glorious sound as well.
To complete the system, Matt from J&J Audio (a great supporter of our events!) brought an LTA MicroZOTL line stage, another very interesting design by David Berning. For the “budget” turntable, Matt offered the Michell Gyrodec with the entry-level T3 tonearm (Rega RB300 clone) and the Goldring Eroica-H high-output MC cartridge with the “standard” 47k loading, to simplify the setup of six phono stages. All the components other than the amp were on power conditioners and the cabling was my own Oritek X-2 interconnects and S-1 speaker cables (not available for sale any more…). The expectations were high to achieve near the finest sound one can hope for. Well, sometimes the total is greater than the sum of the individual parts, sometimes it’s less…
That’s what happens when you have a last minute setup with no time to tune up the sound. Unfortunately we ended up with a slightly warm sound. Maybe it’s the synergy between components, maybe the acoustic absorption of 20 people right in front of the speakers, maybe the (surprise!) relatively low position of the tweeter in the S7t towers. It wasn’t a bad sound, just not the greatest to my own subjective taste. Other people may disagree and like it as-is!
Which brings me to the real point I wanted to make: why do we hold live events or go listen to other people systems? The answer is simple. We will never encounter such issues with world-class or earthly components unless we experience them in person and we will not learn a thing if we just listen to one system with no other reference. That’s why I published the exact tracks we’re playing at the event ahead of time, so people can try it at home on their familiar system ahead of time and come to the event with that reference information. That’s how you get the most out of the listening experience.
PART TWO: Personal Impressions
This is the section where I want to post my own quick (and very subjective) observations of the phono stages we played at the event.
First was the iFi Zen. It’s a $200 unit that is all the rage on the forums since its introduction a few years ago. It uses the lowest noise opamps and the RIAA network is made of many tiny TDK capacitors in parallel, supposedly better than large metalized caps. Cost cutting is also evident in the switchmode power supply. While the brochure claims is a great supply, the owner company AMR offers more expensive phono stages with linear supplies. Hmmm…
If you’re limited to this budget, it’s a very accomplished phono stage. It lacks the attack and decay transient speed of the best units and the sweetness of the tube units.
Second was my own DIY battery-operated unit. Whatever I’ll write about it will face skepticism, so I won’t… Leave it to other people to comment - for the good or the bad!
I included it in the event for the fun factor and also to demonstrate the low noise level one can achieve on very limited means. It does not use exotic JFETs in parallel and it does utilize negative feedback in the gain stages, but not in the RIAA circuit. Proper architecture of a phono stage is much more important than marketing buzzwords…
Next on the chopping block was another over-achiever, at least on the forums at the time it was introduced – the Hagerman Cornet tube unit. It features a tube rectifier (the recent version does not!) and a classic circuit with a passive RIAA in between the gain stages. The output is a low-impedance cathode-follower tube. This design is very similar to the EAR 834P, which has a solid-state supply and puts the RIAA network in the feedback path. Sometime in the future we’ll play them side by side, but for this event we had a better choice, which is the next unit.
The Cornet is a tube unit that is not all sweet, but it has a smooth and relaxed sound. It uses decent Multicap capacitors and needs no excuses, despite its low price point around $800 at the time. It has decent treble response and retains most of the harmonic structure. Bass has somewhat less impact than the solid-state units, but it maintains a pretty good balance across the audio range. I’d still consider it an over-achiever at the price point, especially older used units with the tube rectifier and hopefully a set of credible NOS tubes, like the demo unit had. Music is flowing very gracefully and you get a good sample of the very best units you can buy.
And here is one of these. The Luxman EQ-500 looks like a luxury piece of gear and a peek inside shows that not much was spared in its implementation. It’s not perfect, but build quality is impressive. It has very unique features, like an output (!) transformer and two different step-up transformers (SUT) for MC-lo and MC-hi. These may not be a Tango quality, but at the price point it’s quite surprising to find.
With all the attention to details, the engineers forgot to offer a more flexible MC loading, but that didn’t bother us during this session, since the Eroica-H cartridge specifies a standard 47k loading.
The audio path itself is very similar to the Cornet: a passive RIAA between two gain stages and a buffer stage for the output. All stages are SRPP circuits, a slightly more complex implementation (than the cornet) which offers a better power-supply noise rejection and a more linear mode of operation for the triode tubes. Considering the low-level signals throughout the phono circuit, all these refinements seem minor but they add up. Sometimes the total is greater than the arithmetic sum… The Luxman is a very listenable phono preamplifier. You can listen to scratchy pop records and not get a headache.
It has just a touch of tube sweetness, enough to pull you into the emotional side of the music, but it never implies even remotely a greater than life feel. No one would blame the Luxman for being too dry or too syrupy. It seems to have found a golden path in between. This unit is a must-listen to any vinyl lover.
After a lovely experience with the two tube units in this demo, we went back to solid-state, and this time it’s a just as famous PS Audio Stellar Phono. I’ve read quite a bit about it and saw the interviews and introduction by the designer Darren Meyer, which is obviously a passionate audiophile. I am not familiar with the exact circuit, but the PCB and Darren’s intro point to surface-mount discrete opamps that were tweaked for best open-loop linearity before applying a low-level of negative feedback.
Companies like Boulder Audio and Pass Labs are utilizing discrete opamps very successfully, but no one offers such an elaborate design at the $2000 price level. A lot of stars had to line up just right to make this happen and lucky for us we managed to arrange a ride for Don Naples’ Stellar Phono down from Healdsburg to San Jose (thanks Larry!). Needless to say that the expectations were high!
And here we go once again. The sum of 720 discrete parts make this whole unit but do they make it sound divine? The exact same preamp was in a previous phono shootout at Don’s house last year, and the comments were lukewarm, dry sound, and not much detail. And the exact same impressions are what I thought when listening to this unit in our completely different setup. All are features that I usually attribute to a high negative feedback design and average capacitors, even though the RIAA circuit in this unit seems to have somewhat decent caps. It was also interesting to note a change in sound character when switching from low to medium gain (MM mode). I expected a level change, not better sound. There was no time to dig into the configuration issues with this preamp, but the best sound it produced was still not at the top shelf level.
Maybe the first stage of a phono stage is better off using zero (local) feedback in a discrete low-noise circuit rather than an opamp. There is not much headroom requirement so why bother with a complex opamp circuit there? Whatever the reason is, the Stellar phono gave us a significantly less than stellar performance, especially obvious when played right after the world-class Luxman EQ-500 and another surprise phono stage, a hot-rodded Pearl II.
Never heard of a Pearl II phono stage? You are not a DIY person for sure… The famous Pass Labs company used to have two principal designers: Nelson Pass who needs no introduction mainly designs the power amplifiers, and Wayne Colburn, who designs the preamps and other low-level products. Wayne operates quietly in the shadows of a giant (Nelson) but those in the business know that preamps are way more complicated to design than brute power circuits…
Following Nelson’s many articles about a generic “Zen” amplifier for the enthusiast DIY crowd, Wayne released the Pearl phono stage for the same audience. Pass Labs formed the PassDIY subsidiary to supply kits, or sometimes just PCBs following these articles. After feedback from the field, Wayne refined the design and released the Pearl II, which borrows a lot from his commercial XONO design. In some sense, the Pearl is a much simpler and therefore more purist design. It has parallel JFETs zero-feedback front-end driving a passive RIAA network. It’s followed by a two-stage discrete opamp and the output is capacitor-coupled. Many people built the original design and commented that it sounds more “tubey” than the relatively dry XONO. Price point was much lower for the Pearl II kit, but that’s not considering the long hours and much sweat that you have to put into it… It was a labor of love from conception to a final product!
So here comes one enthusiast, our own Jim Hunton, who decides to build a few PassDIY kits. Im almost built it myself (I had PCBs ready) but got busy with my own design and when I saw the lovely two-chassis Pearl II at Jim’s house my heart skipped a beat (I know, what a geek…). A quick listen was less than acceptable and after some investigation Jim found a mistake in the cartridge loading and all was good. That was a real-life example for those who don’t believe in cartridge loading!
Next was a mini shootout in my system, where the Pearl II hardly outperformed the $200 iFi Zen. I knew what changes I’d implement in my own build and I suggested those to Jim. Fast forward 6 months, all changes implemented (quite skillfully!) and it was time for a second shootout, this time against the Luxman EQ-500. The modified Pearl II sounded like a different product, way better than the original. The Luxman did not. We opened up the case to check the tubes and… a Eureka moment! Some smarty rolled tubes and inserted a 12AU7 in a 12AX7 socket. It still works, just like a Yugo engine in a Ferrari… Wec swapped tubes and life was good. Interesting to note that the “fixed up” Luxman sounded close to the modified Pearl II in my system, and I deliberately put it in that order.
And that’s just about what I thought of the Pearl II+ in the event system. It was exemplary, extended and extremely well balanced. The system is much warmer than my home system. In my home system you can hear ticks and pops from the record surface. They are obvious and they stand outside the music soundstage. You didn’t hear this level of detail at the event, but I guaranty you will hear it in a well-refined system. If you want your champagne at beer prices and are willing to put in the time and effort, then the modified Pearl II+ is a no-brainer. Now, since I have a part in its design, you have to take my comments in the right context. I like details, pronounced treble response, complete harmonic structure and not much of a syrupy warm tube guy. Don’t get me wrong, I like tubes but I tune them to sound “right to my ear”, exactly like any self-respecting designer should aspire to achieve. In some cases, a tube seems to outperform a very refined solid-state circuit, but it’s a win on points rather than a devastating knockout.
If you like warm tubey sound, the Luxman is your better option. If you’re like me, give the Pearl II+ a serious audition. Whether you like it or not, you’ll learn something about sound or a taste in sound. In the end, audiophilia is all about the learning experience and in that sense we all gain.
Let’s go back to the basics… we had a real fun event on a sunny Saturday in San Jose. It was great to listen to music in good company. Some of us came in for the class before 10AM and left after the listening session around 4PM. Not many left in the middle, no one complained… In fact, I appreciate the supporting comments at the end of a long and tedious day. That alone is worth all the effort that was put into this event by Jim, Matt, Dennis and myself. A big THANK YOU to all who attended for making this a major success!
Let’s continue to spin more vinyl and just enjoy the experience!!!