Gramophone Dreams #47: Hana Umami Red, Musical Surroundings Nova III, Ampsandsound Bigger Ben Page 2
A Bigger Ben The humans I admire most are the makers: those who physically make things with their hands, whether it's paper doilies, loaves of bread, or steel bridges. I venerate makers because the sacred rituals of fashioning objects force makers to understand the spiritual, cultural, and economic value of their work. That is why I chose to be a maker, not a merchant or a scholar.
When I encounter other makers, I feel an immediate kinship, accompanied by a need to investigate the workings of their mind. Ampsandsound's creator Justin Weber is one of those people (footnote 4). He is one of the most inspired, natural-born builder-mechanics I've met. I admire him because he is an unusually sincere, humble human who creates some of the finest loudspeaker and headphone amplifiers I've encountered. Between design gigs, he works full-time as a social worker specializing in psychiatric and medical social work.
A couple of years back, I spent a few months enjoying Ampsandsound's Mogwai KT88 headphone/speaker amplifier, but my first official experience with a Justin Weber–designed amplifier was my Gramophone Dreams #35 review of ZMF Audio's $2000 Pendant headphone amp, which Weber designed and built for ZMF. In that report, I concluded, "The Pendant seemed like the best all-purpose headphone amplifier I have used since I died and flew to heaven reviewing the $5899 Woo Audio WA5."
I am now living with Ampsandsound's $4950 Bigger Ben, a single-ended, triode-wired, no-negative-feedback tube amplifier designed to drive both loudspeakers and headphones. The Bigger Ben is intended to improve on the Mogwai by making everything bigger: bigger capacitors, bigger transformers, a bigger choke. According to its designer, the Bigger Ben can generate approximately 8Wpc into 8 ohms and 5Wpc into 32 ohms (when equipped with a solid state rectifier and KT88 output tubes). There's just one input via a pair of RCA connectors. Volume is controlled by a stepped attenuator.
My review sample arrived in a large Pelican flight case. It came equipped with Russian-manufactured TungSol–branded 6L6GC output tubes, JJ Electronic 6SL7 input tubes, and a Russian-made Electro-Harmonix 5U4GB rectifier. The Bigger Ben's single-ended (RCA) inputs are transformer-coupled, offering a 10k ohm input impedance. The power supply is filtered by a massive choke. The power and output transformers are "bigger" than the Mogwai's and over-spec'd compared to what would normally be used to support the currents and voltages of the Bigger Ben's circuit. Users can choose between an octal solid state rectifier plug-in or a variety of tube rectifiers.
The Bigger Ben's output transformer secondaries are tapped at 8 ohms for speaker cable outputs, and along the amplifier's left side are five ¼" headphone jacks labeled Low Z, 16 ohms, 32 ohms, 100 ohms, and High Z.
According to Justin Weber (via email), "Low Z accesses the output transformer's 8 ohm tap. A switch at the amplifier's rear allows users to choose between using that winding for headphones or speakers. HiFiMan's HE6s and Dan Clark Audio Ethers work well via the Low Z. The High Z is a 300 ohm tap, which pairs super well with ZMF's Eikons through Vérité or Sennheiser's HD600/HD800s, as well as Beyerdynamic's 600 ohm DT 880."
In my previous experiences, Ampsandsound's 5Wpc KT88 Mogwai and ZMF's 3Wpc Pendant amplifiers exhibited no SPL limitations driving the 97dB/W/m, 16 ohm Zu Audio Soul Supreme speakers designed by Sean Casey. All genres of music flowed easily and dynamically from the Zu's 10.5" full-range pulp-cone drivers. Those amplifiers are long gone, but during these current auditions, I thought the 6L6GC-tubed Bigger Ben powered the Soul Supremes to greater levels of transient and timbral exactitude than either Mogwai or Pendant—or most any other amp I've tried. The 6L6GC "Ben/Zu" combo specialized in highly tactile, microdetailed sound.
That same sense of dynamic, highly textured precision dominated my impressions of the 6L6GC Bigger Ben powering my DeVore Orangutan O/93s. I noticed no clipping or skewing of tone. With the O/93s, I compared the Ben to the First Watt F8 and Elekit TU-8600 and found it every bit as natural and engaging—as "live happily forever" satisfying—as those amplifiers.
I was more surprised by how easily the lower-watt Bigger Ben powered the low-sensitivity (83dB/2.83V/m), high-impedance (15 ohms) Falcon LS3/5a (Gold Badge Edition) speakers. With 6L6GC tubes and a strong tailwind, the Ben might put out 3Wpc—a far cry from the gigawatt Parasound Halo A 21+ I'd been using to power them just before.
I substituted the KT88 tubes for the 6L6s, still driving the Falcons. I played bluegrass, jazz, ska, and Mahler, at levels averaging 80dB with 90dB peaks (at 2m). I never once felt a need for more power. What I did feel was a special joy at discovering another tube amplifier that brought life and musical excitement to those venerable BBC monitors.
The Bigger Ben's circuit uses zero feedback, which permitted the JJ KT88s to show off their superclear third-harmonic character. In contrast, the 6L6GCs sounded second-harmonic misty. Drums and piano sounded softer. But I did not care, because the 6L6GCs extracted so much tiny-sprouts-in-a-forest detail they filled in all the KT88's empty spaces with infinite little things I hadn't noticed before.
The Ampsandsound Bigger Ben has a radiant quality—as if the sound were illuminated from within—that can be difficult to notice when playing highly processed, multitrack studio recordings. But that quality plays a leading role in pleasurable two-channel field recordings such as Pallavi: South Indian Flute Music (1973 LP, Nonesuch Explorer Series H-72052), engineered and mastered by Bob Ludwig (Sterling Sound Inc.). T. Viswanathan and L. Shankar are sitting onstage, playing flute and violin, respectively, in an arc with T. Ranganathan on mridangam and K. Ramiah on tambura. I listened through HiFiMan's 60 ohm, 83dB/mW, openback, planar-magnetic Susvara headphones connected to the Bigger Ben's 32 ohm output, KT88 tubes driving. The Hana Umami was driving the Musical Surroundings Nova III, loaded at 100 ohms.
I wish you could hear what I heard. It was almost scary. Audio accuracy is like pornography: difficult to define, but you sure as hell know it when you hear it. With the Ben/Susvara combo, I heard accuracy, and it was unforgettable. Of course, through headphones, the image mapping was less satisfying than it was through the LS3/5a monitors. Nevertheless, my mind was right there in front of every stage microphone. The actual, physical density and intensity of each voice or instrument was as jaw-droppingly real as I have ever heard from an audio system. Drums sounded startlingly—nay, almost completely—lifelike. The Ben's KT88s made percussion come alive.
Switching back to the 6L6GCs, still driving the Susvaras, my heart melted when I heard Anoushka Shankar's voice introducing her Live at Carnegie Hall appearance (16/44.1 FLAC Warner Classics/Qobuz). Until then, I'd only thought I was in love. Timbral nuance, inner-inner detail, and rhythmic fluidity permeated the Bigger Ben/Susvara presentation of this live recording.
Bigger Ben vs Z10e I find this new category of integrated headphone/speaker amplifiers very appealing. However, I like it most when the amplifier allows me to switch between at least two line-level sources. Ampsandsound's Bigger Ben does not. I like it even more when the integrated amplifier comes with a remote volume control; the Bigger Ben does not.
That is why my favorite product in this category has been Linear Tube Audio's $6950 Z10e integrated headphone and speaker amplifier (see Gramophone Dreams #36). Designed by David Berning, the Z10e has three line-level inputs, a remote control, and a powered output for electrostatic headphones. It is specified to deliver 12Wpc into 8 ohms and up to 3Wpc into 32 ohms. It drives all headphones, plus my DeVore, Zu, and Falcon speakers, with spark and vigor. But the Z10e sounded quite different than Ampsandsound's Bigger Ben.
Both amplifiers excelled at driving ZMF's 300 ohm Vérité closed-backs. But the class-AB push-pull Z10e seemed more focused and brightly lit through the midrange. With the Z10e, Anoushka Shankar's Carnegie Hall performance felt like more of a grand, full-tilt tour de force (which it was) than it did with the Bigger Ben. The Z10e emphasized the urgency of rhythms. The Bigger Ben (with KT88s) emphasized the body and harmonics of the instruments and the sensual humanity of Shankar's voice. With the Ben, the Carnegie stage floor played an active, soundboard-like part in Shankar's performance.
The Ben showed more physicality. The Z10e showed more of the "air" above the stage. Both amps showcased a stark-but-enticing you-are-there clarity.
January 10, 2021 These are strange "Herb hides in the bunker" times. Nevertheless, I find myself feeling more grateful than ever. I have health and heat and sufficient gruel. And as you can see, I've been incredibly fortunate when it comes to music, amps, and speakers. I hope you all are equally blessed. May 2021 be a good year for peace, fellowship, and dream-filled listening.