Tubers are “a much thickened underground part of a stem or rhizome, e.g. in the potato, serving as a food reserve and bearing buds from which new plants arise.” Trafomatic’s Lara “is a fully balanced line preamp using one 6N30 per channel, then Lundahl LL1592 input transformers and output transformers made by us”. The twin-chassis Lara thus has thermionic food reserves and devotees of the breed will expect plenty of sonic buds. Naysayers will expect electrolytic capacitors and compromised S/NR. Here that’s high-voltage Mundorf MLytics and 80dB. Voltage gain is near standard at 20dB, bandwidth at -1dB hits 10Hz and 57kHz end points. The separate PSU runs oﬀ a low-induction toroidal line transformer followed by high-inductivity Trafomatic chokes for ripple suppression and smoothing. Operation is pure class A. There are ﬁve inputs (3:2 RCA:XLR) and XLR/RCA line plus RCA subwoofer outputs. The slim-line boxes measure 40x31x8.5cm WxDxH and weigh a
svelte 10kg. With Trafomatic co-owner Milorad ‘Mica’ Despotovic in charge of ﬁnishing, custom paints or even woods are always just one ask away. Over the years, this Serbian valve gear house has made a name for itself with many quite exotic custom commissions. Some of those pushed circuit designer and chief engineer Sasa Cokic deep into new terrain. This subsequently trickled down into regular production items. It’s how wealthier clients can double as patron saints for the type of hiﬁ which the rest of us can reach for.
Trafomatic’s oﬃce system. Quad cartridge custom Collins phono stage on top of Trafomatic’s new production rack.
Thinking readers will have recognized the 6N30 glass as dual triodes to wonder whether our Serbians conﬁgured the two halves in push/pull to arrive at a fully balanced circuit. That would further necessitate a quad volume control and that the single-ended path be symmetrized upon entry and desymmetrized upon exit. If instead the volume control was a classic stereo aﬀair and the RCA path run straight through, it would not
be a balanced but single-ended circuit with transformer-generated XLR like our Nagra. Either approach is fully optimized for just one format.
The back panel shows the comprehensive socketry including a ground post, phase toggles, a ground lift and the 8-pin power input. The externally accessible 115/230V switch of the PSU unit makes for convenient power conversion and one global model.
For tubular contrast, I had our Nagra Jazz preamp, for transistors the Wyred4Sound STP-SE Stage II. About truly balanced, “the input transformers’ primary windings become the balanced input (for unbalanced the low end is grounded), the two secondaries act as phase splitter. The potentiometer is a four-gang unit on one shaft, so one stereo pot per channel. The output uses each 6N30 in push/pull and the output transformers are push/pull as well. For XLR out, the secondary windings aren’t grounded but one is again for RCA. This is a very simple conﬁguration and truly i/o balanced.”
With Trafomatic, these things are exactly as advertised. Many competitors are less punctilious when calling a circuit ‘balanced’. With perfectly matched impedance, true balanced signal processing exploits common-mode rejection aka CMMR to lower distortion. Here precision execution of the phase splitter, transformer windings and four-gang motorized Alps Blue potentiometer plus close tolerance of each
triode’s halves become vital factors. Lara’s clean/dirty- box architecture exploits another trick. It segregates the noise-sensitive signal path from the grimier power supply magnetics. The dirty laundry goes into the lower box, the neatly folded starched lot ends up in the upper box. A short umbilical connects the two.
Those in need of even more socketry have the Reference One model.
Diligent shoppers will want to know how the Lara and Trafomatic’s own Reference One models compare at the ear. Putting this question to designer Sasa Cokic forced him to judge two of his own kids. Here’s how he danced that jig. “Our Reference One is similar in using the same tube for voltage gain but it then uses a tube as phase splitter and 3dB of negative feedback to address the 2nd harmonic. The Lara uses zero NFB and as
a consequence, is more detailed and less coloured. Transients too are quicker because there are no coupling caps in the Lara as there are in the Ref One.”
Expertly danced! Direct-coupled tube preamps are quite rare. So are true balanced ones. On those two counts, lady Lara from Mladenovac already stood apart. With her simple circuitry relying on top-quality parts for counter-phase precision, how would she play it sonically between the
Aqua Hiﬁ Formula DAC’s balanced output and the fully balanced LinnenberG Allegro mono ampliﬁers?
A black Lara on the assembly bench, one of the two chokes prior to potting in the insert.
By way of preview, at the Munich HighEnd 2017 show, Trafomatic had collaborated with Audiobyte, Rockna, Skogrand Cables and Tune Audio.
Sasa’s amp contributions there were obviously his oﬃce system Elysium monos. Having heard this room at previous shows with Engström and ModWright electronics, this year’s showing with the big Avaton was my favourite yet especially after the system had settled in over two days.
The Lara preamp held down the preamp fort, showing herself in quite elite company. Delivered in a stout chip-board crate with metal handles and inner cardboard box followed by thick foam liners and protective cloth covers, the review loaner emerged in immaculate matte black paint. The red detailing on the remote control was the only concession to orange being the new black. A very recent minor cosmetic redesign of the control knobs meant that mine didn’t yet sport the hair-line scale of the white unit at left. Since that’s the ﬁnal look, we’ll go with the stock image.
Once opened, ground wire connection between metal liner and bottom removed, the head unit’s small input transformers and four-gang attenuator proved to be hidden beneath the inverted circuit board at the front. The potted massive chokes hid expectedly inside their canisters, with their in- and outgoing brown cables tightly twisted. Mounted horizontal in military fashion, the tubes were attached to a solid metal brace whose back, via standoﬀs, hosted their matching circuit board. With the main signal cabling thickly insulated, lady Lara’s undercoat was just as ﬁnely made as her outer garments. It’s reasonably rare to ﬁnd hiﬁ components clad in a wooden chassis which here get fully lined in metal to conform with international radiation standards.
The four footers turned out to be solid metal cylinders ﬁnished oﬀ with thick black felt pads to protect the paint of the PSU beneath it since the short included umbilical mandates such a stacked placement. The power supply duplicated the same hybrid wood/metal construction… with more chokes and sundry voltage regulators.
As the name Trafomatic suggested in the ﬁrst place, their balanced preamp would sport plenty of iron to get the job done. That’s a very diﬀerent approach from typical modern solid-state preamps.Here we see how the second RCA line-outs are labeled ‘sub’ but they could just as well be used for bi-amping with two stereo ampliﬁers; or to feed a separate headphone amp.
To get going merely required connecting the umbilical and ﬂipping the power rocker on the PSU’s left cheek. The recessed positioning nubs in the male 8-pin plugs were very hard to see but they were there to insure that the female ends of the cable would only enter in the one intended way. Without any status indicators on the front panels, the lone visual
reminder of ‘on’ was a small red LED below the side-mounted power switch for tastefully subdued operation.
After the preceding review of the two-stage tube-powered HQ9038 DAC from Vietnam which splendidly interfaced with our nCore 500-based class D monos, that’s the ﬁrst ampliﬁcation Lara played to. With stout volumes attained below 7:00 on the dial and increasing rapidly from there to never make it to anywhere near 8:00, I had to ask Sasa about his circuit’s gain. Either that was unexpectedly high; or the attenuator’s taper very steep. After all, very few amps sport as low an input sensitivity as his 3.5Vrms Elysium monos.
“Gain is just 20dB. Probably your source voltage is too high.” That certainly was a possible answer. Another would be that a balanced preamp should be tailored to modern balanced sources, most of which output twice on XLR what they do on RCA to mean 4V if not more. Combine that with amps of 0.5-1V input sensitivities and a well-judged volume taper ought to allow one to gradually hit 10:00 before things blow up. All of this would be so much easier if core hiﬁ specs were standardized. But they aren’t. Now impedance and gain mismatches are very common. In our case, the balanced sources rate at 16V (COS Engineering), 6V (hq audio), 4.6V (Fore Audio), 4V (Auralic) and 3.8V (Aqua Hiﬁ) whilst our balanced amps deliver full power at 0.7V (Pass), 1.5V (LinnenbergG) and 2.5V (Nord), all with roughly 26dB of voltage gain. In such scenarios, nobody needs a preamp for gain, just for source switching and volume. That a preamp can still sound better than a source-direct connection is one of hiﬁ’s mysteries.
Round #1 (Formula, Lara, nCore 500, Codex). In our hardware/ear context, when I ﬁt the socketed Sonic Imagery 994 not Sparkos Labs SS3602 discrete opamps to Nord’s input buﬀer with discrete voltage regs, our class D monos emphasize subjective detail density but also set tonality to cool and cadence to somewhat clipped. Yet even with our essentially passive albeit actively buﬀered Wyred preamp, these qualities can work a treat into very meaty ﬁercely dynamic but hard-to-drive boxes like Mark & Daniel’s faux-marble Maximus II monitors. Those rely on ultimate control to launch fully. They thrive on ultra-low output Ω and
take class D’s massive negative feedback in stride without drying out. Yet on our Audio Physic 4-ways, the same combo gets too lean and pedantic.
However; when I’d replaced our usual Aqua discrete R2R DAC with hq audio’s HQ9038—2x12AU7 I/V stage, 2×6922 balanced outputs—the powerful valve signature of the Vietnamese/Danish DAC had prompted a course correction from too cool to straight down the middle. This expertly avoided any thick or fuzzy tube-dominant outcome. Given that happy precedent, I expected that back to our Aqua converter, injecting tubular action into the preamp stage instead should net a similarly happy nCore/ Codex marriage of amp to 89dB speaker. And so it was. Despite hitting desired levels at 7:00 where clients with similar conditions would surely specify attenuators with a far shallower taper, I had neither channel imbalance nor sonic signs of a mismatch. This included noise; or rather, the blessed absence thereof. Without signal but ear on tweeter, the ﬁrst onset of subliminal power-supply hum occurred at ~2:00 which even at full tilt remained very minor. Considering the wildly excessive gain of my ﬁrst chain, this suggested excellent circuit design.
Unlike the late Terry Cain who happily tolerated how his favourite best- sounding tube amps all hummed into his hi-eﬀ widebanders, I ﬁnd noise unacceptable. Whether mechanically buzzing transformers or electrical power-supply surf, noise is the enemy of ﬁne detail. As such it should have no place in costly high-end hiﬁ. At the volume settings I actually used and well beyond them, Lara was dead quiet. With her one need make no excuses for listening to last-century tube tech.
This segues straight into the roguish accomplishment of my ﬁrst round. Rogue Audio’s Mark O’Brien has long since and very successfully packaged 12AX7 tubes with Hypex class D and linear power supplies. Consider his well-regarded Sphinx and Pharaoh