Country of Origin



Reviewer: Srajan Ebaen
Financial interests: click here
Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 14.4), PureMusic 3.02, Audirvana 3, Qobuz Hifi, Tidal Hifi, COS Engineering D1, Denafrips Terminator, Soundaware D300Ref,  AURALiC Vega 
Preamplifier: Vinnie Rossi L2 Signature with WE VT52/300B or Elrog 50/300B, Nagra Classic, Wyred4Sound STP-SE Stage II, Vinnie Rossi LIO (AVT module)
Power & integrated amplifiers: Pass Labs XA30.8; FirstWatt SIT1 monos, SIT3, F5, F6, F7; Goldmund/Job 225; Aura Note Premier; Wyred4Sound mINT; Nord Acoustics NC500 monos; LinnenberG Audio Liszt monos
Loudspeakers: Audio Physic Codex; Cube Audio Nenuphar; Kroma Audio Mimí; Albedo Audio Aptica; EnigmAcoustics Mythology 1; Boenicke Audio W5se; Zu Audio Druid V & VI & Submission; German Physiks HRS-120; Eversound Essence; Fram Midi 150 & 120; Acelec Model One
Cables: Complete loom of Allnic Audio ZL3000 and Zu Event; KingRex uArt, Zu and LightHarmonic LightSpeed double-header USB cables; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Black Cat Cable redlevel Lupo; Ocellia OCC Silver
Power delivery: Vibex Granada/Alhambra on all source components, Vibex One 11R on amps/sub
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands 
Sundry accessories: Acoustic System resonators
Room: 4 x 6m with high gabled beam ceiling opening into 4 x 8m kitchen and 5 x 8m living room, hence no wall behind the listening chairs
Review component retail: $2'495

Compact separates packaged different: current Simon Audio Series 5 of CDP/DAC + integrated amp vs. April Music Stello MkII Pre/head amp with basic USB + power amp.

"With the i5 integrated amplifierI wanted to make an amp which brings us back to the happy listening days of old regardless of loudspeakers. Rated at a very deceptive 45wpc (75wpc/4Ω, Ed.) this is a real killer, with driving power beyond your imagination. After a short break-in of 2-3 weeks, you will hear the clear difference from many existing amplifiers.

"Musically close to correct is always my motto and I think that this cutie comes very close to the target. It's not cheap but my margin is very low which means that I put very high raw costs into this small beauty. My good friend Alain Pratali of Marseille's Rouault Acoustic has a Model Three loaner on hand so you can hear it together with our amp. He has already made three models which I helped tune. We call them the M line which presently contains the Model One and Three, with the Zero Junior model coming soon and the Model Zero later. The Model One and Three are finalized and for EU customers already ship from France.

"I've been a music guy since 1965 when my father played the guitar and my older sister sang "Voi Che Sa Pete" every day. A few days ago I passed my 65-year mark. Alain's speakers are the only ones I listen to these days. I tried so very many over more than 40 years as an avid audiophile and have come to the conclusion that these are the ones for all of our homes."

That was Simon Kwangli Lee, ex April Music boss who now heads Simon Audio from Seoul. As I put it in a recent review, "the $2'500 MkII combo of HP100/S100 Stello from April Music, after nearly two decades on the beat, is still my favorite compact pre/power twofer. It's why these minis have traveled with us until now whilst lots of other stuff has found new homes."

Let it think in. It's 2020. Nearly identical functionality of Simon's old minis now packs into a single chassis which is styled even classier. Only the ¼" headphone port and ultra-basic USB input are lost but balanced inputs gained. Seven years later, the price for that repackaging hasn't risen by a cent. If you do want a second chassis, Simon now has the CDA5, a top-loading CD player and DAC. That showed above stacked atop the i5, both hugged by Simon's €4'500/pr M3 monitors with 6.5" Accuton mid/woofer and horn-loaded custom tweeter.

To mark Simon's reemergence after his April Music departure, I'd reviewed his AIO all-in-one CD/streamer receiver a year ago. That makes good reading to start today's continuation of this story.

CDA5 | i5

Here we just saw his new twofer from the front and back. As has always been Simon's preference for a mid-power amp, the fully balanced DC-coupled i5 without signal-path capacitors runs just one output transistor per phase. Hence there's just a quartet of transistors—two per channel, one push, one pull—to forego the inaccuracies of multi-parallel schemes. It all fits into a 21 x 6.3 x 31cm WxHxD chassis of 6.5kg.

Where the Stello HP100MkII used op amps, the class A preamp stage of the i5 uses discrete Fets. Where the S100MkII ran complimentary Toshiba 2SC5200 and 2SA1943 pairs, the i5's Darlington* outputs use 25A/100V bipolar Onsemi TIP35C and TIP36C. The Stello's input impedance of 68kΩ grew to 100kΩ for the i5.

Chassis size gives away that this is biased in class AB. To accommodate a subwoofer, there's a pre-out whilst three analog inputs are on XLR and dual RCA. The volume control is a digitally actuated 64-step discrete analog attenuator. Its numerical value shows on the green display next to the chosen input number. A remote is standard.

There's UltraFi which could just be TrophyFi to impress rich friends with. There's LowFi. Then there's the vast middle class of sound hardware. That's where we play here, arguably in its lower end. Simon's i5 is for folks whose hobbies extend well beyond hifi. Now a stereo's footprint, physical and fiscal, must reflect that. It must coexist with books, paintings, vacations. There could be a motorcycle in the garage,  vintage wheels on an extended restoration.

Our local shoe-repair man is working on an MG whilst taking his whole family on 2-week sun-filled holidays each year. That doesn't leave much in his slush fund. Others might have cameras with exotic lenses. Those could want regular field trips to get pointed at beautiful things. Some people are major foodies. The ways to spend discretionary coin on non-essentials are legion. But if you live in a refugee camp, you won't have any.


* From Wikipedia: Invented by Sidney Darlington in 1953, a Darlington pair connects two bipolar transistors such that the second transistor further amplifies the already amplified current of the first transistor. A Darlington pair behaves like a single transistor with one base, collector and emitter. It typically creates high current gain of 1'000 or more and very high input impedance which means an equal decrease in output impedance.