Gainclones and chip-amps



In the photo above we see the innards of the Audio Sector Patek chip-amp would be just one of many finely tuned products along the "chip-amp" evolutionary order. So too is the Decco and one reason I chose the Decco for a review subject is because it offers so much more. The brief history of the chip-amp and Gain clone especially, originated by accident when approximately ten years ago Mr. Junji Kimura of 47-Labs had been designing his stand alone CD-transport, 4704 PiTracer. An early review on the unit can be found here at Stereophile.

A truly unique product and one which seemed to warrant positive reviews, its forte' was a revolution of the laser mechanism and at $19k it better be unique. During Kimura's continual testing and tweaking of his transport he required a bench-test amplifier which produced a clean, consistently musical sound, based on few parts and low cost. Basically every audio amplifier maker's dream, but the laws of engineering / physics prevent to this day since such thunderous power mated with tube like mid-range and imaging make it almost impossible to produce in a small cheap box. Nonetheless he came up with a rather revolutionary concept of using simple op-amp chips, found in lower cost car stereos and portable devices.

Unlike the massive class-A discrete solid state amps with 60lbs of copper Torrods and Red Bull sized capacitors, Kimura's design took advantage of fewer parts, shorter signal paths, and what most have overlooked, has mostly to do with manipulating NFB (Negative FeedBack). In 1999 47-Labs's infamous: 47-Labs Gaincard 4706 was born and reviewers such as in this Enjoythemusic review were taken a back.



Unfortunately the original 47-Labs amplifier with external power supply would run approximately $3,300 which in the audiophile world is a low budget piece and this in my opinion is part of the problem. Regardless $3.3k gives you a multitude of options, such as a number of integrated 300B vacuum tube amp, for example the Cayin 300B integrated at $3.1k. There actually is no comparison, but if by some chance you would insult a 300B owner by placing them side by side, all nine parts including the chip itself in the Gaincard 4706 would run home to momma which would be the "Boombox" as its true parents were revealed. In this respect I do not condone $10k and up amps which pander to an obsession which bore the term WAF for Wife Acceptance Factor.

The Woman Acceptance Factor (WAF) – sometimes referred to as Woman Approval Factor or Wife Acceptance Factor – is the playful estimation of the acceptance or refusal of a new acquisition or project by the significant other. It relies on the cliché that men are driven by a certain geekiness when it comes to acquisitions like home theater or PCs, disregarding the stereotypically female aspects of aesthetics, design and practical/financial considerations, let alone ease-of-use. The first known WAF reference was in a 1989 article about wives rebellion against "oversized loudspeakers."

What could be more offensive from a group of individuals, many of who consider themselves at the "top" of the Audiophile food-chain. I digress. Gain clones have brought more people back to the DIY experience and when you pay under $50 they do sound very good. Even "some" (and I use this term reservedly) of the Retail models such as the Patek do sound pretty good, although $1.8k is still pushing it, when you consider what you get for $800 in the Decco. The following 6moons Gaincard review left me with a foreign object stuck in my musical craw. Nagging at me I asked the question; are we Audio Enthusiasts so starved for a product both musically involving and affordable, we are blinded as to the sonic validity of a $3.3k product which cannot begin to compete musically with most vacuum tube amps in its price range? As far as chip-amps which differ only slightly from Gain clones and T-Amps (based on the Tripath 2020 op-amp) Sarajan Ebean of 6moons describes the concept in his Decco review:

So-called chip amps run operational amplifier (op-amp) integrated chips (ICs) at the outputs. The now burgeoning trend began with 47Labs' Gaincard. Working on his PitRacer digital transport, Junji Kimura wanted a basic work horse amp whose parts voicing he knew inside out. To not waste time on lengthy R&D, he assembled a basic chip amp. When word of its performance leaked, he found himself pressured to offer it up commercially. After suitable tweaks, the 47Labs Gaincard hit the market as using "the world's smallest number of parts - 9 per channel; shortest signal path - 32mm; and shortest feedback loop - 9mm". Because the Model 4706 Gaincard was expensive, copies dubbed Gainclones soon appeared. This kicked off the chip amp phenom. Today, DIYAudio.com has an entire forum dedicated to it.

The most popular chips are the National LM3875 and LM4780. They limit output power to between 40 and 50wpc. The Art Audio-marketed Gill Audio Lissa with remote control adds a Lundahl amorphous input transformer and, with remote, sells for $3,500. AudioZone's Amp-1 goes for $2,395 Canadian. My AudioSector Patek SE is $1,800 Canadian. Musical Laboratory's monos with outboard SMPS begin at €3,800. These all use the same chips. This also explains how a true high-quality amplifier could possibly fit inside the Decco's enclosure along with everything else.

Decco not only offers a fully operational chip-amp, its tête à tête is a vacuum-tube driver stage and on-board DAC both designed in collaboration with Scott Nixon. The following interview albeit brief give some insight into particular tube based DACs;Scott Nixon thoughts at Head-Fi. Deco use s solid state DAC section based on a Phillips TDA1543 D/A converter chip (there are actually two used in the D/A - A/D section). The pre-amp is however driven by a vacuum pre driver stage. The photo taken from Tubedac+ and 3XAC power supply (6moons review) exemplifies Scott Nixon's own products.



With all due respect to Mr. Kimura and 47-Labs what was revolutionary about the chip-amp was its low cost and in this respect their very first product fails. Despite what many Audiophiles see as affordable relative when compared to the astronomic costs of some amplifiers, I fail to see anything cutting edge about assembling an amp and power supply from low cost parts and selling it for $3,300, for that price it should sound great. Its in 47-Labs own philosophy / marketing hyperbole they make a case against themselves. If they can build a exceptional sounding amplifier using just 9-parts including the op-amp device and then market their product at $3,300, the only thing revolutionary is they've reincarnated Phineas Taylor Barnum's business model. And this is one reason the Decco at $800 is a real value. Decco epitomizes my goal to find products you can integrate with your PC disproving two theories: 1.) Audiophile quality components must be costly thus equating the term High End = High Cost. 2.) Audio equipment associated with a PC cannot produce "High End" sound.



Decco is not simply another chip-amp, Scott Nxion juxtaposed his USB DAC philosophy in which he's been using a vacuum tube buffer stage. To understand what exactly these external DACs do (and the Decco's DAC) the following 6moons Scott Nixon Tube Dac+ article a must read. It helps to understand why many feel the 24-bit/96kHz digital (over)sampling may do more harm then good in its attempt to improve 16-bit/44kHz of the CD and most recordings. Poll some of the very best digital designers in High End where they are not designing for mass Production and Mass Productions sonics and they'll tell you we haven't got all we can from the 16-bit/44kHz standard, hence all the NOS (Non OverSampling) High End products out there.

In the next section we delve deeper into the designers’ topology and specific parts...