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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: APL HiFi NWO 3.0-GO; Ancient Audio Lektor Prime; Yamamoto YDA-01
Preamp/Integrated: ModWright DM 36.5; Esoteric C-03
Amplifier: Yamamoto A-09S, FirstWatt F5
Speakers: ASI Tango R
Cables: ASI Liveline lo/hi-level + one power cord, Crystal Cable Ultra power cords
Stands: 2 x Ikea Molger, Ikea butcher-block platforms with metal footers
Powerline conditioning: 2 x Walker Audio Velocitor S
Sundry accessories: Furutech RD-2 CD demagnetizer; Nanotech Nespa Pro; extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: The sound platform is 3 x 4.5m with a 2-story slanted ceiling above; four steps below continue into an 8m long combined open kitchen, dining room and office, an area which widens to 5.2m with a 2.8m ceiling; the sound platform space is open to a 2nd story landing and, via spiral stair case, to a 3rd-floor studio; concrete floor, concrete and brick walls from a converted barn with no parallel walls nor perfect right angles; short-wall setup with speaker backs facing the 8-meter expanse and 2nd-story landing.
Review Component Retail: €3000 intro offer until April 30, 2009 - €3,250 thereafter

The e-mailer was Peter Steinfadt of the Frankfurter Hörgesellschaft. "We had some previous contacts as I am the German distributor for Samuel Furon's fine Ocellia speakers and electronics. Today I would like to introduce to you another fine brand, Crayon Audio from Austria. I am currently organizing the worldwide distribution. Why? Just because they manufacture a very outstanding amp - very transparent and 'tubish', with a very modern technical and industrial design. No, the usual marketing malarkey won't follow now. I am simply terribly impressed by their CFA-1 integrated. This amp is more than a good alternative to tubes. Its concept and sound are truly unique."

A quick google session confirmed the basic concept. This DC-coupled class A/B bridged-output design works in local-loop symmetrical current-feedback mode*. Operating parameters are set with a digital control-system IC. It performs diagnostics and adjustments only during input selection and volume control 'intermissions', i.e. during deliberate user acts of 'interference' with the music signal. During normal playback, this circuitry is in sleep mode as is the display. All inputs including their ground pins are decoupled by current-compensating wide-band chokes to damp HF interference in the 1-300MHz band. Circuit board construction adopts findings by Prof. Dirks that were published in Elektronik Praxis ("Die Leiterplatte 2010") to reduce power-plane impedance to below 1 ohm up to 1GHz in bandwidth. This guarantees very high immunity to ultrasonic interference but "also affects the audible range since our output MOSFETs aren't inactive in the HF range where they act as diodes (rectifiers) to demodulate ultrasonic signals."

*________________
Since around 1994, the largest manufacturers of analog ICs like Analog Devices, Burr Brown, TI or Linear Technology have produced op-amps with so-called current feedback. Crayon Audio "deploys output transistors as current amplifying elements. The industry inserts an emitter follower as current amplifier and a buffer at the output and therefore requires a capacitor to limit the bandwidth of open-loop gain. They also run global feedback. We don't require these measures due to our C-Current feedback approach where C stands for Crayon."

The power MOSFETs of the CFA-1 are configured as drain followers, i.e. the drain pin is connected to the output and not source pin as in conventional designs. Crayon's current feedback also claims advantages with smooth clipping to "sound like a vacuum tube amp with the control and precision advantages of transistors." The inbuilt phono stage is a 3-stage design with a discrete 20/31dB gain (MM/MC respectively) symmetrical NPN/PNP transistor preamplifier stage. That is followed by an impedance-compensated passive RIAA equalization network with 0.1% resistors and 2% SMD ECHU plastic-film capacitors by Panasonic. Claimed amplitude linearity is +/- 0.2dB from 25 - 20,000Hz. The third stage revolves around an AD825 opamp from Analog Devices with a 100kHz cut-off and 24dB of gain. Phono gain adjustments span 28dB in 2dB increments. Standard settings are 42dB MM and 56dB MC and input sensitivity is 5mV and 0.8mV respectively.

The rear-panel phono adapter inputs are for impedance matching. The stock input impedance is 53.33K. The adaptor plug inserts a 392K resistor and 47pF capacitor in parallel to lower input impedance to 47K and input capacitance to approximately 200pF. A L/R-channel pair of cinch adaptors is included. Custom values are available to order.
Input selection, tone and volume control including mute use an ST Micosystems IC. Volume control is over a 79dB range in 1dB steps. Input switching prompts a volume fade down/up process over 1.8 seconds. Software-driven bass, mid and treble controls offer +/-14dB of cut and boost in 2dB steps and are centered on 100, 1000 and 12,000Hz. Balance is adjustable in 1dB steps also in the software domain. The loudness controls can be disabled under 'personal settings' in the setup menu and are automatically defeated for volume settings above 46 when engaged. In that case, bass and treble automatically increase by 2dB between 38 and 46 and by 4dB below 38. These and other advanced features such as key delay, phono settings, input gain, balance and display contrast remain 'hidden' in the software unless called up.
Pressing both channel up/down buttons on the box enters setup mode
This image opens to 2000 x 1500 pixels at 336KB in a new window

That reduces the day-to-day control systems interface to the basic functional simplicity of channel selection, volume control and standby on/off. The display and backlighting turn off automatically 18 seconds after each command prompt. Operational status then is confirmed by two red LEDs for minimal optical intrusions. All in all, a very brainy machine.

The power supply is a switch-mode variant of Swiss origins which accepts mains voltages from 88 - 264 to be immune to most under/over voltage conditions. Its presence perhaps also explains Crayon's obsession with 'immunizing' their circuit to ultrasonic signals. The SMPS eschews linear power regulators in favor of cross regulators to "maintain a constant current level at ground". A soft-start circuit prevents turn-on transients without output relays and the power-up cycle of the power supply is software driven just as is channel switching. There are 3 line-level inputs plus phono, one record out and power specs of 28/40wpc into 8/4 ohms. The monolithic aluminum chassis sports eight 'heat ducts' or machined holes across the top for thermal exchange. A smartly styled machine indeed, with a matching (SA)CD player already in the wings to presumably dock on the mirror-imaged top footers.

At this stage of my fact gathering, I returned to Steinfadt's "One World, One Speaker, All Music" full-ranger logo which greets one prominently on his website. I also took note of the fact that he had Crayon Audio participate with Austria's Horn Manufaktur Maestoso speakers at Fattura Peccioli Ad Alta Definizione April 6/7 2008.

It's nearly a truism that widebanders favor tubes. To see a widebander aficionado so smitten with a transistor amp as to join forces during public exhibits and take on global distribution... well, 'twas highly unorthodox. And what ever did the engraved nomenclature imply? CFA-1: Crayon Fast Amplifier? Fabulous? Furious? Fiendish? I couldn't decide on the 'f'. Perhaps my audition would be suggestive.

The two images above are of the switch-mode power supply which, to valvoholics, would be anathema. The 28wpc power rating they'd find more recognizable but not its higher 40-watt figure into 4 ohms. An 80-into-4 version is also available. The construction of the enclosure by the way is a clam-shell type. Four threaded rods between top and bottom footers link cover and base and the top discs apply connective torque when tightened down like oversized nuts. The side panels are neatly captured between them with two mini shafts each above and below, the rear panel is inset into the sides. The end result are no visible screws on top, front, cheeks or back. It's a clever and mechanically effective way of assembling a rectangular box. The vertical air exchange chimneys meanwhile are bored through the massive internal heat sink and the top and bottom plates simply correspond with precisely matched openings.

Probably to avoid unintentional shorts between the speaker posts -- they all carry about 12VDC from the permanently bridged output circuits to be hot -- speaker cable connections are by banana exclusively. The attractively shaped remote isn't plastic but metal and the German/English owner's manual is uncommonly comprehensive particularly about the many adjustment options in the menu layer. The mother board is populated with many tiny surface-mount bits. They require advanced robotic construction quite beyond the ubiquitous point-to-point wiring of parts you need no loop and pincers for. That; the flawless fit & finish; the advanced software-driven options; the presence of an ambitious phono stage; the remote-controlled volume, mute and input switching; design and manufacture in Switzerland, Austria and Teutonia... well, cough and blush, Crayon's introductory €3,000 asking price makes many competitors seem crude, simplistic and yes, overpriced by comparison.


At this stage in my CIA investigations -- Crayons In Audio -- I became highly suspicious. Perhaps Herr Peter Steinfadt's earlier introductions to this amp weren't spin, his Escher-ish business card not clever while fishy but indeed very much to the point? From the first few bars into the first cut, things advanced to conviction indeed.
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