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Reviewers: Marja & Henk
Sources: CEC TL5100, Audio Note tube DAC, Philips DVP 5500S SACD/DVD player
Preamp/integrated: TacT RCS 2.0 room control system], modified Audio Note Meishu with WE 300B (or AVVT, JJ, KR Audio 300B output tubes); Moscode 401HR [in for review]; Trends Audio TA-10
Speakers: Avantgarde Acoustic Duo Omega; Avantgarde Acoustic Solo in HT 2.0 setting; Audio Note AN/Jsp silver-wired
Cables: Audio Note AN/Vx interconnects; Siltech Paris interconnects; Gizmo silver interconnect; Qunex 75 reference interconnect; Crystal Cable CrystalConnect Reference interconnect, CrystalDigit S/PDIF RCA/RCA and RCA/BNC, Y-cable, Crystal Cable Piccolo iPod to XLR, CrystalPower Reference AC-Eur/IEC; CrystalSpeak Reference; Audio Note AN-L; Gizmo silver LS cable; Virtual Dynamics Revelation power cords [in for review], Harmonic Technology Magic Woofer, Magic Tweeter & Pro AC11 [in for review]
Power line conditioning: Omtec PowerControllers
Equipment racks: Two double sets of Solid Tech Radius; Acoustic System amplifier shelf
Sundry accessories: IAR carbon CD damper; Boston Audio graphite CD damper, Denson demagnetizer CD; Furutech DeMag; Nanotech Nespa #1; TacT RCS calibrated microphone and software; Exact Audio Copy software; Compaq server w/Windows Server 2003 and XP; wood, brass and aluminum cones and pyramids; Xitel surround processor; Manley Skipjack; Boston Audio Design TuneBlocks
Room treatment: Acoustic System Resonators; Gizmo's Harley Davidson cap
Review component retail: € 2.500 excl. tax and shipping

The man behind TentLabs is Guido Tent. During electronics studies already, he made a name for himself working for the Dutch Audio Note distributor. His study thesis was on the linearity of direct-heated triodes, a rather intuitive subject for a chap working with Audio Note equipment. Degree in hand, he then began plying his trade at Philips, in electromagnetic compatibility and signal integrity applications. Later he developed recordable DVD storage. After 10 years, it became time to bid farewell to regular employment, go solo instead and start his own company. This became TentLabs, known now for its retrofit high-quality modules and components such as the Tentlabs XO precision clocks which fight RedBook jitter and the Tentlabs heater supplies for direct-heated triode amplifiers.


Then the time arrived to develop, test and market his own complete CD player. All the knowledge Guido had gathered over the years culminated in this design. Instead of offering a complete 'plug'n'play' machine, Guido markets the player as a DIY kit. This way he can offer his best for a very reasonable price.


Don't worry though. 6moons is not going down the path of solder-slinging techno geeks. The kit is meant for anyone who loves good sound, is patient enough to read a good manual, has some experience in soldering and knows how to handle basic tools. Alas, we did receive a completely assembled example of the TentLabs DIY CD player for review.

TentLab's goal with all products focused on CD reproduction is to rid them of 'digital sound'. This nasty habit of many playback systems is, Guido feels, predominantly caused by poor jitter handling. Guido knows first hand how jitter can be addressed and corrected when using appropriate measures. In the DIY CD player, he uses all of them. The player starts with the sturdy base of a quality drive. Many high-end manufacturers have arrived at the same choice of Philips CDpro2M. This is a top loader so a tricky drawer system was unnecessary. For the drive's servo and control logic, Guido uses two separate power supplies to avoid crosstalk between them and minimize jitter in the signal path.


Data from the drive is carried to the DAC via an I²S connection. Contrary to the routine protocol of S/PDIF, I²S is immune to data-dependent jitter effects and that, after all, is the goal at this stage. TentLabs then bypasses the standard clock incorporated in the CDpro drive. The clock used instead is the master clock located on the separate PCB of the DAC. To accept the external clock, Guido had to modify the drive, again to minimize jitter. To protect the drive from external mechanical influences, a rubber-sprung heavy metallic sub-chassis suspends it from the player's casing.


For the converter stage, Guido uses a pair of Texas Instruments PCM1704 multi-bit DACs while omitting any digital filtering. Filters tend to introduce jitter and he prefers to run the converters at 1/8th the normal clock speed instead. Both converters receive their power from analog supplies that are stabilized by four shunt regulators. Cross talk is avoided and the noise floor remains low.

TentLabs then uses proprietary interface logic to convert the 16-bit I²S data into a format that the PCM1704 is able to convert directly. Unique to this approach is how the data from the serial I²S stream -- both channels behind each other -- are split by stop-clock operation. This way only data for the channel active at that moment gets delivered to that channel. In traditional designs, what arrives at the 'active' converter is stereo rather than mono information. Do we need to mention that the incoming data signal is reclocked by the low jitter Tentlabs XO master clock prior to entering the DAC chips? The XO clock derives it power from a shunt supply.


In order to use the DIY CD player as just a spinner, a S/PDIF digital output is provided. This signal comes off the CD drive module but is re-clocked on the DAC board using the master clock. A buffer stage insures correct 75-ohm impedance and a digital transformer acts as galvanic decoupling device.


The output from the PCM1704 converters is current of course which needs to become voltage after which the voltage needs to be amplified and buffered. All this is performed by a tube-based I/V converter stage. That board carries a so- called transconductance (or current source amplifier) that outputs a current proportional to its input voltage with two active elements, a transistor and an E88CC tube. This amplifier works completely in the current domain to eliminate power supply noise. The circuit presents a sub 1-ohm impedance to the PCM1704 chips to insure low distortion. An Audio Note tantalum resistor converts current to voltage before being high-passed at 6dB/octave. Another tube, a 6x4 rectifier chosen for its musical properties, oversees the high voltage supply on the I/V board.

Inside the player, TentLabs also uses three large toroidal transformers. One is dedicated to the drive, one supplies the I/V converter board and the third the DAC board. These circuit boards use surface-mount devices and are based on Guido's know-how with EMI and signal integrity while working at Philips. They help to reduce noise in the digital to analog conversion, crosstalk and of course keep jitter at bay as far as possible. From the three power supplies clearly visible in the photos, two supply the drive, one the display.


As already stated, we received the player pre-assembled . With its wooden side panels, brushed and black anodized fascia and top, the product looks very modest and non-obtrusive. Under the blue display window, the control buttons appear in standard configuration. The loader is accessible by pushing the top lid slightly down and then back before you look straight on top of the drive. No frills whatsoever dress up the insides any fancier than bare bones. A little magnet becomes the CD hold-down puck. Around back, there's the IEC power inlet plus mains switch, a pair of RCA analog outputs and a BNC connector for the S/PDIF digital signal. Some extra holes are pre-cut to facilitate an already announced USB input. In the near future TentLabs will offer an add-on USB board to interface with computer-based sources.


With the player we also received the kit builder's assembly manual. This 70-odd page manual takes the DIY CD player builder through the assembly process in clear text and pictures. And it is fittingly called assembly manual because the really tricky part of SMD-peopled PCBs are already pre-stuffed by TentLabs. What the DIYer needs to do is place the PCBs on their mounts, bolt the transformers in place, attach the drive to its mount and run some wiring. There is no heavy soldering involved. The manual is very clear and from reading it carefully, it appears that only two areas could prove to be a bit laborious. The first of those is the assembly of the display PCB and the controls panel, the other is the assembly of the bridge that holds the sliding door. This is metalwork requiring a small hammer. Though not speaking from experience, the whole assembly should not take more than half a day's work for anyone handy. Almost all cables are preterminated or precut. As with all electrical work, most important is measuring the thing before you fire it up. If you are not confident enough to do the assembly yourself, a more able person could help. A case of wine after the build is completed to satisfaction or a handful of CDs might prove to be a good exchange then?

We were lucky to merely have to connect the player to the rest of the system and grid. After switching on the power, the familiar iconic "no dISC" Philips display lit up. Loading the disc was easy: push and slide the door open, remove puck, place CD, attach puck, slide door closed, hit the play button. The player comes with a standard Philips remote by the way. We let the player settle in for a couple of hours by casually playing background music. Even while playing softly, the DIY player was reaching out for attention. Many players even at price levels way beyond this machine can be real background players. They go about their assigned job without attracting any attention. This player begged. And that's what it got just a bit later.


Our first formal listening session took place at night. All the usual hustle and bustle of the city had calmed down somewhat just as the at times annoyingly busy elevators of our building. In this as-good-as-it-gets environment, we started the first CD, the fabulous La Segunda by Sera una Noche [MA Recordings M062A]. This recording was captured in an Argentinean monastery and contains not only wonderful music but also a lot of subtle background noises and sounds that would never appear in a studio recording. These tiny artifacts make the sense of 'live' and 'real' very palpable. Only a few CD players we know of are able to completely revive these subtleties from the millions of lands and pits on a shiny disc. Too many players bury these nuances in a blur of noise. We have to say that the Tentlabs CDP belongs to that handful of players able to pass on all these very fine data due to apparently its extreme low noise floor.


As for the outer ends of the aural spectrum, the TentLabs machine has no tendency to roll off the highest highs nor being shy in the very lowest bass region. Bass in fact is produced in very nice contrast. Though low bass is aplenty and adds to a sense of big sound, it does not overpower the lower mids as often happens in such cases. No, the overall balance is preserved in a nice way.

Mids and highs are well defined without emphasis or dulling. They simply display the character of the music. None of the CDs and CDRs we played displayed the typical jittery sound. The player is by no means neutral, however. It has a definite signature - and a musical signature at that. This signature is pleasant to the ear. It is as if you were assigned a great seat in the concert hall. Your vision on the stage is good and there are no annoying concertgoers making noise. The idea here is that the player is able to transport you into the event venue. Timbre or tone don't stand out but possess an energetic quality due to the controlled but ample amount of bass foundation that is present.


The TentLabs DIY player owes this signature to the combination of design, electronics and, surprising enough, the exact materials used in its construction. Where most top-loading drives including those using the same Philips spinner will react positively when a CD mat of some sort is used, the TentLabs instantly dulls down. It appears that the counter-intuitively shiny interior of the CD compartment is part of the tonal balance provision. The same goes for the somewhat cheap-seeming top cover whose thin aluminum is far from damped. Tapping it produces a loud tinny sound in fact. But don't make the mistake of damping the cover. It will take the life out of the music, suggesting that despite certain budget suggestions, this player has undergone serious tuning.

With a kit price of € 2,500 or roughly $3,375 without taxes and shipping, this CDP is a bargain. It can and will blow many far more expensive CDP out of the musical waters without much effort. Granted, you have to build the thing yourself or find a friend to help you. That will add a couple of hours of building joy or a little extra cost. In the end though, you wind up with a fantastically musical machine that, with the announced USB port, is even future proofed for the time when CDs will disappear in the same niche status vinyl is already said to be in now.
Manufacturer's website