AH! Njoe Tjoeb 4000 CD player
By Chip Stern   •   November, 2003 Audiophiles once took it as given that LPs sounded better than CDs—end of discussion. Things are no longer so cut-and-dried. In my seven years as a contributing editor to Stereophile, I've seen an enormous improvement in the quality of digital software and playback-delivery systems. The early-1980s recording and remastering anomalies that made listening to early digital recordings so fatiguing are largely things of the past, though advocates of massive compression, jacked-up gain, and compensatory EQ ("Sounds-better-on-cheap-radios," they dully chant) continue to sully the waters of natural resolution.

While the new digital formats of DVD-Audio and SACD offer audiophiles pricey glimpses of a nearly perfected sonic future, dedicated music-lovers and engineers have continued to tweak the venerable "Red Book"-standard CD playback systems—to the point where, nowadays, high-resolution, no-compromise sound is no longer the exclusive province of the well-heeled.

What would you pay?
Consider the notion of an exceptionally musical, single-chassis CD player with a tubed output stage that evinces the kind of soundstaging depth, liquidity, timbral accuracy, high-frequency detail, and top-to-bottom smoothness for which, barely five years ago, consumers might have eagerly coughed up $3000 and more. Add a specially tweaked AC cord and a set of special vibration-damping isolating footers. Finally, throw in the option of replacing the player's already high-quality op-amps and Philips Bitstream DAC with a special 24-bit/192kHz upsampling board. You can practically hear Bob Popeil cooing away suggestively on one of his late-night infomercials: "What would you expect to pay for this level of high-end resolution? Fifty thousand? A quarter of a million? Your firstborn child?"

Well, Rumpelstiltskin ain't my name, but would you believe me if I told you that all this is yours for a thousand bucks and change? A no-frills, basic version of the Dutch-made AH! Njoe Tjoeb 4000 CD player costs $699. It's based on a player that Kevin Deal, of US importer Upscale Audio, tactfully calls an "OEM 4000"—it's a Marantz under the skin. This basically provides the case, front-panel display, drive mechanism, DAC, headphone jack, and remote control. The mystery unit is then substantially tweaked. Deal says this process begins with the replacement of the transistorized muting circuit with a mechanical relay and the stock clock with a low-jitter unit called a Supercrystal. An AC Noise Killer, in a small black box mounted near the AC cord, purportedly contributes to a slightly quieter midband response.

The most sonically significant change to the stock player is a tube output board made in The Netherlands, where all these modifications are done. Power-supply stability is enhanced by use of a dedicated toroidal transformer just for the tube stage, in addition to the larger power-supply transformer that replaces the stock unit. The new board has high-quality tube sockets, a host of filter caps and regulator chips, premium parts by Wima and Vishay, a Philips TDA1546 DAC chip, and dual-mono Burr-Brown OPA604 op-amps for voltage gain.

"These are in sockets, and can be fine-tuned with plug-in Tjoeb Tjoens flavor packs," Deal explained. "For $27/pair, the Analogue Devices AD825 offers a warmer sound, while at $44 for the Burr-Brown OPA627 you get a more resolved sound with a little more pop. It's a cheap and easy way to give the player a nudge to fine-tune the tonal balance of the overall system."

However, if you opt to add the 24-bit/192kHz TjoUpsampler board for an additional $299, it replaces the aforementioned DAC and op-amps, plugging into their vacated sockets. Anagram Technologies of Switzerland, who have designed and built components for such high-end mainstays as Nagra and Audio Aero, did the engineering for the TjoUpsampler. It uses an Analog Devices AD1895 chip—a second-generation 24-bit, asynchronous sample rate converter—for the upsampling and a Wolfson Microelectronics WM8740 DAC chip, this a 24-bit, 192kHz-capable two-channel part.

Both of the Tjoeb 4000 samples I auditioned were gussied up with a set of Tjoeb Shoes ($69) vibration-control devices, made by Suspension String Concepts of Germany; and the AC Direkt power cord ($79), terminated with a high-quality Wattgate plug. This brings the suggested retail price to $847. Upscale Audio offers other packages as well, including sets of NOS tubes.

Setup
The maximum output voltage of the AH! Njoe Tjoeb 4000 is adjustable via an internal solder trace, offering purchasers the option of configuring the 4000 to 700mV, 1.25V, 2.5V, or 5V—a nice feature for system-tuning purposes, or for those folks who want to use the 4000 sans preamp, and/or with self-powered speakers (the remote features a 20-step volume control).

I've never much liked the sound I've gotten by driving a power amp with a digital source, so I used the 2.5V default output with my reference preamps. Then it was just a matter of installing the internal Marantz CD clamp and a pair of 6922 dual-triodes. The basic unit comes stock with Philips ECG tubes; after I'd tweaked my TjoUpsampler-equipped review sample with a pair of NOS Amperex PQ 7308 tubes and AH!'s tube damping rings, I was good to go.

I substituted the smoother, more frequency-extended update of the classic Synergistic Research Designer's Reference speaker cables for my reference Acoustic Zen Hologram II cables. The overall character of SR's new Solid State Reference X-Series Active speaker cables was very similar to that of the Acoustic Zens, though the SRs' high-resolution depiction of the soundstage was a touch more centered and less point-source. Otherwise, everything in my system was much the same as it has been for the past year or so—save for a constant shuffling of digital front-ends.

So that I'd have a more convenient basis for comparison, I had Upscale Audio send me a Njoe Tjoeb 4000 with the basic trimmings, as well as the totally tweaked model with 24/192 TjoUpsampler already installed. The latter was the unit I ended up spending the most time with.