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AH! Njoe Tjoeb 4000 CD player

"New Tube 4000"

[Italian version]

Product: AH! Njoe Tjoeb 4000
Company: AH!
US Distributor: Upscale Audio
Approx. cost: MSRP $579 USD/Euro
Reviewer: Scott Faller
Reviewed: January 2002

New Tube 4000

Trivial Bits

As the great debate still rages on about analog vs. digital, I don't know if it will ever end. It might someday. Maybe when they (the digital gurus out there) finally figure out that CD's sound, well … digital. When somebody figures out how to rid the common CD of that harsh, analytical, electronic sound, they may well be hailed (by the audio community) as the next coming. We will heap praise, shower them with gifts (of money), and worship them as a demigod.

Don't misunderstand what I appear to suggest. I love CD's, just as I love my vinyl. Over the years I've gathered quite a CD collection. But lets face a simple fact, if you don't own a CD player you are missing out on some great music. Newly released music on vinyl is a rarity but the vast majority new music won't ever get released on vinyl (in the foreseeable future).

This still brings us back to the digital problem. The vast majority of music recorded and released in digital format just sounds digital. Now, it has gotten immensely better. Higher sampling rates that provide better resolution and differing D/A design philosophies (amongst others) are bringing the digital medium much closer to analog.

So the question remains, how do we make CD's sound less analytical. Enter the tubed D/A converter as one option. The concept isn't new, by any stretch. Over the years several manufacturers have incorporated tubes into their D/A designs. Some of the more notable tubed CD players are the Heart, Jolida and the Cal Audio players. All have gotten good reviews from both the audiophile community and the consuming public.

Some time ago at our online discussion group I noticed an email from Herman van den Dungen. Someone was asking about advice about a new CD player. Along with the usual suspects being suggested, Herman chimed in with his AH! Tjoeb 99.

Herman is one of those infamous manufacturers that lurk in the shadows of our group. He doesn't surface very often, maybe two or three times a year. His posting caught my attention. At the time I was in the market for a new CD player. I had narrowed my selection down to two different players. The Arcam 8se and the Tjoeb 99. So, I struck up a conversation with him about his CD player and life in general. Herman told me he was about to release the updated version of his Tjoeb 99, the Njoe Tjoeb 4000 or New Tube 4000.

As it turned out, I bought the Arcam rather than the Tjoeb. Not because of any problems but only because I hadn't had the opportunity to hear the Tjoeb. I was able to audition my Arcam. I brought it home, ran it through it's paces, compared it to my old player, everything an informed buyer should do. With the Tjoeb 99, Kevin Deal at Upscale Audio was (and still is) the only dealer here in the States. Kevin was more than happy to send me the Tjoeb 99 but, unfortunately for me, I was inpatient and purchased the Arcam.

Well, after a few more months of communicating with Herman, I decided to ask if I could review his latest creation, the Njoe Tjoeb 4000 and he agreed.

I Love Taking Things Apart

About a month ago I received a box from Kevin at Upscale that had the Ah! Machine. Both Kevin and Herman suggested that I plug the Njoe in and let it run for about 48 hours before I listened to it.

Transformers and Muting Relay

Before I go too far, let talk about it's construction. As you are probably aware, the Tjoeb 99 was built around an OEM'ed CD-38. The Njoe has been "upgraded" to the more stylish (and more expensive) CD 4000. One of the main reasons Herman has chosen to OEM the CD 4000 (along with the CD-38) is primarily because of the Philips Servo drive. It's a proven, time tested, drive that is used on numerous "high end" player and transports.
The Ah! still utilizes the Burr Brown OPA604 opamps with gold plated sockets. This is a great option for those chronic tweakers (like me) that like to change things, if for no other reason, just because we can. Both machines have two transformers, one that drives the laser and servo drive (plus a few other things) and a separate custom wound toriod to power the tubed D/A converter.
As I look at the newly redesigned D/A board, I see WIMA and Ero caps used in the small value range. The larger dielectrics are typically the BC brand. Also the standard muting circuit has been replaced by a relay based muting system. Now, rather than hearing that annoying click come across your speakers between tracks, there is silence.

Tube Sockets

At first glance the Njoe CD 4000 is a much nicer looking unit than the old CD-38. Herman also removed the original factory nameplate and installed a Njoe Tjoeb placard. This can also be found on the dedicated remote control. Speaking of the remote, the OEM'ed unit comes from the factory with a variable output. Though some people say variable outputs have negative effects on the sound, I heard nothing, it was totally transparent. The Njoe comes standard with JAN 6922 tubes.

D/A Board

The Njoe has several differences from the original Tjoeb 99. The Njoe now sports more than twice it's original DAC power supply capacitance, 30,000 uF. The high voltage supply has also been increased and stabilized resulting in better sonics. The tube filaments are now in parallel rather than in series as it was with the Tjoeb 99. The filtering capacitance for the tube filaments has also been increased to more than double it's original value of 3000uF.
Rather than the dual opamp in the Tjoeb 99, the Njoe has dual mono opamps. The tube sockets have been upgraded also. The new sockets put a death grip on the pins, so much so, when I was rolling the tubes I was afraid I was going to break the circuit board. Most of the old Tjoeb 99's left Kevin's shop with the Supercrystal upgrade (jitter reduction) along with the AC noise killer and the coax digital output. These are now standard accessories rather than options.

OK, What Did It Sound Like?

Now, before I tell you about my listening experiences I need to tell you how I actually compared these two machines. Several years ago I purchased an NEC AVX910 audio/video switching unit. This was the top of the line Renaissance reference series from the days when NEC was into hifi. The unit is very transparent and it comes with a remote for us lazy sods:-) This allows me to do an a/b comparison without having to get up, switch the input selector on my pre, then listen to the same piece of music for comparison purposes.

When it comes to using my Arcam 8se as a reference, I think that's reasonable. Forget that it costs (or used to cost) $1300, it is a fine sounding player. It has an exceptional soundstage and is very smooth considering it's cost. The interconnect cables used on both machines are identical versions of my home brew silver and teflon, braided interconnects using WBT look-a-likes.

Musically what I've done, is made two copies of several CD's on my trusty Phillips 770 dual deck CD recorder. This will allow me to due an accurate a/b listing test of the Njoe Tjoeb.

My choices in music varied to cover nearly everything. I recorded Keb Mo for raw acoustic guitar and vocals, Bobby McFerrin for male vocals and nearly all instruments, Lorena McKennit for female vocals and some interesting choices of instruments, Pat Metheny for acoustic jazz and layers upon layers of heavily orchestrated music. And my final choice was Depeche Modes, Exciter. It has crushing bass plus lots of unique synth created sounds.

The first real listening session was more than surprising, astonishing might be a better word. Immediately, you could tell that the tubes added what most CD players lack ...... warmth.
On nearly every piece of music I chose, my Arcam 8se seemed to fall short. Switching back and forth, the soundstages between the two machines were nearly identical. Width, height and depth were almost dead on with a very slight favor to the AH!. When it comes to the placement of the instruments in the stage, the Arcam had a slight edge. That is because of the (now seemingly) analytical approach to the music. The AH! at first may seem "bloated" and slightly inaccurate but it really isn't. It just brings out more music realism than it's solid state contemporaries.

I found the Arcam was technically, very accurate, yet I'm finding it (now) somewhat clinical in it's approach to music. The Ah!'s approach is far less analytical but somehow the detail remains. As hard as I listened and compared, I didn't hear the Tjoeb miss a lick. From low level details, to transients, to decays of notes, the Njoe Tjoeb matched or bettered the Arcam in every way.

If you've ever listened to a tubed system, they tend to add more realism to musical notes and vocals, especially in the mid bands. I have trouble putting into words, how tubes sound (as do other people). Most resort to saying (as I did above) that they have a "warm" or "lush" sound to them.
A true solid state guy would call it a "bloated" sound, but that's not the case here at all. The Ah! has added that key element that I find missing in all but the most expensive CD players, musicality. Guitars, vocals, and music in general, just sound more real and lifelike when played on the AH!.

Although I used my Arcam from comparison purposes, live music is still my true reference. I love going to live shows, that or just listening to my family and friends play acoustically. Live, acoustic music is the only true measure for how a piece (or system) sounds.

Factory Availible Tweaks

The Tjoeb Shoes are a direct replacement of the stock OEM feet that come on the CD4000. Rather than the low profile look of the cheap plastic and rubber combination of the OEM feet, the Shoes are slightly taller by about ½" (12mm) and are fashioned out of metal and anodized in a pewter color. The Shoes utilize a thick felt-like substance to absorb the vibrations.

The A/C Direkt power cord is a substantial improvement over the stock zip cord that comes with the OEM version. The Direkt uses braided copper wire and adds a earth connection to the power cord. The Direkt is just what it implies, it connects directly to the incoming power terminals on the board rather than an IEC connection. On the other end of this power cord is a rather beefy 15 amp hospital grade plug (available in the US).

If you are thinking about buying this unit I would seriously consider getting the upgrades. Not that they are needed but the unit sounds a more accurate with them as opposed to without them. The combination of the Tjoeb Shoes and the factory installed A/C Direkt power cord (at $108 for the pair on special) provide slightly tighter bass and a wider and deeper soundstage. It's well worth the investment.

When it comes to tubes, Kevin offers several different options. Now don't take what I am stating here as you "must" change tubes or it will sound bad. That isn't the case. The individual "sound" of tubes is a very personal choice at best. Each of us hear differently and expect a piece of equipment to reproduce music as we think it should sound. Take me for instance. I expect clear and refined treble, a warm, lush, yet accurate, midrange to the point of almost being liquid and firm, almost bone crushing bass that will register on the Richter Scale (I'm talking Krell territory here). That's not asking for too much is it?

The other thing to keep in mind, realistic sound reproduction has everything to do with system matching, period. I use a tube pre-amp in front of solid state amps. To give you an idea, when I listen to different amps in my rig, often times I have to change my tubes to get (what I feel is) the proper sound. Sometimes it takes more than just a tube change, I have to swap cables too, or maybe interconnects to get the proper sound.

Now keeping all that in mind lets talk about the different tubes I played with.

The stock JAN's had a very nice sound. The treble was refined and non-fatiguing. The midrange was extremely warm to the point of almost leaving puddles on the floor. The bass, though quite good down to about 50 to 75 hz, below that it was just not quite tight enough for my system (I use 12" woofers in an EBS enclosure).

The next up were the Seimans 7308's at $ 60 for the pair. Now we're cookin' with Crisco. Very nice treble. Extended without being overbearing. Far smoother than my Arcam. I found a slightly tighter, more refined midrange that still retained all the realism of the mids, but yet they allowed a bit more detail to show through. The bass firmed up quite nicely (for my personal tastes). Overall the 7308's sound more accurate than the JAN's in my system.

Next up were a vintage, matched pair of Ediswan CV2492's. These are extremely difficult to find and come at a premium. These sounded completely different from the other tubes. They were far tighter up and down the frequency scale. Very nice sounding. If you have one of those really lush sounding systems, these could be the ticket.

Now, that was just my opinion so YMMV. So, to continue with some more opinions (since I have your attention :-) if you listen to an all solid state system and mini monitors, you may find the JAN's to be the best sounding tube. On the other hand if you have an all tube system that is "colored" already, you may need some serious tightening of your system, so the CV's might sound better. In my case with the tube pre and solid state amps and full range speakers (that go well below 20hz), the Seimens fit the bill quite nicely.

Lets Pick Some Nits

Well, I really don't have many. Overall this player is very good.
Keep in mind this is an OEM'ed CD 4000. That being said, the case could use some internal damping. A nice thick layer of rope caulk or self adhesive bitumen sheets should do wonders to cut down the internal vibrations at higher SPL's.
Tube dampeners do help quite a bit with the microphonics of the tubes, again at high SPL's. I installed a vintage thick rubber pair that I have. I found the sound tightened up quite a bit. This isn't unique to the AH! machine, most all tubes suffer from some form of microphonics.
The display isn't quite legible from where I sit, in fact it's pretty dim. I sit about 15 feet (5 meters +/-) away from my rack. I don't know if it's the display or my eyes are just getting old :-)
So basically, I didn't have any major complaints about the way it makes music. Straight out of the box, this is a very good sounding player.

So........

Is it analog? No. Is it closer? You bet. Herman and his compadres have done one heck of a job engineering and producing a fine piece of equipment that plays music. Plus it's extremely affordable considering the costs of "reference" CD players, transports and DA converters. For the money, you will be really hard pressed to find much (if anything) that makes better music.

I used to think my Arcam 8se was the "cats meow" for the money. Now I'm thinking eBay.
Oh, by the way, I bought this one. I've really got to stop doing that :-)

I'd like to thank Herman van den Dungen at AH! and Kevin Deal at Upscale Audio for the use of the Njoe Tjoeb 4000. They both were a true pleasure to deal with and very accommodating.

Manufacturers Comments

Scott,
I am glad that the result of our efforts pleases you. We had 9 months (coincidence!) of discussions (and sometimes some hard words) and experiments to get the maximum out of Frank's design. It's always amazing to hear that parts with the same specs but of different make, can sound so very much different. We spent a lot of time to compare so-called "audiophile" and standard parts.
Sometimes an audiophile part was favorite sometimes it was .... not. Those things make the full project so very interesting. Personally I like to try to get the maximum quality out of the most basic parts. Having seen the good results from this philosophy, I demand that in the Njoe Tjoeb 4000 design we will not change parts, unless unavailability forces us, and only if it does not change the final results.

We are working on a new dac/upsampler (24/192) design for the AH! Njoe Tjoeb 4000. This board will also fit as an option in all existing Njoe Tjoeb 4000 machines. Next to that I still would like to issue the copper-foiled damping material option I am already talking about for years .... If I had only more time!

We just finished the AH! Tjoeb 66 design and 15 pieces are living together now with some die-hard audiophile listeners. Next thing we are doing is handbuilding a batch of 50 pieces to learn what we have to learn to do the first run of 500 pieces. This amp is based on the integrated amplifier PM66SE or PM6010-OSE.

So, if we keep on working hard, you can keep on listening and writing. I thank you again for that.
Best regards,
Herman van den Dungen
AH!

© Copyright 2002 Scott Faller - http://www.tnt-audio.com

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