NHB-108 model one User Manual Version B
darTZeel NHB-108 model one User Manual, version B 1.
Table of contents First Section, User Manual 1. 2. 3. Introduction .......................................................................................................5 Brief description ................................................................................................5 The NHB-108 in details......................................................................................6 3.1. 3.2. 3.3. 4. 5. Who am I? ...............................................................................
Technical Section T1. T2. T3. T4. Introduction .....................................................................................................18 Genesis of NHB-108 ........................................................................................18 Criteria..............................................................................................................19 Structural aspects ...........................................................................................19 T4.1. T4.2. T4.
darTZeel NHB-108 model one Version B User Manual 1. Introduction The result is what you can see, touch and hear… right now. Congratulations for purchasing a darTZeel NHB108 model one. Our machines are designed and hand built for very long lasting use and musical pleasure. One of the secrets of the darTZeel NHB-108 model one can be found in two words: The darTZeel NHB-108 model one is a highly unusual power amplifier, and requires special care.
3. The NHB-108 in details 3.1. FRONT PANEL 1. Identification Plate 2. The Eyes 3. The Power Nose 3.2. REAR PANEL 4. 5. 6. 7. 8. 9. darTZeel NHB-108 model one 50Ω BNC Zeel Inputs RCA Inputs Speakers Terminals XLR Inputs IEC Power Socket Input Impedance Selector User Manual, version B 1.
3.3. TOP VIEW 10. 11. 12. 13. 14. darTZeel NHB-108 model one DC Offset Trimmer Jumpers Speaker Impedance Switch Fuse Holder Operating Voltage Selector User Manual, version B 1.
5.2. 4. Who am I? Your darTZeel NHB-108 model one bears, on its front panel, its Identification Plate (1). On this 24k gold plated brass plate are engraved your name, and the serial number. Do not unscrew the plate since it is the identity card of your machine! The serial number can be read as follows: The heat sinks shutdown point is at around 70°C, and the power supply starts up again when the temperature has dropped to 55 °C.
5.4. Choice of the input Only one input can be used at a time. All inputs are paralleled, so you cannot select them separately. If you do not own a darTZeel NHB-18NS preamplifier yet, we suggest you use either RCA (5) or XLR (7) inputs, with the Input Impedance Selector (9) switched on "RCA Hi Z" (mid position, physically speaking), or "XLR Bal". (lower position), respectively.
6.3. The speaker's impedance switch is located at the upper left of the transformer (upper right for the right channel), User parameters The darTZeel NHB-108 model one must be correctly set, accordingly to the loudspeakers' nominal impedance. Your machine is already factory set for speakers having nominal impedance from 3Ω to 8Ω, as is usually the case. If your loudspeakers' nominal impedance is between 1.5Ω and 2.5Ω, or if you connect two paralleled 4Ω speakers, you must adapt your NHB-108 to that load.
7. Maintenance 6.4. Jumper settings Before making any change in the jumper settings, power off the amplifier, REMOVE the AC cord, and wait for 5 minutes before removing the glass cover. On the inside rear panel (see chapter 3.3. "Top View", no. 11), where the input circuit boards are located, you will see 3 jumpers per channel: 7.1. Fuse(s) replacement The following procedure concerns the left channel. For the right channel, the procedure is the same but that the fuse is in a mirror image configuration.
while using the supplied long nosed pliers (fig. 5), Then turn again 180° counter clockwise and let the fuse fall onto the inner side of the front panel, as shown in fig. 8 Fig.5 – Supplied tools Fig. 8 gently turn the fuse holder, as shown in fig.6, 180° counter clockwise, Pick up the fuse with pliers and check that the glass envelope is dark or black, indicating a blown fuse. Remove it and simply install a new fuse in the holder.
7.2. DC voltage drift Every single NHB-108 model one is lovingly checked, tested and listened to before leaving our workshop. Output DC voltage drift normally does not need any further adjustment, provided you use your amplifier in a room temperature ranging from 59°F to 95°F (15°C to 35°C). Furthermore, the version B now features a built-in DC compensation circuit. In order to fully benefit from total lack of any overall negative feedback, you can disable this circuit. Please refer to chapter 6.4.
8.2. Troubleshooting While setting up your NHB-108 model one, it is possible that you may not obtain the desired results. Hereunder we list the most frequent problems you are likely to encounter. If the problem cannot be solved, please do not hesitate to contact us directly at: troubles@dartzeel.com In all cases it is important to know the working environment in which you will use your darTZeel NHB-108 model one.
manual in order to better know how the Crowbar circuit works. Fuses can blow if the nominal impedance of your speakers is less than 3 Ω and your NHB-108 model one has not been set up to drive such a load. Please refer to chapters 6.3. "User parameters" and 5.1 "Important prior notice". Then again check your fuses if you are in doubt, by taking a look at point 7.1. "Fuse(s) replacement". Be sure that you are using fuses of correct rating and type. 8.2.8.
9.2. Conditions of use 10. Assistance darTZeel Audio SA company disclaims any responsibility in case of damage or injury directly or indirectly due to any misuse, incorrect manipulation, or simply the non-observance of red warnings, and/or advice formulated in this entire manual, including the technical section.
11. Technical data darTZeel NHB-108 model one, version B Nominal output power : 100 watts RMS @ 8 (Hi) and 2 (Lo) ohms. 160 watts RMS @ 4 (Hi) ohms. Gain : 26 dB @ 8 ohms. Input impedances : RCA: BNC: XLR: Output impedance : < 0.33 ohms, from 20 Hz to 20 kHz (measured under 8 ohms). Frequency response : Rise time : < 0.8 µs. Slew rate : > 88 V/µs, peak-peak. DC voltage output drift : > 30 50 > 15 > 15 kohms, 5 Hz to 100 kHz. ±1 ohm, 1 Hz to 1 MHz. kohms bet. Pin 1 and 2. kohms bet.
darTZeel NHB-108 model one Technical Section through products. Not all of them are still in business, Alas! T1. Introduction Thank you for studying this technical section devoted to true audiophiles, demonstrating proof of your interest in the darTZeel NHB-108 model one. First of all, please do not think for a minute that we consider audiophiles differently from music lovers. We know perfectly well that audiophiles love music too, and we are very happy with this.
End of the digital trip. It is interesting to note that several manufacturers offer digital amplifiers, with greater or lesser success. The theoretical limits remain the same, even if better managed than in the '80s. Analog fortunately does not have to cope with such limitations. After several months of deep thinking, circuit designing, and circle squaring attempts, the project was revived (in 1990) on brand new bases.
5mm thick bottom plate, in the form of a sandwich. All cables and wires are routed in this sandwich, minimizing the influence of electromagnetic fields. Furthermore, such an arrangement is of extreme rigidity ensuring exceptionally good mechanical coupling between the mother plate and heat sinks modules. interfering with the electrical origin of the signal. You can hear it if the amp is hooked to a dummy load, since in normal use, loudspeakers fortunately mask this disconcerting internal “singing”.
T4.5. TIO, Totally Identified Object It is however the final touch that makes this darTZeel machine, now installed in your listening room, your darTZeel NHB-108 model one: We refer to the identification plate, fully described in the first part of this manual. Made from 24k gold plated brass, it is a unique handmade piece, just like the machine on to which it is affixed.
strumentation measurement, assuming this result necessarily leads to outstanding sound purity. We take this with some caution, since it recalls for us the 70-80' Japanese philosophy, by which "performance" implies "quality". We have to be fair by acknowledging that such designs can be liked and even loved by audiophiles. The world is big enough for multi musical tastes.
ally is. It is one of our favourite subjects for discussion, since it is here that we can find the key to the problem. Since the CD came on the scene, lots of water has flowed under bridges. In the ‘nineties, a big bug reared its ugly head on the "perfect sound for ever" road. Its name is "Jitter", and it is, more scientifically speaking, an "uncertainty of chronometer precision". Jitter is nowadays well known, and well explains why temporal errors, even when small, lead to amplitude distortion.
So for now, and maybe for still a little while, we will probably not use them directly in audio applications. T5.2.3. Bipolars T5.2.2. FETs FET stands for "Field Effect Transistor", of which there are two main categories. For small signals, they are called as is, FETs. For power applications, their most common name is MOSFET, which stands for "Metal Oxide Silicon Field Effect Transistor". They behave similarly to FETs, but their internal structure may vary.
No output DC voltage drift compensation when this function is released – please refer to the first section of this manual – offering a truly breathtaking sound, from whispers to loud shouts. Only a single, small, local symmetrical DC NFB, leading to extremely wide bandwidth, included in the very low frequencies, without addition of any multi polar phase shift. The use of a very compact printed circuit board (PCB) reduces track lengths to the strict minimum. Reliability.
We also placed inputs connectors directly on the input PCB, themselves very close to the entry audio PCB points, altering as little as possible the still unamplified incoming music. Dozens of other small things have been thought about and implemented. We would need too much space to describe all of them; furthermore, such a description would be much too boring. Please believe us, we have done our best to look after the precious and delicate musical signal, leaving as little as possible to chance. T5.4.
The medium can also be steel. The hammer hitting the string, in a piano, generates a pulse which creates a propagating wave in the string, making it vibrate. Then this vibration will be eventually transmitted into the air. Air: this is the ultimate medium where man-made music propagates. Music is spread in wave form, the latter being described by a physical law, called "wave propagation theory".
Over longer lengths, external disturbances like hum, RFI and so forth take on a greater degree of importance. The disturbances' intensity can be figured out by computing the RMS signal to noise ratio, in decibels. A balanced, high quality, floating line can reach more than 120 dB of rejection, or -120dB relative to the signal, which represents one part per million, 1 ppm, a truly remarkable performance. In full balanced mode, the result is far inferior, and in practice is barely better than -60dB, 0.1%.
T6. Onboard safety A power amplifier like the darTZeel NHB-108 model one cannot but offer the highest quality level when it comes to monitoring and protection. Purity. But we did not call this part of the NHB-108 model one the "protection circuit", by far preferring "supervision system", or "monitoring circuit", as you prefer. Indeed, this very sophisticated module is kept totally outside the signal path, electrically and physically, again so as not to disturb the delicate musical message. Reliability.
the fuses. The metal in the latter literally evaporates instantaneously against the glass envelope, as testified by the latter’s black silver colour. While you are replacing the melted fuse with a new one, the Crowbar circuit will have reset itself in the meantime, and will now be ready to work again, just in case.
The better the quality of the source energy, the easier the task of modulating it into sound waves. This modulation is truly the audio signal you listen to. It is this same signal that will deliver the energy supply to your loudspeakers, which in turn will excite the air molecules to vibration, producing that magical feeling we audiophiles call "music". In your darTZeel NHB-108 model one, the power supplies are not really standard ones. The amplifier is a true dual mono.
By switching the secondary windings accordingly, the power transfer is optimized and the power transistors in the output stage remain within their safe working range. So we can only use one single output transistor pair per channel. The signal path is shorter, uniform, and only passes though one silicon junction at a time. Music is thus reproduced with unprecedented ease, purity and fidelity, simply impossible with more complex designs. T7.3.
What is far less known is the mathematical relationship between expected lifespan and high temperature exposure. Many studies have shown that for each 5°C increase, lifespan is halved! Sorry about not converting into Fahrenheit - the law doesn’t work out so easily. Sometimes the metric system is not so bad, especially when one wants to launch a probe to Mars… But that’s another story. Back to our story.
Furthermore darTZeel keeps permanently in touch with the industry, with the aim of anticipating any shortage or ending of production as regards every component entering into the building of the NHB-108 model one. In the worst case, "perishable" stock will be renewed accordingly in order to offer maximum availability at brand new specifications. Our wish is to be capable of offering you true and full customer service for many generations to come.
- T12. Special adjustments T12.1. Output DC voltage drift When using the NHB-108 with the DC compensation offset off, Eyes could eventually blink, meaning that an output DC voltage greater than ±0.6 volt is present at the terminal speaker outputs. An adjustment is then necessary. - Procedure: DO NOT FORGET THAT THE AMPLIFIER WILL BE POWERED ON! NEVER TOUCH THE COPPER BUS BARS, WHICH ARE AT A POTENTIAL DIFFERENCE OF 115 VOLTS DC.
