User Manual

darTZeel NHB-108 model one Audiophile's technical manual Page 3 of 28
TABLE OF CONTENTS
1. Introduction ................................................................................................................................................... 5
2. Genesis of NHB-108 ..................................................................................................................................... 5
3. Criteria........................................................................................................................................................... 6
4. Structural aspects........................................................................................................................................... 6
4.1. The case modules ............................................................................................................................ 7
4.2. Divide to conquer............................................................................................................................ 7
4.3. Eliminating vibrations..................................................................................................................... 7
4.4. Everything is transparent................................................................................................................. 8
4.5. TIO, Totally Identified Object......................................................................................................... 8
5. The audio electronics..................................................................................................................................... 9
5.1. What is distortion? .......................................................................................................................... 9
5.1.1. Keeping in harmony ............................................................................................................ 9
5.1.2. Inter Modulation Distortion............................................................................................... 10
5.1.3. Temporal Distortion .......................................................................................................... 11
5.2. What application field? ................................................................................................................. 11
5.2.1. IGBTs................................................................................................................................ 12
5.2.2. FETs .................................................................................................................................. 12
5.2.3. Bipolars ............................................................................................................................. 13
5.3. The circuit of darTZeel ................................................................................................................ 13
5.3.1. Criteria of choice............................................................................................................... 13
5.3.2. darTZeel schematics ........................................................................................................ 13
5.3.3. Component layout ............................................................................................................. 14
5.4. Symmetrically balanced? .............................................................................................................. 14
5.4.1. From the microphone… .................................................................................................... 15
5.4.2. To the loudspeakers…....................................................................................................... 15
5.4.3. And into the air….............................................................................................................. 15
5.4.4. Via the darTZeel .............................................................................................................. 16
5.5. darT to Zeel 50Ω......................................................................................................................... 17
6. Onboard safety............................................................................................................................................. 18
6.1. Crowbar circuit.............................................................................................................................. 18
6.1.1. Crowbar activation ............................................................................................................ 19
6.1.2. Crowbar cycle ................................................................................................................... 19
6.2. Supervision system........................................................................................................................ 20
6.2.1. Current sensing.................................................................................................................. 20
6.2.2. For its eyes only ................................................................................................................ 20
7. Power supplies............................................................................................................................................. 20
7.1. From mains to loudspeakers.......................................................................................................... 21
7.2. Voltage or current?........................................................................................................................ 21
7.3. Received idea ................................................................................................................................ 22
8. The sound of darTZeel ............................................................................................................................... 23
9. Reliability .................................................................................................................................................... 23
9.1. Quantified longevity...................................................................................................................... 23
9.2. Long term availability .................................................................................................... ............... 24
9.2.1. Spare parts......................................................................................................................... 24
9.2.2. Self-preservation instinct................................................................................................... 24
10. The next darTZeel ................................................................................................................................. 25
11. Keeping an open door............................................................................................................................. 26
12. Special adjustments ................................................................................................................................ 26
12.1. Output DC voltage drift................................................................................................................. 27
12.2. Monitoring circuit ......................................................................................................................... 28
12.3. Version B ...................................................................................................................................... 28
12.4. Future developments ...................................................................................................... ............... 28