User guide

darTZeel NHB-108 model one User Manual, version B 1.0 Page 4 of 35
Technical Section
T1. Introduction .....................................................................................................18
T2. Genesis of NHB-108 ........................................................................................18
T3. Criteria..............................................................................................................19
T4. Structural aspects ...........................................................................................19
T4.1. The case modules......................................................................................................................... 19
T4.2. Divide to conquer......................................................................................................................... 20
T4.3. Eliminating vibrations.................................................................................................................. 20
T4.4. Everything is transparent..................................................................................... 20
T4.5. TIO, Totally Identified Object ..................................................................................................... 21
T5. The audio electronics......................................................................................21
T5.1. What is distortion? ....................................................................................................................... 21
T5.1.1. Keeping in harmony..................................................................................................................... 21
T5.1.2. Inter Modulation Distortion ......................................................................................................... 22
T5.1.3. Temporal Distortion..................................................................................................................... 22
T5.2. What application field? ................................................................................................................ 23
T5.2.1. IGBTs........................................................................................................................................... 23
T5.2.2. FETs............................................................................................................................................. 24
T5.2.3. Bipolars........................................................................................................................................ 24
T5.3. The circuit of darTZeel ................................................................................................................ 24
T5.3.1. Criteria of choice.......................................................................................................................... 24
T5.3.2. darTZeel schematics .................................................................................................................... 25
T5.3.3. Component layout ........................................................................................................................ 25
T5.4. Symmetrically balanced? ............................................................................................................. 26
T5.4.1. From the microphone… ............................................................................................................... 26
T5.4.2. To the loudspeakers… ................................................................................................................. 26
T5.4.3. And into the air… ........................................................................................................................ 26
T5.4.4. Via the darTZeel .......................................................................................................................... 27
T5.5. darT to Zeel 50Ω.......................................................................................................................... 28
T6. Onboard safety ................................................................................................29
T6.1. Crowbar circuit ............................................................................................................................ 29
T6.1.1. Crowbar activation....................................................................................................................... 29
T6.1.2. Crowbar cycle .............................................................................................................................. 29
T6.2. Supervision system ...................................................................................................................... 30
T6.2.1. Current sensing ............................................................................................................................ 30
T6.2.2. For its eyes only........................................................................................................................... 30
T7. Power supplies ................................................................................................30
T7.1. From mains to loudspeakers......................................................................................................... 30
T7.2. Voltage or current?....................................................................................................................... 31
T7.3. Received idea............................................................................................................................... 32
T8. The sound of darTZeel ....................................................................................32
T9. Reliability .........................................................................................................32
T9.1. Quantified longevity .................................................................................................................... 32
T9.2. Long term availability.................................................................................................................. 33
T9.2.1. Spare parts.................................................................................................................................... 33
T10. The next darTZeel............................................................................................34
T11. Keeping an open door.....................................................................................34
T12. Special adjustments........................................................................................35
T12.1. Output DC voltage drift ............................................................................................................... 35
T12.2. Monitoring circuit ........................................................................................................................ 35