ceci est un Cube... - Version imprimable +- MELAUDIA :: forums (https://forums.melaudia.net) +-- Forum : espace public (https://forums.melaudia.net/forumdisplay.php?fid=10) +--- Forum : électronique (https://forums.melaudia.net/forumdisplay.php?fid=32) +--- Sujet : ceci est un Cube... (/showthread.php?tid=7260) Pages :
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RE: ceci est un Cube... - JM Plantefeve - 30/06/2018 Sébastien, ...je parlais de livres orienté audio pour comprendre toutes ces théories Oups ! J'aurais pu comprendre tout de suite. Sur la page théorie, j'en recommande cinq. Mais en excellent rapport disponibilité*qualité/prix, je vois celui-ci : https://www.amazon.fr/dp/0750656360/ Bien à toi, Jean-Marc. RE: ceci est un Cube... - UltimateX86 - 30/06/2018 Ok pour Douglas Self C'est l'édition de 2002, les suivantes n'apportent rien ? RE: ceci est un Cube... - JM Plantefeve - 30/06/2018 Sébastien, C'est l'édition de 2002, les suivantes n'apportent rien ? Assurément qu'elles apportent des plus. Mais avec des prix sensiblement plus élevés (plus 44% pour la dernière édition). J'ai personnellement l'édition de 1996 (the first) en 315 pages. C'est déjà très riche d'enseignements. A toi de voir, je voulais juste donner un conseil des plus raisonnables. RE: ceci est un Cube... - forr - 30/06/2018 thierry38 a écrit :Accessoirement,en //, L'utilisation de zener est plutôt à proscrire pour les CCS et cascode.Ce sont de jolis générateurs de bruit blanc (jonction PN de diode ou tr. bipolaire). Pour une source de courant constant (CCS), il ne faut pas considérer la tension de bruit mais son rapport à sa référence de tension. Dans le Cube, celle-ci est donnée par le courant dans R6, elle-même étant parcouru par un courant constant issu de J2. Les étude de CCS sont rares, voici celles que j'ai relevées. Walter Jung : http://www.audioxpress.com/article/Sources-101-Audio-Current-Regulator-Tests-for-High-Performance-Full-Article Michael Kiwanuka : Je ne crois pas qu'elle ait fait l'objet d'une publication (me demander copie par MP). Il y traite de la toute bête CCS à deux transistors en contre-réaction, l'un faisant à la fois office de référence de tension avec son Vbe et de contrôle de courant dans l'autre. Cette configuration offre une impédance de sortie très élevée, mais elle est sensible à la température, 50° de différence entrainant une variation d'environ 0.1 du Vbe de référence. Boxall-Baxandall : Impédance de sortie encore plus élevée mais un schéma très original de sensibilité délicate, semble-t-il http://www.diyaudio.com/forums/solid-state/25172-baxandall-super-pair.html Christer, membre de Diyaudio : ci-dessous, son compte-rendu d'expérimentations menées il y a quelques années Noise measurements for LEDs and zener diodes -------------------------------------------- © Christer at DiyAudio.com You are allowed to copy and use this information for your personal and non-commercial use. v. 1.3 Added more devices. Introductory text not changed to reflect this. v. 1.4. Added new experiment (number 2) at the end. EXPERIMENT 1 ============ DESCRIPTION OF TEST RIG ----------------------- The test rig uses three current sources of approx. 1, 5 and 20 mA built using low-noise BJTs (BC559) to feed the device under test (DUT) alternatingly. The noise was measured using two op amps in in non-inverting configuration cascaded, both having a gain of 34, making a gain of 1156 in total. The first op amp is a very-low-noise model (LT1115) and uses a gain resistor of only 10 Ohms in the feedback network. The gain resistor is thus 330 Ohms which works since the op amp is only expected to output very low-level signals. The second op amp is a low-noise type (NE5534) with gain and feedback resistors of 100 Ohms and 3.3 kOhms. The output was measured using a PC soundcard (Creative Audigy LS in 16-bit 44.1 kHz mode). Each measurement consists of a 10 second capture of the soundcard input and the RMS value for this 10 s. signal was computed. The program was calibrated (using a sine wave and an oscilloscope) to give aprroximately correct voltage readings and all measurements were divided by 1156 to give the equivalent input RMS noise at the first op amp, ie. at the DUT. No extra filters except what is on the soundcard were used. TEST METHOD ----------- A spectrum of LED types ranging from IR to blue and of approximately the same type were measured. All LEDS were selected to have an max If of at least 20 mA, since this current was used in the test. Further four 0.5W types of zener diodes were tested, two of them (5.6 and 6.8 V) were deliberately selected close to each other but such that the 5.6 V diode should be expected to have true zener breakdown and the 6.8 V one to have avalanche breakdown. The other two were selected to be far away from this "transition region". Two 1.3W zeners were also tested to see how the power rating affects noise figures. For each type of DUT, two devices (denoted #1 and #2 and presumably from the same batch) were tested at the three test currents 1, 5 and 20 mA and the equivalent noise at the DUT was measured and calculated as described above. For each combination of device and current, five 10-second measurements were made. For reference, the voltage drop at each test current was also measured for one device of each type. MEASUREMENTS ------------ All values are RMS values, five measurements for each case. Idle noise: ---------------------------------------------------- Measured idle noise of amplifier with grounded input: 0.19 0.19 0.19 0.19 0.18 uV (The theoretical max value was calculated to 0.16 uV for 20kHz bandwidth and 0.22 uB for 40 kHz bandwidth). Measured idle noise of amplifier with 100 Ohm source resistor: 0.26 0.25 0.24 0.26 0.26 uV (The theoretical max value was calculated to 0.20 uV for 20kHz bandwidth and 0.28 uB for 40 kHz bandwidth). Diodes: --------------------------------------------------- 1N4148 (unknown brand): #1 @ 1mA: 0.28 0.28 0.28 0.27 0.27 uV #1 @ 5mA: 0.25 0.25 0.22 0.22 0.22 uV #1 @ 20mA: 0.24 0.21 0.22 0.25 0.23 uV #2 @ 1mA: 0.38 0.27 0.28 0.26 0.29 uV (Vf = 0.57 V) #2 @ 5mA: 0.23 0.22 0.23 0.23 0.23 uV (Vf = 0.65 V) #2 @ 20mA: 0.23 0.21 0.21 0.21 0.24 uV (Vf = 0.75 V) 1N4004 (unknown brand): #1 @ 1mA: 0.31 0.29 0.29 0.29 0.29 uV #1 @ 5mA: 0.26 0.24 0.26 0.26 0.25 uV #1 @ 20mA: 0.27 0.23 0.23 0.24 0.23 uV #2 @ 1mA: 0.29 0.25 0.25 0.27 0.26 uV (Vf = 0.55 V) #2 @ 5mA: 0.29 0.24 0.25 0.23 0.23 uV (Vf = 0.62 V) #2 @ 20mA: 0.23 0.23 0.22 0.21 0.22 uV (Vf = 0.71 V) LEDs: ---------------------------------------------------- Brand is Everlight unless otherwise stated. IR204/P1 (IR): #1 @ 1mA: 3.7 3.7 3.7 3.7 3.7 uV #1 @ 5mA: 0.67 0.66 0.65 0.66 0.66 uV #1 @ 20mA: 0.24 0.23 0.24 0.23 0.23 uV #2 @ 1mA: 3.8 3.8 3.7 3.7 3.7 uV (Vf = 1.05 V) #2 @ 5mA: 0.65 0.64 0.64 0.64 0.64 uV (Vf = 1.11 V) #2 @ 20mA: 0.24 0.25 0.23 0.24 0.22 uV (Vf = 1.17 V) EL202HD (red): #1 @ 1mA: 0.31 0.32 0.31 0.31 0.32 uV #1 @ 5mA: 0.26 0.26 0.27 0.27 0.27 uV #1 @ 20mA: 0.39 0.36 0.37 0.36 0.37 uV #2 @ 1mA: 0.39 0.37 0.38 0.38 0.35 uV (Vf = 1.82 V) #2 @ 5mA: 0.32 0.30 0.30 0.30 0.31 uV (Vf = 1.89 V) #2 @ 20mA: 0.41 0.40 0.41 0.41 0.46 uV (Vf = 2.09 V) EL1254HD/T2 (red): #1 @ 1mA: 0.36 0.35 0.35 0.34 0.35 uV #1 @ 5mA: 0.30 0.29 0.31 0.32 0.30 uV #1 @ 20mA: 0.51 0.56 0.54 0.55 0.53 uV #2 @ 1mA: 0.53 0.42 0.39 0.41 0.40 uV (Vf = 1.82 V) #2 @ 5mA: 0.30 0.30 0.31 0.29 0.29 uV (Vf = 1.90 V) #2 @ 20mA: 0.42 0.42 0.42 0.43 0.43 uV (Vf = 2.17 V) L934ID/B (red): #1 @ 1mA: 0.29 0.28 0.28 0.27 0.28 uV #1 @ 5mA: 0.27 0.24 0.24 0.23 0.24 uV #1 @ 20mA: 0.39 0.32 0.29 0.48 0.29 uV #2 @ 1mA: 0.34 0.28 0.28 0.28 0.27 uV (Vf = 1.64 V) #2 @ 5mA: 0.24 0.24 0.25 0.24 0.25 uV (Vf = 1.72 V) #2 @ 20mA: 0.30 0.25 0.27 0.30 0.28 uV (Vf = 1.89 V) (Brand is Kingbright) EL204ID (red-orange): #1 @ 1mA: 0.31 0.30 0.31 0.31 0.31 uV #1 @ 5mA: 0.25 0.26 0.26 0.26 0.24 uV #1 @ 20mA: 0.41 0.41 0.48 0.40 0.41 uV #2 @ 1mA: 0.35 0.31 0.29 0.30 0.32 uV (Vf = 1.64 V) #2 @ 5mA: 0.25 0.26 0.27 0.26 0.30 uV (Vf = 1.74 V) #2 @ 20mA: 0.40 0.40 0.39 0.40 0.41 uV (Vf = 1.90 V) EL204YD (yellow): #1 @ 1mA: 0.42 0.30 0.29 0.29 0.28 uV #1 @ 5mA: 0.28 0.26 0.25 0.33 0.27 uV #1 @ 20mA: 0.42 0.39 0.39 0.40 0.40 uV #2 @ 1mA: 0.31 0.30 0.31 0.30 0.31 uV (Vf = 1.78 V) #2 @ 5mA: 0.28 0.47 0.28 0.26 0.25 uV (Vf = 1.87 V) #2 @ 20mA: 0.34 0.34 0.35 0.34 0.34 uV (Vf = 2.02 V) EL204GD (green): #1 @ 1mA: 0.68 0.50 0.50 0.47 0.46 uV #1 @ 5mA: 0.35 0.30 0.28 0.28 0.29 uV #1 @ 20mA: 0.36 0.35 0.35 0.35 0.35 uV #2 @ 1mA: 0.46 0.46 0.44 0.44 0.41 uV (Vf = 1.82 V) #2 @ 5mA: 0.36 0.33 0.32 0.33 0.32 uV (Vf = 1.92 V) #2 @ 20mA: 0.39 0.40 0.39 0.41 0.40 uV (Vf = 2.12 V) EL1254GD/T2 (green): #1 @ 1mA: 0.36 0.36 0.34 0.33 0.34 uV (Vf = 1.84 V) #1 @ 5mA: 0.40 0.40 0.38 0.41 0.40 uV (Vf = 1.96 V) #1 @ 20mA: 1.8 1.9 1.9 1.9 2.1 uV (Vf = 2.20 V) #2 @ 1mA: 0.46 0.41 0.36 0.37 0.39 uV (Vf = 1.82 V) #2 @ 5mA: 0.41 0.42 0.35 0.34 0.31 uV (Vf = 1.93 V) #2 @ 20mA: 0.48 0.50 0.48 0.50 0.51 uV (Vf = 2.27 V) (Measured Vf of both devices for potential correlation with differing noise figs. at 20 mA. Obviously no such correlation found.) EL204UBD (blue): #1 @ 1mA: 4.6 4.5 4.6 4.5 4.6 uV #1 @ 5mA: 3.2 3.2 3.2 3.2 3.2 uV #1 @ 20mA: 2.8 2.8 2.7 2.7 2.7 uV #2 @ 1mA: 4.4 4.4 4.3 4.2 4.3 uV (Vf = 3.26 V) #2 @ 5mA: 3.1 3.2 3.2 3.1 3.2 uV (Vf = 3.44 V) #2 @ 20mA: 2.9 2.8 2.8 2.8 2.7 uV (Vf = 3.69 V) Zeners: --------------------------------------------------------- (All zeners of brand Temic.) BZX55/C2V7 (0.5W 2.7V): #1 @ 1mA: 1.1 1.1 1.1 1.1 1.1 uV #1 @ 5mA: 1.0 0.88 0.85 0.86 0.87 uV #1 @ 20mA: 1.0 0.81 0.72 0.72 1.1 uV #2 @ 1mA: 1.2 1.1 1.1 1.1 1.1 uV (Vr = 2.03 V) #2 @ 5mA: 0.91 0.88 0.87 0.86 0.85 uV (Vr = 2.50 V) #2 @ 20mA: 1.1 0.80 0.77 0.73 0.71 uV (Vr = 3.02 V) BCX55/C3V9 (0.5W 3.9V): #1 @ 1mA: 1.7 1.8 1.7 1.6 1.6 uV #1 @ 5mA: 1.1 1.1 1.1 1.2 1.1 uV #1 @ 20mA: 0.94 9.76 0.84 0.79 0.77 uV #2 @ 1mA: 1.6 1.6 1.6 1.5 1.6 uV (Vr = 3.17 V) #2 @ 5mA: 1.2 1.1 1.1 1.1 1.1 uV (Vr = 3.83 V) #2 @ 20mA: 0.97 0.78 0.86 0.76 0.77 uV (Vr = 4.45 V) BZX55/C5V6 (0.5W 5.6V): #1 @ 1mA: 5.3 5.3 5.3 5.3 5.3 uV #1 @ 5mA: 2.9 2.9 2.9 2.9 2.9 uV #1 @ 20mA: 1.7 1.6 1.6 1.6 1.6 uV #2 @ 1mA: 5.3 5.3 5.3 5.3 5.3 uV (Vr = 5.68 V) #2 @ 5mA: 2.9 2.9 2.9 2.9 2.9 uV (Vr = 5.77 V) #2 @ 20mA: 1.8 1.6 1.6 1.6 1.6 uV (Vr = 5.81 V) BZX55/C6V2 (0.5W 6.2V): #1 @ 1mA: 9.0 8.9 8.9 8.9 8.9 uV #1 @ 5mA: 3.7 3.6 3.6 3.6 3.6 uV #1 @ 20mA: 1.7 1.6 1.6 1.6 1.6 uV #2 @ 1mA: 9.4 9.4 9.3 9.3 9.3 uV (Vr = 6.31 V) #2 @ 5mA: 3.7 3.7 3.8 3.7 3.7 uV (Vr = 6.33 V) #2 @ 20mA: 2.6 1.8 1.8 1.8 1.7 uV (Vr = 6.38 V) BZX55/C6V8 (0.5W 6.8V): #1 @ 1mA: 16 16 16 16 16 uV #1 @ 5mA: 21 21 21 21 21 uV #1 @ 20mA: 5.8 5.5 5.5 5.5 5.6 uV #2 @ 1mA: 25 25 25 25 25 uV (Vr = 6.93 V) #2 @ 5mA: 13 13 13 13 13 uV (Vr = 6.96 V) #2 @ 20mA: 4.6 4.7 4.5 4.5 4.4 uV (Vr = 7.00 V) (Rechecked both devices due to their inconsistent behaviour for 1 and 5mA). BCX55/C7V5 (0.5W 7.5V): #1 @ 1mA: 116 116 116 116 119 uV #1 @ 5mA: 50 50 50 50 50 uV #1 @ 20mA: 25 24 24 24 24 uV #2 @ 1mA: 118 117 116 117 116 uV (Vr = 7.58 V) #2 @ 5mA: 50 50 50 50 50 uV (Vr = 7.62 V) #2 @ 20mA: 18 18 18 18 18 uV (Vr = 7.72 V) (The high readings seem to correlate with scope readings. These devices were possibly of a different brand.) 8.2V (unknown brand, probably 0.5W): #1 @ 1mA: 108 109 109 109 109 uV #1 @ 5mA: 49 49 48 48 48 uV #1 @ 20mA: 15 15 14 14 14 uV #2 @ 1mA: 108 107 107 106 106 uV (Vr = 7.93 V) #2 @ 5mA: 39 39 39 39 39 uV (Vr = 7.97 V) #2 @ 20mA: 14 13 13 13 13 uV (Vr = 8.10 V) BZX55/C12 (0.5W 12V): #1 @ 1mA: 0.35 0.37 0.37 0.39 0.39 uV #1 @ 5mA: 0.30 0.28 0.28 0.28 0.30 uV #1 @ 20mA: 0.24 0.25 0.25 0.26 0.25 uV #2 @ 1mA: 0.32 0.33 0.32 0.33 0.32 uV (Vr = 11.32 V) #2 @ 5mA: 0.26 0.26 0.27 0.32 0.26 uV (Vr = 11.37 V) #2 @ 20mA: 0.25 0.26 0.28 0.24 0.30 uV (vr = 11.42 V) BZX85/C2V7 (1.3W 2.7V): #1 @ 1mA: 0.77 0.77 0.77 0.77 0.76 uV #1 @ 5mA: 0.62 0.61 0.63 0.61 0.60 uV #1 @ 20mA: 0.55 0.55 0.54 0.55 0.55 uV #2 @ 1mA: 0.78 0.78 0.78 0.78 0.78 uV (Vr = 1.30 V) #2 @ 5mA: 0.62 0.62 0.61 0.62 0.62 uV (Vr = 1.61 V) #2 @ 20mA: 0.57 0.56 0.57 0.56 0.56 uV (Vr = 1.92 V) BZX85/C12 (1.3W 12V): #1 @ 1mA: 0.49 0.53 0.48 0.50 0.52 uV #1 @ 5mA: 0.54 0.55 0.58 0.46 0.48 uV #1 @ 20mA: 0.44 0.35 0.38 0.36 0.33 uV #2 @ 1mA: 0.42 0.43 0.46 0.48 0.41 uV (Vr = 9.84 V) #2 @ 5mA: 0.40 0.35 0.35 0.37 0.29 uV (Vr = 9.89 V) #2 @ 20mA: 0.34 0.33 0.31 0.30 0.31 uV (Vr = 9.94 V) Miscellaneous: ----------------- TL431 (Ref tied to cathode to work as 2.5V zener diode): #1 @ 1mA: 20 20 20 20 20 uV #1 @ 5mA: 20 20 20 20 20 uV #1 @ 20mA: 20 20 20 20 20 uV #2 @ 1mA: 20 20 20 20 20 uV #2 @ 5mA: 20 20 20 20 20 uV #2 @ 20mA: 20 20 20 20 20 uV (No cheating, the measurements actually were so consistent.) TL431 (strapped as 5V ref. using two 1kOhm resistors): #1 @ 1mA: 3.2 3.2 3.2 3.2 3.2 uV #1 @ 5mA: 41 41 41 41 41 uV #1 @ 20mA: 42 42 42 42 42 uV #2 @ 1mA: 3.2 3.3 3.2 3.3 3.3 uV #2 @ 5mA: 41 41 41 41 41 uV #2 @ 20mA: 42 42 42 42 42 uV BC549 BE diode forward biased: #1 @ 1mA: 0.24 0.24 0.24 0.24 0.24 uV #1 @ 5mA: 0.22 0.23 0.22 0.24 0.23 uV #1 @ 20mA: 0.22 0.21 0.20 0.22 0.20 uV #2 @ 1mA: 0.23 0.23 0.25 0.24 0.24 uV (Vf = 0.73 V) #2 @ 5mA: 0.23 0.23 0.23 0.23 0.22 uV (Vf = 0.78 V) #2 @ 20mA: 0.21 0.22 0.21 0.20 0.21 uV (Vf = 0.86 V) BC549 BE diode reverse biased: #1 @ 1mA: 56 59 59 56 57 uV #1 @ 5mA: 8.1 8.2 8.3 8.4 8.4 uV #1 @ 20mA: 4.7 4.7 4.8 4.9 4.8 uV #2 @ 1mA: 60 56 54 52 50 uV (Vr = 8.33 V) #2 @ 5mA: 18 17 16 15 14 uV (Vr = 8.39 V) #2 @ 20mA: 4.8 4.8 4.8 4.9 4.8 uV (Vr = 8.68 V) EXPERIMENT 2 ============ TEST RIG -------- Almost the same set up as in experiment 1, but one single current source was used with a 500 Ohm trim pot in series with 10 Ohm as emitter resistor. TEST METHOD ----------- One or two devices of selected LED types were tested at currents 2, 4, 6 and 8 mA with the purpose of spotting a tendency towards a noise optimum at some current. Depending on these results, measurements at certain other currents were sometimes added. In those cases where two devices were tested, device numbers may be swapped compared to experiment 1. Voltage drop was added to the tables in these measurements. As previously, five rms noise readings over 10 s each were taken. MEASUREMENTS ------------ EL202HD (red): #1 1.5mA 1.86V Noise: 0.32 0.34 0.30 0.31 0.34 uV #1 2.0mA 1.87V Noise: 0.31 0.30 0.31 0.31 0.31 uV #1 3.0mA 1.90V Noise: 0.30 0.29 0.29 0.27 0.28 uV #1 4.0mA 1.92V Noise: 0.28 0.28 0.28 0.27 0.27 uV #1 5.0mA 1.94V Noise: 0.30 0.28 0.28 0.28 0.29 uV #1 6.0mA 1.96V Noise: 0.30 0.30 0.28 0.28 0.29 uV #1 8.0mA 1.99V Noise: 0.30 0.33 0.32 0.30 0.31 uV #1 10.0mA 2.03V Noise: 0.71 0.68 0.66 0.63 0.62 uV #2 2.0mA 1.88V Noise: 0.35 0.28 0.28 0.28 0.28 uV #2 3.0mA 1.90V Noise: 0.28 0.29 0.26 0.28 0.27 uV #2 4.0mA 1.92V Noise: 0.27 0.28 0.27 0.27 0.27 uV #2 5.0mA 1.94V Noise: 0.28 0.27 0.27 0.27 0.26 uV #2 6.0mA 1.95V Noise: 0.27 0.28 0.26 0.26 0.26 uV #2 8.0mA 1.98V Noise: 0.31 0.30 0.30 0.32 0.30 uV L934ID/B (red): #1 2.0mA 1.70V Noise: 0.28 0.25 0.28 0.25 0.27 uV #1 4.0mA 1.75V Noise: 0.43 0.27 0.25 0.27 0.26 uV #1 5.0mA 1.76V Noise: 0.39 0.25 0.25 0.25 0.24 uV #1 6.0mA 1.78V Noise: 0.27 0.31 0.25 0.27 0.25 uV #1 8.0mA 1.80V Noise: 0.34 0.31 0.30 0.30 0.32 uV EL204ID (orange-red): #1 2.0mA 1.71V Noise: 0.42 0.31 0.27 0.27 0.27 uV #1 4.0mA 1.76V Noise: 0.30 0.32 0.32 0.29 0.27 uV #1 5.0mA 1.78V Noise: 0.27 0.26 0.26 0.28 0.27 uV #1 6.0mA 1.80V Noise: 0.28 0.27 0.27 0.28 0.43 uV #1 7.0mA 1.82V Noise: 0.31 0.29 0.27 0.30 0.28 uV #1 8.0mA 1.83V Noise: 0.60 0.35 0.36 0.35 0.33 uV #2 2.0mA 1.71V Noise: 0.26 0.34 0.28 0.33 0.30 uV #2 4.0mA 1.76V Noise: 0.27 0.26 0.28 0.62 0.40 uV #2 5.0mA 1.78V Noise: 0.37 0.26 0.37 0.27 0.25 uV #2 6.0mA 1.80V Noise: 0.29 0.28 0.27 0.26 0.26 uV #2 7.0mA 1.81V Noise: 0.30 0.35 0.44 0.28 0.32 uV #2 8.0mA 1.82V Noise: 0.40 0.35 0.36 0.32 0.35 uV EL204YD (yellow): #1 1.5mA 1.83V Noise: 0.32 0.31 0.41 0.31 0.28 uV #1 2.0mA 1.85V Noise: 0.26 0.26 0.26 0.60 0.26 uV #1 3.0mA 1.88V Noise: 0.26 0.28 0.25 0.28 0.24 uV #1 4.0mA 1.90V Noise: 0.30 0.25 0.26 0.26 0.24 uV #1 5.0mA 1.92V Noise: 0.28 0.28 0.28 0.26 0.27 uV #1 6.0mA 1.93V Noise: 0.29 0.27 0.27 0.27 0.28 uV #1 8.0mA 1.96V Noise: 0.31 0.31 0.31 0.32 0.32 uV EL204GD (green): #1 2.0mA 1.89V Noise: 0.39 0.36 1.41 0.36 0.36 uV #1 4.0mA 1.95V Noise: 0.48 0.41 0.34 0.34 0.32 uV #1 5.0mA 1.97V Noise: 0.33 0.33 0.32 0.31 0.31 uV #1 6.0mA 1.99V Noise: 0.30 0.31 0.30 0.29 0.30 uV #1 7.0mA 2.02V Noise: 0.33 0.32 0.35 0.31 0.30 uV #1 8.0mA 2.04V Noise: 0.34 0.35 0.33 0.32 0.31 uV §§§ RE: ceci est un Cube... - forr - 30/06/2018 JM Plantefeve a écrit :Sébastien,Je peux vous assurer d'une chose, la sixième édition est un excellent investissement. Même pour ceux qui n'ont pas envie de bâtir sur l'architecture classique utilisée par Douglas Self. Etre bien documenté permet des économies considérables de temps et d'argent. RE: ceci est un Cube... - JM Plantefeve - 30/06/2018 Forr, Je me demande qui va ici analyser ce copier-coller de 200 lignes de chiffres... RE: ceci est un Cube... - UltimateX86 - 30/06/2018 Jean Marc, Est ce que trop de dissipation peut être mauvais pour un ampli ? Merci RE: ceci est un Cube... - JM Plantefeve - 30/06/2018 Sébastien, Est ce que trop de dissipation peut être mauvais pour un ampli ? N'as-tu pas l'impression que la réponse est dans ta question ? Jean-Marc. RE: ceci est un Cube... - forr - 30/06/2018 JM Plantefeve a écrit :Forr,J'aurais du mentionner l'adresse de la source de ces données, tu pourras sans doute y trouver réponse à ton interrogation : http://www.diyaudio.com/forums/parts/35821-noise-measurements-leds-zener-diodes.html RE: ceci est un Cube... - forr - 30/06/2018 UltimateX86 a écrit :Forr, tu veux parler de ceci : Figure à droite, c'est un push-pull de Sziklai utilisé en étage suiveur de tension : Pour limiter les dérives du courant de repos, il faut remplacer D1 et D2 par un transistor (et deux résistances) qu'on accole à Q1 ou Q3. |