Manuale d’uso / di manutenzione del prodotto MPC del fabbricante JBL
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21 MPC Series Power Amplifiers Owner ’ s Manual TD-000074-00 TD-000074-00 R e v . C.
1 T able of Contents T able of Contents .............................................................................................................. ..................................................................... 1 W ar ning notices ..........
2 Rack Mounting Precautions T o a void dama ge to the amplifier mounting ears and/or rack rails , the amplifier must be supported at all four corners when used in portable racks . Consult JBL Ser vice Dept for av ailability of R ear Support Brac ke ts .
3 Description T he MPC Series from JBL is a line of professional pow er amplifiers specifically designed for contracting applica tions . There are six models , eac h with two independent channels .
4 1 22 5 12 12 33 4 4 5 12 2 4 12 12 CH1 CH2 CH1 CH2 BRIDGE MONO BRIDGE MONO LOW IMPEDANCE LOW IMPEDANCE DIR. OUTPUT DIR. OUTPUT ISOL.OUTPUT ISOL.OUTPUT AUDIO TRANSFORMER AUDIO TRANSFORMER 70V 70V 25V.
5 b) Dept hThe amplifiers require a r ac k depth of 45.7 cm (18 in) to clear the rear support ears . T he r ear panel is 42.9 cm (16.9 in) behind the plane of the fr ont mounting rails , allo wing some room for r outing of wires .
6 Outputs Cover ed barrier strips located on the r ear panel allow safe , shockproof speaker ca b le connec- tions to the amplifier outputs . See the dia grams for details on connecting speaker s and/or distributed (25V , 70V , 100, 140V , and 200V) lines .
7 Driving Distributed Lines Make sure the sum of the pow er settings of all the speaker s does not exceed the po wer rating of the amplifier . Be aware tha t the actual power dra w on some loudspeakers can v ary considerably from their tap labels .
8 Loading an amp channel Be careful not to o v er load the c hannel when combining low- impedance and distributed loads on the same amplifier c hannel, because either load af fects the amount of p ow er a vaila ble for the other . T he next two par ag raphs explain how the y load the amplifier output.
9 The tables below ar e general guidelines on which combinations ar e acce ptable. MPC200T Sum of Speaker T aps Connected to AUDIO TRANSFORMER Outputs 0 W 22 W* 44 W** 88 W*** 175 W**** Load connected.
10 Using Multiple Distributed Line V oltages The MPC amplifiers allo w you to connect distributed lines to an y of the 100V , 70V , and 25V outputs at the same time. F or example, a single c hannel could driv e both a 70V and a 25V line; such flexibility could sa ve y ou the e xpense of an additional amplifier .
11 Bridged Mono Input Connection The follo wing dia grams show input and output connections for bridged mono mode . Note that the MPC200 and 200T models use a different method for bridged mono than do the MPC300, 300T , 600 & 600T .
12 Low Impedance Bridged Mono Applications T he bridged mono mode produces higher output v oltages with the trade-off of requiring a higher impedance load and providing a slightly lo wer damping factor . Never - theless , it is an eff ectiv e way of pr oviding v er y high power le vels to loudspeak er s such as 4 Ω or 8 Ω subw oofers.
13 Controls T he c hannel atten uator controls , labeled in dB of atten uation, are located on the r ear panel. T hey ha ve 11 detents and are adjustable from 0 dB (full gain) to ∞ (full attenuation). Displays T he LED displa ys on models MPC200 and 200T are dif f erent from those on models MPC300, 300T , 600, and 600T .
14 AC Power The MPC amplifiers are av ailable for 120 or 220240 V A C, 50 or 60 Hz operation. Eac h amplifier is factory configured for the line volta g e of the market into whic h it is sold. Operation Before fir st turning on the amplifier, tur n the gain controls of fi.
15 Shor t-Circuit Pr otection MPC amplifier s use the prov en Output A veraging short circuit protection system. The circuit per mits full output cur rent even into r esistiv e or r eactiv e 2 Ω load, but reduces the current saf ely by about 75% if the output is shor ted.
16 Specifications Direct Output Models Audio Transfo rmer AND Direct Outputs Electronics MPC200 MPC300 MPC600 MPC200T MPC300T MPC600T Direct P ow er Out 4 Ω bridge 1 kHz, 1% THD 1 700 W 900 W 1800 W.
17 Power Consumption Some background on A C ratings is necessar y to fully understand po wer consumption specifications . Essentiall y , ther e are thr ee ratings of interest: (1) the legal operating .
18 Heat Emission Any pow er that enters the amplifier thr ough the power cor d and does not exit through the speaker outputs turns into heat, which the amplifier m ust rid itself of by exhausting it to the outside . In indoor use this may pr esent a challenge to the building s air conditioning system.
19 T roubleshooting PROBLEM: Channel will not come out of muting . Reduce the gain to ∞ a tten uation. If this releases the muting , raise the gain bac k up slowly while you watc h the SIGN AL and CLIP indicators .
20 For Further Assistance WITHIN THE UNITED ST ATES: General Infor mation or T echnical Assistance F or more inf or mation on JBL products , inc luding these power amplifier s , contact your nearest JBL Professional products dealer or the JBL factory at the address below .
22 JBL Professional 8500 Balboa Boulevard, P .O. Box 2200 Northridge, California 91329 U.S.A. A Harman International Company MPC MANUAL 6/98.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il JBL MPC è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del JBL MPC - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso JBL MPC imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul JBL MPC ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il JBL MPC, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del JBL MPC.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il JBL MPC. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo JBL MPC insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.