50-20.000 Hz EQUIVALENT INPUT NOISE (150-ohm source)2 -128 dBu typical OUTPUT NOISE AT TRANSFORMER ISOLATED OUTPUTS, ALL FADERS DOWN EXCEPT AS INDICATED — Master at Nominal ("0”)J -80 dBu typical One Input and Master at Nominal (67-dB gain)1 -61 dBu typical MAXIMUM VOLTAGE GAIN -Mic Input to Transformer Isolated Outputs 90 dB typical FADER RESERVE GAIN 12 dB ADJACENT CHANNEL CROSSTALK AT 1,000 Hz -65 dB POWER REQUIREMENTS 95-130 volts. 50 Hz.4 25 watts maximum COLORS, MATERIALS, AND FINISHES — Chassis: black painted metal with light grey graphics Knobs: grey (3 shades) and red Switches: black DIMENSIONS -Height: 22 2 cm (8 75 in.) Depth: 12.0 cm (4.7 in.) Width: 48.3 cm (19.0 in.) NET WEIGHT — 7.5 kg (16.5 lb) SHIPPING WEIGHT — 8.9 kg (19 5 lb) 1. 0 800 ohms -60 dBu -20 dBu -40 dBu 0 dBu LINE Gain Control Maximum Gain Control Minimum 12,000 ohms -30 dBu +10 dBu -10 dBu + 30 dBu STACKING ■flSSWO ohms +4 dBu + 18 dBu AUX 27.000 ohms +4 dBu + 30 dBu OUTPUT OUTPUT LOAD NOMINAL MAXIMUM IMPEDANCE IMPEDANCE OUTPUT OUTPUT Balanced Transformer Isolated Mains 27 ohms >600 ohms +4 dBu +18 dBu j (600-ohm load) (600-ohm load) Unbalanced Transformer Isolated 600-0hm Out 600 ohms ÿ 10.000 ohms +4 dBu +18 dBu (10 K load) (10 K load) Headphone 47 ohms >8 ohms I -10 dBu ' 0 dBu (8-ohm load) (8-ohm load) + 4 dBu +18 dBu (600-ohm load) j (600-ohm load) < two |Ey| 8108 SERVICE MANUAL GENERAL SERVICING INFORMATION Most EV circuitry is built around commonly available 1C operational amplifiers. A certain amount of familiarity with operational amplifier theory and operation will facilitate servicing this unit Throughout this manual, the following convention will be used when discussing the various amplifier stages: U1 (1). This is to be interpreted as follows: Chip designation U1( output pin = 1. The output pin of the op-amp is particularly significant because all of the unit’s stages are referenced to ground. Thus, the normal quiescent voltage at any op-amp output is 0 volts dc, give or take a few millivolts. Any op-amp output that is not at 0 volts dc is suspect, especially if it is at or near one of the direct supply rails. Beware, however, as much of the circuitry is direct coupled. Thus, it is important to look backward towards the input to localize the exact cause of trouble. Block Diagram DISASSEMBLY INSTRUCTIONS The 8108 is equipped with unique locking XLR-type input (female) and output (male) connectors that must be unlocked before the back cover can be removed This is done by inserting a thin flat blade screwdriver in the hole located between the connector pins and rotating the locking tab approximately y8 turn counterclockwise. Next, remove the 10 phillips head screws holding the back cover to the chassis Remove the 6-V2" nuts and washers securing the Stacking input and Aux input phone jacks to the back cover and remove the back cover To reassemble, reverse the procedure making sure all the insulators are in place including the insulating washers on the Stacking and Aux input jacks, and all XLR-type connectors are locked. BLOCK DIAGRAM three Еу 8108 SERVICE MANUAL Input Assembly sj K s s' ft: 1 is «K N * Is «;« M & V| V 1 g 1 tu a: 6: <* 1 s ¡s * s rr fvj £ n; £M tv M 3 s "S Vl ^0 VJ Vi 8 I *V I 1 iS V Si V •v ? 1 I X* V &J 1 1 £ 1 *1 § I 1 I £ 1 § Gs «0 1 I »n (V4 VI § * 1 § 1 § 1 § 1 1 v* <*) o 8 1 s s a o *"v 1 0 fM tt) § I <5> Vi 1 CVi 1 CSj N <\J 8 ? 55 N *x. "V. 5 <\j •v "s. *v . p/?/ur£i> c/pco/r 23 300/20 cartJicrox, '4 ppoa£ JZ, J3, J4,J5,Ji,J7 22 300//3 CMMCTO* y*PMM£ 777CP, H/O JS 2/ 3OOOS0 H£AO£e, .044 P/SHrMtSLij ¿¡SZas^a 2W 30004 7 H£/)D£P,/)45 SQS'6*r ¿¡U3&S-+ /3 00B049 2/0£>£, 5/6MPL ,/*4**7 D+.D5 /3 0070/3 OPCJ/fj Mr£6PMr£D, I>uPL, //£5532 U2 /7 006023 MATiS/SPM, £/UCOfJ,MP//, 2//CSS/ 02 /6, OOiOOt, TPfiNS/STOP, S/i /CO/i, 7/P//. 2M4SS--* 03 ...
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