Index

2N4403 transistor, 215, 216

2N5457 transistor, 494

2N5459 transistor, 494

2SB737 transistor, 20, 193, 196–198, 217, 459

2.0Db step switched attenuator, 246

2.5Db step switched attenuator, 247

3.0Db step switched attenuator, 248

± 15V power supply, 527–529

± 17V power supply, 529–531

± 48V phantom power supplies, 538–540

4000 series analog gates, 398

4016 analog gates, 398, 398–400, 402, 405–407

4066 analog gates, 399–402, 404

5532 op-amp:

active panpots, 439

ADCs, 545, 547

balanced inputs, 361

bias current, 99

bipolar input amps, 105–108, 198

cost, 100, 126

electronic cartridge loading, 200

heavy loads, 389–390

input offset voltage, 98

LM 4562 op-amp, 121–123

low-noise balanced inputs, 374

MAGNOISE spreadsheet model, 193–195

negative feedback, 120

noise, 23, 96, 197

OPA2134 comparison, 133

postfade amplifiers, 428–430

selection, 115–117

slew rate, 97

summing amplifiers, 456–457, 458

supply-rail voltages, 525–526

tone-control stage, 298

virtual contact, 395

5534 op-amp, 194, 196, 198, 378, 428–430, 456–458, 545, 547

7824/7924 integrated circuits, 534

A-weighting and noise, 9, 196–197

Acronyms xx1–xx11

Active balance controls, 252–254

Active clipping:

op-amps

clamping, 514

feedforward, 519–521

negative feedback, 514–519

transistors, 510–512

Active filters, 138

Active gain controls, 8, 158

Active gain stage (AGS) control system, 235, 237–238, 291, 299–301

Active input impedance, 201

Active panpots, 438–439

Active preamplifiers, 154–156

Active volume controls, 231–235

AD797 op-amp, 23, 96, 97, 100, 124, 378–380

AD1854 DAC, 546

AD1871 ADC, 543

AD1974 ADC, 543, 544

AFL systems, 471–472, 473

All-pass filters, 139–140, 504

ALPS SPUN switch, 393, 442

Ambler concept (tone), 269, 271

Amplification:

moving-coil head amplifiers, 208–209

preamplifier architectures, 156–157

quiet, 25–26

then attenuation, 6–7

Amplifiers:

hybrid summing, 459–464

CA3080E, 496

Cambridge Audio 840A, 249

components mismatch, 357–359

current, 2, 3

DBX2150 voltage-controlled, 498

high input impedance, 92

instrumentation, 368–369

Johnson noise, 15–16

line inputs, 340

LM13600, 498

LM13600/13700, 496

Neumann SAL 74B, 168

noise, 14–16

Radford HD250, 157

stereo power, 41

SU900, 186

summing, 456–465

type, 2–3

See also op-amps

Analog-to-digital converters (ADCs), 541–542, 542–543, 543–546

Attack artefacts, 503

Attenuation:

quiet, 23–25

then amplification, 7

Attenuator volume controls, 241–249

Audio Note Cartridge, 207

Audio Precision (AP) SYS-2702 measuring system, 71, 79

Augustadt, Herbert, 148

Auxiliary sends and panpots, 446

Bailey, Arthur, 185

Bainter filters, 148

Balance controls:

active, 252–254

mono/stereo switches, 254

passive, 250–252

width controls, 254–255

Balanced hybrid summing amplifiers, 462–465

Balanced inputs:

cables and interference, 346–348

combined unbalanced/ balanced, 362–363

connectors, 348

high-impedance, 366–367

instrumentation amplifier, 368–369

interconnections, 344–346, 349–350

inverting two op-amp, 367–368

practical, 359–362, 362–369

signal levels, 348

switched-gain, 364–365

variable-gain, 365–366

Balanced line outputs, 386

Balanced summing systems for panpots, 449–451

Balanced-feedback hybrid microphone preamplifier, 326–329

Bandpass filters, 138

Bar-graph metering, 486–488, 488–491

Bateman, Cyril, 52, 56

Baxandall configuration:

active gain stage, 8, 237–238, 300

active volume controls, 235–237

Baxandall, Peter, 235

Baxandall tone controls:

middle, 271, 271–273

one-capacitor LF control, 260–263

switched frequency, 266–267

three-banded EQ in one stage, 273–275

two-capacitor HF control, 265–266

two-capacitor tone control, 263–264

BBC, 241, 363, 503

Benet, Stephen Vincent, 525

Bessel filters, 141–142

Beta (h_fe) ratio, 66

Bias current in op-amps, 99–100

Bipolar junction transistors (BJTs), 8

+48V phantom power supplies, 538

op-amps, 97, 117–127

OPA2134 op-amp, 134

Bipolar transistors:

current noise, 17–20

noise, 16–20

voltage noise, 16–17

Blackmer, David, 498

Blue noise, 9

Boctor filter, 150

Bootstrapping:

collector, 93

junction field-effect transistors, 114–115

series-feedback amplifiers, 116

supply rail, 110–114

Braided screen cables, 346

Bridged-differentiator notch filter, 149

Bridging impedance, 312

Broadcast consoles, 304–305, 465, 506

Brownian motion, 9, 337

Bus:

residual, 448, 458

spelling history, 424

trim control, 310, 319

Butterworth filters, 140–144, 168, 191, 201–204, 335

CA3080E amplifier, 496

Cables:

braided screen, 346

mercury, 35

overlapping foil screen cables, 346–347

ribbon, 423, 425–426, 448, 451–452, 469, 471

wiring resistance, 36

Cambridge Audio:

840A amplifier, 249

840E preamplifier, 249

840W power amplifier, 377

P50 integrated amplifier, 235

Capacitance:

impedance and crosstalk, 41

Johnson noise, 10–11

PCB track-to-track crosstalk, 39

resistors, 45

Capacitors:

blocking, 52–53, 266, 268, 326, 329, 335, 340, 360, 362

ceramic, 52, 542

decoupling, 52, 129, 477, 488, 526, 539

electrolytic, 58–61, 458

head microphone amplifiers, 335–337

input sampling, 545

leakage, 51

non-linearity, 52–53

electrolytic, 58–61

non-electrolytic, 53–57

polyester, 53, 145–146

polyethylene terephthalate, 53

polypropylene, 51, 53, 136–137, 145–147, 203, 361, 545, 548

polystyrene, 53

properties, 51–53

reservoir, 527, 529, 532

tan-δ (tan-delta), 51

X2, 57

Capsule polarizing voltage, 135

Carbon composition resistors, 42, 47

Carbon-film resistors, 42, 46, 48

Cartridges:

DC/AC coupling, 183

impedances, 10, 181–182, 194, 207, 210

loading, 181–182, 194, 197

CAST See Current Audio Signal Transmission

CBS (broadcaster), 483

CD players, 155, 156, 163

Ceramic capacitors, 52, 542

Channel modules:

group module circuit blocks, 446

in-line, 319–321

routing, 443, 445

split-format, 310–313

Chebyshev (elliptical) filter, 140

Clamping diodes, 371, 545

Clipping:

biased diode, 510–511

by clamping, 514

diodes, 508–511, 514

feedforward, 519–521

negative-feedback, 514

op-amps, 512–521

soft, 474

transistors, 510–512

CMOS analog gates:

control voltage feedthrough, 407

current mode, 404–405

series-shunt current mode, 406–407

signal switching, 397–407

voltage mode, 399–404

CMOS technology, 544

Collector bootstrapping, 93

Colpitts oscillator, 74

Columbia (record label), 161

Combined LED indicators, 483

Combined low-pass/high pass filters, 139

Combined unbalanced/ balanced inputs, 362–363

Common-mode (CM) range for op-amps, 98

Common-mode rejection:

balanced inputs, 354–355

line inputs, 349–352

op-amps, 354–355

Common-mode rejection ratio (CMRR):

amplifier component mismatch, 357–359

balanced inputs, 360

balanced interconnections, 349–351

electrostatic coupling, 346–354

high-input impedance balanced inputs, 366–367

instrumentation amplifier, 369

inverting two-op-amp, 368

low-noise balanced inputs, 372

magnetic coupling, 347

microphone pads, 329–331

microphone preamplifiers, 324

mixer inputs, 424

op-amp frequency response, 355–357

switched-gain balanced inputs, 364–365

transformer microphone inputs, 325

transformers, 346

unbalanced outputs, 381

variable-gain balanced inputs, 365–366

Complementary feedback pair (CFP):

configuration, 66, 73

constant-current, 77

emitter-follower circuits, 73–79

parametric middle EQs, 284

push–pull operation, 75, 78

two-transistor series feedback gain, 87

Component lifetimes in mixer subsystems, 478–479

Compressors, 499–506

Compressors/limiters:

attack artefacts, 503–504

combination, 500–503, 505

decay artefacts, 504–505

Conductors:

cables, 36

copper, 34–35

gold, 35–36

properties, 34

silver, 34

wire resistance, 36

Connor, Gareth, 465

Consoles:

broadcast, 304–305, 465, 506

cooling in mixer subsystems, 477–478

Constant-current emitter follower circuits, 70–71, 77

Constantan, 34

Control interaction, 259, 268, 272, 274, 276, 299

Control law, 219–223, 226, 228–236, 301, 324, 428, 430, 494–495, 499

Control-room monitor (CRM), 306–308

Cooling:

electronic, 201

fan, 537

Copper:

balanced cables and interference, 346

cable and wire resistance, 36

conductors, 33

metallurgy, 35

mixing bus systems, 424

moving-coil transformers, 209

PCB track resistance, 37–38

properties, 34–35

Correlated noise, 14, 195, 379

Cost of op-amps, 100

Crosstalk:

impedances, 40–42

inductors, 61

input-select switching, 394–395

inter-bus, 448

Current amplifiers, 2, 3

Current Audio Signal Transmission (CAST), 1

Current feedback amplifiers (CFAs), 3

Current source:

Johnson noise, 11

noise in amplifiers, 15–16

transconductance amplifiers, 2

See also individual circuits

Current-carrying capacity, 38

Current-mode connections, 1

Current-sharing, 211

DBX2150 voltage-controlled amplifier, 498

DC:

blocking capacitors, 52–53, 266, 268, 326, 329, 335, 340, 360, 362

discrete JFET switching, 420

drain resistors, 343, 361

potentiometers, 238–239

Decay artefacts, 504–505

Decoupling capacitors, 52, 129, 477, 488, 526, 539

‘Destructive solo’, 473

Differential amplifier array, 377, 378, 379

Differential filters, 150

Digital domain interface:

analog-to-digital converters, 541–542, 543–546

digital-to-analog converters, 541–542, 546–548

nominal levels and ADCs, 542–543

printed-circuit boards, 541–542

Digital-to-analog converters (DACs), 3, 138, 541–542, 546–548

DIN interconnection standard, 2

Dinsdale, Jack, 184

Diode clipping, 508–511, 514

Direct outputs in mixer subsystems, 430–431

Discrete circuitry and power supplies, 534

Discrete JFETs switching:

advantages, 407–408

changeover circuit, 420–421

control-voltage feedthrough in JFETs, 421

current mode, 414–417

DC, 420

JFET drive circuitry, 418–421

physical layout/offness, 419–420

reducing distortion by biasing, 417–418

voltage mode

series switch, 408–413

shunt JFET switch, 413–414

Discrete transistor circuitry:

bipolars/FETs, 64–65

gain stages, 80–88

high-input-impedance bipolar stages, 92–94

op-amps, 88–92

reasons for use, 63–64

transistor equation, 65–66

unity-gain buffer stages, 66–80

Distortion:

op-amps, 101–115

operational transconductance amplifiers, 496

reduction by biasing, 417–418

Sallen-and-Key filters, 145–147

ways of quoting, 102

Distributed gain control, 157, 224

Distributed peak detection, 481–483

Distributed summing systems for panpots, 452–456

Dominant-pole compensation, 183, 186

Dual supplies from a single winding (power), 533–534

Dual-action volume controls, 223–226

Dynamic range, 5–6, 24, 161–162, 345, 499, 502, 525, 542–543, 546

Dynamics section, 312, 426, 508

E3 capacitor values, 171

E12 resistor values, 242

E24 resistor values, 145, 168, 242–244, 365, 475

E96 resistor values, 168, 548

Early Effect, 65, 93, 108

Early, Jim, 65

Ebers–Moll transistor equation, 65–66

Effects return modules, 313

Effects return (split-format), 313–314

Efficient LED bargraph architecture, 488–489

Einstein, Albert, 12

Electret microphones, 317, 473

Electrolytic capacitors, 58–61, 458

Electrolytic tough pitch (ETP) copper, 35

Electronic balanced line inputs, 352–354

Electronic cooling, 201

Electronic switching, 397

Electronic v. transformer balanced inputs, 349

Electrostatic coupling, 346, 346–347, 479, 537

Emitter-follower (EF) circuits:

CFP, 73–79

constant-current, 70–71, 77

push–pull, 71–72, 78

simple, 67–70

stability, 72–73

End-stop resistors, 260, 263, 270

Equalizers (EQs), 61, 139, 267–269, 273–276, 280–283, 283–286

Equivalent input noise (EIN), 16, 87, 191, 193–198, 216–217, 326

Equivalent series resistance (ESR), 51

Evaluation boards, 542

Excess resistor noise, 46–48

External signal levels, 339

Fader flip facility, 310

Fader-start switches, 230

Faders:

linear, 240

short, 310, 319

slide, 229

Faders (mixer subsystems), 428

Fairchild uA709 op-amp, 95

Fan cooling, 537

Feedforward:

clipping, 519–521

compressors/limiters, 502–504

Field-effect transistors (FETs):

balanced summing systems, 449–451

CMOS analog gates, 398, 407

compressors/limiters, 502, 505

control-voltage feedthrough, 421

distributed peak detection, 483

gain-control, 494

JFETs in current mode, 414–415

line-up oscillators, 477

noise, 8

noise gates, 506–508

op-amps, 100, 108–110, 343, 402

prefade listen, 471

shunt JFET switch, 413

Filters:

active, 138

all-pass, 139–140, 504

Bainter, 148

bandpass, 139

Bessel, 141–142

Boctor, 150

Butterworth, 137, 140–144, 167–168, 191, 201–204, 335

characteristics, 140–145

Chebyshev (elliptical), 140

combined low-pass/high pass, 139, 204

differential, 150, 548

high-pass, 138–139, 146, 201–203, 335

low-pass, 138, 141, 204

multiple-feedback, 548

multiple-feedback bandpass, 147–148

notch, 139, 148–150

passive, 137

pinkening, 523–524

radio frequency, 341, 345

roofing, 137

Sallen-and-Key, 140–145, 201, 203

distortion, 145–147

state-variable, 139, 150

subsonic, 162, 201–204

subsonic/ultrasonic combination, 204

third-order, 202

Filters low pass, 138, 141, 143

First Age of Vinyl, 138

First Law of Thermodynamics, 11

Flicker noise, 8, 12, 17

Foldback, 305–306, 308, 313–314, 317

Four-layer summing, 456

Frequency response:

all-pass filters, 139

Bessel filters, 142–143

Butterworth filters, 141–143, 202–203

cartridge-preamplifier interaction, 183

electrolytic capacitors, 58

equalization, 166

high-pass filters, 146

moving-coil transformers, 209–210

negative feedback, 4

non-electrolytic capacitors, 53

notch filters, 148

op-amps, 355–357

RIAA amplifiers, 52

Sallen-and-Key filters, 145

ultrasonic filters, 143

vinyl, 163

violet noise, 9

Front of house (FOH) mixer, 305

Gain law, 237, 326, 331, 366, 501, 506

Gain stages, 120–121, 235

one-transistor shunt-feedback, 80–82

op-amps, 101, 120–121

two-transistor series-feedback gain stages, 87–88

two-transistor shunt-feedback, 82–87

Gain structures, 6–8

Gain-control:

history, 493

junction field-effect transistors, 493–495

operational transconductance amplifiers, 496–497

voltage controlled amplifiers, 495, 497–499, 502, 505

Gain-distribution and preamplifier architectures, 156–157

Galvanic isolation, 61, 346–347, 349, 388, 397

Gaumont, Leon, 431

Gershwin’s Law (‘it ain’t necessarily so’), 33, 68

Gilbert, Barrie, 66

Gold, 13, 34–36, 241

Gold-plating, 35, 230

Graphic equalizers:

constant-Q, 289

description, 286–289

LCR filters, 61

proportional-Q, 289

Gray noise, 9

Green noise, 9

Groove curvature, 165

Ground plane, 40, 301, 423, 542

Ground summing systems for panpots, 451–452

Ground voltages, 348, 354, 383, 451

Ground-canceling outputs, 314, 383–384

Group modules:

circuit blocks and panpots, 446–447

split-format, 314–315

Heat sinks, 537

Heavy loads line outputs, 389–392

Hi-fi preamplifiers, 432

High frequency (HF) correction pole, 170

High input impedance amplifiers, 92

High-impedance inputs:

balanced, 366–367

bipolar stages, 92–94

preamplifiers, 293–294

High-pass filters, 138–139, 141, 144–148, 146, 193, 201–203, 296, 312, 335

Hitachi Cable Company, 35

Hofer, Bruce, 388

Holman, Tomlinson, 180

Hybrid microphone preamplifier, 325–326

Hybrid summing amplifiers, 459–464

Hysteresis, 192

I-V converters, 547, 548

IEC 98 standard, 166

IEC 60098 standard, 166

‘IEC Amendment’, 166–171, 175, 180–181, 191–192, 201, 291

Impedances:

bridging, 312

crosstalk, 40–42

In-line channel modules (mixer architectures), 319–321

In-line mixer architectures, 308–310

Inductance, 10, 15, 43–45, 61, 73, 171, 181–183, 189, 191–197, 207, 368, 370

Inductors, 61

Input:

bias current, 92, 95, 108, 132, 238, 343, 428, 430

offset voltage, 98, 368, 371–372

op-amps, 97

overvoltage protection, 371

sampling capacitors, 545

selector switch, 219, 291, 341

signal and nominal level, 7–8

Input-select switching, 394–395

Insert:

point, 312–313, 316, 319, 382, 423–426

return, 314

send, 314, 316, 425–426, 430, 456–457

Instrumentation amplifier, 368–369

Insulation-displacement connectors (IDCs), 423

Integrated circuits (ICs):

transconductance amplifiers, 2

volume controls, 250

Inter-bus crosstalk, 448

Interfacing with digital domain, 541–548

Internal signal levels, 339–340

Intrinsic emitter resistance, 9, 16

Inverse RIAA equalization, 178, 179

Inversion, quiet, 26–28

Inverting two op-amp balanced input, 367–368

Johnson, John B., 9

Johnson noise:

amplifiers, 15–16

description, 9–11

electronic cartridges, 197, 199

emitter-followers, 73

field-effect transistors, 108–109

low-noise balanced inputs, 375

moving-coil transformers, 209

noise, 12

noise measurements, 23

op-amps, 22

RIAA preamplifiers, 191, 194

switched attenuators, 241

tone-control, 296

virtual-earth summing, 448

Junction field-effect transistors (JFETs):

5532 op-amp, 120–121

bootstrapping, 114–115

capacitor microphones, 335

gain-control, 493–495

input op-amps, 97, 117

noise, 20–21

op-amps, 110, 114–115, 128–136

switching

cascaded FET switches, 412–413

changeover, 412

control voltage feedthrough, 421

current mode, 414–417

DC blocking, 420

drive circuitry, 418–419

electronic, 397, 407

physical layout/offness, 419–420

reduced distortion by biasing, 417–418

series switch (voltage mode), 408–413

shunt switch (voltage mode), 413–414

soft changeover circuit, 420–421

Larger power supplies, 534–536

Late Effect, 65

Laws:

sine/sine squared, 431–432, 439–441

thermodynamics, 11

volume controls, 220–221

LCD meter displays, 491

Leakage from capacitors, 51

Left-Center-Right (LCR):

filters, 137, 504

graphic equalizers, 61

panpots, 439–442

Level control and gain-control elements, 493–499

Level indication:

distributed peak detection, 481–483

peak, 479–481

signal-present, 479

Light emitting diodes (LEDs):

bar-graph metering, 486–488, 488–491

combined, 483

distributed peak detection, 481

metering, 526

moving circuit blocks, 427

panpot offness, 437

signal-present indication, 479–480

virtual-earth PFL detection, 469

Limiters, 499–506

Line inputs:

amplifier component mismatch, 357–359

amplifier functions, 340

balanced, 359–362, 362–369

balanced cables and interference, 346–348

balanced interconnections, 344–346

balanced signal levels, 334

common-mode rejection, 349–352, 354–355

electronic balanced, 352–354

electronic v. transformer balanced inputs, 349

external signal levels, 339

input overvoltage protection, 371

internal signal levels, 339–340

low-noise balanced, 372–377, 377

op-amp frequency response, 355–357

pads and microphone preamplifiers, 329–331

preamplifiers, 293

transformer balanced, 370–371

ultra-low-noise balanced, 378–380

unbalanced, 340–343

Line outputs:

balanced, 386

ground-canceling, 383–385

heavy loads, 389–392

quasi floating, 386–388

transformer balanced, 388–389

unbalanced, 381–382

zero-impedance, 382–383

Line-up oscillators, 474–477

Linear faders, 240

Linearity in circuits, 68–69

Linkwitz–Riley crossover, 141

Lipshitz, Stanley, 175

‘Listen’ facility, 318

LM 833 op-amp, 96, 97, 100

LM317/337 variable-voltage IC regulators, 531–533

LM338K variable-voltage regulator, 534–535

LM741 op-amp, 96, 97, 103, 118

LM833 op-amp, 97, 100

LM3914 integrated circuit, 488

LM3915 integrated circuit, 488

LM4562 op-amp, 23, 96–98, 100, 121–124, 195, 198, 356, 378–380, 526

LM7815 fixed IC regulator, 527

LM7824 fixed IC regulator, 534

LM7915 fixed IC regulator, 527

LM7924 fixed IC regulator, 534

LM13600 amplifier, 496

LM13700 amplifier, 496

Load synthesis, 199–201

Loaded linear pots (volume controls), 221–223

‘Low-impedance design’, 219

Low-noise:

balanced line inputs, 372–377, 377

operational amplifier circuitry, 22–23

Low-pass filters, 138, 141, 143, 204

LP records (33⅓ rpm), 161

LT1028 op-amp, 23, 96, 97, 100, 195, 356, 378–379

LT1083CK variable-voltage regulator, 535–536

Magnetic conductors, 33

Magnetic coupling, 345, 347–348

MAGNOISE model, 192–193, 198

Manganin, 34

Master module (split-format), 316–317

Master section, 306, 308, 310, 316–317, 423, 465–466, 471, 473

MathCAD software, 192

MC33078 op-amp, 96, 97, 100

Mechanical switches, 393

Mercury:

cables, 35

properties, 34–35

Metal Electrode Face-Bonded (MELF) resistors, 43

Metal oxide semiconductor field-effect gates (MOSFETs), 398

Metal-film resistors, 42

Metal-oxide resistors, 42–43, 46

Metering:

LCD meter displays, 491

LED bar-graph, 486–488, 488–491

PPM meters, 485–486

vacuum fluorescent displays, 491

VU meters, 483–484

Metering and light emitting diodes (LEDs), 526

Mic/line switch, 312, 329, 333–334

Microcontroller and relay supplies, (power), 537–538

Microgroove technology, 161

Microphone capsules, 115, 324, 335

Microphone preamplifiers:

balanced-feedback hybrid, 326–329

capacitor head, 335–337

line-input pads, 329–331

padless, 331–335

requirements, 313–314

transformer microphone inputs, 324–325

Microphone transformer, 197, 325

Middle controls (tone), 271

Miller compensation, 120

Mixer architectures:

description, 305–306

in-line, 308–310

in-line channel, 319–321

internal levels, 304

performance, 303–304

split mixing, 306–308

split-format modules, 310–319

Mixer bus systems, 423–424

Mixer subsystems:

AFL systems, 471–473

component lifetimes, 477–478

console cooling, 477–478

direct outputs, 430–431

equalization, 424

faders, 428

group modules circuit blocks, 446–447

inputs, 424

insert points, 424–426

line-up oscillators, 474–477

mixer bus, 423–424

moving circuit blocks, 426–428

panpots, 431–442

PFL systems, 465–471

postfade amplifiers, 428–430

routing systems, 442–446

solo-in-place systems, 473

summing amplifiers, 456–465

summing systems, 447–456

talkback microphone amplifiers, 473–474

Molly-guard, 473

Monitor mix, 305, 308, 310, 314, 419

Monitor mixer, 305

Mono/stereo switches, 254

Motorized potentiometers, 239–240

Moving-coil (MC) head amplifiers:

amplification strategies, 208–209

cartridges, 207–208

circuit, 216

configuration, 213–215

input amplifiers, 210–213

performance, 216–217

transformers, 209–210

Moving-magnet (MM) disc inputs:

cartridges

DC/AC coupling, 183

impedances, 181

loading, 181–183

pre-amplifier interaction, 183

‘Neumann Pole’, 168

noise

A-weighting, 196

electronic cartridge loading, 197–201

measurements, 196–197

preamplifiers, 191–196

op-amps, 187–191

RIAA equalization

components, 175–178

discontents, 166–168

inverse, 178–179

passive/semi passive, 171–175

physical inverse, 178

spurious signals, 162–163

stages, 183–191

subsonic filters, 201–204

vinyl medium, 161–163, 163–165

Mr Spock (Star Trek), 40

Mu-metal, 139, 197, 209, 324

Multipath amplifiers and ultra-low-noise, 28–32

Multiple voltage controlled amplifiers (VCAs), 500

Multiple-feedback bandpass filters, 147–148

Multiple-feedback filters, 548

Mute bloc, 312, 414–417, 419–420

Mutual shutdown circuitry and power supplies, 536

Mutual-shutdown facility, 535

NBC (broadcaster), 483

NE5532 op-amp, 120–121, 356, 525

NE5532/5334 op-amp, 118–120

Negative feedback, op-amps, 519

Negative feedback (NFB):

5532 op-amp, 120

cartridge preamplifier interaction, 183

clipping, 514–519

discrete op-amps, 90

noise in RIAA amplifiers, 194

properties, 4–5

simple emitter-follower, 67

two-transistor shunt-feedback gain, 82–84

Negative-impedance-converter (NIC), 438

Neumann pole, 168

Neumann SAL 74B amplifier, 168

Nickel, 36, 44, 46

NJM4556 op-amp, 96, 97

NJM4556A op-amp, 389

Noise:

A-weighting, 196–197

active gain control, 238

amplifiers, 14–16

bipolar transistors, 16–20

blue, 9

correlated, 14, 195, 379

description, 8–9

electronic cartridge loading, 197–201

excess resistor, 46–48

flicker, 8, 12, 17

gain

5532, op-amp, 298

active volume controls, 232

balanced input, 361

balanced output, 386

bipolar input op-amps, 105

CMOS gates in current mode, 405

common-mode distortion, 104

DC, 420

ground-canceling summing systems, 452–453

JFETs in current mode, 417

LM4562 op-amp, 122

negative feedback clipping, 519

op-amps, 22, 27

OP275 op-amp, 129

OPA627 op-amp, 136

routing, 442–445

summing amplifiers, 458

virtual-earth summing, 448

gates, 312, 485, 506–508

generators, 26, 521–522, 521–523

gray, 9

green, 9

junction field-effect transistors, 20–21

measurements, 23

op-amps, 21–22, 197

pink, 9

red, 9

resistors, 46–48

RIAA

measurements, 196–197

preamplifiers, 191–196

routing systems, 444

simple balanced amplifiers, 361

sources, 13–14

summing systems, 454–455

violet, 9

voltage, 10, 12, 15–19, 21–23, 96–97, 195–196, 343, 374, 378–379

white, 9, 11

See also Johnson noise

Noise figure (NF), 16, 191

Nominal levels and ADCs, 542–543

Nominal signal levels, 5, 7–8, 339, 407

Non-conductors, 34

Non-electrolytic capacitors non-linearity, 53–57

Non-linearity:

capacitors, 52–53

electrolytic capacitors, 58–61

non-electrolytic capacitors, 53–57

resistors, 48–51

Normalling contacts, 312, 319, 423

Notch filters, 138, 148–150

Offness:

CMOS gates in voltage mode, 399–404

mute bloc, 416

panpots, 437, 444

physical layout, 419–420

routing systems, 444

Ohm, Georg Simon, 33

Ohm’s Law, 33, 48

One-capacitor LF control (Baxandall tone controls), 260–263

‘One-ounce copper’, 37

One-transistor:

hybrid summing amplifiers, 460

series-feedback gain stages, 82

shunt-feedback gain stages, 80–82

Op-amps (operational amplifiers):

active clipping, 512–521

bias current, 99–100

BJT input, 117–127

common-mode range, 98

common-mode rejection, 354–355

common-mode rejection ratio, 357

cost, 100

discrete, 88–92

distortion

bipolar input, 104–108

bootstrapping series-feedback JFET op-amps, 114–116

common-mode, 104, 106, 110–113

internal, 101

loading, 103–104

rail bootstrapping to reduce CM distortion, 110–113

simple rail bootstrapping, 113–114

slew-rate limiting, 101–103

thermal, 104

field-effect transistors, 100, 108–110, 343, 402

frequency response, 355–357

gain stages, 101

gain-distribution dilemma, 156

history, 95–96

input, 97

input offset voltage, 98

integrated circuits, 96, 374

JFET input, 128–136

Johnson noise, 22

line inputs, 341

loads, 103

microphone preamplifiers, 325

MM disc input stages, 187–191

negative feedback, 519

noise, 21–22

Sallen-and-Key filters, 141

selection, 115–117

supply-rail voltages, 525–526

See also individual names OP27

op-amp, 96, 97, 100, 124–125, 195, 356

OP270 op-amp, 96, 97, 125–126

OP275 op-amp, 96, 97, 100, 117, 126–127

OPA604 op-amp, 96, 97, 132–134

OPA627 op-amp, 96, 97, 100, 356

OPA2134 op-amp, 96, 100, 110, 113, 117, 131–132, 134, 135–136, 198, 356, 403, 420

Operational transconductance amplifiers (OTAs), 2–3, 496–497

Oscillators, 9, 34, 48, 50, 73–74, 276, 317–318, 337, 474–477

Overlapping foil screen cables, 346–347

Overload margin, 163, 169–170, 172, 179–181, 186, 251

Padless microphone preamplifiers, 331–335

Palladium, 44

Panpots (panoramic potentiometers):

active, 438–439

auxiliary sends, 446

full-width LCR, 440–441

group module circuit blocks, 446–447

half-width LCR, 440–442

law bending, 433–434, 436–437

laws, 431–437, 438–439

Left-Center-Right, 439–442

mixer subsystems, 431–442

negative-impedance-converter, 438

offness, 437, 444

passive, 432–437

routing systems, 442–446

sine/sine squared laws, 431–432

summing systems, 447–456

Parametric equalizers, 285

Parametric middle EQs tone controls, 283–286

Passive balance controls, 250–252

Passive filters, 137, 504

Passive panpots, 432–437

Passive preamplifiers, 153–155, 250

Passive tone controls, 258–259

Passive/semi passive RIAA equalization, 171–175

PCM1794A stereo audio DAC, 546, 547

PCM1802 stereo ADC, 543, 544

Peak detection, distributed, 481–483

Peak indication, 479–481

Peak program meters (PPMs), 485–486

Perpetual motion machine of the second kind, 11

PGA2310 integrated circuit, 250

Phantom power, 312, 323–326, 336–337, 526, 538–539

Phono connectors, 348

Physical inverse RIAA equalization, 179

Pink noise, 9

Pinkening filters, 523–524

Platinum, 34–35

Polyester capacitors, 53, 145–146

Polyethylene terephthalate capacitors, 51, 53

Polypropylene capacitors, 51, 53, 136–137, 145–147, 203, 361, 545, 548

Polystyrene capacitors, 53

Popcorn noise, 13

Postfade amplifier, 312, 314, 428–429, 481

Postfade sends, 306, 313, 430

Potentiometers:

DC in, 238–239

motorized, 239–240

Power supplies, ‘wall-wart’, 533

Power supplies:

±15V, 527–529

±17V, 529–531

+48V phantom, 538–540

discrete circuitry, 534

dual supplies from a single winding, 533–534

larger, 534–536

microcontroller and relays, 537–538

mutual shutdown circuitry, 536

op-amps supply-rail voltages, 525–526

ripple performance, 531, 532–533

variable voltage regulators, 531–532

very large, 536–537

Power supply rejection ratio (PSRR), 526

Practical balanced inputs, 359 ‘Pre-echo’, 164

Preamplifiers:

active, 154–156

active gain control, 158, 291, 299, 300–301

amplification, 156–157

architecture, 153–159, 291–293

description, 291–293

evolution, 154

gain-distribution, 156–157

Hi-fi, 432

high-impedance input buffer, 293–294

hybrid microphone, 325–326

line inputs, 293

LM7824, 534

microphone, 323–337

passive, 153–155, 250

performance, 301–302

philosophy, 291–293

postfade, 312, 314, 428–429, 481

precision, 181, 238, 291

recording, 158

tone controls, 158–159

tone-control stage, 294–300

Precision preamplifiers, 181, 238, 291

Prefade listen (PFL):

AFL, 471–472

channel module (split format), 312

detection, 468–469

in-line channel module, 319

master module, 317

peak indication, 479

simple, 468

split mixing, 306, 308

summing, 466

switching, 466–468

systems, 465–466

virtual-earth detection, 469–471

Prefade sends, 313

Printed-circuit boards (PCBs):

digital domain interface, 541–542

layout, 405, 541–542

mixer bus systems, 423–424

Signal Transfer Company, 191

track current capacity, 38

track resistance, 37–38

track-to-track crosstalk, 39–40

Progressive Electronics, 281

Protection diodes, 400, 528–529

Psychoacoustic weighting, 196

Public address (PA), 138, 305, 325, 388, 478

Push–pull:

CFP emitter-follower, 73–75, 76, 78

CFP follower, 78

emitter-followers, 71–73

Quasi-floating line outputs, 386–388

Quiet amplification, 25–26

Quiet attenuation, 23–25

Quiet balance, 28

Quiet inversion, 26–28

Radford HD250 amplifier, 157

Radio frequency (RF):

field strengths, 388

filters, 341, 345

Rail bootstrapping, 110, 112–115

RC smoothing, 538

RCA connectors, 348

RCA Victor (record label), 161

Recording Industry Association of America (RIAA):

amplifiers, 52, 375

differential amplifiers, 375

equalization, 178, 179

amplification, 208–209, 217

Audio Note cartridge, 207

cartridge-–preamplifier interaction, 183

components, 175

tolerances, 175–178

curve, 164, 166–168, 168–171

input signals, 7

inverse, 178, 179

moving-magnets disc input, 185

noise in preamplifiers, 191–193

non-electrolytic capacitors, 53

passive/semi passive, 171–174

physical inverse, 179

subsonic filters, 201

moving-magnet input stages, 184–186

noise in preamplifiers, 191–196

overload margins, 179–181

preamplifiers, 125

signal levels on vinyl, 163–165

Recording and preamplifiers, 158

Red noise, 9

Relay switching, 397

Relay-switched volume controls, 249, 249–250

Reservoir capacitors, 527–529, 532

Resistances and Johnson noise, 10

Resistors:

carbon composition, 42, 47

carbon-film resistors, 42, 46, 48

common-mode rejection ratio, 351

end-stop, 260, 263, 270

imperfections, 45–46

MELF, 43

metal-film, 42

metal-oxide, 42–43

noise, 46–48

non-linearity, 48–51

surface-mount, 43–45, 48–50

switched attenuators, 246–248

temperature coefficient, 34, 42–45

thick-film, 44, 46

thin-film, 44, 46

through-hole, 43–45

tolerances, 242, 331, 351, 358, 372, 375, 388

voltage coefficients, 48–49

wirewound, 43, 46

Return-to-flat (RTF) tone-control, 295, 298

RF filtering, 138, 340–341, 345, 360

Ribbon cable, 423, 425–426, 448, 451–452, 469, 471

Ripple performance (power supplies), 526, 528, 531, 532–533

Roofing filters, 137

Routing systems:

back grounding, 442

matrix, 430, 446, 451

offness, 444

panpots, 442–446

Rumble and record decks, 162

Ruthenium oxide, 44, 46

Safe-operating-area (SOA), 538

Sallen-and-Key filters:

capacitor microphones, 335

description, 140–145, 203

distortion, 145–147

subsonic filters, 201, 203

Schlotzaur configuration, 79, 327, 507

Screening, 39–40, 197, 209–210, 301, 324, 337, 346–347, 426, 542

‘Sea of micro-diodes’, 33

Second Law of Thermodynamics, 11

Series-feedback, 4, 22, 82–83 See also individual circuits

Servo integrator, 327, 507

Short fader, 310, 319

Shot noise, 8, 12

Shunt-feedback, 3–4, 22 See also individual circuits

Shure M75ED 2 cartridge, 193, 200

Sidechain, 295, 501

Signal switching:

CMOS analog gates, 397–407

discrete JFET switching, 407–421

input-select switching, 394–395

mechanical switches, 393

offness, 399–404, 416, 418–419

relays, 397

virtual contact, 395–397

Signal Transfer Company, 191, 217, 377

Signal-present indication, 479

Signal-to-noise, 2, 4–6, 24, 28, 187, 193, 211, 217, 304, 337, 386, 542

Signals, warp, 163

Signals on vinyl (RIAA), 163–165

Silver properties, 34, 209

Simple emitter-follower (EF) discrete circuit-block, 67–70

Sine laws, 431–432, 439–441

Sine-squared laws, 431–432, 439–441

Sine/cosine characteristic, 431–432

Single jack insert, 425

Single transistor series-feedback gain stage, 82–83

Single-gang sweep middle tone controls, 278–280

‘Slate facility’, 317

Slide faders, 229

Slide faders (volume controls), 229–230

Soft clipping, 474

Solo-in-place systems (SIP), 473

Soundcraft 3200

recording console, 465

SPICE simulation, 23, 48, 68–69, 76, 79, 178, 192, 202, 350, 355

Split mixing (mixer architecture), 306–308

Split-format modules:

channel, 310–313

effects return, 313–314

group, 314–315

master, 316–317

mixer architectures, 310–319

oscillators, 317–319

talkback, 317–319

Splitter box, 305, 388

Spurious signals and moving-magnet disc inputs, 162–163

Star Trek, 40

State-variable filters, 139, 150

Stepped volume controls, 240

Stereo image, 219, 221, 254, 294, 306

Stereo power amplifiers, 41

Stylus acceleration, 165

SU900 amplifier, 186

Subsonic filters, 162, 201–204

Subsonic/ultrasonic filters combination, 204

Subtractive VCA control, 505–506

Summing amplifiers:

5534/2 op-amp, 456–459

balanced hybrid, 462–465

hybrid, 459–462

one-transistor hybrid, 460

two-transistor hybrid, 461, 462, 463

Summing noise sources, 13–14

Summing systems:

amplifiers, 456–465

balanced, 449–451

bus residual, 448

distributed, 452–456

four-layer, 456

ground-canceling, 451–452

noise, 454–455

three-layer, 456

two-layer, 453–456

virtual-earth summing, 445, 448–449

voltage summing, 447–448

Superbal input, 363–364

Supply-rail voltages and op-amps, 525–526

Surface-mount (SM) resistors, 43–45, 48–50

Sweep middles tone controls, 276–278

Switched attenuator:

resistors, 246–248

volume controls, 241, 243, 250

Switched frequency Baxandall tone controls, 266–267

Switched peak/shelving LF/HF EQs tone controls, 281–283

Switched-gain balanced inputs, 364–365

Switched-Q variable-frequency Wien middle EQs tone controls, 280–281

Symmetrical clipping, 474

Szilaki configuration, 74

Talkback:

microphone amplifiers, 473–474

split-format modules, 317–319

Tan-δ (tan-delta in capacitors), 51

Tapped volume controls, 226, 226–229

Temperature coefficient, 34, 42–45

Thermal distortion, 104

Thermodynamics laws, 11

Thevenin–Norton transformation, 11

Thick-film resistors, 44, 46

Thin-film resistors, 44, 46

Third-order filters, 202

Three-layer summing, 456

Through-hole (TH) resistors, 43–45

Time-constants, 53, 166–167, 169–172, 174–175, 178–179, 295–296, 504–506, 523, 545

TL052 op-amp, 129–131

TL072 op-amp:

Baxandall tone controls, 265

cost, 100

DC conditions, 420

distortion, 115

distortion due to loading, 103

field-effect transistors, 109, 195, 238

frequency response, 356–357

junction field-effect transistors, 128–129

low-cost mixing consoles, 117

noise, 96, 193, 198

noise generators, 522–523

notch filters, 148

offness, 402–403

OPA2134 op-amp, 132

postfade amplifiers, 428

rail bootstrapping, 112

RIAA networks, 180

slew-rate, 97

supply-rail voltages, 526

volume controls, 216

TL783C high-voltage regulator, 538

Tolerances of resistors, 242, 331, 351, 358, 372, 375, 388

Tone controls:

Ambler concept, 269, 271

Baxandall, 259–267, 271–273, 273–275, 300

description, 257–258

graphic equalizers, 286–289

middle, 271

parametric middle EQs, 283–286

passive, 258–259

preamplifier architectures, 158–159

return-to-flat, 295, 298

single-gang sweep middle, 278–280

sweep middles, 276–278

switched peak/shelving LF/HF EQs, 281–283

switched-Q variable-frequency Wien middle EQs, 280–281

tone-balance, 269–271

variable frequency LF/HF EQs, 267–269

Wien fixed middle EQ, 276

Tone-balance controls, 269–271

Tone-cancel switch, 296, 300

Tone-control stage and preamplifiers, 294–300

Total harmonic distortion (THD):

bipolar input amplifiers, 107

bootstrapping series-feedback amplifiers, 116

capacitors, 52–53

distortion

presentation, 101–102

Sallen-and-Key filters, 145–146

emitter follower circuits, 68, 77

input overvoltage protection, 371

LM741 op-amp, 118

LM4562 op-amp, 122

non-linearity

capacitors, 53

electrolytic capacitors, 58

non-electrolytic capacitors, 53–55, 57

resistors, 48, 51

OP270 op-amp, 127

resistor voltage coefficients, 48–49

TL072 op-amp, 128–129

two-transistor shunt-feedback, 83, 86

unity gain buffers, 79–80

Track current capacity, 38

Track resistance in printed-circuit boards, 37–38

Track-return/group switch, 319

Track-to-track crosstalk, 39–40

Transconductance amplifiers, 2–3

Transformer balanced line inputs, 370–371

Transformer balanced line outputs, 388–389

Transformer-tap volume controls, 250

‘Transient intermodulation distortion’ (TID), 155

Transimpedance amplifiers, 3

Transistor equation, 65–66

Transmission gates, 397

Transmission of signals, 1–2

Twin-T notch filter, 148–149

Two layer summing, 453–456

‘Two-ounce copper’, 37

Two-transistor hybrid summing amplifier, 461, 462, 463

Two-transistor series-feedback gain stages, 80–82

Two-transistor shunt-feedback gain stages, 82–87

UA709 op-amp, 95

Ultra-low-noise:

amplifiers, 30–32

balanced line inputs, 378–380

multipath amplifiers, 28–32

voltage buffers, 29–30

Unbalanced line inputs, 340–343

Unbalanced line outputs, 381–382

Uncorrelated noise, 14, 211

Unipolar peak detector, 480

Unity-gain buffer stages, 64, 66–80, 90, 129, 140, 143, 145, 155–156

Vacuum fluorescent displays, 491

Van de Gavel, Marcel, 195, 197, 199–200

Variable frequency LF/HF EQs tone controls, 267–269

Variable voltage regulators, 531–532

Variable-gain balanced inputs, 365–366

Varigroove technology, 161, 162

Very large power supplies, 536–537

Vinyl disc, 161, 163–164, 303

Vinyl medium:

description, 161–162

maximum signals, 163–165

Violet noise, 9

Virtual contact (signal switching), 395–397

Virtual-earth PFL detection, 469–471

Vogel, Burkhard, 181

Voltage coefficient, 42–45, 48–50

Voltage controlled amplifiers (VCAs), 2, 495, 497–499, 500, 502, 505

Voltage doubler, 533–534, 539–540

Voltage noise, 10, 12, 15–19, 21–23, 96–97, 195–196, 343, 374, 378–379

Voltage-followers, 30, 110, 114, 372, 395

Volume controls:

active, 231–238

attenuator volume controls, 241–249

Baxandall active, 235–238

gain stage, 237–238

dual-action, 223–226

integrated circuit, 250

laws, 220–221

loaded linear pots, 221–223

potentiometers

and DC, 238–239

motorized, 239–240

relay-switched, 249–250

slide faders, 229–230

stepped, 240

tapped, 226–229

transformer-tap, 250

VU meters, 81, 483–485

Walker, H.P., 185

‘Wall-wart’ power supplies, 553

Warp signals, 163

Wet monitoring, 308, 321

White cathode-follower, 71

White, Eric, 71

White noise, 9, 11

Widlar, Bob, 95

Width controls (balance), 254

Wien bridge configuration, 475

Wien fixed middle EQ tone controls, 276

Wirewound resistors, 43, 46

Wiring resistance and cables, 36

WM8726 stereo DAC, 548

WM8740 stereo audio DAC, 547

WM8782 stereo ADC, 543, 544–545

X2 capacitors, 57

XLR connectors, 326, 345, 347–348, 372, 381–382

YAC523 integrated circuit, 250

Zero-impedance, 178, 382–383, 430, 4426

Zobel networks, 210, 324, 349, 370–371