Electro-Voice Dx38 User manual

Dx 38
24 BIT DIGITAL SOUND SYSTEM PROCESSOR
SERVICE MANUAL

WARRANTY (Limited)
Electro-Voice products areguaranteed against malfunctiondue to defectsin materials or workmanshipforaspecified
period, as noted in the individual product-line statement(s) below, or in the individual product data sheet or owner’s
manual, beginning with the date of original purchase. If such malfunction occurs during the specified period, the
product will be repaired or replaced (at our option) without charge. The product will be returned to the customer
prepaid.
Exclusions and Limitations: The Limited Warranty does not apply to: (a) exterior finish or appearance; (b) certain
specific items described in the individual product-line statement(s) below, or in the individual product data sheet or
owner’s manual; (c) Malfunction resulting from use or operation of the product other than as specified in the product
data sheet or owner’s manual; (d): malfunction resulting from misuse or abuse of the product; or (e): malfunction
occurring at any time after repairs have been made to the product by anyone other than Electro-Voice or any of its
authorized service representatives.
Obtaining Warranty Service: To obtain warranty service, a customer must deliver the product, prepaid, to
Electro-Voice or any of its authorized service representatives together with proof of purchase of the product in the
form of a bill of sale or receipted invoice. A list of authorized service representatives is available from Electro-Voice
at 600 Cecil Street, Buchanan, MI 49107 (616-695-6831) and/or Electro-Voice West at 9130 Glenoaks Boulevard,
Sun Valley, CA 91532 (213-875-1900).
Incidental and Consequential Damages Excluded: Product repair or replacement and return to the customer are
the only remedies provided to the customer. Electro-Voice shall not be liable for any incidental or consequential
damages including, without limitation, injury to persons or property or loss of use. Some states do not allow the
exclusion or limitation of incidental or consequential damages so the above limitation or exclusion may not apply to
you. Other Rights: This warranty gives you specific legal rights, and you may have other rights which vary fromstate
to state.
Electro-Voice Electronics are guaranteed against malfunction due to defects in materials or workmanship for a
period of three (3) years from the date of original purchase. Additional details are included in the Uniform Limited
Warranty Statement.
Specifications subject to change without notice.
600 Cecil Street, Buchanan, Michigan 49107, Phone [phone], Fax: [phone]
TELEX/EVI Audio Canada, 705 Progress Ave. Unit 46 Toronto, Onatario, M1H 2x1, Canada , Phone: [phone], Fax: [phone]
TELEX Communications A.G., Keltenstrasse 11, CH-2563 IPSACH, Switzerland, Phone: [phone], Fax: [phone]
EVI Audio Deutschland GmbH, Hirschberger Ring 45, D-94315, Straubing, Germany, Phone: [phone], Fax: [phone]
EVIAudioFranceS.A.,ParcdeCourcerin-AlleeLechWalesa,Lognes,f-77185MarneLaVallee,France,Phone:[phone],Fax:[phone]
EVI Audio Japan Ltd., 2-5-60 Izumi, Suginami-ku, Tokyo, Japan 168, Phone: [phone], Fax: [phone]
EVI Audio (Aust.) Pty., Unit 24, Block C, Slough Business Park, Slough Ave., Silverwater, N.S.W 2141, Australia, Phone [phone],
Fax: [phone]
EVI Audio (Hong Kong) Limited, Unit E & F, 21 /F., Luk Hop Industrial Bldg., 8 Luk Hop St., San Po Kong, Kowloon, Hong Kong, Phone: [phone],
Fax: [phone]

Table of Contents
-Safety and Service Instructions
-
-Warranty
-
-Architects and engineers specifications
-
-Measuring data
-
-Bill of materials
-
-Service notes / infos / instructions
-
-Spare parts plan
-
-Circuit diagrams
Electro-Voice
600 Cecil Street,
Buchanan,
Michigan 49107
Phone [phone]
Fax [phone]
e-mail [email protected]

The lightning flash with arrowhead symbol, within an equi-
lateral triangle is intended to alert the user to the presence
of uninsulated “dangerous voltage” within the product’s
enclosure that may be of sufficient magnitude to constitute
a risk of electric shock to persons.
The exclamation point within an equilateral triangle is
intended to alert the user to the presence of important
operating and maintance (servicing) instructions in the
literature accompanying the appliance.
IMPORTANT SAFETY INSTRUCTIONS
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a damp cloth.
7. Do not block any of the ventilation openings.
Install in accordance with the manufactures instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus that produce heat.
9. Only use attachments/accessories specified by the manufacturer.
10. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been
damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen
into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has
been dropped.
For US and CANADA only:
Do not defeat the safety purpose of the grounding-type plug. A grounding type plug has two blades and a third grounding prong.
The wide blade or the third prong are provided for your safety. When the provided plug does not fit into your outlet, consult an
electrican for replacement of the absolete outlet.
1. Security regulations as stated in the EN 60065 (VDE 0860 / IEC 65) and the CSA E65 - 94 have to be obeyed when
servicing the appliance.
2. Use of a mains separator transformer is mandatory during maintenance while the appliance is opened, needs to be
operated and is connected to the mains
3. Switch off the power before retrofitting any extensions, changing the mains voltage or the output voltage.
4. The minimum distance between parts carrying mains voltage and any accessible metal piece (metal enclosure),
respectively between the mains poles has to be 3 mm and needs to be minded at all times.
The minimum distance between parts carrying mains voltage and any switches or breakers that are not connected
to the mains (secondary parts) has to be 6 mm and needs to be minded at all times.
5. Replacing special components that are marked in the circuit diagram using the security symbol (Note) is only permissible
when using original parts.
6. Altering the circuitry without prior consent or advice is not legitimate.
7. Any work security regulations that are applicable at the location where the appliance is being serviced have to be strictly
obeyed. This applies also to any regulations about the work place itself.
8. All instructions concerning the handling of MOS - circuits have to be observed.
Note: SAFETY COMPONENT (HAS TO BE REPLACED WITH ORIGINAL PART ONLY)
IMPORTANT SERVICE INSTRUCTIONS
CAUTION: These servicing instructions are for use by qualified personnel only. To reduce the
risk of electric shock, do not perform any servicing other than that contained in the
Operating Instructions unless you are qualified to do so. Refer all servicing to
qualified service personnel.
1-2

BESCHREIBUNG
Mit 48 Bit Filteralgorithmen, 24 Bit AD/DA Wandlern und einem Dyna-
mikbereich von 115 dB setzt der Dx 38 neue Maßstäbe für digitale
Lautsprecher Kontroller und Prozessoren. Der Dx 38 ist ein universell
einsetzbarer Digitaler Sound System Processor mit 2 Eingängen und
4 Ausgängen, sowie zusätzlich einer internen Summe der Eingänge 1
und 2. Die Ausgänge können in einer Matrix auf einen beliebigen
Eingang oder die Eingangssumme geroutet werden. Es können Ste-
reo bzw. Dual 2-Weg-Systeme oder 3-Weg+Direct und 4-Weg Syste-
me, jeweils auch mit Mono Sub-Kanal, aber auch Fullrange Systeme
konfiguriert werden.
InallenBetriebsartenstehen Hoch- und Tiefpaß-Filter für die Frequen-
zweichen-Funktionen zur Verfügung. Die Auswahl umfaßt Linkwitz-
Riley, Butterworth und Bessel Filter mit wählbaren Flankensteilheiten
von 6, 12, 18 oder 24 dB/Okt. Eine große Anzahl weiterer Filter
ermöglicht eine äußerst flexible Frequenzgangskorrektur. In den Ein-
gängen finden Sie jeweils einen 5-Band Equalizer, dessen einzelne
Filtersektionen beliebig mit High- und Low-Pass, High- und Low-Shel-
ving oder parametrischen Peak-Dip-Filtern belegt werden können. In
den Ausgängen sind neben den Frequenzweichen-Filtern jeweils 4
weitere Filter enthalten, die ebenfalls als High- und Low-Pass Filter,
High- oder Low-Shelving-Filter, parametrische Peak-Dip-Filter, oder
Allpass-Filter programmiert werden können. Weitere Filtermöglichkei-
ten sind z. B. Hochpässe 2. Ordnung zur Realisierung von B-6 Align-
ments, oder spezielle LPN-Filter (Lowpass Notch / Tiefpaß-Sperrfilter)
zur Korrektur des Frequenz- und Phasengangs von Baßreflexboxen.
Zusätzlich ist jeder Kanal mit einem Delay, einem Polaritätswahlschal-
ter, einem programmierbaren Pegelsteller und einem digitalen Kom-
pressor / Limiter ausgestattet. In den Eingängen befinden sich
außerdem noch die Master-Delays.
Der Anwender hat die Wahl zwischen zwei Bedien-Modi: Im einfach-
sten Fall (No Edit Mode) brauchen nur die verwendeten Lautsprecher-
kombinationen aus der Liste der Factory Preset Programme aus-
gewählt werden. Das Gerät ist danach optimal auf die Audioanlage
eingestellt und sofort betriebsbereit. Im Full Edit Mode hingegen
besteht Zugriff auf sämtliche Parameter, so daß beliebige Einstellun-
gen programmiert und gespeichert werden können. Es stehen insge-
samt 80 Programmplätze - 50 für die Factory Presets, und weitere 30
für frei programmierbare User-Programme - zur Verfügung.
Die AD/DA-Wandlung im Dx 38 erfolgt mit linearen 24 Bit Wandlern,
wobeiessichin der AD-Sektion um gainrangingSigma-Delta-Wandler
mit128-fachemOversamplinghandelt. Im DA-Bereich wird mitSigma-
Delta Wandlern mit 128-fachem Oversampling gearbeitet. Die Signal-
verarbeitung erfolgt auf zwei 24 Bit Motorola Signalprozessoren.
DESCRIPTION
Providing 48-bit filter algorithms, 24-bit AD/DA conversion and a
dynamic range of 115 dB, the Dx 38 sets new standards for digital
loudspeaker controllers and processors. The Dx 38 is an universal
Digital Sound System Processor that provides 2 inputs and 4 outputs;
plus internal summing of the inputs 1 and 2. Via matrix it is possible to
assign the outputs to any input or to the sum of the inputs. It is further
possible to establish the following configurations: Stereo or Dual
2-Way systems, 3-Way + Direct and 4-Way systems, each with Mono
Sub-channel, but also full range systems.
High and low-pass filters are provided for the frequency crossover
functions in all operation modes. The selection includes Linkwitz-Ri-
ley,ButterworthandBesseltypefilterswithswitchableslopesbetween
6, 12, 18 and 24 dB/oct. A huge number of additional filters offers
extremely flexible correction of the frequency response. Each input
incorporatesa 5-band equalizer,allowing to assignhigh and low-pass,
high and low-shelving or parametric peak-dip filters to its individual
filter sections. Next to the frequency crossover filters, four additional
filters are employed in each output channel, which also can be set to
work as high or low-pass, high or low-shelving filters, parametric
peak-dip filters, or all-pass filters. Additional filtering is provided
through 2. order high-passes for the realization of B-6 alignment, or
special LPN-filters (Low-Pass Notch filters) for correcting the frequen-
cy and phase responses of optimally vented woofer cabinets. Each
channel additionally provides a delay, a polarity switch, a program-
mable level control and a digital compressor / limiter while the master
delays are located in the input channels.
The user can choose between two operation modes: the “No Edit
Mode”allows to simplyselect the requiredcombination of loudspeaker
systemsfromthefactorypresetprogramlist.Afterwards,the appliance
is optimally matched to the sound system and can be operated
instantly. The “Full Edit Mode” on the other hand offers access to all
parameters, allowing to freely program and store basically any setting.
A total number of 80 memory addresses - 50 preset and 30 freely
assignable user-programs - are available.
Technische Informationen
Architects and engineers
specifications
Dx 38
24 BIT DIGITAL SOUND
SYSTEM PROCESSOR
Weitere Merkmale sind:
- FLASH Speicher für Software und Preset Updates über
serielle Schnittstellen
- PC Bedien- und Konfigurationssoftware unter Windows 95 /
Windows 98
- MIDI-Schnittstelle standardäßig
- RS-232, RS-485 Schnittstellen oder Umschaltkontakte optional
- Grafik-Display mit 122 x 32 Dots, hintergrundbeleuchtet
- Ein- und Ausgänge elektronisch symmetrisch in XLR
- Trafosymmetrierung für die Eingänge optional
- Input / Output Pegelsteller, Output Mute Schalter, Kanal-
Funktionsanzeigen SUB, LO, MID, HI
- Input / Output Aussteueranzeigen, Kompressor- und Clip-LED’s

Within the Dx 38, AD/DA conversion is taken care of by linear 24-bit
converters; where the AD-section employs 128 times oversampling,
gain-rangingSigma-Deltaconverters.TheDA-sectionoffers128times
oversampling Sigma-Delta converters. The overall signal processing
is performed by two 24-bit Motorola signal processors.
DESCRIPTION
Avec ses algorithmes de filtrage travaillant en 48 bits, ses convert-
isseurs A/N et N/A 24 bits et sa gamme dynamique de 115 dB, le Dx
38 définit de nouveaux standards dans le domaine des contrôleurs et
processeursnumériquesdehaut-parleurs.LeDx 38estunprocesseur
numériquedediffusionuniversel;ilestpourvude2entréeset4sorties,
uncircuitinternepermettantdesommerlesentrées1et2.Unematrice
permet d’assigner les sous-bandes du signal d’entrée stéréo (ou
sommé en mono) à n’importe quelle(s) sortie(s). D’origine, les confi-
gurations suivantes sont disponibles : systèmes stéréo 2 voies, mono
2 voies, 3 voies + sortie directe, ou système mono 4 voies, tous offrant
éventuellement une sortie mono pour canal Subwoofer et une sortie
“large bande”.
Danstouslesmodesdefonctionnement,cesontdesfiltrespasse-haut
et passe-bas qui se chargent de répartir le spectre audio en plusieurs
bandes de fréquences (crossover). Ces filtres peuvent être de type
Linkwitz-Riley, Butterworth ou Bessel, avec des pentes commutables
entre 6, 12, 18 et 24 dB/octave. De nombreux autres correcteurs
permettent de modeler la courbe de réponse à votre guise : chaque
entrée possède par ailleurs cinq correcteurs, pouvant être un filtre
passe-haut ou passe-bas, un correcteur d’aigus ou de graves de type
Shelve (en plateau), ou un filtre paramétrique. Une fois le signal
d’origine réparti en plusieurs bandes, quatre autres correcteurs peu-
vent prendre place sur chaque canal de sortie : eux aussi peuvent
travailler en modes passe-haut ou passe-bas, correcteur d’aigus ou
de graves de type Shelve (en plateau), filtre paramétrique, voire filtre
passe-tout. Des fonctions de filtrage supplémentaires sont encore
prévues, sous la forme de filtres passe-haut du second ordre permet-
tant la réalisation d’alignements de type B-6, ou des filtres spéciaux
de type LPN (pour Low-Pass Notch, filtres passe-bas de type Notch)
permettant de corriger la réponse en fréquence et en phase d’encein-
tes de graves travaillant en bass-reflex.
Chaquecanaloffreenplusundélai,uninverseurdephase,unréglage
de niveau programmable et un compresseur/limiteur numérique, les
délais principaux se trouvant au niveau des canaux d’entrée.
Deux modes de fonctionnement sont à la disposition de l’utilisateur :
le mode “No Edit”, qui ne permet que de sélectionner la combinaison
d’enceintes désirée dans la liste donnée par le Programme Preset
d’usine. Dans ce cas, l’appareil est configuré de façon optimale en
fonction de l’installation, et peut être exploité instantanément. Enfin, le
mode “Full Edit”, lui, permet d’accéder à tous les paramètres, ce qui
permet de programmer en toute liberté et de mémoriser ses Program-
mes. L’appareil compte 80 emplacements mémoire - 50 pour les
Programmes Presets d’usine et 30 pour les Programmes utilisateur.
À l’intérieur du Dx 38, les conversions A/N et N/A s’effectuent en 24
bits linéaires (Delta-Sigma, suréchantillonnage 128 fois), et les traite-
ments du signal sont calculés par deux DSP Motorola 24 bits.
Additional features are:
-FLASH memory for software and preset updates via serial
interfaces
-PC-based operation and configuration software running under
Windows ‘95 / Windows ‘98
-Standard MIDI-interface
-RS-232, RS-485 interfaces or switching contacts optionally
available
-Back-lit graphic-display with 122 x 32 dots
-Inputs and outputs are electronically balanced, XLR-type
connectors
-Input transformer-balancing is optionally available
-Input / Output level controls, Output-Mute switch, channel
function indicators SUB, LO, MID, HI
-Input / Output meter instruments, compressor and clipping LEDs
Parmi les autres caractéristiques :
- Mémoire FLASH pour le logiciel d’exploitation et les Presets,
ce qui permet la mise à jour via interface série.
- Logiciel de configuration et de commande pour PC, tournant
sous Windows 95/98.
- Interface MIDI Standard.
- En option, commande via interfaces RS-232, RS-485 ou
commutation par contacts.
- Affichage graphique rétro-éclairé, 122 x 32 points.
- Entrées et sorties sur XLR, symétrie électronique.
- En option, symétrisation par transformateur d’entrée.
- Potentiomètres de réglage des niveaux d’entrée et de sortie,
commutateur de coupure des sorties (Mute) indicateurs SUB,
LO, MID, HI par canal.
- Visualisation par VU-mètres des entrées/sorties, du compresseur,
LED d’écrêtage.
TECHNICAL SPECIFICATIONS
Mains voltage
90 - 250 V AC / 50 - 60 Hz
Power consumption 20 watts
Safety class I
Inputs 2 x XLR IN, electronically balanced,
transformer optional available
2 x XLR OUT (Direct Out)
Input voltage (nominal) 1.55 V / + 6 dBu
Max. input voltage 24.5 V / + 30 dBu
Input impedance 20 kohms
Common mode rejection > 40 dB
AD-conversion 24-bit, Sigma-Delta, 128 times
oversampling, linear phase
Outputs 4 x XLR OUT, electronically balanced
Output voltage (nominal) 1.55 V / + 6 dBu
Max. output voltage 8.7 V / + 21 dBu
Output impedance < 100 ohms
Min. load impedance 600 ohms
DA-conversion 24-bit, Sigma-Delta, 128 times
oversampling
Frequency response 20 Hz - 20 kHz (- 0.5 dB)
S/N ratio 115 dB (typical)
Distortion without transformer < 0.01 %
Distortion with transformer < 0.05 %
Frequency crossovers 6, 12, 18, 24 dB/oct. slope;
Butterworth, Bessel, Linkwitz-Riley
Filters 26 parametric equalizers
Low-Shelving equalizer,
LPN (Lowpass-Notch) switchable
Hi-Shelving equalizer, 6 / 12 dB slope
switchable, Lo-Cut filter (B-6 alignment
switchable), Hi-Cut filter, All-Pass filter
Compressor / limiter 4 digital compressors / limiters
Delay 3 master delays (2 ms - 900 ms)
4 channel delays (0 ms - 900 ms)
delay-increment 21 µsec.
Data format 24-bit linear AD / DA conversion,
48-bit processing
Sampling rate 48 kHz
MIDI IN / OUT / THRU Data Dump, Master / Slave operation,
Remote Control
Display 122 x 32 Dots, graphic LC-Display with
LED-background lighting
Dimensions 483 x 43.6 x 374 (WxHxD in mm), 19", 1 HU
Weight 5 kg / 11 lbs
Locking function Protection against inadvertent operation
via function-lock
Accessories PA 1 plexiglas cover 1 HU
Options NRS 90244 Input transformer
NRS 90247 RS-485 interface
NRS 90246 Contact Closure interface

1
Measuring data Dx 38 – complete device
1. Power Supply
1.1 Operation Voltage U Mains 90 - 250 V AC, 50 - 60 Hz
1.2 Operation Current at U Mains = 110 V AC 200 mA
at U Mains = 230 V AC 130 mA
1.3 Power Consumption 14 W
1.4 Internal Operation Voltage +5 V ±0,1 V
+18 V ±1 V
-18 V ±1 V
1.5 Internal Operation Currents +5 V max. 460 mA
+18 V max. 400 mA
-18 V max. 250 mA
1.6 Power Supply Switching Frequency 192 kHz
2. Inputs
2 x XLR IN, electronically balanced, 2 x XLR Direct Out,
Input transformers (NRS 90244) are optionally available
2.1 Input Impedance electronically balanced 20 kΩ
2.2 Input Voltage [1] 4,5 V = +15 dBu
Max. Input Voltage 24,5 V = +30 dBu
2.3 Common Mode Rejection CMRR ≥40 dB
3. Outputs
4 x XLR OUT, electronically balanced
3.1 Output Impedance < 100 Ω
3.2 Min. Load Impedance 600 Ω
3.3 Max. Output Voltage [1] 8,7 V = +21 dBu
3.4 Output Symmetry [1] [2] ≥-40 dB
4. Frequency Response
4.1 Frequency Response [3] fig. 1 30 Hz ... 20 kHz -0.5 dB
5. Crosstalk
5.1 Crosstalk Attenuation [3] > 80 dB

2
6. Distortion
6.1 THD+N [4] fig. 2 , fig. 3 20 Hz ... 20 kHz < 0.01 % @ +10 dBu
7. Interference Voltages
7.1 Wide Band Noise Voltage [5] ≤50 µV = -84 dBu
7.2 Noise Voltage (CCIR 468-3) [6] ≤140 µV = -75 dBu
7.3 Noise Voltage (A-weighted) [7] ≤18 µV = -93 dBu
8. Retrofitting Input Transformers
Retrofitting input transformers NRS 90244 results in the change of the following values:
8.1 THD+N [4] figure 4 70 Hz ... 20 kHz < 0.01 % @ +10 dBu
THD+N [4] figure 4 20 Hz ... 20 kHz < 0.05 % @ +10 dBu
9. Other Specifications
9.1 Operation Temperature Range +5 ... +40 °C
9.2 Temperature Range During Storage And Shipment -40 ... +70 °C
10. Dimensions And Weight
10.1 Dimensions W x H x D 19" (483 mm) x 1 HU (43,6 mm) x 374 mm
10.2 Installation Depth Without Connectors 356 mm
10.3 Installation Depth Incl. Connectors approx. 430 mm
10.4 Weight 5 kg
10.5 Weight with 2x NRS 902445.2 kg
11. Standards
11.1 Safety Class according to EN 60065 safety class I, grounded
11.2 Electrical Safety In Accordance To EN 60065 (VDE 0860) or IEC 65
UL, CSA
11.3 EMC In Accordance To EN 50081-1, EN 50082-1, EN 55022-B
12. Retrofiting-Kits
12.1 NRS 90244 input transformer for 1 input Order No. 112 757
12.2 NRS 90246 contact closure interface Order No. 112 766
12.3 NRS 90247 RS-485 interface Order No. 112 767
13. General
13.1 The following equipment had been used for measuring:
Digital Multi-Meter PM 2517 X Philips
System One Audio Precision
Oscilloscope 2465 A Tektronix
Regulation de-coupling transformer RT 5A Grundig
Watt-Meter (electronical) Dynacord

3
13.2 Comments about measurements
- Unless differently stated, all measurement has been performed at 20°C ±2°C
- All stated levels ±1 dB
[1] all controls set to their clockwise margin
[2] Service program 'SINE WAVE OUT' , set a level of 0 dB,
Output voltage = approx. 8,9 V = +21 dBu = 0 dBr,
+ and - outputs summed via 10 kΩ/ 0,1 % resistors, with VR301 ... VR601
adjusted for minimum levels U ≤87 mV = -19 dBu = -40 dBr
[3] measured with service program 'ORIGINAL THRU' , level 0 dB, all controls set to their
clockwise margin, input level +10 dBu
[4] measured with service program 'ORIGINAL THRU' , level 0 dB,
input controls at center position, output controls set to their clockwise margin
[5] measured with service program 'ORIGINAL THRU' , level 0 dB, all controls
set to their clockwise margin,
measurement via bandpass filter 22 Hz ... 22 kHz, weighting filter set to 20 kHz Lo-Pass,
Q-Peak, input terminated with 600 Ω
[6] measured with service program 'ORIGINAL THRU' , level 0 dB, all controls
set to their clockwise margin,
measurement via bandpass filter 22 Hz ... 22 kHz, weighting filter set to CCIR 468-3,
Q-Peak, input terminated with 600 Ω
[7] measured with service program 'ORIGINAL THRU' , level 0 dB, all controls
set to their clockwise margin,
measurement via bandpass filter 22 Hz ... 22 kHz, weighting filter set to 'A-weighting',
RMS, input terminated with 600 Ω
Figure 1 Frequency Response [dBr] [3]
04/09/99 12:28:14
Frequency response
-3
+1
-2.5
-2
-1.5
-1
-0.5
-0
+0.5
d
B
r
20
20k
50
100
200
500
1k
2k
5k
10k
Hz

4
Figure 2 THD+N [%] as a function of the input level [dBu] [4] , f = 1 kHz
Figure 3 THD+N [%] as a function of the frequency [Hz] [4] , input level = +10 dBu
Figure 4 THD+N [%] as a function of the frequency [Hz] [4] , input level = +10 dBu
with input transformer (NRS 90244) installed
04/19/99 17:01:22
THD+N vs Level
0.002
1
0.005
0.01
0.02
0.05
0.1
0.2
0.5
%
-40
+25
-35
-30
-25
-20
-15
-10
-5
+0
+5
+10
+15
+20
dBu
04/20/99 08:53:11
THD+N vs Frequency
0.002
1
0.005
0.01
0.02
0.05
0.1
0.2
0.5
%
20
20k
50
100
200
500
1k
2k
5k
10k
Hz
04/20/99 11:46:46
THD+N vs Frequency
0.002
1
0.005
0.01
0.02
0.05
0.1
0.2
0.5
%
20
20k
50
100
200
500
1k
2k
5k
10k
Hz

5
14. Specifications
Mains voltage 90 - 250 V AC / 50 - 60 Hz
Power consumption 20 watts
Safety class I
Inputs 2 x XLR IN, electronically balanced, transformer optional
available 2 x XLR OUT (Direct Out)
Input voltage (nominal) 1.55 V / + 6 dBu
Max. input voltage 24.5 V / + 30 dBu
Input impedance 20 kohms
Common mode rejection > 40 dB
AD-conversion 24-bit, Sigma-Delta, 128 times oversampling, linear phase
Outputs 4 x XLR OUT, electronically balanced
Output voltage (nominal) 1.55 V / + 6 dBu
Max. output voltage 8.7 V / + 21 dBu
Output impedance < 100 ohms
Min. load impedance 600 ohms
DA-conversion 24-bit, Sigma-Delta, 128 times oversampling
Frequency response 20 Hz - 20 kHz (- 0.5 dB)
S/N ratio 115 dB (typical)
Distortion without transformer < 0.01 %
Distortion with transformer < 0.05 %
Frequency crossovers 6, 12, 18, 24 dB/oct. slope;
Butterworth, Bessel, Linkwitz-Riley
Filters 26 parametric equalizers
Low-Shelving equalizer, LPN (Lowpass-Notch) switchable
Hi-Shelving equalizer, 6 / 12 dB slope switchable,
Lo-Cut filter (B-6 alignment switchable),
Hi-Cut filter, All-Pass filter
Compressor / limiter 4 digital compressors / limiters
Delay 3 master delays (2 ms - 900 ms)
4 channel delays (0 ms - 900 ms)
delay-increment 21 µsec.
Data format 24-bit linear AD / DA conversion, 48-bit processing
Sampling rate 48 kHz
MIDI IN / OUT / THRU Data Dump, Master / Slave operation/ Remote Control
Display 122 x 32 Dots, graphic LC-Display with
LED-background lighting
Dimensions 483 x 43.6 x 374 (W x H x D in mm), 19", 1 HU
Weight 5 kg / 11 lbs
Locking function protection against inadvertent operation via function-lock
Accessories / Options PA 1 plexiglas cover 1 HU
NRS 90244 Input transformer
NRS 90247 RS-485 interface
NRS 90246 Contact Closure interface

6
15. Service Programs
The Dx 38 provides several onboard service programs that allow testing internal function blocks.
The service mode is entered by simultaneously pressing the ' EDIT ' and ' > ' keys while the unit is
powered on.
The display shows briefly: SERVICE MODE
Selecting the service programs in sequence is possible by using the SELECT keys or via the rotary
encoder. Pressing the ' RECALL ' key launches the previously selected program or, while a service
program is running, to cancel the test.
Switching the device off or by use of the < QUIT > command, the service mode is ceased.
Available Service Programs:
•µP-ROM TEST
•µP-RAM TEST
•EEPROM TEST
•KEY TEST
•ENCODER TEST
•LED TEST
•DISPLAY TEST
•RS232 TEST
•RS485 TEST
•CONTACT P TEST
•MIDI TEST
•DSP-RAM TEST
•HW-CONN TEST
•ORIGINAL THRU
•SINE WAVE OUT
•PINK NOISE
•WHITE NOISE
•A/D GAIN CALIB
•A/D GAIN RNG 1
•A/D GAIN RNG 2
•INITIALIZE MEM
•FLASH PROGRAM
•STATISTICS
•QUIT
µP-ROM TEST
The Flash-ROM (IC102 on the 80449 Digital Board) gets tested by calculating the checksum of
the memory contents. If no error has been detected, the display shows ' OK '. If a faulty condition
has been detected, the calculated checksum appears on the display.
µP-RAM TEST
The µP-RAM (IC103 on the 80449 Digital Board) is tested. If no error has been detected, the
display shows ' OK '. If a faulty condition has been detected, the corresponding address or
respectively the erroneously read data appear on the display.

7
EEPROM TEST
The EEPROM (IC105 on the 80449 Digital Board) is tested. If no error has been detected, the
display shows ' OK '. If a faulty condition has been detected, the corresponding address or
respectively the erroneously read data appear on the display.
KEY TEST
The function of all keys gets tested. The function of the key that gets pressed appears on the
display. Testing is canceled by pressing the rotary encoder.
ENCODER TEST
The function of the rotary encoder gets tested. When turning the wheel, the direction (+/-) and
the amount of impulses is displayed.
LED TEST
All LEDs on the front of the appliance are checked. All LEDs are accessed in sequential order.
Upon ending the test, all LEDs light.
DISPLAY TEST
This program is meant for testing the LC-display and setting its contrast. Using the rotary
encoder lets you adjust the LCD-contrast in a range between -10 to +10.
After pressing any key, a graphic pattern appears on the display, which allows checking whether
all pixels are active.
RS232 TEST
The RS-232 interface gets tested by sending and reading back data. During this test, pins 2 and
3 of the RS-232 connector have to be bridged by using a special bridging-plug.
If no error has been detected, the display shows ' OK '. If a faulty condition has been detected,
the display shows whether the data was corrupted during the internal reading (in the UART, IC1)
or at the external bridging plug.
RS-485 TEST
The optional RS-485 interface gets tested by sending and reading back data.
If no error has been detected, the display shows ' OK '. If a faulty condition has been detected,
the display shows whether the data was corrupted during the internal reading (in the UART, IC1)
or at the external RS-485 driver (IC2).
CONTACT P TEST
The optional contact closure port is tested. Therefore the bit-pattern which is present at pins 1-8
is read and shown on the display. By connecting external contacts to ground potential, the pins
can be pulled to "0". The test is completed with OK when each contact had been closed at least
once.
MIDI TEST
The MIDI interface gets tested. Therefore you have to connect the MIDI IN and MIDI OUT
connectors with a MIDI-cable. If no error has been detected, the display shows ' OK '. Otherwise,
the display shows: FAIL (no receive).
DSP-RAM TEST
Here, the delay memory gets tested. The data and address busses from the DSP to the RAMs
(IC203 and IC204 on the 80449 Digital Board) are tested in sequential order. If no error has been
detected, the display shows ' OK '. If a faulty condition has been detected, the number of the
faulty data or address bus appears on the display.
HW-CONN TEST
This test checks internal status and control lines. Special hardware is necessary to perform this
test. It is not recommended to perform this test with the appliance being a standalone
unit. Instead, always use a testing-adapter.

8
ORIGINAL THRU
Within this program, the incoming data is directly send to the outputs, without employing
additional signal processing. Output is carried out in a 2 in 2 configuration, i. e. input 1 is
assigned to the outputs 1 and 2, Input 2 is assigned to 3 and 4.
The rotary encoder lets you control the level in the range between 0 to -99 dB.
SINE WAVE OUT
This program tests the entire output signal path (DSP, D/A converters, output channels). After
starting the program, a 1 kHz sine signal is generated in the DSP, which is output to all 4
channels.
The default level setting is -24 dB. The rotary encoder lets you control the level in the range
between 0 to -99 dB.
PINK NOISE
"Pink noise" is generated in the DSP, which then is output to all 4 channels. The default level
setting is -24 dB. The rotary encoder allows controlling the level in the range between 0 and
-99 dB.
WHITE NOISE
"White noise" is generated in the DSP, which then is output to all 4 channels. The default level
setting is -24 dB. The rotary encoder allows controlling the level in the range between 0 and
-99 dB.
A/D GAIN CALIB
This program serves for calibrating the gain-ranging AD-converters. The difference in the levels
between high and low inputs at the ADC is automatically measured and stored.
For automatic calibration, a sine signal with approx. 0dBu / 1kHz has to be fed to both inputs.
Level differences are measured and displayed. Too high or too low signal levels are also
indicated on the display. CAUTION: The use of this program should be left to the
experienced and well-educated service technician. Inaccurate calibration can result in the
degradation of the dynamic range or even in erroneous functioning of the appliance.
A/D GAIN RNG 1
This program serves for precisely displaying and adjusting the level difference between the gain-
ranging A/D converter's two channels of input 1. The value is indicated in dB and in hex-code. in
the degradation of the dynamic range or even in erroneous functioning of the appliance.
CAUTION: The use of this program should be left to the experienced and well-educated
service technician. Inaccurate calibration can result in the degradation of the dynamic
range or even in erroneous functioning of the appliance.
A/D GAIN RNG 2
This program serves for precisely displaying and adjusting the level difference between the gain-
ranging A/D converter's two channels of input 2. The value is indicated in dB and in hex-code.
CAUTION: The use of this program should be left to the experienced and well-educated
service technician. Inaccurate calibration can result in the degradation of the dynamic
range or even in erroneous functioning of the appliance.
INITIALIZE MEM
This program erases all entries of the user preset memory U01 - U30 and re-sets the unit's
programming to the initial state (as shipped). The initialize function is ended with a software
reset. Upon re-start the appliance is set to the factory program F01.
CAUTION: To prevent the total loss of user-defined data, previously backing-up the
contents of the user preset memory, using the Dx 38 editor software, onto a PC or
notebook computer is strongly recommended.

9
ENCODER TYPE
This program allows setting the appliance to the employed type of encoder. Changing the
encoder type is only necessary when older models with serial numbers up to 11228 (Dx 38) are
updated to a new operating system (V1.10 or newer). When shipped, the appliance is always
correctly factory-set, matching the employed encoder type.
STATISTICS
This program provides indication of how often the appliance has been switched on (Power on
count) and its hours of operation (Opr. Time).
QUIT
This command ceases the test mode. The appliance re-starts with the program that was active
before entering test mode.
Testing The µP-System During Power-On
During switching on the unit or performing a hardware reset, the indication of the status-LEDs D101
and D102 (located on the Digital PCB 80449) lets you localize a fault in the processor system.
The following happens in sequential order during a hardware reset of the Dx 38 CPU-system:
1. Hardware Reset →D101 lights D102 lights
2. CPU Start and Initialization
o. k. →D101 dimmed D102 lights
3. Checksum Test Bootload-ROM
fault →System 'hangs'
o. k. →D101 lights D102 dimmed
4. External RAM Test
fault →System 'hangs'
o. k. →D101 dimmed D102 dimmed
5. Checksum Test Application-ROM
fault →bootloader controls LEDs and RS232
D101 blinks with non-irq-task
D102 blinks with irq-task
o. k. →application starts and controls LEDs and RS232
D101 blinks with non-irq-task
D102 blinks with irq-task

Option:
RS-485
INTERFACE
1 2
3
1 2
3
A
D
A
D
12
3
D
A
12
3
D
A
12
3
D
A
12
3
D
A
1 2
3
1 2
3
A
D
A
D
24 BIT
DIGITAL
SIGNAL PROCESSOR
DRAM
1M x 8
16 BIT
HOST
CPU
RESET
WATCHDOG
128k x 16
FLASH 32k x 8 RAM 8k x 8 EEPROM
LCD
122 x 32 DOTS
LEDs
LEVEL METER
KEYBOARD
ROTARY ENCODER
I/O SPI
SPI
AUDIO
CONTROL
UART
OUT 1
OUT 2
OUT 4
OUT 3
GAINRANGING
24 BIT ADC
GAINRANGING
24 BIT ADC
IN 1 LEFT
/ MONO
IN 2
RIGHT
INPUT 1
INPUT 2
OUTPUT 1
OUTPUT 2
OUTPUT 3
OUTPUT 4
LPF
LPF
LPF
LPF
DUAL
24 BIT DAC
DUAL
24 BIT DAC
OUTTHRUIN MIDI
CLOCK
48 kHz
AC
DC
90 - 250V ac
50-60Hz 30W
+18V
-18V
+5V
Option:
CONTACT
CLOSURE PORT
RS-232
PC INTERFACE