Electro-Voice DX-38 Service manual

SERVICE MANUAL

Dx 38

24 BIT DIGITAL SOUND SYSTEM PROCESSOR

WARRANTY (Limited)

Electro-Voice products are guaranteed against malfunction due to defects in materials or workmanship for a specified
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 from state
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]
EVI Audio France S.A., Parc de Courcerin-Allee Lech Walesa, Lognes, f-77185 Marne La Vallee, 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 [e-mail]

IMPORTANT SAFETY INSTRUCTIONS

The lightning flash with arrowhead symbol, within an equi­lateral 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.

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.

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. 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)

1-2

BESCHREIBUNG

Mit 48 Bit Filteralgorithmen, 24 Bit AD/DA Wandlern und einem Dyna­mikbereich 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 Ste­reo bzw. Dual 2-Weg-Systeme oder 3-Weg+Direct und 4-Weg Syste­me, jeweils auch mit Mono Sub-Kanal, aber auch Fullrange Systeme
konfiguriert werden.
In allen Betriebsarten stehen Hoch- und Tiefpaß-Filter für die Frequen­zweichen-Funktionen zur Verfügung. Die Auswahl umfaßt Linkwitz­Riley, 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 Ein­gängen finden Sie jeweils einen 5-Band Equalizer, dessen einzelne
Filtersektionen beliebig mit High- und Low-Pass, High- und Low-Shel­ving 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 Filtermöglichkei­ten sind z. B. Hochpässe 2. Ordnung zur Realisierung von B-6 Align­ments, oder spezielle LPN-Filter (Lowpass Notch / Tiefpaß-Sperrfilter)
zur Korrektur des Frequenz- und Phasengangs von Baßreflexboxen.
Zusätzlich ist jeder Kanal mit einem Delay, einem Polaritätswahlschal­ter, einem programmierbaren Pegelsteller und einem digitalen Kom­pressor / Limiter ausgestattet. In den Eingängen befinden sich
außerdem noch die Master-Delays.
Der Anwender hat die Wahl zwischen zwei Bedien-Modi: Im einfach­sten Fall (No Edit Mode) brauchen nur die verwendeten Lautsprecher­kombinationen aus der Liste der Factory Preset Programme aus­gewählt 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 Einstellun­gen programmiert und gespeichert werden können. Es stehen insge­samt 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,
wobei es sich in der AD-Sektion um gainranging Sigma-Delta-Wandler
mit 128-fachem Oversampling handelt. Im DA-Bereich wird mit Sigma­Delta Wandlern mit 128-fachem Oversampling gearbeitet. Die Signal­verarbeitung erfolgt auf zwei 24 Bit Motorola Signalprozessoren.

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, Kanal­Funktionsanzeigen SUB, LO, MID, HI

- Input / Output Aussteueranzeigen, Kompressor- und Clip-LED’s

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-Ri­ley, Butterworth and Bessel type filters with switchable slopes between
6, 12, 18 and 24 dB/oct. A huge number of additional filters offers
extremely flexible correction of the frequency response. Each input
incorporates a 5-band equalizer, allowing to assign high 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 frequen­cy and phase responses of optimally vented woofer cabinets. Each
channel additionally provides a delay, a polarity switch, a program­mable 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 simply select the required combination of loudspeaker
systems from the factory preset program list. 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.

Within the Dx 38, AD/DA conversion is taken care of by linear 24-bit

90 - 250 V AC / 50 - 60 Hz

converters; where the AD-section employs 128 times oversampling,
gain-ranging Sigma-Delta converters. The DA-section offers 128 times
oversampling Sigma-Delta converters. The overall signal processing
is performed by two 24-bit Motorola signal processors.

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

DESCRIPTION

Avec ses algorithmes de filtrage travaillant en 48 bits, ses convert­isseurs 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
processeurs numériques de haut-parleurs. Le Dx 38 est un processeur
numérique de diffusion universel ; il est pourvu de 2 entrées et 4 sorties,
un circuit interne permettant de sommer les entrées 1 et 2. Une matrice
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 confi­gurations 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”.
Dans tous les modes de fonctionnement, ce sont des filtres passe-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 peu­vent 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 permet­tant 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’encein­tes de graves travaillant en bass-reflex.
Chaque canal offre en plus un délai, un inverseur de phase, un réglage
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 Program­mes. 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 traite­ments du signal sont calculés par deux DSP Motorola 24 bits.

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
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

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

1

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 90244 5.2 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

2

13.2 Comments about measurements

04/09/99 12:28:14

Frequency response

- 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]

3

Figure 2 THD+N [%] as a function of the input level [dBu] [4] , f = 1 kHz

04/19/99 17:01:22

THD+N vs Level

04/20/99 08:53:11

THD+N vs Frequency

04/20/99 11:46:46

THD+N vs Frequency

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

4

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

5

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.

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