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3  Specifications 

 
 
 
 

Type 

D750 – The Little Brick 

Description 

Tube input bass amplifier 

Mains voltage 

230 VAC 50 Hz 

Mains connecting device 

Standard mains cord 

Inrush current limiter 

NTC 

Power consumption 

Max. 900 W 

Output power 
/100Hz continuous sine/ 

750W @ 2.66 Ohm 
550W @ 4 Ohm 
300W @ 8 Ohm 

Minimal load impedance 

2.66 Ohm 

Bandwidth -+3dB@1W 

25 Hz – 22 kHz 

Power amplifier 

Class D 

Speaker output connectors 

Neutrik Speakon – Jack combo 
NLJ2MD-H 

Input 1 connector (front panel) 

Neutrik 6.3 mm Jack 
NMJ4HFD2 

Input 2 connector (back panel) 

Neutrik 6.3 mm Jack 
NMJ6HFD2 

Input impedance 

Input 1: 1 Mohm 
Input 1 (with -12dB pad): 48 kohm 
Input 2: 57 kohm 

Preamplifier tube (1 pc) 

6N2P-EV (6

Η

2

Π−ΕΒ

Line out 

500 mVp @ 600 Ohm 

Working temperature range 

0 – 40 °C 

Storage temperature range 

-25 – 60 °C 

Cooling 

Fixed  speed  ventilator  based  on  heatsink 
temperature 

Weight 

2.2 kg 

Dimensions 

Width: 251 mm 
Depth: 205 mm, + 15 mm knob 
Height: 60 mm, + 5 mm foot 

 

Summary of Contents for D750 The Little Brick

Page 1: ...PROLUDE AMPLIFICATION D750 User s manual for the tube preamplifier version ...

Page 2: ...1 2 ...

Page 3: ...IC PRECAUTIONS 2 5 2 2 WARNINGS USED ON THE AMP 2 5 2 3 GROUNDING INSTRUCTIONS 2 5 2 4 CE MARK FOR EUROPEAN HARMONIZED STANDARDS 2 5 3 SPECIFICATIONS 3 6 4 INFORMATION FOR INSTALLING 4 7 5 CONTROLS AND FUNCTIONS 5 8 5 1 THE FRONT PANEL 5 8 5 2 REAR PANEL 5 10 5 3 BLOCK DIAGRAM 5 11 5 4 OTHER FUNCTIONS PROTECTIONS 5 11 6 MAINTENANCE CLEANING 6 11 ...

Page 4: ... role within the music have all contributed to my enthusiasm To start with my studies and my sphere of interest have both moved me to the direction of electronics As a result PROLUDE AMPLIFICATION was born at the beginning of the new millennium My goal is to provide bass players with the best possible sound quality Being an electrical engineer I m doing it mainly with a technical mindset However a...

Page 5: ...l servicing should be referred to qualified service personnel 11 For continued protection against the risk of fire replace fuses only with those of the same type and rating 2 2 Warnings used on the amp The lightning flash with the arrow head symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated dangerous voltage within this product s enclosure that may ...

Page 6: ...r amplifier Class D Speaker output connectors Neutrik Speakon Jack combo NLJ2MD H Input 1 connector front panel Neutrik 6 3 mm Jack NMJ4HFD2 Input 2 connector back panel Neutrik 6 3 mm Jack NMJ6HFD2 Input impedance Input 1 1 Mohm Input 1 with 12dB pad 48 kohm Input 2 57 kohm Preamplifier tube 1 pc 6N2P EV 6Η2Π ΕΒ Line out 500 mVp 600 Ohm Working temperature range 0 40 C Storage temperature range 2...

Page 7: ...er cabinets Use high quality Neutrik SPEAKON SPEAKON speaker cable with at least 2 x 1 5 mm 2 or more cross section They are reliable robust and have less influence on the sound Use a speaker cable in good condition and connect the speaker cabinet to the amplifier before you switch on the amplifier Try to minimize the number of power strips used to connect the amplifier to the mains Use high quali...

Page 8: ...clock position This setting gives you the most linear transmission of your instrument s sound 5 1 4 Volume Controls the overall volume of the Speaker Outputs The DI Out is not affected by this knob 5 1 5 Mute Mutes the Speaker Outputs and the DI Out If the button is pressed the Mute LED is red Note This Mute LED gives you additional information too see below 5 1 6 DI Out Balanced DI Out with Neutr...

Page 9: ...Lights green when the amplifier is switched on Lights red during the ventilator test when the power stage is overheated or short circuit on Speaker Outputs Lights green but flashing red power section is reached its maximum level the limiter is active ...

Page 10: ...s and Treble controls 5 2 3 Speaker Outputs Neutrik Speakon Jack combo outlets They are connected parallel inside the amplifier Both of speakon or 6 3mm jack plugs are suitable to connect speaker cabinets The minimum load impedance should not be less than 2 66 ohm Note The speakon connector is a more stable robust and reliable solution Use this if you have one instead of jack Avoid long speaker ca...

Page 11: ... high speed when the temperature reaches 50 C and switches itself back to low speed when temperature decrease below 40 C Do not cover the ventilation cutouts 6 Maintenance cleaning The amplifier has no need for particular maintenance Occasionally check the starting of the ventilator when you switch on the amplifier The preamplifier tube is a long life type probably you will never have to replace i...

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