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6—11 

5.3  Block diagram 

 

 

5.4  Other functions, protections 

5.4.1  Short circuit protection 

The amplifier contains a protection circuit against wrong / shorted / speaker cable or burnt speakers. 

5.4.2  Speaker protection 

Protecting the cabinets from harmful direct current. 

5.4.3  Overheat protection 

Due  to  insufficient  ventilation,  ventilator  fault  or  too  high  environment  temperature  while  playing  at  high 
volume,  overheating  may  occur.  In  such  a  case  the  protection  circuit  stops  the  power  section  until  the 
temperature of the power stage cools down. This is being displayed by the Mute LED. 

5.4.4  Ventilator control 

The  control  of  the  cooling  ventilator  is  based  on  the  temperature  of  the  power  stage’s  heat  sink.  It 
automatically switches itself to 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  it  because  of  aging. 
However, if  you feel  you are losing sound quality  you  can easily check it by using the Input  2 on  the  back. 
Replacing tubes must be done by a qualified person. Only replace by using tubes of the same type. 
 
Use only soft and dry or dampened cloth for cleaning. Avoid aggressive, caustic cleaning materials. 
 
 
 

 

Budapest, 2017.08.23.

 

Tube 

preamp 

 

6N2P-EV 

Mixer 

Speaker 

Prot. 

Volume 

Control 

Power 

Amp. 

Line 

Buffer 

Fan 

Control 

Input 1 

Input 2 

Volume 

Gnd Lift 

DI Out 

Overheat 

Sense 

Speaker 

Outputs 

-12dB, Bass, Treble 

Aux input 

stage 

Limiter 

Содержание D750 The Little Brick

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

Страница 2: ...1 2 ...

Страница 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 ...

Страница 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...

Страница 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 ...

Страница 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...

Страница 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...

Страница 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...

Страница 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 ...

Страница 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...

Страница 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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