icon Audio MB 845 MK 2 Instruction Manual Download Page 1

*See engineers notes at rear

 

 

 

Page 1 

icon Audio 

 

Instruction Manual Covering: 

 

MB 845 MK 2 Super Amplifier 

                                              

 

Shown with upgraded driver valves 

Contents 

 

1 Introduction & Final Inspection 

 

2 Quick Set Up Guide 

 

3 Connecting inputs & outputs 

 

4 Getting the best performance 

 

5 Trouble Shooting 

 

6 Bias Adjustment 

 

7 Valve Replacement  

 

8 Specifications 

 

9 Guarantee 

 

10 Packing Instructions 

 

1 Introduction 

 

Thank  you  for  purchasing  the 

MB 845 

MK II

.  These  pure  valve  mono  block 

amplifiers  are  the  result  of  years  of  careful  design 
and  listening  tests  with  a  wide  range  of  speakers. 
The amplifiers are hand built using carefully selected 
audiophile  components.  The  transformers  are  hand 
wound  using  low  oxygen  copper  and  special 
Japanese  long  grain  iron.  Finally  each  amplifier  is 
valved,  carefully  commissioned  and  tweaked  for 
best performance in Leicester UK.

 

In order to get the best out of your amplifier, please 
read  the  “SET  UP”  notes.  These  contain  important 
information  about  the  correct  operation  and  safety. 
Should  you  be  uncertain  about  anything  please 
contact your dealer or one of our team. 
Valve amplifiers do need a little more attention than 
their  solid-state  counterparts,  but  the  sonic  results 
are  well  worth  it.  In  this  manual  we  have  tried  to 
include everything that you need to know. Please let 

us know  if  you  find  any  errors  or  feel  that  we have 
missed anything out. 
The 

MB 845 

are  push-pull  all  triode  power 

amplifiers using the fabulous 845 high power triode 
valves.  These  have  very  special  characteristics 
which  many  people  consider  give  the  finest 
reproduction  of  any  valves.  Similar  to  the  300B  but 
with more power and punch. These are in fixed-bias 
mode  which  gives  maximum  power,  cool  running 
and  low  distortion.  You  MUST  occasionally  check 
the bias (at least twice a year). The driver and phase 
splitting  are  also  triode  for  best  sound  quality  and 
low noise. The MB 845s are sensitive enough to be 
used  with  any  pre-amplifier  or  passive  in  most 
situations.    .  Their  simplicity  coupled  with  point  to 
point  hand  wiring  without  the  use  of  printed  circuit 
boards  results  in  an  open  euphoric  sound  that  is 
wonderfully detailed and warm.  

          IMPORTANT! 
THIS MANUAL CONTAINS 
ESSENTIAL HEALTH & 
SAFETY INFORMATION FOR 
YOU AND YOUR AMPLIFIER. 
PLEASE READ & KEEP SAFE 
AND REFER TO IF NECESSARY 

Summary of Contents for MB 845 MK 2

Page 1: ...ase contact your dealer or one of our team Valve amplifiers do need a little more attention than their solid state counterparts but the sonic results are well worth it In this manual we have tried to...

Page 2: ...N A Run min 6 hour test Check input Output Valve Bias level v Sound Quality Channel Balance Valve Microphony Valve Seating Hum level L R mv RF Test LED brightness Serial No sticker and recorded Mains...

Page 3: ...rear Page 3 MB845 MK II Layout and Features If you are inserting the 845 valve for the first time it may be helpful to observe the slot in the valve base to indicate the degree of rotation needed to...

Page 4: ...way Brown to Live terminal Blue to Neutral terminal and Green Yellow to Earth terminal 6 SWITCH ON The blue mains indicator should light up The 845s will glow bright yellow You will likely hear a humm...

Page 5: ...Connect the system up and play some music with plenty of bass e g dance music preferably in mono FM tuners are usually switchable to mono and stand the speakers close together If correct you should he...

Page 6: ...ping things around to eliminate or prove which component if the problem Left or right amplifier If both probably the source unit Try another source If one amplifier is distorted check the bias No bias...

Page 7: ...e in the exposed hole And the other in the test socket adjacent to the valve on test Set the Icon meter to 2000mv or the black mark See pics Making the earth connection 3 Checking Bias You should get...

Page 8: ...the procedure If changing all the 845s be ready to adjust the bias in order not to overload the power supply Don t worry how low the reading goes this will not cause damage Do final adjustment when th...

Page 9: ...ed for normal domestic hi fi use It is not guaranteed for commercial Public Address use or use in other situations The guarantee becomes void if the unit has been modified in any way not approved by I...

Page 10: ...transformer will be useful to operate the amplifier on reduced power in order the trace the fault or overload Make sure the bias for the 845s is correct If the AC fuse is blowing with the HT fuse disc...

Reviews: