Revox B77 ( PR99) boards upgrade project

Record and Reproduce amplifier board design

record board wave form test 

                                               new reproduce board 

new record board

 

 

-------------------------------- ---------------------------------

I also upgraded many parts in other boards such as

 

1. All electrolytic capacitors are upgraded to Panasonic Organic Polymer Capacitor (OSC).

 

2. All brittle nude trimmers were upgraded with sealed gold plated Copal (Japan) trimmers or other good sealed trimmers such as Bouns .

 

3. Tantalum capacitors in signal path are upgraded with German Wima Film capacitors.

 

upgraded input amplifier 

upgraded monitor amplifier board

OP Amps are upgraded to NE5534 

upgraded 150Khz bias frequncy osillator board

Tape drive control boad before and after upgrade

 capstan motor drive board before and after upgrade

 

fully upgraded IN/OUT pannel ( ext.EQ balance out put is directly connecteted to reproduce head )

 

tube type external tape head amp with seperate power supply (  ECC83 : 3,  6X4 :1 ) .

 

 all finished revox B77 and PR99

 

any inquiry  mail to pcaudio@hanmail.net