Hello this is a Thread for build help MP-99 microphone mic pre by General Audio Research
Microphone preamplifier inspired by superior performance jensen 990 opamp & john hardy schematic
Features
-GAIN +50db very clean & distortionless
-Électronique solid state mic pre
-Lundahl in & out transformer superior performance
-990 DAO superior sonic performance
-high-performance discrete op-amps laid out directly on the main circuit board.
-Elimination of all coupling capacitors from the signal path
-Easy to build
-Easy to upgrade : tone , pad , Tpad volume
+/-24VDC requirements
Build guide :
Step 1 : mp99 pcb
Step 2 : place resistors on pcb
R: 10k
R: 200r
R: 6k8
R: 3k92
Step 3 : place condensator
C: 100pf
C: 680pf
C: 1000uF
Step 4 : AOP 2520 compatible
this preamp are specialy selectioned for AOP 990 (run with +24 & -24 vdc )
Step 5 : Transformer and OPA mounting on pcb
mp99 use high-performance lundhall transformer
1:2 ratio input ll1527
1:1 ratio output 1517
this preamp Gives the possibility of adding multiples option if you are motivated
- pad
- switch polarity
- output 600 t pad
i recommande output psu symetrical
this preamp are sensitive with transformer radiation .
sam.
Microphone preamplifier inspired by superior performance jensen 990 opamp & john hardy schematic
Features
-GAIN +50db very clean & distortionless
-Électronique solid state mic pre
-Lundahl in & out transformer superior performance
-990 DAO superior sonic performance
-high-performance discrete op-amps laid out directly on the main circuit board.
-Elimination of all coupling capacitors from the signal path
-Easy to build
-Easy to upgrade : tone , pad , Tpad volume
+/-24VDC requirements
Build guide :
Step 1 : mp99 pcb
Step 2 : place resistors on pcb
R: 10k
R: 200r
R: 6k8
R: 3k92
Step 3 : place condensator
C: 100pf
C: 680pf
C: 1000uF
Step 4 : AOP 2520 compatible
this preamp are specialy selectioned for AOP 990 (run with +24 & -24 vdc )
Step 5 : Transformer and OPA mounting on pcb
mp99 use high-performance lundhall transformer
1:2 ratio input ll1527
1:1 ratio output 1517
this preamp Gives the possibility of adding multiples option if you are motivated
- pad
- switch polarity
- output 600 t pad
i recommande output psu symetrical
this preamp are sensitive with transformer radiation .
sam.