Replace MN3002 with MN3004

Started by ebuprofen, July 22, 2017, 01:46:10 PM

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ebuprofen

Hey, everybody!

I have this problem, to make Roland amps chorus a bit quieter, I have decided to put MN3004 BBD instead of MN3002 and when the chip arrived  I checked the datasheets and saw, that they have different pinout :X stupid me
Can someone guide me? how should I rewire MN3004 so it would work properly? For now I have no effect in chorus or vibrato mode, only clean sound.


Scruffie

The pinouts are identical except for pin 1 of the 3004 goes to ground and pin 7 should be unconnected.

The 3004 also has far less insertion loss so you'll need to adjust the output mix.

ebuprofen

tried it and no effect in chorus or vibrato mode, but dry signal is there (in either mode)

Fender3D

#3
It has BBD's fixed bias.
you'd better put a trimmer instead of R363 and R366

edit:

BTW
I don't know where you got MN3004, are you sure it works?
"NOT FLAMMABLE" is not a challenge

ebuprofen

with those standard resistors I had about -4v on the pin3 of mn3004, datasheet says -5v to -10v, tried at -7.6v - nothing, tried by ear, nothing.
bought new mn3004 from china, so maybe it is faulty already.
the NC pins of mn3004 are mostly connected to -15v, but as they are NC, so should bother me, right?