• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Click here to find out how to win free radios from Retevis!

D104 preamp/compressor board install

Hawkeye351

Well-Known Member
Jun 27, 2021
569
477
73
57
Got a friend wanting me to install this D104 Pre-Amp plus compressor board into his D104.

The D104 has the factory amp board in it, and I had to unsolder that board to install this board in it's place. The mic is of the TUP design.

Here is the wire colors:

Green
Yellow
Red battery
Black battery
White
Black
Brown
Violet

D-104 with both PTT's.

Now I know where the red battery and black battery wires go, along with the yellow and green input wires, as well as the white output wire, and of course the black ground wire.

The 2 I'm confused about is the brown and violet.

The instructions aren't very helpful. The board has the following solder pads marked as:

+ - battery positive
G - battery negative

Out - audio out
G - audio ground
S - shield

Input + - audio positive input
Input - - audio negative input

Shdn - shutdown
(This is the wire that shuts down the current draw from the board when it's not in use, keyed up).

This is how I have it wired up:

Wiring:
Green to J1 square pad
Yellow to J1 round pad
Red battery to + pad
Black battery to G pad
White to out pad
Black to S pad
Brown to G pad
Violet to SHDN pad

Do those wirings sound right?
Oh, and should the black wire (not for the battery) go to the shield pad marked S, which is for the shield or the G pad?

Here are pics of the original amp board I pulled, and of the new board wired in, but haven't applied power to it yet until I'm sure my wiring is right. Also a YouTube video of the exact same board by the designer testing it out.

IMG_20240315_181354165_HDR.jpg

IMG_20240315_181333487_HDR.jpg


 
Last edited:
  • Like
Reactions: Enterprise312ok

Got it wired right.
Hooked it up to my dx959 and sounds pretty good with a 1:1 setting. There's 3 settings.
1:1 (local rag chew and periodic skip)
2:1 (heavy skip and DX conditions)
10:1 (extreme DX conditions)

You can even wire a spst switch in to one of the above settings pad to switch between standard amplified mic and compressor operated mic.
 
one thing you might want to make sure of is that the negative lead of the battery is only connected to ground when the mic is keyed.
other than that it sounds like you've got it nailed.
LC
 

dxChat
Help Users
  • No one is chatting at the moment.