sony str-dh770

[Numba132505]

Has anyone been able to add preamp outputs to this unit?

 

[PianotunerNJ]

I have Sony DN1050 and I use HDMI for everything, except my turntable. Any analog input works fine and the label for the input can be customized to reflect what’s there. I use a parasound pre, works beautifully. I think I use the stereo CD input.

 

[Radio73]

Has anyone been able to add preamp outputs to this unit?

I don't have the 770, but someone gave me its little brother, a 550 with bad HDMI and USB boards. I could not stand the sound that came out of it and threw it in a closet. Pulled it out the other day and was going to strip it for parts when I came up with the same idea!!
I got a schematic, (550 and 770 use same) determined where the signal enters the amp at the Front Left and Right, then hacked it up and made a FrankenAmp out of it.
The first capacitor after the DIR chip for Front Left is C610 and C660 for the Front Right. They are both 10uF@50V.
Desolder or clip the Negative lead of the caps and attach your wires to that lead and the spot on the board where it went and voila! PreAmp Out and MainAmp In are now yours!

 

[Radio73]

And yeah, it sounds FANTASTIC now with an EQ.

 

[Numba132505]

@Radio73 Do your remember where you got the wiring diagram?

 

[Radio73]

I think I got it from here. I just checked this one and the block diagrams and schematics are in it.
https://www.electronica-pt.com/esquema/audio/sony-audio/sony-str-dh550-str-dh750-32298/
Just scroll down under the picture of the cover and hit the Download button and it will open in Drive viewer or Adobe or can just download it to the computer.

 

[Radio73]

Here's some pics of how I butchered it. First an overall photo of what went where. Notice I just clipped the legs of the capacitor and soldered my wire straight to it and the spot left on top of the board. That way you wont have to pull the whole board out to do it.


Here's the jacks I ran them to. I dont use these input jacks for anything so I just whacked them off at the board and soldered my wire to what was left. Yes, I know I should have used some shielded wire but this was just a test to see if it could be done.


Here's as best of a closeup of the capacitors that got snipped. Yeah its crude. But its Franken-Amp so I didn't care. And since it was free and the HDMI board and the USB input were both toast, I really didnt care. LOL!