Quad SPST Analog Switch

[RCruz]

Hi All

I have been modding my meridian 101b and found a DG308CJ on the output stage of this preamp.

It sits near the output opamp but I can not understand what it is for.

Also would like any opinion about the three 10uF16v caps in the pcb... decouplers ?

I can not find any output caps and this module has balanced output wiring. (Does this obviate the output caps ?)

Sorry for the poor quality pic

Ricardo

 

[RCruz]

Another pic with the pcb in place... with the new LM4562.... big difference 😉

 

[RCruz]

Should I replave the 10uF16v el caps by some 33uF BG N ?

 

[RCruz]

Should I replave the 10uF16v el caps by some 33uF BG N ?

I replaced the caps but there was no improvement on the sound.... Just noticed a bigger turn on time lag (now 2 secs). I believe the caps are used to turn the switch on during power on.

I can not imagine why this switch is after the opamp outputs.

As I am now using a LM4562, maybe I could short the DG308 2/3 and 6/7 pins.

Hope someone has any idea.

Regards

Ricardo

 

[Jan Dupont]

The DG308 is used as an output relay with delayed turn on to prevent "plops" in your speaker.

You can find the datasheet here;
http://pdf1.alldatasheet.com/datasheet-pdf/view/72689/MAXIM/DG308.html

 

[RCruz]

The DG308 is used as an output relay with delayed turn on to prevent "plops" in your speaker.

By reading the datasheet, I understand that the Drain / Source resistance and capacitance may vary depending on input voltage.

I do not like this is my signal path....

how should I disable the switch ?

Short legs 2 3 14 15 and 6 7 10 11 ?

Can you sort what are the electrolityc caps for ?

I just replaced them for HiQ caps (what a waste) and the only difference was a longer turn on time lag.

I apreciate your input... 🙂

Regards

Ricardo

 

[darian]

Teh caps are there to set the turn on delay. Just shortcut this chip, from D to S, no need for desoldering I think.

 

[RCruz]

Thank you indeed !

I will short D and S legs and report latter.

Ricardo