panasonic lm4780

[karma]

basically this digital panasonic Receiver had a dead digital amp
so i removed the old amp and replaced it with the lm4780.

yes its commercial and a total wast of time but it worked and it sound Really Good

first chipamp i have built that has optical in and out and all the other toys

theres more pics on my webpage.


cheers

[karma]

[john65b]

Wasn't the panny a digital amp? The LM4780 is analog...how did you get the amp to work - unless you were dealing with the analog input from the panny to the LM4780...or input to LM4780 post panny DAC (at speaker outputs)?? You mention utilizing the digital input on the panny through the LM4780...

Was there a dual voltage (+/- 25 - 35V) in the panny, or did you have a separate power supply outside of the panny to power the LM4780?

I would be very interested is seeing how you completed this...your website has a few pics but need a bit moire clarification...

Maybe the panny digital amp is not digital PWM after all and its all analog??

[karma]

the Receivers headphone amp and power amp are not together.
so the headphones still worked so what i did was run the lm4780
off the headphone amp in the inside.

i ended up using another transformer for the lm4780 the power
supply in the amp is a steping power supply. so there was no work around.

what i used was a 24v=24v hand wound transformer.and by luck
there was room for it.

i watched Batman Begins last nite with the optical in. what a
Difference from analog. the lm4780 sounds way better with all digital
up to the amp.

when i get a chance ill update the webpage with better info



cheers

[john65b]

Oh, I got it...is the output from the headphone amp section to ther LM4780 around 2 volts?

Is there a separate DAC on the headphone amp section, or is it the main DAC on the panny preamp section?

Your toroidal tranny sits on top of the power supply board section? Can you post a few pics of that too?

This is interesting...

[karma]

to hold the transformer in place i drilled a hole in the pcb plus the bottom of the unit to hold it down. being carefull not to over tighten and crack the pcb.


the headphone jack needs to be used or the unit comes up with a error code when it trys to swich to surround mode and it turns off. f10 i think.

here is a pic to show where everthing is.

the dac and preamp is on one pcb it pulls off the mainboard.

it only takes 3 screws to remove the chipamp from the rest of the unit if i ever need to work on it.


i had to remove a few parts ics to fool the unit into thinking everthing is good with the amp or it would come up with errors

the headphone jack is around 2volts hard to tell my bel merit has issues.

cheers

[john65b]

Cool! How did you wire up the outputs? Directly to the 5 way binding posts?

[karma]

yes when i remove the parts from the old amp i use the old output
wires that are already there. i just remove the surround sound
wires and posts.

[Tube_Dude]

Originally posted by karma
i just remove the surround sound
wires and posts.

Hi Karma

I do the same thing...great minds think alike.

Look at:


http://www.diyaudio.com/forums/showt...080#post114080

Cheers

[karma]

i never was a big fan of surround sound