Marantz CD63 & CD67 mods list

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#4,641
Thanks Ray, yeah I wasn't sure where the DC was coming from in your circuit, that's all.

I got excellent results in my Denon tuner by replacing the op-amp (G=1) buffer with 2xBUF634 in TO-220 package.... but it was a terrible op-amp (a JRC part but below 2114 spec) and originally had NO decoupling within about 6 inches of it. My gran could have designed it better.
 
#4,643
6h5c said:

Be aware that the 15mV offset figure only indicates the offset generated by the device itself. For example if you offer 1,000V DC at the input you'll get 1,015V at the output 😀. You still have to get rid of the DC offset generated by the DAC.

Regards,

Ray
Click to expand...

Now that would be cool!!!

Who wants to try first......and who will take the pics of the smoke hehe

Ad I bet you could muster that one up

LOL

Brent
 
#4,644
Malefoda said:
Hi there, I've noticed that the HPhones outlet is too loud, any idea to low the volume there? Change some resisitor to higher values? I've 1% res left from the list, maybe I can use one, and many from the 2 changed at the RCA (big ones from Ray's Bible).
Click to expand...


Change the ratio of the resistors on the input of the op amp

Not got the manual in front of me but if i remember correctly the opamps after the dac use 27K and 10K giving an amplification (gain) of X2.7
So look at the phones op amp and change accordingly

Brent
 
#4,646
Hi Guys,

I just finished the installing of BG capacitors and on my headphone it is already a better sound.

Here a photo of the audio output part.

Cant wait to listen on the audioinstallation downstars but i have to wait until tommorow the rest of the family is already to bed:bawling:

Next mod will be the regulator for DAC analog supply, and see what this wil bring.

I never knew that my speakers had so much more to give!😱 😀

Peter
 
#4,649
Peter - what are those filter caps?

I used LCR film and foil polystyrenes but I wonder if there are better options.

What did others use? I've seen mica used in some people's machines and am intrigued. I imagine the choice has a big influence on the sound.
 
#4,650
6h5c said:
Be aware that the 15mV offset figure only indicates the offset generated by the device itself. For example if you offer 1,000V DC at the input you'll get 1,015V at the output 😀. You still have to get rid of the DC offset generated by the DAC.
Click to expand...

rowemeister said:
Now that would be cool!!!

Who wants to try first......and who will take the pics of the smoke hehe

Ad I bet you could muster that one up

LOL

Brent
Click to expand...

I guess for you British guys I should write 1.000V, to put things in perspective 😀.

Ray
 
#4,651
Hi Glenn,

I ordered them from Conrad electronics and they are 1% polypropylene BC capacitors sounding wonderfull.

Im just looking in the harsh sound i got from giving the analog part off the DAC its own 5V regulator:bawling:

I think i need to put another 0,22 uF capacitor bypassing the 100uF i used on the output pin.

Peter
 
#4,654
AndrewT said:
Hi,
now, if you had written 1kV then all would be clear, or did you mean 0.001kV?
Click to expand...

That's another way to put it, 0.001000kV and 0.001015kV 😀
I meant just 1V + 15mV...

Peter Venema said:
Ray,

If im can remember a earlier post it said you never bypass a BG!
Is this correct?

I'm getting a trebble with a harsch attitude and is this because i left in place CD12 and 13 after replacing CD15 and 16 by BG 470uF/16V?

Peter
Click to expand...

Hi Peter,

It SHOULD not be needed to bypass a BG, because they claim that it's low ESR runs all the way up to the MHz region. It's possible some nasty ringing occurs when you do bypass them. But BG's also need some decent run-in time to be able to judge their sound properly. When I first put them in my tubeamp they sounded harsh and horrible too, so give them some time. I doubt a small 47n ceramic is responsible for this harshness, but with a few snips from the cutters you'll know for sure 😀.

Regards,

Ray
 
#4,655
Peter Venema said:
Ray,

If im can remember a earlier post it said you never bypass a BG!
Is this correct?

I'm getting a trebble with a harsch attitude and is this because i left in place CD12 and 13 after replacing CD15 and 16 by BG 470uF/16V?

Peter
Click to expand...

Hi Peter,

BG is most definately not why it sounds harsh. I just replaced all the important decoupling caps with BG 470 and 330uF, and the sound became less harsh. It is unbelievably good now, and even tough discs like Dark Side of the Moon are controlled and have a minimum of harshness.

I only removed one ceramic cap (near decoder I think) and I replaced it with BG 10uF.

You have probably exposed a problem elsewhere, or you just need some hours of settling to let it sing.

Simon
 
#4,656
Ray,

I Solder them out and put a 0.22uF film across the output of the new 7805 regulator and see whats "hearing"😀

The new regulator gave me a more relaxed and detailed sound except from the harshness, so i could be happy with the overall sound but have experiment al little and give the BG's some time to

Thanks again Ray,

Peter
 
#4,657
Peter Venema said:

Im just looking in the harsh sound i got from giving the analog part off the DAC its own 5V regulator:bawling:

I think i need to put another 0,22 uF capacitor bypassing the 100uF i used on the output pin.

Peter
Click to expand...


Hi Peter - where are you getting the feed for this regulator? Is it the same as the digital feeds (i.e., not the +12v analogue)?

Glenn
 
#4,660
Peter Venema said:
Is your project ever going to give you the time to let things burn in?😉 the changes are rapidly taking place.

Peter
Click to expand...

Yes, it'll have some days to burn in and let me get used to it. Then more power supplies and another transformer. And I need to give my preamp some attention, and speakers, and do a new power amp. It's never ending. But I am very happy for now!

Simon
 
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