Marantz CD63 & CD67 mods list

[martin clark]

that's a good point (and one of the reasons I hat eelcos too!).
Combining large caps can indeed lead to some very odd effects, too, often you can clearly see on a scope two overlapping rates in the settling 'tail' after a step change in voltage. No wonder it sounds odd.

Yes big caps can give 'big' bass; they can also give you very, very wrong bass too, unless you are lucky or willing to work through a lot of permutations!

[jnewbold]

Hi Martin,

Thanks for your reply.

It's a fair concern unless you have more than ~0.2ohnms between the reg output an d the coscon in the form of PCB track ressitance; if you have a 'scope it would be worth looking at

Don't have a scope but my multimeter indicates that the track resistance is lower that 0.2ohms.

There's a very easy wrok-around though - just add acheap electrolytic of at least the same (total) capacitance value at the regulator.

OK. I can do that.

On the other hand, would I need to use this "work around" if I used Black Gate or Rubycon ZL caps in this position. I understand that their ESR is not so low as the Os-Con.

On the analog op amps I have put the rayrags very close to the chips and bypassed with 220uF Silmic II. This seems to work well - obviously the Silmic II are not very low ESR.

Thanks again for your advice,

Joe

[poynton]

Over 11000 posts.........

What did you start, Ray ?????



Andy

[6h5c]

I didn't even notice it was another thousand...

I guess it's becoming a normal thing...

Ray

[jnewbold]

Hi Martin,

afterthought - here's a bit more I wrote on the how& why low-esr caps can cause a problem: http://www.acoustica.org.uk/t/3pin_reg_notes3.html

I have read the article and it was most helpful. In regard to my previous question about 220uF Os-cons, I now see the issue. They work fine when there is a long track from the reg to the chip, but when the track is very short the resistance is lowered band the Os-cons becomes a liability, I am now quite happy to remove them and replace with a more suitable cap for this job. Perhaps a 47uF or even 100uF Black Gate STD or Rubycon ZL.

I also note Brent's comments about potential issues with two large caps at the output.

In the schematic for the discrete output stage on Ray's website, the 7812/7912 regs are followed by a 100uF Black Gate. This looks like the same arrangement I have, but with LM317 based rayreg, so can I presume that 100uF BG or Rubycon ZL will be OK for my application?

Just a note that Black Gates are hard to get in Australia and even more expensive when ordering from OS,now that the AU$ has taken a 30% nose dive. However, RS components up the road from me stock Rubycon ZL in several values.)

Thanks,

Joe

[sherphing]

i just buy a used unit marantz cd67se, is fully in stock condition without any modification... i heard from this someone can do same modify to improve the sound quality...i saw from this thread regarding disable the HDAM can improve the sound...so mine is in stock condition, can i just disable it without doing other modify to improve the sound? how to disable it?....pls help me

[RCruz]

Originally posted by sherphing
i just buy a used unit marantz cd67se, is fully in stock condition without any modification... i heard from this someone can do same modify to improve the sound quality...i saw from this thread regarding disable the HDAM can improve the sound...so mine is in stock condition, can i just disable it without doing other modify to improve the sound? how to disable it?....pls help me

Hi

Just go to the first post and follow Ray´s indications.

IMO if you disable the HDAM, you should upgrade the output opamps with something better or the gains will not be as expected. (I used LM4562 with great success).

Ricardo

[sherphing]

hi, what is the opamp location? is it Q605 & Q606? is it just take out the old opamp and put the new one? have to do other? how many pcs opamp i need? where the actual location on pcb of the opamp? sorry...i not newbie on this...pls help

Originally posted by RCruz


Hi

Just go to the first post and follow Ray´s indications.

IMO if you disable the HDAM, you should upgrade the output opamps with something better or the gains will not be as expected. (I used LM4562 with great success).

Ricardo

[Fidelity Audio]

Originally posted by 6h5c
I didn't even notice it was another thousand...

I guess it's becoming a normal thing...

Ray

Excellente

And I got my first mini milestone post

Brent

[Fidelity Audio]

Originally posted by sherphing
hi, what is the opamp location? is it Q605 & Q606? is it just take out the old opamp and put the new one? have to do other? how many pcs opamp i need?

Yep Q605 and Q606 are the opamps, just remove them and replace with another dual opamp (LM4562 works well with Black Gate or ZA caps).

Brent