Marantz CD63 & CD67 mods list

[awpagan]

Originally posted by poynton



Hi.

What about replacing the LC filter between the 2 op amps with an active filter?/


Andy

or fet balanced stage

allan

[philpoole]

Sorry Allan, I wasn't very clear.

I was thinking of ideas for Rowemeister's
"""Now what do I do now...... """

It does look good doesn't it? I thought I recalled he might of padded out his transport slightly (might of imagined it, this is now a very long thread ), and I also recall he weighed it and it was a good weight, and adding to that is always worth it .

I did also wonder once if there was any merit in mounting the transport and pcbs using rubber washers in an attempt damp vibrations. I think it would be a real 'scraping the barrel' mod, but I think Rowemeister has done nearly everything else!

BTW, I've modded a friends CD63 with both electronic and mechanical mods, but mine has simply had (more) electronic mods and sounds better IMO, so I wonder about the scope of mechanical mods, just suggesting them.

Allan, compared to Rowemeister's, my box is only part modded (Kwak clock, opamps, vregs for DAC, HDAM removed, capacitor upgrade, silver mica and 0.1% resistors on analogue filter, PSU diodes swapped for schottky etc) and I can wholeheartedly recommend modding to any level. My first mod was the opamp upgrade and removal of muting transistors and output caps. Even that impressed at the time, and I keep going back to my trusty Marantz for further tweaking.
Glad there is still work for me to do and improvements to be made. Half the fun is hearing how other's have progressed and planning what the next mod will be.

Cheers,
Phil

[poynton]

Originally posted by awpagan


or fet balanced stage

allan

Hi,

A balanced stage , whether TUBE or fet, will only cancel "common mode noise" but noise is, by its very nature, random.

The LC notch filter is tuned ( I forget whether F or nxF ) and complements the filtering performed in the DAC and by the RC filter post-DAC.

This is the type of filter ( active ) found in BurrBrown data sheets. ( not that is necessarily 'good'.)

http://www.hagtech.com/notch.html

This gives nice results with 44k notch and 1000pF (Si-Mi) caps

Andy

[Fidelity Audio]

Thanks for the praises everyone

I have done sound deadening on the chassis and used aluminium paste to bond the chassis to the extra plate (SE and KI) so there is no vibration. I put some deadening material under the strut bar and on the transport.

This mod improved bass and treble a little.

It weighs just under 7KG now lol

Phil you too have done some very good mods, keep it going

[Fidelity Audio]

Ray

Has you know I have the OPA627 and OPA132 set up.

What difference would an all OPA627 setup sound like?

[6h5c]

Originally posted by rowemeister
Ray
Has you know I have the OPA627 and OPA132 set up.
What difference would an all OPA627 setup sound like?

Hi Brent,

A dual 627 setup doesn't sound bad of course, but I found it a bit too dark, too "brown" if you like. I think the 132 sounds more open compare to the 627. It still has the typical Burr-Brown sound many people talk about, but less of it.

At the moment my favorites are OPA627 or AD8610 after the DAC, with OPA132 or AD8510 in the filter.

Regards,

Ray.

[6h5c]

Originally posted by poynton
Hi,

---The LC notch filter is tuned ( I forget whether F or nxF ) and complements the filtering performed in the DAC and by the RC filter post-DAC.---

Andy

Hi Andy,

You got me wondering why the notch filter is no longer present in the CD57/67 (the 1000pF and 220uH in the CD63). Maybe just a simple cost-reduction that no-one will hear.

It is supposed to be tuned to 8*Fs. I entered the whole Marantz filter in Micro Cap, and i'm going to do some more simulations to see if I can optimise it further. I want to improve the group-delay as mentioned on Pedja's site, and re-tune the notch filter closer to 8*Fs and see how that sounds.

Ray.

[poynton]

Originally posted by 6h5c


You got me wondering why the notch filter is no longer present in the CD57/67 (the 1000pF and 220uH in the CD63). Maybe just a simple cost-reduction that no-one will hear.


........ re-tune the notch filter closer to 8*Fs and see how that sounds.

Hi.

Not having diagrams for the 57/67 , I did not know that !

Are the post-dac components the same??


EDIT. Oh, yes. I have !!!!!


With only the 1000p cap and no inductor, it would roll off at 6db/octave (??) rather than notch? what would be the knee freq.? I can't compute - no software.

What effect would there be in adding an extra RC ( 10k/120pF ) stage in front of the first op amp?

Similarly, adding an extra 10K and 1000pF ( and for 57/67 an extra 220uH ) between the op-amps??

Andy

[ash_dac]

Hi,

I finally got around to looking at the schematics for the CD63.

Seems Marantz slapped everything on one 5V reg, and added a 3300uf cap after the regulator.

Never used the optical out on the player, and looking at the schematics it's tied to that potentially noisy 5V rail!

What's the strategy for 'fixing' the 5v rail ?

[poynton]

Originally posted by ash_dac
Hi,

I finally got around to looking at the schematics for the CD63.

Seems Marantz slapped everything on one 5V reg, and added a 3300uf cap after the regulator.

It's cheaper!

Never used the optical out on the player, and looking at the schematics it's tied to that potentially noisy 5V rail!

And so is everything else that uses 5v !

What's the strategy for 'fixing' the 5v rail ?

See Rowe's posts - the pictures sum it up !
Basically, split the analog sections off, power by extra transformers and more regulators.

And place an order for our custom transformer !

Andy