Marantz CD63 & CD67 mods list

[6h5c]

Originally posted by kptseng
Hi All,

I've heard of some mod that bypass or replace the HDAM circuit with Op-amp.
I'm using CD6000 and hope I can get some insight to this mod.
Thanks.

King

Hi King,

The CD6000 is a different story. It uses two SM5872 DACs (lucky you...). The 'normal' CD6000 then uses one 2114 dual opamp per channel in the filter and a HDAM circuit as buffer, the OSE uses dual HDAM in the filter, on a separate PCB, and a HDAM as buffer.
I think it would make more sense to try and replace these two 2114 opamps with decent ones.
The HDAM buffer part uses differential inputs because of the dual DACs. It's difficult to bypass this because it also does some kind of differential-to-single-ended conversion.

Ray.

[Fidelity Audio]

yeah ditch those 2114 before anything else

[6h5c]

Originally posted by Luke


Hi Ray,

so what your saying is that if you use a crap opamp, the hdam will improve the sound. If you use a good opamp the hdam will improve the sound?
Seems to me KI would be well aware of this wouldnt he? Surely a decent opamp is not as expensive as the sexy copper cans alone
But you got me curious and I would like to try this although its not minor and I blew my last player up

cheers Arthur

Hi Arthur,

Well, allmost. With a crappy opamp the extra HDAM circuit MAY improve the sound. With a good opamp already in place, chances are great that the extra circuitry will degrade the sound.

As I said, the shiny cans and the HDAM circuit are a great selling point, you don't get it in a CD57. Also they don't want the player to sound TOO good for it's money. The CD57/67/67OSE/67KI all use the same PCB, DAC, decoder and so on. They just change a few parts in production to make different sounding players. But this 2114 opamp is even used in more expensive players, like the CD17!

Ray.

[6h5c]

Originally posted by rowemeister
Sweet!

I will be bypassing mine with a little bit of silver wire

You have sharp vision, this is silver too

Ray.

[SimontY]

Originally posted by Luke

so what your saying is that if you use a crap opamp, the hdam will improve the sound. If you use a good opamp the hdam will improve the sound?
Seems to me KI would be well aware of this wouldnt he? Surely a decent opamp is not as expensive as the sexy copper cans alone

I understand fully your point of view, but I feel that this sort of hi-fi product is not designed to be as high fidelity as possible. It is designed, I feel, to give an impressive sound. I'd describe the unmodded 63ki as giving a 'thrilling wallop'. But it doesn't deliver the musical goods. We mod to give great sound in every way, but players are manufactured with costs in mind, and things like good psu bypassing of op-amps is perhaps not so easy to do for them. We don't need to compromise. And don't forget the little HDAM badge on the front. And the sort of sonic change this brings is perhaps the sort that will impress in a very quick listen.

[Fidelity Audio]

Well there is only one way to find out!!!!

But has I said before less is more. We remove output caps, muting transistor etc to minimise the component count that can and will effect the audio. So bypassing the HDAM must be better.

On a lighter note here is a little pic of a section of my KI.

A few more very good mods on the way too.

[Fidelity Audio]

And another of the 12V regs

[6h5c]

Originally posted by rowemeister
Well there is only one way to find out!!!!

But has I said before less is more. We remove output caps, muting transistor etc to minimise the component count that can and will effect the audio. So bypassing the HDAM must be better.

On a lighter note here is a little pic of a section of my KI.

A few more very good mods on the way too.

Hi rowemeister,

Nice pics!

I see you have C901/902 still in there, that lead to the headphone part. These traces run alongside the DAC and will take some noise with them, right into the analog part. If you take them out you can prevent that. While you are at it, take out U139/140 to disable the +/- 12V.

Here's my latest mods list that I made while modding a CD57. It has more detailed info than the previous lists.

Ray.

[SimontY]

Mmm, Audiocom regs

I will be getting some soon, as soon as I have money!

[Fidelity Audio]

I will look into that.

I have on order some black gates caps 16V 470uF for the opamps (C611-614)

Replacing schottky diodes with HexFRED ones.

Building seperate regulation for clock (12v) and DAC/DEC (5V) using audio com regs and black gate caps with inductors. The 5V reg for the DAC will be a INVUSUS one

I am waiting for some Browndog pcbs to arrive so I can replace the OPA2134 with OPA627

Does anyone know the cheapest place to get these OPA627 from?