Marantz CD63 & CD67 mods list

Re: Mod on HDAM

kptseng said:
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.
 

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Luke said:


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.
 

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Luke said:

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.
 
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.

An externally hosted image should be here but it was not working when we last tested it.
 
rowemeister said:
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.
 

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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 :D

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

Does anyone know the cheapest place to get these OPA627 from?
 
6h5c said:

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.

Looks like a nice little mod. I simply unplugged my headphone socket, but I will go further and do as you suggest here. I would actually use the socket with my Sennheiser HD600s, but it sounds bloody awful!!! The cans are restricted to compuer use :xeye:
 
rowemeister said:
That makes me feel better :( cheers :bawling:

I can get them through work for £25 each (OPA627 S08) and I need 4 :cannotbe:

Sorry, couldn't resist....

www.farnell.com is a little cheaper, especially if you are satisfied with the A grade. But why do you want to use four of them? You can use a cheaper one in the filter, it's less critical. And it will make your player sound less ''Brown'', if you know what I mean.

If you look in my opamp list you'll see OPA124 has good spec's also.
You can also sign up with Analog's sample program and get some AD8610, for free ;)

Ray.
 
Wow. Turn your back for a minute and there's a million posts!:D

I got my opa627's from usacaps on ebay. Cost about $20 for 5.
Dip rather than so8 though.

Regarding the audiocom regs, I remember some grumbling on the forums that these were not that great....I'm no expert here, but it might be worth some investigation before spending your money.

I notice tentlabs have just released some similar devices, and then there's the ALW jung superregs...

Just to complicate things.:bawling:
 
rowemeister said:
OPA124.. mmmmm

So what you are saying is that 4X opa627 is not very good?

If I buy 2 opa124 does this solder to the bottom of the browndog pcb or the top?

It is good, but there are even better and cheaper alternatives, even for free if you use the sample programs. I didn't pay for all of these :D

The OPA124 or AD8610 can be used instead of OPA627 after the DAC, and then goes on top of the adapter, that's IC1. In the filter I use OPA132, AD8510 or also AD8610, this goes on the bottom.

If you look in the opamp table you can pick one that has nice specs. For the DAC low input offset voltage and low input bias current seems to work well. The more yellow the better.

Ray.
 

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rowemeister said:
LOL nice stock. It looks a like my stock of eproms I program for car ecu's.

I have purchased 2X OPA627AU and 2X OPA124UA from Farnell.

They came to £42 ish. I thought this was ok.

So with these chips I put OPA124 ontop (ic1) and the OPA627 on the bottom (ic2)

I have just ordered some gold plated sockets for the pcb to fit into also :D

Hi,

No, i'm afraid you didn't read everything and ordered too fast. :whazzat:

The OPA124 or AD8610 can be used INSTEAD of OPA627 after the DAC, and then goes on top of the adapter, that's IC1. In the filter I use OPA132, AD8510 or also AD8610, this goes on the bottom, so that would be IC2 on the adapter.

Ray.