Silent CD6000OSE KI Sig (pops on play/stop)

[Hacker]

I've modded my Marantz CD6000OSE K.I Signature in the following ways:

- Bitumen vibration deadening from Wilmslow on every available surface
- Tent Labs XO module clock
- External PSU (25-0-25 toroid, stepped down to 12VDC by 317 reg) fed into a 5v ALWSR in the CD player which powers the clock
- Internal 12v rail powered by ALWSR instead of standard 7812 reg

This is all pretty standard stuff. However, after hooking it all up there was music for a moment, then some crackling from the right speaker (music continued on the left) then a pop and then silence. Uh oh.

I tested the output of the 12v ALWSR and found it was producing approximately 18v (which would be the input voltage minus the 2.5v overhead of the TPR). I suspect that this was caused by the AD825 op amp being incorrectly soldered to the SR (loose/dry joints due to my crappy technique). I corrected this, but now the CDP is ******ed:

- Turn on clock PSU - ok
- Turn on CDP - ok. Finds disc, reads TOC
- Press play - not ok. Disc spins up, then there's a pop from the speakers followed by a distinct lack of music (silence). The disc spins as normal.
- Press stop - not ok. Another pop. Silence. The disc stops spinning.
- Girlfriend moans that I should just leave the bloody thing alone... I'm inclined to agree.

So, what have I blown? The Marantz HDAMs? Output caps? Transistors?

The popping at 'play' and 'stop' sounds like the pop that people report when they remove the output muting transistors... but I don't know where to go from here.

Help! Any offers in the way of diagnosing the fault? I can provide pictures and all sorts. Unfortunately, I don't have a service manual... can anyone provide a link to one?

Cheers folks,
Carl

[ash_dac]

Hi,

Did you do all the mods at the same time?

I normally do one mod at a time so I can reverse them if they create problems / worsen the sound.

What works:-

Reads TOC so clock must work!

.

I tested the output of the 12v ALWSR and found it was producing approximately 18v (which would be the input voltage minus the 2.5v overhead of the TPR). I suspect that this was caused by the AD825 op amp being incorrectly soldered to the SR (loose/dry joints due to my crappy technique). I corrected this, but now the CDP is ******ed:

How do you mean incorrectly soldered? wrong way round? shorted?

Check the AD825 datasheet, and see if it can handle 18V. As you got music for a moment i'm guessing that it was all connected ok!


Kind regards,


Ashley.

[Hacker]

Originally posted by ash_dac
[B]Hi,

Did you do all the mods at the same time?

I normally do one mod at a time so I can reverse them if they create problems / worsen the sound.

Me too. I did the clock first and it worked a treat. I went onto add super-regulation (using Andy's superregs, see http://www.alw.audio.dsl.pipex.com/jung_schematic.htm) for the 12v rail and that's where things have gone pear-shaped. This is due to my implementation, not Andy's regs I hasten to add!

How do you mean incorrectly soldered? wrong way round? shorted?

Just bad soldering of the AD825 surface-mount device onto the ALWSR pcb.The legs of the AD825 weren't fully soldered onto the pcb.

Check the AD825 datasheet, and see if it can handle 18V. As you got music for a moment i'm guessing that it was all connected ok!

Not a problem, this part of the circuit wasn't designed by me and has been tested by hundreds of people around the world!


Regards,
Carl

[Hacker]

Anyone else got any ideas? This thread has also been posted to Pink Fish where there have been a few suggestions: http://pinkfishmedia.net/forum/showthread.php?t=17173

Cheers,
Carl

[guido]

Originally posted by Hacker

- Tent Labs XO module clock

Wonder if it does any good with that TC160G11 working on the dig signals. Wonder if it is jittery (?)

Originally posted by Hacker

- Internal 12v rail powered by ALWSR instead of standard 7812 reg

Why only the +12 and not the -12 You're lucky the +12 is only for the analog part as far as i can see at a glance. As for fixing it, send me a pm and make shure youre mailbox can handle 5.5MB

My guess, more mute transistors The HP out and the analog out have separate mute transistors

[Hacker]

Wonder if it does any good with that TC160G11 working on the dig signals. Wonder if it is jittery (?)

What does the TC160G11 do (I assume it's an IC)? Why would it have an effect on clock jitter if the clock is powered from an completely isolated PSU?

Why only the +12 and not the -12

Because my -ve boards are still on order through the PFM group buy They're going in very soon!

My guess, more mute transistors The HP out and the analog out have separate mute transistors

Correct! The analog out muting transistors had blown. I pulled them out and music came out of the CD player again

The problem is that it was distorting on one channel. Sounded like a blown cap (it has happened to me before when a polypropylene cap had popped off the PCB track; I soldered it back up and things were normal again) so I removed what I thought were the output caps and replaced them with wire links (8 in total) but then there was no sound at all

It turns out that there are only 4 output caps (2219,2220,2221,2222) and I've removed too many. I'll have to put some of them back in tonight and hope that I've not damaged anything by shorting +12v to ground on caps 2223,2224,2225 & 2226.

Hopefully I'll have a working CD player by the end of tonight!

Cheers,
Carl

[guido]

Originally posted by Hacker

What does the TC160G11 do (I assume it's an IC)? Why would it have an effect on clock jitter if the clock is powered from an completely isolated PSU?

Look on page 11, it should be the part you have connected the tent clock to (pen 36)

This chip then generates clock signals towards the dac's and the decoder (see the overview on page 7: the TC part is the L/R SEPARATING LOGIC CIRCUIT INTERFACE (where did i hear that before ) Question is if this is done with a lot of jitter or not (not shure if the clock needs to be divided or not, but i guess it needs to be).

So a good clock could be of little use, regardless of the PSU, if this TC has a lot of jitter. But i dont know this TC chip at all, so just guessing here. Maybe it is build for low jitter, anyone ? Otherwise reclock between it and the dac's (?).

It might be beneficial to even power part of it by the clock PSU, but it has too many VDD pens to know which ones. A datasheet would be required to know (there are 10..). I would know good use for such a chip, if i had the datasheet

Did something similar on my cd63: tent clock with ALW reg for PSU, feeding the clock and the VDDclock of the DAC (And a separate 5V ALW for VDDanalog of the DAC). Like it

[Extreme_Boky]

I suggest you to check the supply voltage rails first. Make sure they are all okay. If the voltages are all okay, check for each rail loading. You can assume that something is wrong if the measured voltage is too low and the regulator is getting too hot.

Next, choose one end and start from there. It can be analog end (RCA's) or pick-up "end". Check for presence of signal and for correct mute states when in play, ff / rev, stop, pause. Get the diagram.

It appears you damaged analog / DAC section, so better start from RCA's and work backwards towards the pick-up unit. You have probably shorted two IC pins together on one of the IC’s…

Good luck

Extreme_Boky

[Hacker]

About a week has gone by now and I'm pleased to say that it's all sorted out and sounding better than ever I've even screwed the case back together in the false hope that I'm not going to do any further mods to it.

So, what have I done? Well, the EMC problem is now totally gone - I'm using an on-board PSU for the Tent clock and it's eliminated all the popping/stopping/error problems. I'll run through all the changes that have now been made to the player:

- Added Tent Labs XO module clock
- Added dedicated clock PSU (9-0-9 centre-tapped trafo, 4700u smoothing, ALWSR 5v)
- Replaced silicon rectifier diodes (1n4003) with schottkys (11dq10)
- Removed HDAM (2 op amps built from discrete components) daughter board
- Added AD8620 op amps in place of HDAM
- Replaced L7812CV / L78912CV monolithic regs with ALWSR +12v / -12v
- Removed muting transistors (they were blown anyway )
- Removed output capacitors
- Disconnected signal ground from the chassis (it's like that when produced)
- Added vibration-deading bitumen to just about every internal surface
- Disconnected headphone circuitry
- Added thick, shielded mains cable
- Replaced crappy mains cable clamp with nice tension-relieving jobby
- Removed crappy mains cable connector and soldered it direct to PCB

It took a while, but the sound is now Here's a few pics:

The AD8620s on the DIL adaptors:


Crazy wiring for the analog stage +12v / -12v and clock +5v:


The soldered mains cable, clock PSU and cable clamp:


A nice view of the sturdy tension bar (filled with bitumen underneath):


Gratuitous *** shot (showing the soldered-in MK plug and clip-on ferrite):


Cheers folks
Carl

[georgehifi]

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