Marantz CD63 & CD67 mods list

[marct10]

Im feeding it into a 41hz amp3 which in turn feeds a pair of Nagaoka Swans.
I suppose I can lower the gain of the Amp3 or lower the gain of the final op amp in the 63 (ive bypassed the HDAM, removed the output coupling caps muting transistors etc.
Has anyone done any comparisons on the sound quality difference between using the vairable out vs a good quality stepped attenuator?...Im guessing the variable out should sound better as its done in the digital domain ?

 

[awpagan]

very quiet on there lately

ugraded the cd67 till no work no more

well it played 1 to 2 tracks or more then just stops
hit start again and ok for a few more
spent the weekend tracking problem.
think i have found it.
using inductors for 5v links has dropped voltage down to ~3.8v on the saa73272 which controls the transport.
must be closed to border line voltage

i really need to make some extra psu's

allan

 

[awpagan]

very quiet on there lately

ugraded the cd67 till no work no more

well it played 1 to 2 tracks or more then just stops
hit start again and ok for a few more
spent the weekend tracking problem.
think i have found it.
using inductors for 5v links has dropped voltage down to ~3.8v on the saa73272 which controls the transport.
must be closed to border line voltage

i really need to make some extra psu's

allan

maybe not the problem

seems the turntable motor has problem starting.
I know the clock(psu) needs to stablize first, slow startup on clock psu doesn't help
the motor sometimes makes whrring noise when running.

has anyone heard of a problem with the motor?

allan

 

[6h5c]

Im feeding it into a 41hz amp3 which in turn feeds a pair of Nagaoka Swans.
I suppose I can lower the gain of the Amp3 or lower the gain of the final op amp in the 63 (ive bypassed the HDAM, removed the output coupling caps muting transistors etc.
Has anyone done any comparisons on the sound quality difference between using the vairable out vs a good quality stepped attenuator?...Im guessing the variable out should sound better as its done in the digital domain ?

Hi marct10,

That amp uses the TA2021B, right? What values did they use for Ri and Rf? You could adjust the gain of both the amp and the player, to bring them closer together. But I think you should first consider putting a decent attenuator between them .

If you're not using a preamp (like me), the best solution is a stepped attenuator. If you use the digital attenuator in the DAC you will lose resolution and the S/N ratio will go down.
You can read a bit more here.

Regards,

Ray.

 

[6h5c]

using inductors for 5v links has dropped voltage down to ~3.8v on the saa73272 which controls the transport.

allan

Hi Allan,

If the PSU voltage after the inductors is that low, there is something wrong with the DC resistance of your inductors, it's too high. It should be only a few ohms.

Ray.

 

[awpagan]

Hi Allan,

If the PSU voltage after the inductors is that low, there is something wrong with the DC resistance of your inductors, it's too high. It should be only a few ohms.

Ray.

inductors are 30ohm
bypassing at present and it ran longer

will look at the others

allan

ps your filter and tranistor buffer works well

 

[6h5c]

inductors are 30ohm
bypassing at present and it ran longer

That's a bit high

ps your filter and tranistor buffer works well

Thanks! I'm enjoying it too!

Ray.

 

[ash_dac]

That's a bit high



Thanks! I'm enjoying it too!

Ray.

Hi,

Where's your filter ?

I lose track of the posts on this thread!

 

[awpagan]

Hi,

Where's your filter ?

I lose track of the posts on this thread!

i used 4.7mh chokes with a ferrite bead instead of 5v wire links


ray
they are 30ohms 4.7mH chokes
will drop them down to 1-ohm max
or just use the ferrite beads

allan

 

[awpagan]

Hi,

Where's your filter ?

I lose track of the posts on this thread!

ashley

http://www.diyaudio.com/forums/showthread.php?s=&postid=849442&highlight=#post849442


allan

 

[6h5c]

Hi,

Where's your filter ?

I lose track of the posts on this thread!

Hi ash,

Here's the thing with a tubestage, and here with the SACD Enhancer-like transistor stage behind it.

Regards,

Ray.

 

[6h5c]

ray
they are 30ohms 4.7mH chokes
will drop them down to 1-ohm max
or just use the ferrite beads

allan

Yeah, 1R will work better. The 4.7mH is nice, but DC resistance is too high. May work in low-current circuits, but the DAC and decoder are too hungry. I often use small EPCOS 220uH/3.3R (511-651) or the bigger 470uH/2.5R (517-070). Their 1mH is 3.8R, that is also not that high.

Ray.

 

[awpagan]

Yeah, 1R will work better. The 4.7mH is nice, but DC resistance is too high. May work in low-current circuits, but the DAC and decoder are too hungry. I often use small EPCOS 220uH/3.3R (511-651) or the bigger 470uH/2.5R (517-070). Their 1mH is 3.8R, that is also not that high.

Ray.

I used the 4.7mH filter with the bc550c buffer.
Havn't been able to get to farnel lately for the 10mh's

Q inductors in paralel, like caps or resistors?

allan

 

[awpagan]

Inductors

Inductance adds in parrallel for AC (frequency) can be more than double. "oops need to check this again"

but DC resistance halves, similar to resistors.


ray,
might be useful for DC power
as long as it attuenates ac!


allan

or am i missing something

 

[poynton]

Parallel Inductors

Hi.

See this !

http://www.allaboutcircuits.com/vol_1/chpt_15/4.html

Andy

 

[Fidelity Audio]

I have fitted 3 TX to the KI that had a faulty TX.

It works perfectly well, I just have the 3.6v supply for display to sort out.
My Dc to the 12V regs is 26.5V
and to the 5v regs is 12V

Here is a pic

 

[Fidelity Audio]

and another

 

[philpoole]

Hi Awpagan,

I had an equally frustrating time, but at least you got to hear Rays filter and transistor stage!
I fitted the stage and since then, the CD spins up for a short while then stops. Sometimes, when inserting a disc, it would spin one way, then the other(for about a second and stop)! I disconnected the new output stage and still had the problem. So I think I have a dry/damaged joint somewhere, either feeding a power rail (I have gone down the many regulator route) or, more likely my clock module (either power or the clock signal itself.
Ho hum. its pretty useless at the moment, and I'm not going be able to 'pop the lid' for a while to fix it.
I was so looking forward to hearing the new mod too.
I'm very glad I haven't done any coax mods yet!
I think this project will end soon for my box as it has a lot of extra boards attached now (and I don't know how to fit this new output stage in!).

Cheers,
Phil

 

[poynton]

It works perfectly well, I just have the 3.6v supply for display to sort out.

Hi.

RS used to do a 3-0-3 200mA Tx ( I have one ) but it is now sadly discontinued !

What about a wallwart for a Gameboy. I think they used 3v. You may be able to get a suitable Tx and repot in a plastic box.

Andy

 

[awpagan]

Hi Awpagan,

I had an equally frustrating time, but at least you got to hear Rays filter and transistor stage!
I fitted the stage and since then, the CD spins up for a short while then stops. Sometimes, when inserting a disc, it would spin one way, then the other(for about a second and stop)! I disconnected the new output stage and still had the problem. So I think I have a dry/damaged joint somewhere, either feeding a power rail (I have gone down the many regulator route) or, more likely my clock module (either power or the clock signal itself.
Ho hum. its pretty useless at the moment, and I'm not going be able to 'pop the lid' for a while to fix it.
I was so looking forward to hearing the new mod too.
I'm very glad I haven't done any coax mods yet!
I think this project will end soon for my box as it has a lot of extra boards attached now (and I don't know how to fit this new output stage in!).

Cheers,
Phil

i made a pcb for the filter buffer, small enought to sit over the opamp to hdam circuit.

allan