Marantz CD-17 Mods

[audio_tony]

Here are some pics of mods done to my CD-17.

I can't remember exactly what has been replaced part for part, but you can see the general idea from the pics.

Shown are pics of the DAC area, servo area, HDAM (removed) and the PSU.

Most of the upgrades were improved capacitors (Oscons around the servo) and some other 'muse' capacitors around the DAC as well as a couple of low ESR caps in the PSU lines. The 3300uF caps in the main PSU were replaced with 10000uF items.

Also on view are the Brown Dog converters which have LM4562NA's mounted, replacing the SMD NJM 2114's. This has to be the most significant upgrade so far.

Inspiration for these mods came from this page as well as here on DIY Audio.

[UV101]

Hi Tony! Cant believe that there are no replies!!!

I must admit I really like that DAC7 chip. My favourite caps for digital rails are OsCon SEPC solid polymer caps. I modded a friends TEAC VRDS10 which had twin TDA1547's so loads of caps went in.

If you are looking to take this player further, a clock with direct feeds to both the 7372 and TDA will further improve things. I see you've already replaced the main smoothers! Thats a good move for sure. Although it could be perceived as overkill (which its not!), the servo will definitely appreciate the increase.

Not sure if the servo is unregulated like most other marantz players but if it is, its poss running about +/-10v unregulated. Try regulating the rail at 8v.That will also help loads!

[UV101]

oh 1 other thing! The TDA1547 has onboard opamps for the I/V conversion. If you were feeling adventurous, you could take the I/V external using better opamps!!!! That will bring gains for sure

Is there any DC on the output before the blocking caps?

[QSerraTico_Tico]

Originally Posted by UV101

oh 1 other thing! The TDA1547 has onboard opamps for the I/V conversion. If you were feeling adventurous, you could take the I/V external using better opamps!!!! That will bring gains for sure

Is there any DC on the output before the blocking caps?

You can't fully disconnect the internal opamps

[UV101]

can the differential current out not be picked up on pins 10,11 for right and 22,23 for left channel?

Chip diagram attached

[Thomo]

Hello. You can as Ian said take the output from before the opamps, but they are still connected internally. You can also disconnect the +/- supplies to the internal opamps which simply shuts them down (pins 16&17) iirc.

Another really good mod is to replace the zener diodes in the discrete regulators to low-noise devices. Zener's are pretty noisy and replacing them with something like lm329's will make a big improvement to the sound.

Hope this helps, Lee.

[audio_tony]

If I understand the info from Lampizator correctly, the internal opamps can indeed be bypassed.

I'm not sure if I an be asked to go to that extent though, as the tracks are quite fragile.

It would probably be easier to get a 1547 chip, and build a complete new section on it's own board.

In which case I might as well use an external DAC

I have another three external DACs which I have been experimenting with, including a non OS TDA1543. So far, to my ears the TDA1547 still sounds the best though.

[UV101]

Def use those LM329's to replace the Zenors! I use them as the Vref on my regs!! dont we Lee! lol

[QSerraTico_Tico]

Originally Posted by audio_tony

If I understand the info from Lampizator correctly, the internal opamps can indeed be bypassed.

I'm not sure if I an be asked to go to that extent though, as the tracks are quite fragile.

It would probably be easier to get a 1547 chip, and build a complete new section on it's own board.

In which case I might as well use an external DAC

I have another three external DACs which I have been experimenting with, including a non OS TDA1543. So far, to my ears the TDA1547 still sounds the best though.

As I understand Mr Lampizator was not successful at all:
"I decided that this is a good plan and I applied it to TEAC VRDS D10 which uses same chips (but in Mono mode) . Despite wasting a whole weekend - nothing seems to work. I get noises, distortions, even echoes.

I decided to curse this DAC."

[Thomo]

Originally Posted by QSerraTico_Tico

As I understand Mr Lampizator was not successful at all:
"I decided that this is a good plan and I applied it to TEAC VRDS D10 which uses same chips (but in Mono mode) . Despite wasting a whole weekend - nothing seems to work. I get noises, distortions, even echoes.

I decided to curse this DAC."

LOL. Strange, I've done it a few times now. My CD17 runs a fully discrete I/V and output stage.

Index of /images/Marantz CD17

Cheers, Lee.