Marantz CD-17 Mods

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.
 

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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!
 

Thomo

Member
2006-11-30 12:18 pm
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.
 
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.
 
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

Member
2006-11-30 12:18 pm
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.
 
Def use those LM329's to replace the Zenors! I use them as the Vref on my regs!! dont we Lee! lol

Here you go Tony! Get yourself 6 of these Farnell LM329 use 2 in series to replace D856, the same for D855. You will slightly raise the +/-12v rails to about 13v but this is fine. The amount of noise on these rails will be a fraction of what it was with the Zener. These rails are for the output stage and power the opamps and HDAMs (if they were still in circuit) as well as some other stuff. If you have bypassed the HDAM's you should remove the supply resistors so you are not powering them while not in use. I think you'v already changed C854 and C803. I would recommend something like 10000uf Panasonic TSUPs here or something better if you're feeling extravagant! C857 and C858 may benefit from an increase in uF maybe Panasonic TSUP or FC's?

The other Zeners in the PSU D832 and D831 can be replaced replace with a single LM329 and will run the +/- 5v rails a fraction over voltage but with much lower noise again.

A worthwhile upgrade for sure! the LM329's are about £1 each inc VAT! bargain!

Edit* while you are doing this, change caps C833,C834,C855 & C856 for something better too. Maybe Rubycon ZLG at about 220uF/25v as this will also improve the overall noise on the regulation.
 

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Here you go Tony! Get yourself 6 of these Farnell LM329 use 2 in series to replace D856, the same for D855. You will slightly raise the +/-12v rails to about 13v but this is fine. The amount of noise on these rails will be a fraction of what it was with the Zener. These rails are for the output stage and power the opamps and HDAMs (if they were still in circuit) as well as some other stuff.

I was thinking of replacing those with LM117/317, but I'll look into the zener replacements suggested.

UV101 said:
If you have bypassed the HDAM's you should remove the supply resistors so you are not powering them while not in use. I think you'v already changed C854 and C803.

The HDAMS have been completely disconnected and removed.

Main PSU caps have been replaced - nothing fancy though, just ordinary 10000uF caps (still better than the original 3300uF I would've thought).

UV101 said:
I would recommend something like 10000uf Panasonic TSUPs here or something better if you're feeling extravagant! C857 and C858 may benefit from an increase in uF maybe Panasonic TSUP or FC's?

I've already replaced these with some low ESR 2200uF caps.

UV101 said:
The other Zeners in the PSU D832 and D831 can be replaced replace with a single LM329 and will run the +/- 5v rails a fraction over voltage but with much lower noise again.

A worthwhile upgrade for sure! the LM329's are about £1 each inc VAT! bargain!

Again I was thinking about alternative 3 terminal regs here - but will try the LM329.

UV101 said:
Edit* while you are doing this, change caps C833,C834,C855 & C856 for something better too. Maybe Rubycon ZLG at about 220uF/25v as this will also improve the overall noise on the regulation.

I have replaced various other caps, some with OSCONS some with just off the shelf low ESR caps.

The board is a bit fragile, so I don't think I'll be changing them again lol!
 
Hi Tony, more uF in the smoothers is always a good thing! The thing with the Panasonic TSUP is that they are also low esr which is even better.

The regulators in the CD17 are not LM317/337. They are Darlington transistors made to regulate voltage and will be much better from a noise point of view than 317/337's 78xx/79xx etc. This coupled with the low noise voltage refs replacing the original zeners will make very nice regs. If you were thinking about upgrading to commercial discrete low noise regs (super regs, S-Powers etc) they will be a very big improvement on the standard items but obviously they come at a premium. Fragile boards are a problem for sure and I understand why you'd not want to keep changing caps!! ;)