Bypassed Marantz Blueray player UD-7007 HDAM module in the DAC PCB

[Hari Iyer]

This mod has a long history as long as 10 years of my listening time. In 2004 i owned a Pioneer DVD DV-373. This was followed by a used Marantz CD player CD-5400 from around 2011 til 2018. I later purchased a Marantz blueray player UD-7007 for its DAC quality and other attributes. I always did notice that some details from the UD-7007 were missing - not huge but surely yes compared to the Pioneer and the Marantz CD player. I attributed that to my listening degradation due to aging and did not bother much with this and ignored them.

I four months ago came across a video from Amir (ARC founder) where he was comparing some DAC and was mentioning briefly about Denon and Marantz cd players and was telling how the Marantz players added an unwanted HDAM discrete buffer after the Low Pass Filter there by loosing some details and being slightly compressed. Denon did not suffer from this issue as they followed the KISS principle and less was more for Denon. Since i viewed that video 4 months ago, i always wondered how to remove the discrete buffer from the Marantz and i did this today. It was quite simple - just add a jumper wire from the input of the HDAM to the output of HDAM after the coupling capacitor and you are done. As current will always flow from where the resistance to its flow the lowest - the HDAM gets bypassed without any other alteration as it would offer higher impedance than the simple wire. I used a Belden silver wire to make this jumper. I don't know if this jumper also acts like a +ve feedback from the output to the input of the HDAM - but who cares if you are getting a better outcome.

I have been listening now for 2 hours and noticed that there was nothing wrong with my ears and actually the HDAM circuitry was masking the details with the unwanted circuitry. Now i can hear all the masked details like it was in the Pioneer DVD and Marantz CD player. Now i really believe that less is more and this entire mod was done in just 20 minutes.

Thanks for looking.

 

[MaSh]

Wow, awesome mod. Would be great if you could post some pics showing the mod.

MaSh

 

[Hari Iyer]

Wow, awesome mod. Would be great if you could post some pics showing the mod.

MaSh

Thanks MaSh. I missed taking snaps after the mod. I shall open again and post ASAP.

 

[Amarendra]

This mod has a long history as long as 10 years of my listening time. In 2004 i owned a Pioneer DVD DV-373. This was followed by a used Marantz CD player CD-5400 from around 2011 til 2018. I later purchased a Marantz blueray player UD-7007 for its DAC quality and other attributes. I always did notice that some details from the UD-7007 were missing - not huge but surely yes compared to the Pioneer and the Marantz CD player. I attributed that to my listening degradation due to aging and did not bother much with this and ignored them.

I four months ago came across a video from Amir (ARC founder) where he was comparing some DAC and was mentioning briefly about Denon and Marantz cd players and was telling how the Marantz players added an unwanted HDAM discrete buffer after the Low Pass Filter there by loosing some details and being slightly compressed. Denon did not suffer from this issue as they followed the KISS principle and less was more for Denon. Since i viewed that video 4 months ago, i always wondered how to remove the discrete buffer from the Marantz and i did this today. It was quite simple - just add a jumper wire from the input of the HDAM to the output of HDAM after the coupling capacitor and you are done. As current will always flow from where the resistance to its flow the lowest - the HDAM gets bypassed without any other alteration as it would offer higher impedance than the simple wire. I used a Belden silver wire to make this jumper. I don't know if this jumper also acts like a +ve feedback from the output to the input of the HDAM - but who cares if you are getting a better outcome.

I have been listening now for 2 hours and noticed that there was nothing wrong with my ears and actually the HDAM circuitry was masking the details with the unwanted circuitry. Now i can hear all the masked details like it was in the Pioneer DVD and Marantz CD player. Now i really believe that less is more and this entire mod was done in just 20 minutes.

Thanks for looking.

This is surprising since Marantz advertises it as a USP that the product has HDAM

 

[spirovious]

That's great mod Hari. I also find that due to HDAM in Marantz avr, sound is not as enjoyable as older Marantz AVR with opamps. If power supply to HDAM is cutoff, then it may improve further than only bypass l guess.

 

[Hari Iyer]

This is surprising since Marantz advertises it as a USP that the product has HDAM

Yes, I think the transistors and coupling capacitors have their own sound signatures contributing to degradation. They have used a simple 220uF, electrolytic capacitor for coupling, probably that could be the main issue. I can try using a bipolar and bypass that with wima FKP2 type Capacitor, but that's too much work and tinkering with the PCB etc which I want to avoid.

That's great mod Hari. I also find that due to HDAM in Marantz avr, sound is not as enjoyable as older Marantz AVR with opamps. If power supply to HDAM is cutoff, then it may improve further than only bypass l guess.

Maybe but for that I need to cut tracks from PCB. I shall rather only isolate the 220uF, coupling capacitor by removing one lead and that could do the trick. Even for doing this, I need to open the PCB and desolder the capacitor.

 

[spirovious]

Maybe but for that I need to cut tracks from PCB. I shall rather only isolate the 220uF, coupling capacitor by removing one lead and that could do the trick. Even for doing this, I need to open the PCB and desolder the capacitor.

Recently l swapped Wima PP caps from SSP to Muse green caps. To my surprice muse sounded better than wima. Wima had flat and little brighter sound. Muse caps has warm and dynamic sound.

 

[Hari Iyer]

Recently l swapped Wima PP caps from SSP to Muse green caps. To my surprice muse sounded better than wima. Wima had flat and little brighter sound. Muse caps has warm and dynamic sound.

For filtering you need to use WIMA FKPS2 ( foil PP) type. MKP( Metalized PP) and MKS ( polyester) won't do.
Muse I believe is a non-polar type Capacitor.

 

[Hari Iyer]

The next planned mod on the DAC PCB is to remove all the high value bypass capacitor from the op-amps +ve and -ve rails. I am not sure why such high value capacitors are used - 100uF and 0.1uF. Is there so much noise in the PSU? Does the opamp require so high a current for the capacitor needs to supply. I have recently done a trimming of PSU capacitors from my phono preamplifier with very good outcome.

I shall replace all of this with just a single WIMA 10nF capacitor. This will allow music to be better modulated and follow the power supply pulse. There is a 15+ page article by Texas instrument on How not to bypass your OPAMP and is a must read

 

[Hari Iyer]

I quickly glanced through the schematics of the ud-7007 and found that the opamp OP275 has a decoupling capacitor 100uF + 18nF in both the +Ve and -Ve rails. The opamp NJM4565 too have a decoupling capacitor of 100uF + 100pF in both the +Ve and -Ve rails. Both the opamps are fed with +9v regulator IC 7809 / 7909 which inturn if fed from a +12v / -12V from the SMPS. before the 9v regulator is already a 100uF+ 0.1uF and after the regulator a 100uF + 0.1uF + 18nF. So most of the filtering is taken care here and there is no need for further adding a 100uF near the op-amp. So i will be de-soldering the 100uF near the op-amps ( a total 6 of them) and see if there is any power supply ripple to be heard in the output in form of hum. I shall retain the smaller 18nF and 100pF as this will be needed for RF decouple (if any).

The reason to remove the electrolytic capacitors from near the opamp pins are the 7809/ 7909 are dc-to-dc convertor type used here as the input of this regulator is fed from the SMPS section. So the frequency of operation will be above 1MHz and the electrolytic capacitor wont have any role to play here. I can actually gain sonics by removing them from here.

Hopefully the supply will be better modulated with the music and most of the current for the opamp will come from the SMPS and not the capacitor. If i succeed in getting better sound with this mod - then i shall also remove the 100uF just after the regulator IC 7809 /7909 and just keep one 100uF before the regulator. Later i shall also remove this capacitor and replace with a Non-polar type.

Thanks for looking.

 

[spirovious]

I am not sure why such high value capacitors are used - 100uF and 0.1uF. Is there so much noise in the PSU?

I think its common practice. Recently I rearranged SSP and only 0.1uf Wima caps are used for + & -ve power lines. Results are good.Bigger and wide sound.Which ever 100uf cap I added, it made sound odd and colored .

 

[Hari Iyer]

I think its common practice. Recently I rearranged SSP and only 0.1uf Wima caps are used for + & -ve power lines. Results are good.Bigger and wide sound.Which ever 100uf cap I added, it made sound odd and colored .

Exactly my point. If you read my attached document from Texas in post # 9 they have also mentioned the same thing - the Electrolytic capacitors are added by designers without much thought and they create more problem than they solve. Removing these unwanted Electrolytic capacitors will for sure have sonic benefits.

 

[Hari Iyer]

Over the week the following modifications to the Blueray player was done,

1.
Remove the below Electrolytic capacitors from near the OPAMPS
CE4, CE5, CE10, CE11, CE20, CE18 , CE22, CE24 - All these are de-coupling capacitors





Jumpers for coupling capacitors
CE19 - Put jumper from R59 to CE19
CE21 - Put jumper from R80 to CE21

CE25 - Put jumper from R132 to CE25
CE23 - Put jumper from R107 to CE23






Remove the below Electrolytic capacitors from the power supply regulators

CE12, 100uF, 25V electrolytic is to be replaced by CE12, 100uF, 100V non-polr type

CE13, 100uF, 50V to be removed

CE16, 470uF, 16V electrolytic is to be replaced by CE12, 100uF, 100v non-polar type

CE17, 100uF, 50v tobe removed


Remove the 100uF,450V electrolytic capacitor and replace with a 50uf X 2, 630v Metalized polyproplene capacitor









I have listened only for around 2 hours with all the above mods and below is my own impression,

- No hum due to reduction of capacitor from around 1600uF total to around 300uF total.
- Quiter background and more micro-details and more dynamic sound
- Better response to transient music signals
- Smoother response compared to earlier which was quite fatigued after 2 hours of listening

Marantz could have saved a lot of cash by avoiding these capacitors, but again they built for generic customers where in some locations the local electricity could be more polluted and could be used near an AM transmitter needing all these capacitors.

Thanks for looking.

 

[spirovious]

Which brand caps are those?

 

[Hari Iyer]

Which brand caps are those?

Marantz are from TK - Japan - Good quality imo
The MKP that I replaced are EPCOS.

 

[Hari Iyer]

This week planning to replace the LPF opamps from stock JRC NJM4565M to Texas LM4562NA and report. The LMs have a higher bandwidth cand gain and all other parameters better than the. NJM. Don't know if that would mean better performance. Only replace will tell. Searches and could not find any answers for that much.

If that works well, also will replace the I/V converter chip from the stock OP275 to again the LM4562. Not sure if they are good choice there - need to check this. The PCM data sheet says NE5532 but again many have modded 5532 with the 4562 with good results.

 

[Hari Iyer]

This week planning to replace the LPF opamps from stock JRC NJM4565M to Texas LM4562NA and report. The LMs have a higher bandwidth cand gain and all other parameters better than the. NJM. Don't know if that would mean better performance. Only replace will tell. Searches and could not find any answers for that much.

If that works well, also will replace the I/V converter chip from the stock OP275 to again the LM4562. Not sure if they are good choice there - need to check this. The PCM data sheet says NE5532 but again many have modded 5532 with the 4562 with good results.

Whole one month no DIY activity and last weekend resumed by replacing the opamp to LM4562 - TI. The JRC opamp is slightly wider compared to the TI. The difference is earth and outer space. The JRC were bright, edgy, listening fatigue and compressed. The TI are more mellow, neutral, soft, dynamic with more micro-detail. Its like buying a new player.

I don't know why companies like Marantz don't give better chips for saving a few 10s of rupees. They can charge the customer who will willingly pay so that a person like me don't have to take trouble to do modifications. For others it's like suffering in silence or buy a better DAC while the same or better performance can be easily obtained by a simple modifications.

 

[spirovious]

Whole one month no DIY activity and last weekend resumed by replacing the opamp to LM4562 - TI. The JRC opamp is slightly wider compared to the TI. The difference is earth and outer space. The JRC were bright, edgy, listening fatigue and compressed. The TI are more mellow, neutral, soft, dynamic with more micro-detail. Its like buying a new player.

I don't know why companies like Marantz don't give better chips for saving a few 10s of rupees. They can charge the customer who will willingly pay so that a person like me don't have to take trouble to do modifications. For others it's like suffering in silence or buy a better DAC while the same or better performance can be easily obtained by a simple modifications.

You can place opamp socket on PCB and try different options. Once you are convinced, then solder that chip on PCB.

 

[Hiten]

ICs being sensetive, and if are decided to be soldered. it would be safe to switch off soldering iron from mains when it reaches maximum temperature.

 

[Hari Iyer]

You can place opamp socket on PCB and try different options. Once you are convinced, then solder that chip on PCB.

Not possible as these are SMD types chips. Even I don't have soldering skills for them. My elder brother does that for me -