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CD Player Improvements

 
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Mon Jan 01, 2018 4:10 pm    Post subject: CD Player Improvements Reply with quote


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After turning off my Soldering Iron for Video Mods. I soon after got back to tinkering and such with the various CD players I have accumulated over the years. Most were giving to me, and considering I was also looking for a needle for one of my turntables. I decided to look at the Dac's in the CD players and if any real changes could be made to make them sound better.

The real reason for the turntable is twofold; I still like the way they sound and still have a bunch of albums. Second, I still struggle with the CD sound. At times it's hard to sit down and listen to an entire CD. For some reason the CD sound fatigues me, and I end up turning it off. CD sound to me can be too harsh, where certain horns like the Sax, has the tendency to sound artificial and that's also the case with Pianos, guitars and violins. The music goes well, but those instruments seem to be coming from a small area on each speaker rather than just being in the room. I remember when I worked at several High End store. back then they had the Out Board Dac units, that were being praised, but to me they were all still too harsh. At one point I was thinking I preferred the sound of Albums. But after playing around with my CD players, I'm more convinced that they are doing a terrible job at reproducing certain instruments. So that is when I put one on the bench. And then started looking at diagrams and discovered what happens in that whole entire section before the RCA's. And I also realized that they are also doing what I'm doing to improve the analog section on the very latest of my Moome mods.

So right after the DAC, there is a LOW PASS section, that on most of them is made up of two DUAL Op Amps. And what those stages are doing is cutting off the higher frequency range above 20K or the upper audio hearing range. And I also found out, much like the video DAC's. They are not paying enough attention to the Importance of properly separating the Analog supply of the DAC from the Digital operating voltage supply, that should also include the like grounding. And besides that, the actual Op Amps themselves and a few other things, just could be done better.

Well, long story short. I have a ardent High End guy that lives not far from me, who has a ton of expensive High End gear in his listening room, and two of the largest Martin Logan speakers I've seen. Yet, every time he puts a CD in that designer brand CD player, it's like listening to music and also hearing the sound of a nail scratching on glass. In other words to me, the better sound system makes the CD sound really too harsh on his setup. yet he's pleased with it. The other day I called him and told him I had a cheap Marantz 5 disk CD player, It'll blow away both of those fancy CD players he has. He sounded interested, but I also felt he did not want to experience another embarrassing comparisons moment. Anyway, I'm sure he'll get back to me, but he'll wait until his buddy George can also be there. In hopes of George being able to out talk me and explain what I would normally point out as being a normal comparison.

Anyway. Changing caps in these CD players do little of nothing to bring about a real change. But replacing those inferior Op Amps in the Low Pass section with the right chips, and do a few other changes, can really make a cheap player sound really good. This is not new, it is well discussed on the Internet. I just takes things a little further, and the results are quite impressive.

I'll get back here and post some of this as and hopefully someone else may have interest and being able to get some real quality out of some of these units. I can tell you now that it won't work and all and some of them. But it can be mind boggling what you can get to happen with some of them. I fond myself now really getting into the sound that the cheap 5 disk Marantz puts out and have been able to listen for hours..Smile
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gjaky




Joined: 05 Jun 2010
Posts: 2750
Location: Budapest, Hungary


PostLink    Posted: Mon Jan 01, 2018 9:49 pm    Post subject: Reply with quote

I think these days high-end audio is mostly about sound not music...
_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB
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jask




Joined: 17 Mar 2006
Posts: 9570
Location: kamloops BC


PostLink    Posted: Tue Jan 02, 2018 9:02 am    Post subject: Reply with quote

this sounds like a fun project, keep us updated! it would be nice to find a pair of identical players and mod one so you could A/B test them.
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Tue Jan 02, 2018 12:41 pm    Post subject: Reply with quote

gjaky wrote:
I think these days high-end audio is mostly about sound not music...


What's your point here, because this makes no sense. High End Audio regardless, is still very relevant to music. And your thoughts on it being more Sound than Music is shear ridiculous. Do you have the understanding that either sound or music could be routed through multiple DSP (Digital Signal Processing) and still maintain a TRUE enough nature to be considered HIGH END, as it was originally intended... back when there were no tone shaping or filters on the front panel, things that would otherwise be considered "distortion" are back on High End devices, to include there are also DSP and DAC's... and that's considered High End..Rolling Eyes

DAC's have come a long ways over the years, but still a careful ear would still reveal a compromised signal. And don't get me started on those rear and side channels, and we can discuss the tricks they use in a studio to recreate or simulate a Sound Stage so that your multiple channel home theater environment could sound like what you really should be hearing that's on the screen.


But anyway, if you want to have this discussion, simply start a thread dealing specifically with the subject.


Last edited by mp20748 on Tue Jan 02, 2018 3:55 pm; edited 1 time in total
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Tue Jan 02, 2018 1:05 pm    Post subject: Reply with quote

jask wrote:
this sounds like a fun project, keep us updated! it would be nice to find a pair of identical players and mod one so you could A/B test them.


I have that in my plans. Right now I have a Marantz CC4300 carousel player. It was giving to me some years ago, used. It had a MSRP of $310.00 - I've posted a link below that has a few comments stating the merits of making a few changes to these machines. For the most part, it's only a few Op Amps that required to greatly improved the outcome.

The improvements are mostly achieved from making changes only to the Low Pass stage, which seems to be OP AMPs only. Mainly because of how an Op Amp can easily be used as a Low pass filter and cost I'm sure. But a common problem with most of the older units and a bunch of the later ones, seem to be cost conscious use of cheap or inferior Op Amps.

The Chip manufacturers are quite aware of the problem with Op Amps and how terrible they have been sounding, and that explains why they seem to keep manufacturing other and more improved chips. take a cover off of anything audio, and the odds of those chips being there are high. But in no way could anything with these chips be considered High End or High Performance. like how Yamaha puts "Natural Sound" on their units, yet some are loaded with these chips. They can however sound better and as time have moved on they have gotten tremendously. But they still suck to some degree. And for the oddest reasons, the cheaper and most inferior chips are almost anything you can get audio. My Marantz SR5008 has a "DIRECT" switch on the front that supposed to get around both DSP and Op Amps, direct to a discrete transistor final stage. So far, I've only been able to tolerate them in general listening devices, but when sitting down for serious music, I'm not there yet. But have found recently that they do well in the Low pass stage of the CD players, when the right ones are used there.

My Marantz CC4300 required that I find the right chips of of the 5 or 6 that works well in these stages. And once that was done, it is very pleasing to listen to. Very musical and without that bottled up treble sound. I also have a modified Yamaha CDC697 that has a better low end. With the Marantz doing very well in everything, but weak on the lows. One of the chips I think I need to work better to change, and I have one I want to put there and will later. Doing a comparison I think would be a good thing, but with the my Marantz, it was very obvious. Only two parts!



"Submitted by strictlyamateur a Audio Enthusiast

Date Reviewed: February 23, 2006

Bottom Line:
The previous reviewer is right - a nice unit for the money, but the NJM/JRC2114D op amp is very brittle sounding. Upgrade it for a $50 OPA627 op amp module from PartsConnexion.com and you'll be very happy. It won't be easy to remove the stock op amp - you'll have to disassemble the unit to get to the bottom of the circuit board to de-solder it - but it's worth the effort. Happy listening"

There are different options around going for that expensive OPA627 listed above, that are more near the $5.00 cost range


Read some of the reviews here:

http://www.audioreview.com/cat/digital-sources/multiple-cd-players/marantz/cc4300/prd_143984_2758crx.aspx
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jask




Joined: 17 Mar 2006
Posts: 9570
Location: kamloops BC


PostLink    Posted: Tue Jan 02, 2018 10:55 pm    Post subject: Reply with quote

Audio vs sound... Smile
You have me interested in looking at my player now Mike! I have a NAD CD player that sounds good paired with an old Marantz but it would be interesting to look under the hood.
One of my projects this holiday season was to develop a shopping list to do a recap/service on my 2285B and I may just add some "extras" to the order for the CD player.
But that will have to wait ... Today is a blue sky and sunshine ski day Smile
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Tue Jan 02, 2018 11:18 pm    Post subject: Reply with quote

jask wrote:
Audio vs sound... Smile
You have me interested in looking at my player now Mike! I have a NAD CD player


What model number is that NAD, I'd like to look at the manual and suggest a few changes you could make to bring some real life out of it.

That 2285B is a highly regarded classic Marantz. Good idea to recap.
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garyfritz




Joined: 08 Apr 2006
Posts: 11373
Location: Fort Collins, CO


PostLink    Posted: Wed Jan 03, 2018 1:43 am    Post subject: Reply with quote

My brother has an old NAD CD player (and amp, and pream, and...) too. If you decide it's worth improving, I'll find out what model he's got. It's at least 30 years old so recapping would probably be a good idea to.
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jask




Joined: 17 Mar 2006
Posts: 9570
Location: kamloops BC


PostLink    Posted: Wed Jan 03, 2018 5:46 am    Post subject: Reply with quote

same vintage! - mine is a late 80s NAD 5220, just had a look at the schematics and it uses a NJM4560DX op amp... low slew rate but otherwise a decent old op amp. Checking caps esr and swapping out as needed is on my list, while I am doing the Marantz... but Mikes project dovetails right into that!!... and I have not put in my order yet, so maybe I can add a few more items to the list .....I actually like the smell of solder Smile
Google came up with an original service manual that is decent....
https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwiW_pythrvYAhVSx2MKHQT_By4QFggtMAE&url=http%3A%2F%2Fwww.vintageshifi.com%2Frepertoire-pdf%2Fpdf%2Ftelecharge.php%3Fpdf%3DNad-5220-Service-Manual.pdf&usg=AOvVaw2VPov9hAaBv0TWgwDe2dCK

...any thoughts Mike?
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Wed Jan 03, 2018 1:26 pm    Post subject: Reply with quote

Hey Jask, that's looks like a good unit in some ways, but it also shows to be overly filtered (analog out) in other ways.

I would start with pulling out the LM4560 and putting a socket there.

Usually a Low Pass filter section on most CD players, uses two op amp sections per channel as the filter itself, with the first Op Amp section being the actual Low pass filter. You'll also see a few caps going directly to ground, but that's never the case of the better units, because an Op Amp low pass filter section would normally provide a good cut off of everything above the selected frequency band.

On your unit, they have several filters, but are still using the same Op Amp Low Pass circuit that are used by most CD players. For instance in your Low Pass stage, they are using the NJM4560 as a Low Pass filter in the same manner that is more common, but they also show that they are using the FETs (Q509/510) to switch the cap that goes from the output of the Op Amp to the "-" of the same IC. There is also a resistor in series with the cap, which is also first time seeing. But using a cap only in the same manner as a feedback resistor, is all that's usually needed to chop off everything above the desired frequency band. So let's count this stage as Filter 1.

And then look at the DAC itself (diagram). The output (2) on the DAC shows buffers (internally) on its analog out (pins 16 - 30). And if you look a diagram of the chip itself, you'll see (internally) they have very similar Low Pass filters Op Amps inside the chip. To me, that indicates that the chip manufacturer include the Low Pass filters inside the DAC, and this is further supported by the caps that are going from the out of those internal Op Amps to the "-" of same IC. The cap is external to the DAC. And are shown as C520, C522, C21, C523. So let's put this a s filter 2. and now for the third filter (Low Pass). That is Z501 and Z502. And that would conclude our third Low Pass filter, with the DAC actually having two per channel internally built in.

Now, it appears NAD in their use of the chip, really complicated things, unless the DAC itself is extremely noisy. And if that's the case, there's not a lot you could do with it, to make it fully dynamic on the upper frequency listening range.



I would start with the Chip upgrade first, then look at those filters. What you really find in place of those 2200pf caps on the internal Op Amp out and "-" are normally 100PF or 120PF and that would also be the case for the two Op Amp filters (2700pf)

That LM4560, is a terrible chip for best audio, and may within itself be the reason for all the filters, because it's not a low noise chip by any means
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Wed Jan 03, 2018 1:37 pm    Post subject: Reply with quote

garyfritz wrote:
My brother has an old NAD CD player (and amp, and pream, and...) too. If you decide it's worth improving, I'll find out what model he's got. It's at least 30 years old so recapping would probably be a good idea to.



Gary, post the model number of his NAD. Some of those older units can really be made to sound great when upgraded.

My CC4300 has been so improved, that I find myself listening also with the task of hearing stuff I've never heard before.

One of my test sounds is the Eagles Hotel California. It's a later LIVE version. I heard it years ago while at Clearances house. They show the guitar players seated along the front of the stage, then they show the two guitar players dueling it out during their separate solos. It is an excellent recording, that the produces some of the cleanest and best group string reproduction of all. That CD is my best test CD for CD players.
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garyfritz




Joined: 08 Apr 2006
Posts: 11373
Location: Fort Collins, CO


PostLink    Posted: Wed Jan 03, 2018 5:41 pm    Post subject: Reply with quote

My brother's player is a 5170 CD changer. In a quick search I couldn't find a service manual for it.
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gjaky




Joined: 05 Jun 2010
Posts: 2750
Location: Budapest, Hungary


PostLink    Posted: Wed Jan 03, 2018 8:34 pm    Post subject: Reply with quote

mp20748 wrote:
gjaky wrote:
I think these days high-end audio is mostly about sound not music...


What's your point here, because this makes no sense. High End Audio regardless, is still very relevant to music. And your thoughts on it being more Sound than Music is shear ridiculous. Do you have the understanding that either sound or music could be routed through multiple DSP (Digital Signal Processing) and still maintain a TRUE enough nature to be considered HIGH END, as it was originally intended... back when there were no tone shaping or filters on the front panel, things that would otherwise be considered "distortion" are back on High End devices, to include there are also DSP and DAC's... and that's considered High End..Rolling Eyes

DAC's have come a long ways over the years, but still a careful ear would still reveal a compromised signal. And don't get me started on those rear and side channels, and we can discuss the tricks they use in a studio to recreate or simulate a Sound Stage so that your multiple channel home theater environment could sound like what you really should be hearing that's on the screen.


But anyway, if you want to have this discussion, simply start a thread dealing specifically with the subject.


I just wanted to support your observation as you told listening a designer brand (high-end) player with "better sound" is less pleasing to listen than your modified CD player that has "more music" that's all.

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Wed Jan 03, 2018 10:12 pm    Post subject: Reply with quote

garyfritz wrote:
My brother's player is a 5170 CD changer. In a quick search I couldn't find a service manual for it.


It may take awhile, but I'll find the service manual.
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Wed Jan 03, 2018 10:13 pm    Post subject: Reply with quote

gjaky wrote:


I just wanted to support your observation as you told listening a designer brand (high-end) player with "better sound" is less pleasing to listen than your modified CD player that has "more music" that's all.


Thanks for explaining this..
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mp20748




Joined: 12 Sep 2006
Posts: 5585
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sat Jan 06, 2018 4:57 pm    Post subject: Reply with quote

I've been looking for how you can post drawings of a diagram, or create your own drawing of components in a diagram.



Still have not found that schematic Gary, but I'm sure i will.
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