Im ordering some parts now.
I think im going with Nichicon BP-S muse caps for output coupling and Nichicon BP muse for the PCM1702's. Also i will double the PSU caps and replace those with low esr.
I bought a complete low noise regulator on ebay to build a seperate PSU for the analog stage. Not sure if i will actualy use it, but it will be fun to try.
I also will do the trick with the paralel SMD caps.
1 thing i dont fully understand is how to decouple the opamps. Right now the + and -12v are both decoupled to ground with 100nF. I understand that i should place some extra decoupling. I have done a bit of reading... Should i place some 22uF? caps parallel with the current 100nF? help me out here🙂
I think im going with Nichicon BP-S muse caps for output coupling and Nichicon BP muse for the PCM1702's. Also i will double the PSU caps and replace those with low esr.
I bought a complete low noise regulator on ebay to build a seperate PSU for the analog stage. Not sure if i will actualy use it, but it will be fun to try.
I also will do the trick with the paralel SMD caps.
1 thing i dont fully understand is how to decouple the opamps. Right now the + and -12v are both decoupled to ground with 100nF. I understand that i should place some extra decoupling. I have done a bit of reading... Should i place some 22uF? caps parallel with the current 100nF? help me out here🙂
You just caught me lol
If you decouple to ground, then any supply variations "couple" via the cap into that ground with the risk of introducing that "ripple" into the signal path. That problem in some ways is worse with large caps.
What you do is decouple across the actual supply pins of the opamp etc directly.
Have a read at this,
http://focus.ti.com/lit/an/sloa069/sloa069.pdf
I wouldn't add 22uf from supply to ground.
If you decouple to ground, then any supply variations "couple" via the cap into that ground with the risk of introducing that "ripple" into the signal path. That problem in some ways is worse with large caps.
What you do is decouple across the actual supply pins of the opamp etc directly.
Have a read at this,
http://focus.ti.com/lit/an/sloa069/sloa069.pdf
I wouldn't add 22uf from supply to ground.
Im going to read that pdf sometime soon, but i get the idea that its more for high speed opamps and higher freqenties than i am working with.
But do i understand it right that i should leave the current 100n that are placed between V+ and ground, and V- and ground. And also add a cap between the V+ and V- pin? If so, what value should it be? a big 22uF or even more, or should i use a low 1uF?
If it were me, I would add a low esr electroylitic, say 1uf to 4.7uf soldered directly between opamp supply pins (meaning, as in on the pins of the opamp itself... neatly 🙂) and leave the 100n in place.
You have to remember that the rails are pretty good anyway... there won't be much ripple/noise etc there. You have to work with what is already there 🙂
The coupling of PSU disturbance is much more of an issue with power amps etc where the unregulated supplies have a lot of noise/ripple and signal components on them. A large decoupling cap from a rail like that to "ground" can ruin the performance. The trick here is to keep PSU and signal grounds separate, but we can't do that with the Denon... and it doesn't apply in quite the same way as the rails are steady anyway.
You have to remember that the rails are pretty good anyway... there won't be much ripple/noise etc there. You have to work with what is already there 🙂
The coupling of PSU disturbance is much more of an issue with power amps etc where the unregulated supplies have a lot of noise/ripple and signal components on them. A large decoupling cap from a rail like that to "ground" can ruin the performance. The trick here is to keep PSU and signal grounds separate, but we can't do that with the Denon... and it doesn't apply in quite the same way as the rails are steady anyway.
Got it! Im also beginning to understand the whole decouple thing a bit more. Thanks a lot for all the info!
I will be trying this regulator for powering the opamps. It ahs pretty good specs and will fit fine 🙂 I wonder if it will prove te be a big diffrence with the stock PSU. The stock psu will get a few small upgrades and it will poer just the digital part
I will be trying this regulator for powering the opamps. It ahs pretty good specs and will fit fine 🙂 I wonder if it will prove te be a big diffrence with the stock PSU. The stock psu will get a few small upgrades and it will poer just the digital part
RE clock and YM3623...
http://www.diyaudio.com/forums/digital-source/96321-little-denon-dac-mod.html
just checked the DA500 schematic...
as i can see, we short the C126 (10 pf) witn the transistor BC558.
But when it is closed, we have up to 6pf collector-base capacitance.
so this way we have 10 pf at pin 5 and 16 pf at pin 6 of the YM3623.
so i am in doubt about proper work of YM3523.
Can anybody tell me - will it work properly?
http://www.diyaudio.com/forums/digital-source/96321-little-denon-dac-mod.html
just checked the DA500 schematic...
as i can see, we short the C126 (10 pf) witn the transistor BC558.
But when it is closed, we have up to 6pf collector-base capacitance.
so this way we have 10 pf at pin 5 and 16 pf at pin 6 of the YM3623.
so i am in doubt about proper work of YM3523.
Can anybody tell me - will it work properly?
did it affect the sound quality?
Hi SuperKris, I also have a denon da 500 for many years now, but now I was thinking of buying another dac to upgrade my system. That is until I read all the mods that can be done on the da-500. Now I also think about doing these mods. Can you tell me if your mods were a success? How did it affect your sound?
Hi SuperKris, I also have a denon da 500 for many years now, but now I was thinking of buying another dac to upgrade my system. That is until I read all the mods that can be done on the da-500. Now I also think about doing these mods. Can you tell me if your mods were a success? How did it affect your sound?
I added that mod a while ago too, but recently ran into a problem that sometimes, the DAC would lose the signal lock. A friend told me this may have to do with the mod. So I removed it again. Haven't tested yet if the problem is solved.
Quite an old thread 🙂
Yes, I wouldn't be happy just randomly stopping a clock signal without knowing much more about what happens.
Losing lock though may be down to a mismatch in transmitter and receiver clock signals. They can be surprisingly critical and it's often reported in the HiFi press in reviews that such and such a piece of kit was a little outside the spec and that this may cause problems.
So your problem could be down to other things...
Although it is an old thread, I would like to share my "experience" with modding this dac. First off all I did not do the mods myself, I went to a audio repair shop. He did the following mods.
1Clock-killer mod
2Connected the 5V voltage regulator to a not used secondary winding.
3Added Silver-mica caps in the analog power supply
This really took the sound up a notch, more detail and it sounds more at ease. I dont have the locking problem.
1Clock-killer mod
2Connected the 5V voltage regulator to a not used secondary winding.
3Added Silver-mica caps in the analog power supply
This really took the sound up a notch, more detail and it sounds more at ease. I dont have the locking problem.
I ripped the clock mode out of my DA-500 a few days ago, and it just lost signal lock about 10 times. Seems it is not the cause of my problem after all.
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