JSR03 - information

[Keljian]

http://www.amb.org/audio/mmm/ .... surely

yep.. that'd be the one.. I was in a hurry.


will 150uF be ok for C4 and C12? (I can't seem to find 100v/35v panasonic FM)

[peranders]

The exact value isn't critical. Walter Jung used the odd value 120 uF! 47-220 uF is "normal" I think.

[Keljian]

parts ordered, more info about this project here:

http://www6.head-fi.org/forums/showthread.php?t=123686

[Sigurd Ruschkowski]

Indeed,
and
performance
is not the same as good sound :D



Sigurd

Well, yes, I would say that I am kind of DIY audiophile. I do focus much on the quality of components.

Quality isn't the same thing as performance.  :D

[Sigurd Ruschkowski]

P-A,

I see on the head-fi forum that you prefer the LM329 before the LM431"
"The voltage reference given in P-A's stock part list is LM431, he says the LM329 is better, so based on that, that's what I'm going to use.".

I am curious - me being a datasheet reader - why do you prefer the LM329?



Sigurd

[Sigurd Ruschkowski]

Interesting thread, Jazper!

"As for rectifier diodes, diyaudio people seem to like the MUR820, which is overkill but cheap enough to use, so I plan to use a reasonable clone of it."


I would advice against the clones of the MUR820 as I have read that ONSemi's have the best ones. As a matter of fact I would use the soft recovery ones, MSR, instead.


I would definitlively go for a dual mono power supply! and also for each mono channel a dual rectifier bridge setup. For lowest noise and for best stereo separation.

Check out how I did with P-A:s RFB02s in dual bridge setup:
http://www.sjostromaudio.com/phpBB2/viewtopic.php?t=12


As for wires, do try solid silver wire (max 0.5mm in diam) - for everything.



Sigurd

parts ordered, more info about this project here:

http://www6.head-fi.org/forums/showthread.php?t=123686

[/url]

[peranders]

LM329 has less noise and is more stable but can't be adjusted. LM431 hasn't got any noise data but it is higher, still in real life with LP-filter the regulator has pretty low noise, way better than needed in most cases.

So if you want more than 6.9 volt and a very temperature stable output voltage LM329 is OK. If you want to save same money and in the same time want voltages från 2.5 V and up and also want to be able to tune the voltage in an easy way LM431 is to prefer.

[Keljian]

Interesting thread, Jazper!

"As for rectifier diodes, diyaudio people seem to like the MUR820, which is overkill but cheap enough to use, so I plan to use a reasonable clone of it."


I would advice against the clones of the MUR820 as I have read that ONSemi's have the best ones. As a matter of fact I would use the soft recovery ones, MSR, instead.


I would definitlively go for a dual mono power supply! and also for each mono channel a dual rectifier bridge setup. For lowest noise and for best stereo separation.


As for wires, do try solid silver wire (max 0.5mm in diam) - for everything.



Sigurd

The M3 has a rail splitter chip in the design, it's designed to have single supply.

As for the MUR820, I'm not too fussed to be frank, it's going to have 8000uF of capacitance after it, if that doesn't smooth the wave nothing will. The models I'm using are of high enough quality, and it's difficult to get ONsemi stuff in australia (I imagine it's easy in europe). I've just made a bulk order from mouser, so unless you're feeling charitable and feel like sending me some really nice rectifier diodes... :)

I'm sticking to silver coated copper wire.. I think the difference will be marginal compared to pure silver

[peranders]

The most important thing is that it must feel right besides pure technical matters.

Your amp is a low power amp so I feel that choice of diodes are less important  than if it would have been a regular power amp.

[Keljian]

The most important thing is that it must feel right besides pure technical matters.

Your amp is a low power amp so I feel that choice of diodes are less important  than if it would have been a regular power amp.

How do you mean, feel right? (just clarifying)

[Keljian]

ok .. after doing more research I've decided to go ahead and buy some harris RHRP860s locally

[peranders]

It must feel good. That's it! Not more, not less. It's important to like the results and chosen parts.

[Sigurd Ruschkowski]

8000uF of capacitance  will surely give you almost zero 50/60 Hz ripple, but the reason for having the soft recover diodes or the Schokky diodes is to have as little high req noise coming through from the rectifier diodes to the amplifier. If you have seen photos/images of the hf noise from a diode you will understand what I mean.

One way to get rid of the hf noise is to use smaller caps in paralell with the 8000uF caps you are using. I sometimes use 3 different polyprop caps in paralell; each cap 1/100th of the previous larger one.

Another way to minimise hf noise is to use soft recovery diodes or Schottky diodes.



Sigurd

Interesting thread, Jazper!

"As for rectifier diodes, diyaudio people seem to like the MUR820, which is overkill but cheap enough to use, so I plan to use a reasonable clone of it."


I would advice against the clones of the MUR820 as I have read that ONSemi's have the best ones. As a matter of fact I would use the soft recovery ones, MSR, instead.


I would definitlively go for a dual mono power supply! and also for each mono channel a dual rectifier bridge setup. For lowest noise and for best stereo separation.


As for wires, do try solid silver wire (max 0.5mm in diam) - for everything.



Sigurd

The M3 has a rail splitter chip in the design, it's designed to have single supply.

As for the MUR820, I'm not too fussed to be frank, it's going to have 8000uF of capacitance after it, if that doesn't smooth the wave nothing will. The models I'm using are of high enough quality, and it's difficult to get ONsemi stuff in australia (I imagine it's easy in europe). I've just made a bulk order from mouser, so unless you're feeling charitable and feel like sending me some really nice rectifier diodes... :)

I'm sticking to silver coated copper wire.. I think the difference will be marginal compared to pure silver

[Sigurd Ruschkowski]

It is like eating: one wants to eat what one likes.

P-A, I agree with you totally: it has to feel right with the components and with the design! The feeling is what it is all about.



Sigurd

It must feel good. That's it! Not more, not less. It's important to like the results and chosen parts.

[Keljian]

Well the new diodes almost certainly should fix the HF noise if there is any.

I think I understand what you mean, and that is why I've chosen the parts I have for this, and the main motivation behind using your design P-A, because in doing so, I know I'm building a high quality setup.