DIY Discrete regulators

[gareth]

Hi, I am fairly new to this DIY scene and was wondering if it would be possible to build my own discrete regulators to be used with my Marantz CD 63se.

I know there are commercial versions availble using SMT components, but still I would like to try.

What I have seen fit straight into where the existimg LM... type regulators are.

Any help would be appreciated.

Thanks
Gareth

[Mooly]

Hi Gareth, Yes it's possible of course to make a discrete version of a 3 pin regulator, but the the performance of even standard 78xx types is so good you could easily end up with a much poorer supply. Semiconductor manufacturers invest millions in design and it's wishful thinking to think a handful of discrete components will do a better job. That's not to say it's not good fun of course If you want to try tweaking you're player check out some of the other mods first, op-amps and so on. If you make a mistake on a P.S.U. you could easily right the player off. If you are intent on making a discrete regulator I would suggest making one first as a separate project and fully test it (noise, regulation, dropout etc) on the bench rather than in the player.
Regards Karl

[Spartacus]

Here's a good one to try:

http://www.audioasylum.com/forums/pc...s/2/24191.html

Dan

[gareth]

Originally posted by Mooly
Hi Gareth, Yes it's possible of course to make a discrete version of a 3 pin regulator, but the the performance of even standard 78xx types is so good you could easily end up with a much poorer supply. Semiconductor manufacturers invest millions in design and it's wishful thinking to think a handful of discrete components will do a better job. That's not to say it's not good fun of course If you want to try tweaking you're player check out some of the other mods first, op-amps and so on. If you make a mistake on a P.S.U. you could easily right the player off. If you are intent on making a discrete regulator I would suggest making one first as a separate project and fully test it (noise, regulation, dropout etc) on the bench rather than in the player.
Regards Karl

Cheers Karl, I assume that I would need an oscilloscope for testing and fine tuning ? Would I need a signal generator ?

In respect of the op-amps, is it simply a case of a straight swap with the existing ones or will I have to change resistance/capacitance on the PCB ? Do you have any suggestions ?

Thanks
Gareth

[gareth]

Originally posted by Spartacus
Here's a good one to try:

http://www.audioasylum.com/forums/pc...s/2/24191.html

Dan

I AM SPARTACUS ! Right anyway, thanks for the link Spartacus. This seems like an achievable design. Do you agree in that it may not be worthwile in trying to produce these ?

NO I AM SPARTACUS !

Thanks
Gareth

[Spartacus]

Hi Gareth,

definately worthwhile building you own. Take a look at this thread:

SKA Audio

[Mooly]

Have you looked at the "Marantz cd63 cd67 mods" thread on this forum ? It's just below you're thread at this moment. About 450 pages at the last count ! I find one of the easiest and most effective ways to clean up the power supply is to add a 0.1 mfd surface mount cap directly under each elecrolytic. This counters the rise in impedance of the caps at H.F. and assuming a 5mm pitch they can be added so that they look like original fitment. As for op-amps, it depends what is fitted, dual or single. I have had very good subjective performance with OPA604 (single) and OPA2604 (dual). Let us know how you get on.
Karl

[00940]

It is not that difficult to improve over lm78** regulators if you follow well known designs for which PCBs are available (such as the Jung or Sulzer) or simply use a lm317 with some tricks (see : http://www.acoustica.org.uk/ ).

However it is not quite certain that you will get actually improved performances if you just want something that fit into the holes of the previous regulators. The layout of the board (grounding especially) is playing a big part in the performances of regulators.

Easy to build discrete regulator (from Jocko Homo) :

http://www.diyaudio.com/forums/attac...amp=1070501103

[pilli]

Originally posted by Mooly
(...) make a discrete version of a 3 pin regulator (...)
(...) the performance of even standard 78xx types is so good (...)
(...) wishful thinking to think a handful of discrete components will do a better job (...)

(...) check out some of the other mods first (...)

...I hope I'm not misunderstanding something (surprised that nobody reacted before) but it is definitely possible and reasonably easy to do better than the 78xx.

I am really not that good, yet I was able to implement Jung regulators. These are probably not considered the easiet, but based on Jung's and Jan Didden's articles, it's almost "Lego".

My implementation is sure not "impeccable" and yet the improvement over 78xx/79xx (on a Denon DCD-1560) is really astonishing (firmer bass, clearer cleaner sound, air and definition, to describe quickly). We're not talking nuances, it is a definite improvement, tested before and after against the same reference.


Just one of many possible introductions into this subject, and for a summary of good search words, you can start looking at this:
http://tangentsoft.net/elec/opamp-linreg.html

Then spend some time in these forums, you'll find all you need.



...ok, these are not completely "drop-in" to the 78xx, but really, I could make it work using no more than voltmeter and soldering iron and two additional screened cables for "rs".


Then I fully agree with Karl:

- Test "outboard" before installing, at least the output voltage upon different inputs (load with a R+LED is enough)

- Try the other mods too (some are quite "drop-in", though not risk-free)

- Do it on a "disposable" player (get a cheapo on eBay; better, get two of the same and keep one stock, as reference for comparing on improvements)



But by all means, give it a try.




_

[gareth]

Originally posted by Mooly
Have you looked at the "Marantz cd63 cd67 mods" thread on this forum ? It's just below you're thread at this moment. About 450 pages at the last count ! I find one of the easiest and most effective ways to clean up the power supply is to add a 0.1 mfd surface mount cap directly under each elecrolytic. This counters the rise in impedance of the caps at H.F. and assuming a 5mm pitch they can be added so that they look like original fitment. As for op-amps, it depends what is fitted, dual or single. I have had very good subjective performance with OPA604 (single) and OPA2604 (dual). Let us know how you get on.
Karl

So how do I know which type, single or dual, op-amps I should use ?