DIY Discrete regulators

gareth

Member
2008-01-31 3:38 pm
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

Administrator
Paid Member
2007-09-15 8:14 am
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
 

gareth

Member
2008-01-31 3:38 pm
Mooly said:
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
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
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

Member
2003-09-03 12:17 pm
Liège
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/attachment.php?s=&postid=275730&stamp=1070501103
 

pilli

Member
2006-08-15 9:46 pm
Mooly said:
(...) 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

Member
2008-01-31 3:38 pm
Mooly said:
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 ?
 

poynton

Member
2005-03-10 11:57 pm
UK
Use the force ( if not the search button!)

Hi

Looks like you are going over ground already covered in depth on the CD63/67 mods thread!!! Please read !!

For mods to the CD63 , see Ray's page :-

http://home.quicknet.nl/qn/prive/ra.vdsteen/index_en.html


For 'improved' regulators, 'Raygulator" :-

http://www.diyaudio.com/forums/attachment.php?s=&postid=1347230&stamp=1194640833

Various members have made them, search the thread for Raygulator""

For improved opamps , the LM4562 is generally acknowledged as the best drop-in (dual opamp)

The best output stage is discrete :- see Ray's page above.


Andy
 

gareth

Member
2008-01-31 3:38 pm
Re: Use the force ( if not the search button!)

poynton said:
Hi

Looks like you are going over ground already covered in depth on the CD63/67 mods thread!!! Please read !!

For mods to the CD63 , see Ray's page :-

http://home.quicknet.nl/qn/prive/ra.vdsteen/index_en.html


For 'improved' regulators, 'Raygulator" :-

http://www.diyaudio.com/forums/attachment.php?s=&postid=1347230&stamp=1194640833

Various members have made them, search the thread for Raygulator""

For improved opamps , the LM4562 is generally acknowledged as the best drop-in (dual opamp)

The best output stage is discrete :- see Ray's page above.


Andy


Cheers Poynton, i will have a look at these. You can get them from farnell's right?

I've just been reading about biasing these into class-a mode and it sounds interesting and not difficult>

Thanks
Gareth
 

poynton

Member
2005-03-10 11:57 pm
UK
Re: Re: Use the force ( if not the search button!)

gareth said:



Cheers Poynton, i will have a look at these. You can get them from farnell's right?

I've just been reading about biasing these into class-a mode and it sounds interesting and not difficult>

Thanks
Gareth

Biasing to class A has met with mixed reviews.

In its simplest form (adding a resistor) it is easy to implement but it really needs a constant current source/sink for optimum.

However, it is not really needed with the LM4562, which is available from a lot of places inc. Ebay.



Andy
 

gareth

Member
2008-01-31 3:38 pm
Re: Re: Re: Use the force ( if not the search button!)

poynton said:


Biasing to class A has met with mixed reviews.

In its simplest form (adding a resistor) it is easy to implement but it really needs a constant current source/sink for optimum.

However, it is not really needed with the LM4562, which is available from a lot of places inc. Ebay.



Andy

Thanks poynton. I have just bought a pair of these and now I anticipate their arrival. I have also found a Schaffner iec inlet filter in Farnells so I was wondering whether to get one of these even though there seems to be a lot of differing opinions regarding the use of these.

Thanks
Gareth
 
pilli said:



...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".

<snip>

_


While not a Didden-Jung, Jens Rasmussen's PSU 2.2 was a dramatic improvement over 78xx in my active crossovers. A PCB Group buy is brewing here WIKI Original discussion thread here and more concise information at my website. Nominally a +/-15V regulator, it can be scaled up or down fairly easily with a couple of resistors and a voltage reference change if you are going much lower.

I ran the last couple of group buys but will have limited involvement this time. Yes it's one of my babies, so take my enthusuasm with a grain of salt. The psu was well received in the Linkwitz Orion forum, though.
 

poynton

Member
2005-03-10 11:57 pm
UK
Re: Re: Re: Re: Use the force ( if not the search button!)

gareth said:


Thanks poynton. I have just bought a pair of these and now I anticipate their arrival. I have also found a Schaffner iec inlet filter in Farnells so I was wondering whether to get one of these even though there seems to be a lot of differing opinions regarding the use of these.

Thanks
Gareth

The big advantage of an inlet socket/filter is that it allows you to change the mains cables.

BUT

Don't do it until you have finished modding or you will be forever unsoldering.

Unless:-

On the back panel are a couple of lugs which fix to the side panels.
If you break these off, you can remove the back panel complete with the circuit board. Saves unsoldering and adds rigidity.

Beware, the circuit tracks are very flimsy and come detached or break at the soldered joint.
Also the ribbon connecters fail when plugged/unplugged often.

You will get improvements in sound by removing the headphone circuit and removing the muting transistors. (lift the leg and use the transistor to power a reed relay for muting instead)

If you use the LM4562, bypass the HDAM module. The result is excellent.

All the above is in the CD63/67 mods thread.


Andy
 

gareth

Member
2008-01-31 3:38 pm
Right, I have recieved the LM4562NA op-amps and I have bought some holders for these as suggested.

I have removed the feeds for the headphone circuit, installed the op-amps and also an iec inlet filter. To my ears, now, there is better separation with the instruments and there seems to be more control in the bass region. Also the soundstage has improved and music is now more fluid. Previously I thought the top-end could be a little harsh on some cd's and this too has improved.

What I haven't done though is to bypass the HDAM modules (needed access to the PC but couldn't). Will bypassing these help with the top-end ? What I would like to achieve (this may sound contradictory) is a more analog type of sound at the top. In the past I have always used turntables and open reel tapes and always admired the sounds of these.

Thanks
Gareth