Power Supply Boards - recapping & improving

ssouci

ssouci

Well-Known Member
POWER SUPPLY BOARDS > recapping & improving

after studying many threads about recapping and restoring Marantz gear (especially solid state 22XX receivers and related amps), it seems that more and more attention is being paid to the humble power supply boards

not only do these boards seem to be the most prone to outright failures, but surprisingly, the choice of components might have a greater impact on sound quality than one would think (eg. see Patfont's "capacitor shootout" thread)

I'm hoping to start a discussion here revolving around PSBs only, with an emphasis on component choices and possible modifications (during a recap/restoration), in order to squeeze out maximum sound quality, with reasonable consideration to long-term stability and reliability

for example, some of the questions I have:
  • what kind of PSB is found in a typical 22XX receiver?... is it a "switching type" and if so, what does that mean to the layman?
  • how can a PSB affect sound quality so much... after all, doesn't it just provide power?
  • it used to be suggested to just stick in all Panasonic FCs and you're good to go!... but now, seems that all kinds of other and supposedly better recommendations are being made, eg: Panasonic FM, Nichicon PW, Nichicon HE, Elna Silmic II, Elna Cerafine, etc... which *specific* brand caps are the best and why?... do any really stand out & will the differences be noticeable?
  • on the typical PSB, there are usually large and small value caps... should these be different, or is it best to use the same brand for all?
  • what about 85C vs. 105C rated caps... are the higher ones necessary and do they sound worse? (my 2230 runs ice cold and no way approaches 85C.... my 2275 runs warmer plus has a hot resistor on the PSB, and even then might not reach 85C (?))

and the list goes on...

would love to hear from others on this subject -- especially knowledgeable experts!... any photos would be great

thanks in advance
 
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thanks PB Audio!

I've seen the second article, but not the first (which is highly technical and I can't appreciate it all)

unfortunately, the first is getting really old, and was printed before many of the newly available caps were probably even conceived

also, the Juaenda article (more relatable, but also getting old) does not cover some of the more commonly suggested caps, and notably leaves out Elna Cerafine and some of the other Nichicon product lines (eg. PW, HE, FG, etc.)

I'm really hoping to figure out the current state-of-the-art for Marantz power supply rebuilding, and keeping in mind the current parts suppliers and what they offer easily and within reason price-wise (eg. I'd pay $2-5 per cap if it's "great" over a basic $1 cap, but not say $10 or more unless it's just in a few key locations)

eg: what can I get now at Digikey, Mouser, Parts ConneXion, etc.

Patfont came close to this, but there was still some controversy concerning longevity, plus he did not cover all the most common caps suggested for PSBs
 
2 cents....

Walter Jung's and Rich Marsh's article has not aged one bit... The physics have not changed one bit.

We audiophile types owe them a debt of gratitude for writing that doc. Power supplies are much simpler for caps... The idea is to discharge enough power and quickly... Signal path is more complex because you need to charge and discharge quickly.

Power supply's may be in hotter environments. The key is using localize bypass caps, with Marantz did do on most applications.

That article is the best you can possibly find on the physics of what is affecting the sonics.

There has been a slight shift in some ( improvement ) the parameters of some of the brands/types of caps. But the overall issues are still exactly the same for each type.

The major changes have been mainly in the stacked film and the smd chip caps. Otherwise Teflon is still top of heap....

To me it seems like capacitor development has slowed down since the 80s , I wish some one would develop a film cap in the 400uf range with 40v rating and is not much ( 2x the size ) larger than an electrolytic of the same rating. Smaller films would sell like hot cakes....



So the key is recapping with a quality cap.....

Signal path is more critical, but less likely to be roasted by heat.

My 2 cents....

Jk
 
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All the questions you have asked have been answered in this forum, use the search function.

I think you have a 2230 and a 2275, they do not use a switching power supply. You have Nichicon HE's in your power supply, the Nichicon data sheet says for switching power supply. This does not mean you put in the wrong caps. Nichicon HE's are very good. If you look at some of my Sansui, Pioneer, Advent, NAD rebuilds you will see that I have tried and used PW's, HE's etc. I have tried installed and listened to all the caps you mention.
It would be perfect for you to remove the 5 HE's in your 2230 P/S and install maybe Silmic II's and let us know what you think. They are easy to replace and the cap pads are pretty robust on that board. :D

From what I remember you seem to like a more lively and up front sound (like your 2275) you may prefer the Cerafines.

***while on the P/S board after you give a listen then upgrade the 2 diodes, as done in my rebuild.
 
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No vintage Marantz use switchers.... They are all bridge rectifier, zener diode and series shut regulators....

Switchers produce ungodly amounts of noise....
 
ssouci said:
power supply boards not only do these boards seem to be the most prone to outright failures, but surprisingly, the choice of components might have a greater impact on sound quality than one would think (eg. see Patfont's "capacitor shootout" thread)
Click to expand...

I'm only on page 26 or so of that thread. Getting there but not finished.
Many have found benefits to upping the storage capacity of the power supply.

ssouci said:
I'm hoping to start a discussion here revolving around PSBs only, with an emphasis on component choices and possible modifications (during a recap/restoration), in order to squeeze out maximum sound quality, with reasonable consideration to long-term stability and reliability
Click to expand...

Just the boards or the chassis mounted PS caps, too?

What do you consider long-term reliability? We are a few years past the good life for many original Marantz PSBs but the first 25 years were great. Are you looking for more than that? This is the reason many techs here go with the high temp, long life caps, not the audio caps when they do the rebuilds. Just new caps and the unit is going to be better than a unit with old, tired caps.

ssouci said:
questions I have:
it used to be suggested to just stick in all Panasonic FCs and you're good to go!... but now, seems that all kinds of other and supposedly better recommendations are being made, eg: Panasonic FM, Nichicon PW, Nichicon HE, Elna Silmic II, Elna Cerafine, etc... which *specific* brand caps are the best and why?... do any really stand out & will the differences be noticeable?
Click to expand...

There are sonic differences in these caps. Sonic differences are a personal opinion and this is where one can tailor the sound to their liking. Putting a clear, crisp cap into a sluggish, bloated amp or putting in an ultra smooth sounding cap into an amp with a fast, crisp sound will tailor the sound to a more middle ground. Using the information in patfont's thread will help get one to the correct cap for the job.

ssouci said:
on the typical PSB, there are usually large and small value caps... should these be different, or is it best to use the same brand for all?
Click to expand...

This is a project waiting for your experimentation and our reading pleasure of your results. It seems it will make a difference, sometimes significant.

ssouci said:
what about 85C vs. 105C rated caps... are the higher ones necessary and do they sound worse?
Click to expand...

Again, your experimentation on this will help us learn. Others on the web may have done this type of work but like I said, I'm only on about page 26 of one of these. If you really want to determine if an 85°C sounds better than a 105°C you need to use Nichicon (or other suppliers) chart to select what the manufacturer says are identical caps except one being high temperature. You can use this chart to help:
http://www.nichicon.co.jp/english/products/alm_mini/pict_f.htm and select Diagram Search along the top of the image.

The same can be done with the larger caps: http://www.nichicon.co.jp/english/products/alm_larg/pict_f.htm

ssouci said:
eg: what can I get now at Digikey, Mouser, Parts ConneXion, etc.

Patfont came close to this, but there was still some controversy concerning longevity, plus he did not cover all the most common caps suggested for PSBs
Click to expand...

Look over the offerings based on the manufacturer and then seeing what is offered by the vendors is more homework for you. Since the Black Gates are NLA, there has been a bit of discussion about proper caps in audio gear. Lots of work left to do, but if you learn about audio caps now being offered, you might find that you don't need to worry about the traditional caps we use to recap. Knowing about capacitor specifications would help to determine if any specs were better for PS use or not and if an audio cap was not a good choice to try there.


Let us know how your doing on this project.
 
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thanks for the replies everyone

sorry, but I'm not an electrical engineer (mechanical) and have a limited interest in studying the electrical theory, so am looking for some quick & dirty shortcuts to choosing the "best" caps from current suppliers

I assume that the brightest minds at the parts manufacturers have done all the hard work for us, and are now offering their best parts for sale

also, between all the hundreds(?) of amateur rebuilders, hobbyists, and professional techs participating here on AK, we must be able to come up with a bunch of "top picks", especially for caps which seem to be key with aging equipment (including Marantz)... people could then review the top picks and arrive at their own consensus

for example, a "top 5" list (with rating scale) could look something like this (this is a fake sample only!):

Elna Silmic II (9/10)
Elna Cerafine (8/10)
Nichicon PW (6/10)
Panasonic FM (4/10)
Nichicon HE (4/10)

like I said, it used to be easy, just put in Panasonic FCs!

however, after seeing some of the "disruptive" results obtained by Patfont and others who have spent time experimenting with non-traditional choices, it seems that "caps is caps" is probably not true

in fact, the other day I had someone assuredly say that "putting Elna Cerafines into your 22XX power supply board will supercharge it and totally transform your sound"... seeing as I have Nichicon HEs in there now, this sounds hugely interesting!

so before buying new parts, ripping out my carefully-installed HEs, and installing new caps, I just want to know what to use, and also get a gauge of whether or not others (who have already done this) seem to feel it will make any difference

my 2230 sounds very nice, but I have yet to see anyone else say they used HEs in the their power supply, so I have a nagging feeling I could have made a better choice (plus they look kinda boring!... small and plain black)... however, if they are actually a pretty good and common choice, I'll just leave them in

I also want to use the info for possibly RE-capping my recapped 2275, where I had used all FCs back before I knew any better!... also, if I pick up another Marantz, I will surely be recapping it and want to make the best choices

thanks
 
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Buy a unit with all film caps in the signal path and your quest will be easier....
 
Various P/S pics:

I like: (For Marantz)
Silmic II, and in locations where needed to bump up or large values Nichicon KS or KG.
What ever modern cap you choose for your power supply it is going to be way better then what you are removing.



This is Silmic II, with the large cap being a Nichicon KS (2215B) with diode upgrade. (below)















 
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It is going to be very hard to filter the results as only a couple folks have actually compared different caps installed in the same unit. So not much true comparison info will enter into your database.

Those that do respond will have put Brand X Type C into their unit and be very happy with it cause it is new and not at end-of-life. This will skew your data to like most anything that is not compared with something else that is also new.

This means that if you don't step forward to do the work it won't get done and we can fall back to the work that has been done by patfont.

I have used his information to select caps based on their sound to tailor some gear I have. I'm ordering soon and will install but since it is not the Marantz 2230, it will not make any difference in your data collection.

As an ME it shouldn't take you long to learn about caps and what is most desirable for PS applications. But you might find a cap designer to talk to and get that info quick.

Why don't you grab a set of completely different sounding caps for your HEs and install them and let us know what you hear?

For all the trouble and expense of doing all the work to make the 2230 the best sounding it can be, I'd put my money and effort into a different unit. But then I'm not a small receiver guy. Not many of my speakers work well with that kind of power.
 
Thanks for this thread guys. I am trying to take a lesson here, i haven't understand yet how the power supply caps improve the sound.

Is it just a sound quality improvement (noise reduction) or it does change the voice (detail, freq. response, etc)?

I would like to improve the longevity of my Marantz. However, I am reluctant in going that way. It could be caused by aged parts, but I do like the way the unit is sounding.
 
cortico said:
...I am trying to take a lesson here, i haven't understand yet how the power supply caps improve the sound.

Is it just a sound quality improvement (noise reduction) or it does change the voice (detail, freq. response, etc)?...
Click to expand...

IMO, the power supply does impact the sound of an amplifier. In fact, it can be argued that the power supply is very much in the signal path, it's essentially in series with the output stage. Nelson Pass uses the analogy of a water reservoir as the power supply and the output stage as the valve that controls the flow of the water: https://www.passdiy.com/project/articles/power-supplies

If you have a poor and/or inadequate supply, the quality and/or the quantity of water is affected. For an amplifier, a poor/failing power supply capacitor (e.g., low capacity, high ESR) may not be able to supply the voltage/current that the output stage is "asking" for. IMO, this is primarily why improving the power supply (e.g., increasing capacity, lowering impedance/ESR) often does impact/improve the sound of an amplifier.

Generally, independent of brand of capacitors used, I would say that lowering power supply impedance by using low ESR capacitors and increasing the filtering capacitance will be beneficial to the sound from any amp (of course the law of diminishing returns applies). In terms of personal/anecdotal experience, upgrading the power supply (increased the filtering capacitance by 40%) of a power amplifier I was restoring did improve its sound noticeably: http://www.audiokarma.org/forums/showthread.php?t=543774
 
now we're talkin' Patfont!

this is what I'm hoping for: examples of real-life parts that people are using now (and have for *some reason* picked out from the many to choose from), and ones that a mere mortal can afford from the big parts suppliers

to me, the cost difference in utility-grade vs. audio-grade parts is usually so small that it's immaterial... even if a cap costs $2-5, vs. $1, I'd gladly pay an extra $20-50 total to put the best I can inside my unit, and possibly transform it into something special... the biggest cost by far is the time & trouble to recap IMO

great to have some detailed photos!
 
Blue Shadow: thanks for your comments

as much as I'd like to do some experimenting, my desire and ability to be using my treasured vintage Marantz receivers as test beds just isn't there... I live in a tiny apartment, and believe me, fully restoring a 2275 and 2230 caused a LOT of trouble & disruption around my place and I was lucky to accomplish what I did!... so my work time on these is very limited, and I can't afford to be recapping repeatedly, and even then, I wouldn't have the listening time to do proper comparisons... that's why I've been relying on the experiences and advice of others to accomplish this properly -- hopefully the first time around!

also, I think that to do this *properly*, one has to be more scientific about it, so needs to set up some sort of quick-switch A:B test setup, integrated into an actual (Marantz) power supply board... also, a blind test method would be good (mandatory?), or the results will surely be questionable to errors introduced by preconceptions (eg. cap XYZ cost $15 so it sounds better)... sure, huge differences in sound can be picked up otherwise, but if we're talking about smaller ones and splitting hairs, I dunno about that.......
 
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caps

Wow. I just read the first two articles from the links. I really did not understand much of the technical information in the article, but the summary was pretty easy to understand. Thanks so much for sharing so much knowledge. I am really looking forward to actually doing what I have been reading about. I have not even desoldered my first capacitor yet. Thanks for helping me to learn the whys behind the dos and donts.
 
I have a friend that has significantly better hearing and auditory memory than anyone else I have met and discussed sound with and it is nice to have him come over and critique different components. He has the ability to remember enough of the sonic character of a piece of gear from a couple weeks ago to be able to notice differences in the sound of the system if I were to make changes.

When we have evaluation sessions, I can change gear quickly enough to allow others to hear the differences. Blind, A/B, or whatever, sometimes just listening will bring out the differences. In some cases it is long term listening that makes one prefer one device over another.

I haven't done a 2230 but did do a 1030 and used audio caps in it because I like the gold/black caps and because the talk was that they are nice. Sure I could go back and spend that extra 20-50 bucks and really improve things, but I have something close to the way it was and it will go forward for many years without issues. I'm ok with that.
 
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Amen! No need to pull perfectly good caps, especially them. ( I am assuming Nichicon FG's.)





Blue Shadow said:
I have a friend that has significantly better hearing and auditory memory than anyone else I have met and discussed sound with and it is nice to have him come over and critique different components. He has the ability to remember enough of the sonic character of a piece of gear from a couple weeks ago to be able to notice differences in the sound of the system if I were to make changes.

When we have evaluation sessions, I can change gear quickly enough to allow others to hear the differences. Blind, A/B, or whatever, sometimes just listening will bring out the differences. In some cases it is long term listening that makes one prefer one device over another.

I haven't done a 2230 but did do a 1030 and used audio caps in it because I like the gold/black caps and because the talk was that they are nice. Sure I could go back and spend that extra 20-50 bucks and really improve things, but I have something close to the way it was and it will go forward for many years without issues. I ok with that.
Click to expand...
 
Leestereo said:
IMO, the power supply does impact the sound of an amplifier. In fact, it can be argued that the power supply is very much in the signal path, it's essentially in series with the output stage. Nelson Pass uses the analogy of a water reservoir as the power supply and the output stage as the valve that controls the flow of the water: https://www.passdiy.com/project/articles/power-supplies

If you have a poor and/or inadequate supply, the quality and/or the quantity of water is affected. For an amplifier, a poor/failing power supply capacitor (e.g., low capacity, high ESR) may not be able to supply the voltage/current that the output stage is "asking" for. IMO, this is primarily why improving the power supply (e.g., increasing capacity, lowering impedance/ESR) often does impact/improve the sound of an amplifier.

Generally, independent of brand of capacitors used, I would say that lowering power supply impedance by using low ESR capacitors and increasing the filtering capacitance will be beneficial to the sound from any amp (of course the law of diminishing returns applies). In terms of personal/anecdotal experience, upgrading the power supply (increased the filtering capacitance by 40%) of a power amplifier I was restoring did improve its sound noticeably: http://www.audiokarma.org/forums/showthread.php?t=543774
Click to expand...

Good analogy...
Nelson Pass is the MAN!
Thanks for sharing.:D
 
patfont said:
Amen! No need to pull perfectly good caps, especially them. ( I am assuming Nichicon FG's.)
Click to expand...

A few different ones.

Before
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After
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You can see the PS board recapped in the lower right of the pic above.

Interesting that the PS caps were a pair adding up to 4300µF and I went a bit bigger (well not physically) and used only one cap. Picked the coupling caps for their size, to fit the clamps and used the smaller of the two clamps on the single PS cap to clean up the interior. This amp which is cap coupled does not have a + and - rail so only needs one big cap and this one isn't so big.

Before, left to right, coupling cap, coupling cap, 1000µF and 3300µF power supply caps (in parallel for added capacitance)
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After:
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This is a sweet early 1030, engraved faceplate, pre-power connections and the cabinet. Worth the work.
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