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24.19.147.14
I'd like to make sure that a capacitor upgrade involving the same microfarad value but with a higher voltage rating is suitable for this particular circuit design:
-snip-
"These ME7660C are powered in +9V from a 78M09 integrated linear regulator whose voltage is filtered by an electrochemical capacitor displaying the substantial value of 2200 μF/16V, and building a voltage of -9V benefiting from a filtering capacitor of the same value. This way of proceeding allows them to get rid of switching noises at high frequency and to provide very clean supplies to analog electronics (operational amplifiers). Likewise, all the voltage regulations are entrusted to classic linear regulators."
-snip-
The stock capacitors are Panasonic FC 2200uf 16V, to be replaced with Nichicon FW 2200uf 50V capacitors. TIA
See link:
Follow Ups:
There is nothing inherently wrong with replacing caps with a higher rated voltage, but my opinion is going from a 16V electrolytic cap to a 50V electro cap is too much. I would normally limit a replacement to a 25V cap, if I felt that the same rated cap could use an upgrade in spec.Electrolytic Capacitors need to charge near their rated voltage. 50V is safe, obviously, but too far away from the voltage the circuit will see, especially if the 16V cap already has a generous safety margin built in, and from your description, it seems it does (9V DC).
You can substitute higher voltage caps (assuming you have the room, and the budget) with film types in many circuits or passive devices (X-overs) but electrolytics as they are generally used in active circuits like power supplies or amplifier circuits is a different application.
I would spend more time choosing a higher temperature rated cap, as electrolytic cap life is very closely tied to temperature. A 5 degree C reduction can double the cap's life. So changing a 16V 85C electrolytic for a 16V 105C electrolytic would offer greater benefits in my opinion.
As always, it's circuit and application-dependent.
There are definitely sonic differences in capacitors, so choosing the manufacturer and type (both are important) I would leave to you, Duster. But see if you can find something in a higher temperature rated 16V cap with your preferred type. If you can find a genuine trustworthy source, they even made Black Gates in the values that would be appropriate, IMHO.
Edits: 10/23/18 10/23/18 10/23/18 10/23/18 10/23/18 10/23/18
There is good theory to support the notion that with respect to electrolytic capacitors, it is best to use those whose voltage ratings that are just a little higher than the actual voltage demands of the circuit, rather than capacitors rated for voltages that are a multiple of the predicted voltages. This is for best sound and for longest life. This is contrary to the theory as it applies to film type capacitors. So, I doubt you'll be better off with this tweak.
From a sonic POV, the 50V Nichicon FW sounds clearly superior to the 16V Panasonic FC for this application, Lew.
Sorry, Mr. D, but your experiment proves nothing about voltage ratings because you did not control only one variable. Until you exchange a cap for one of the SAME EXACT TYPE with higher voltage rating, you have not made a valid test from which to draw any conclusions about contribution of voltage rating to sonic attributes.
An FW will almost certainly exhibit different characteristics than an FC. Glad you got better sound, but you will never know if it was voltage rating or brand that produced the improvement.
I am interested in this topic. I wish you would retry the experiment with proper controls.
Peace,
Tom E
berate is 8 and benign is 9
When it comes to posting personal opinions of what is heard, there's no need for proof in Tweakers' Asylum. Folks who post their findings after evaluating any given device do not require proof of what they hear. Since I made no claims of facts or figures to contend with, a personal evaluation based on observation is a valid aspect to share without issue in this forum.
I hesitate to emphasize this because you'll accuse me of attacking you, but you missed the point of my post. I believe that it sounds better. You certainly have enough experience to know how to evaluate it, and I don't doubt that at all.
What you did not accomplish, but one of your claims, is proving (or demonstrating, if you prefer that word) that a higher voltage cap sounds better than a lower voltage cap. Since you changed cap types, there is no conclusion to be drawn regarding higher vs lower voltage capacitor. If you had compared the SAME capacitor with different voltages, then we would know if voltage capacity of a capacitor matters.
I know how the forum works, so no need to lecture me on that. I don't need proof that you got better sound. But even you don't know exactly why that happened because your experiment contained two variables, and none of us knows which variable was the effective one. Was it the FW, or was it the higher voltage?
Got it?
Peace,
Tom E
berate is 8 and benign is 9
In fact, I believe it's possible that the difference in sound is due to brand or type, and it may be that using a 16V Nichicon equivalent would sound even better, based on the concept that for electrolytics, you want the capacitor to be maintained near maximum voltage rating, so the plates are near fully charged. You're coming at it from a different angle, but we are suggesting the same thing. And it would indeed be an interesting thing to check.
Okay, Lew. I'm considering the 16V Nichicon FW 2200uf capacitor. Perhaps you can tell me what to listen for in terms of improved performance, and whether it might be something to hear right-off the bat, or if it will take time for the new caps to settle-in before anything notable might be heard.
I don't mean to be facetious when I suggest that you listen to find out whether the 16V, 2200uF Nichicon FC sounds "better" than the 50V, 2200uF Nichicon FC. Only you can define "better". I am curious myself to know what you think.
Therein lies the rub, Lew. When there is no clear reason to go against the idea of, "if it ain't broke, don't fix it", it's a gamble to keep soldering and un-soldering electronic parts on a circuit board. I believe the improved performance already accomplished via the upgrade from the Panasonic FC to the Nichicon FW regardless of the voltage rating is profound enough to leave well enough alone, at this point.
Another thing to mention is that this is the second of the same make/model audio component I've worked with, and the manufacturer actually changed the two stock 16V Panasonic FC capacitors to 10V Panasonic FC capacitors, which is in line with the notion of being a better option for a +/-9V application. In comparison with the first unit that featured the original 16V caps, the unit with 10V caps sounded rather dull and less dynamic with weaker performance at the frequency extremes, and a more restricted soundstage presentation. The 16V caps while sounding more euphonic, were more musical in nature, with a bigger bottom-end vs. the 10V caps. The impression was that the 10V caps sounded "cheaper" in terms of performance from a subjective POV than the more full-bodied 16V caps. Upgrading the 10V Panasonic FC capacitors with the 50V Nichicon FW capacitors provided the same improvements for the second unit as it did for the first unit.
I'm concerned that while it might be be more correct to choose the 16V Nichicon FW vs. the 50V Nichicon FW, I'm not convinced that I should expect the 16V Nichicon FW to actually sound better for the particular device simply based on a concept that is not widely known to be an audiophile rule that should always be followed. It could be possible that my hunch to choose the 50V Nichicon FW might simply sound better to my ear for the application. In this specific case, I don't wish to be an experimenter when the final results are not clearly predictable.
I never claimed that the reason why the 50V Nichicon FW sounds clearly superior to the 16V Panasonic FC is due to a higher voltage rating. If you would stop trying to find fault and denigrate my credibility as a poster in AA, you might have a clearer perspective of things I might say. Otherwise, I have no desire to have discussions with you other than defending myself when you misrepresent my posts and act like an enemy. There is no rule in AA forum politics that requires interaction with those who act as bullies, trolls, or enemies.
I wrote as the OP of this thread:
"I'd like to make sure that a capacitor upgrade involving the same microfarad value but with a higher voltage rating is suitable for this particular circuit design"
Some folks clearly opined that it is okay for the particular circuit, while Lew posted the notion of choosing an electrolytic capacitor with a voltage rating that's closest to the operating voltage, unlike the notion of choosing a substantially larger rated voltage film capacitor. So I understand the premise. The only matter that I had issue with was the statement that claims the 50V Nichicon FW would not be a worthwhile tweak vs. the stock 16V Panasonic FC for the application.
Lew's opinion of:
"This is contrary to the theory as it applies to film type capacitors. So, I doubt you'll be better off with this tweak."
My response was about not being better off with this tweak:
"From a sonic POV, the 50V Nichicon FW sounds clearly superior to the 16V Panasonic FC for this application, Lew."
It's really quite easy to understand what I've said within this thread if a reader has an open mind.
that's all that counts. But you might want to look up the theory behind using lytics that are within the same voltage rating range as the voltage developed in the circuit where they are used. It does make some sense. One of the well known Japanese guru lived by that mantra, but he is no longer with us, either Shindo or the person who designed the Japanese Audio Note equipment.
Quality counts, too. So it may just be the case that the Nichicon FC is a better sounding capacitor than the Panasonic FW. If so, you might want to experiment with using a 16V Nichicon FC in place of the 50V version (or the closest you can get to 16V, while staying above 16V).
I always thought voltge ratings of capacitors should be around double the voltage of the voltage that goes trough them, to have a safety margin and improve capacitor life.
But I just read if you use a bigger voltage capacitor, it will reform after a while to sustain no more than the actual circuit voltage.
If that is true, why do most circuits still use lytics that are around double the circuit voltage?
I don't doubt the veracity of your perspective and information, I just don't agree with the notion that I'm not better off with the 50V Nichicon FW when it clearly sounds better to my ear when used for the particular application, Lew.
Fifteen mm longer, but maybe they can just lay on top of those other tiny components. Keeping the leads short is important, but that shouldn't be a problem with identical spacing, diameter. The KW leads might be appx 0.008" larger diameter (.8mm, can't find FC dia but might be .6mm), and that could cause minor difficulty depending on PCB. Don't see anything else to worry about. If 16v works, 50v might be better, will last longer. Caps don't establish supply voltage.
FC to KW should yield nice improvement. FC can be a bit sterile; KW should warm things up, maybe open it up a little. I'd like to know if higher voltage makes a difference for same model cap. Ever test for that?
C14 and C15 look like small value bypass caps. You might have a look at those when you have the board out. Could be worth a tweak.
Peace,
Tom E
berate is 8 and benign is 9
I've already installed the capacitors in another unit and they fit fine, but barely. The difference in sound was that the Nichicon FW provides a firmer presentation from top to bottom, with better inner detail, better soundstage and imaging, and an overall cleaner sound, while the Panasonic FC sounds more polite and forgiving, which veils the more subtle aspects of the presentation. The tonality of the Nichicon FW is more streamlined with better timbrel rendition, if not higher-resolution, and it simply provides a more enjoyable gestalt than the stock capacitors. Swapping-out the stock footers with something better helps to provide a bit more tonal bloom.
Edits: 07/20/18
Funny you mentioned Nichicon FW. That series is one of my very favorite caps due to their sound quality. It's too bad they aren't available in more values. I much prefer the sound of the FW to the so-called "audio-grade" more expensive Nichicons. In the bias supply of my push-pull amps I even prefer the FW to Blackgates.
Thanks for this. I'm putting a parts list together to resurrect a pair of Dynaco MK-IIIs at some point, and was trying to decide on bias supply caps.
The lure is to opt for low ESR 105ş caps, but I'll put the FW on my short list of contenders, based on your and Duster's recommendation.
Thanks.
"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
The FW used in the bias supplies is 1000uf, 100v which is available from Parts Connexion and Michael Percy for about $2.25 each. That cap was the best out of 6 or 7 I tried there.
I'm curious if you meant one hundred, rather than one thousand micro-farads.
I'm asking because I squirreled away this tidbit of info from Joe Curico regarding bias supply cap value (link below) some years ago. Although he doesn't say what "too large" is when he mentions bias supply caps, he clearly cautions against using "large" caps.
If you did mean 1000 µF, I take it this hasn't been your experience?
"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
Not a typo. I hadn't seen that comment by Joe Curcio before, nor indeed anything cautioning against using too high a cap value in a bias supply, but I agree that this value is higher than normal.
All I can say is that my particular amp came with these Nichicon 1000uf caps already installed and the amps worked fine. In my quest to improve the sound quality, I wanted to replace these "cheap" caps with something better, only to find that all other caps I tried did not sound as good. The other caps I tried were more conventional values---50 to 200uf---so now that I think about it I can't say for sure whether the better sound may have had something to do with the value as well as the type of capacitor. However, I have tried the same 1000uf FW caps in other power supply positions and was pleased with the sound.
I posted regarding the "how much is too much?" question over six years ago. Needless to say, my MK-III project was left in mothballs longer than I expected.
I only got one answer to my question, which is linked at the bottom. If you search DIY Tube for "Regulated bias" you'll get 200+ answers, most of which say not to regulate bias without regulating B+, but nothing I read was clear regarding how much capacitance would cause a bias circuit to act as if it were regulated.
Back to the cap type. I used a couple of Nichicon KW on the B+ "in" position on my Millett LR phono board. I just took a look at the KW vs FW data sheets. If flowery prose means anything, the FW says "Standard, For Audio Equipment", while the KW gushes, "Realization of a harmonious balance of sound quality, made possible by the development of new electrolyte" . Sheesh, someone gets paid to write that stuff.
FW data
KW data
I was going to comment that I'd never heard of the FW before today, but that's not true. I just checked, and have two 22,000 uF on my shelf, waiting to go into [ahem] your preamp (Last PAS). I've grown tired of these two 16 oz beer can 120,000 uF caps dangling off the back after so many years.
"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
Let us hear how the big FW caps do on your heater supply (in place of the really big caps!).
I actually ordered a bunch of FW caps to try on my phono heater supply. I have had some old Panasonic HFQ caps there for over a decade. At the time the HFQ caps were the best sounding of the several heater caps I tried, but that was before I found the Nichicon FW.
By the way my bias supplies have a full wave bridge rectifier. Not sure if that makes any difference given the low current.
It will be interesting to see if I can live with a 2/3 reduction in heater supply capacitance. As you noted in your article, I've always heard improvements when I've temporary added more , as shown in this picture from many years ago. There's about 68,000 uF normally on the heaters. The day of the picture I attached an extra 54,000 uF, along with some ASC motor runs, which all made an improvement.As you can see, I went with the transformer externally mounted, a la Van Alstine, when I built it, so there is room inside for two more 22,000 FW caps.
I've always wanted to try regulating the filaments just to see if I liked it, but the voltage doubler's 25V stopped me. I have a 12.5 regulated supply here, but was reluctant to cut traces just as an experiment. Nothing ventured, I suppose...
Regarding your full wave bridge, there are those who swear by full wave or full wave bridge bias over on DIY Tube, and those who say a half-wave is more than adequate. Typical objective vs subjective banter, but I have no experience to add to the discussion. I have decided to use a Cree diode though, since they're cheap enough, and some swear by them, even in half-wave configuration.
"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
Edits: 07/23/18
Your photo brings back memories for sure. As I recall, the most I ever had was four 72,000 uf caps with each pair in parallel. That was back in the day of electronic surplus stores. I paid $5 each for those caps.
Just like you described, each time I increased the capacitance the sound was better. I wish I had spent more time though trying different supplies—for example, a full wave bridge instead of the doubler or a battery like Trevor Lees recommended. One thing I learned considerably later was the importance of using separate transformers for the heater supply and the B+. That is one of the easiest and most cost effective improvements to any piece of tube equipment.
I thought it might. I had to dig a little to find it, but thought you could appreciate it.
I got my two 120,000 uF caps used, at a hamfest, I believe. I check them periodically with my ESR meter, and they still check good, even after all these years.
As you noted at the time, the PA-211 PAS transformer couldn't supply the current, so the doubler had to be used. It's interesting that we're having this conversation now, because I've been discussing my options with a friend of mine over the past several weeks.
I have an extra, unstuffed regulator board sitting here, since I bought two from Old Colony at the time, "just in case". I've always had the idea of trying it dual mono, which you also mentioned as a possibility. Of course that would require a separate chassis, attached via umbilical(s). If I were going to get that complicated I'd do exactly what you've said, and use a separate filament transformer.
I've had other people tell me "Leave it alone and just build something else". Maybe it's because it was my first successful build, but there's always been this urge to see how far I could take it.
I've said this to you once before, but thanks for the way you wrote up the project, like kit instructions. It gave me (and other new builders) the confidence to learn more, and its worked flawlessly for going on thirty years now. There's been a lot of musical pleasure squeezed out of that little box!
"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
You're certainly welcome. I am glad that it has brought you a lot of musical pleasure over the years. A lot of people got their start in DIY with those PAS mods including a number of well known names in the industry.
I've recapped my active crossover with nichicon KZ troughout (all 100uF 25V) but they don't fit good. they are sitting above the board, some of them with bent leads.
while it sounds good, learning more I understand it's not ideal.I wonder if I'd better swap them to the lower grade fG or fW (wich one is best?) wich are much more standard in size... so they would fit on the board like they should?... it kinda bugs me :-/
Edits: 07/21/18
Museum Wax! (link below)
I had a similar problem with new, physically smaller caps, and Al suggested using Museum Wax. I bought some, and never had a problem with it.
"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
QuakeHold museum putty is ideal for semi-permanent applications. It's superior to Blue-Tak and other sticky tack products.
After all, it's designed to hold somewhat heavy objects within a museum display case vs. a lightweight poster stuck to the wall.
Discussion of the product in AA goes way back to 2004. I posted my impression of the product at the time.
See link:
Interesting to know that you and Al were recommending Museum Wax that far back.
My biggest concern, as noted in my reply to Al, was whether the wax was in any-way conductive, and Al's meter check proved that it wasn't. The newer, smaller, often better spec'd capacitors are nice, but they often leave the caps looking like a clown on stilts. The Museum Wax helps dampen vibration, and provide a secure fix.
Thanks for the link.
"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
Hi KanedaK, the important criteria was a secure solder joint, regardless of how bent the capacitor leads might be. Simply made sure the capacitors fit into the enclosure, with satisfactory sound as the result. I won't second guess the upgrade process. No need to, since I carried through with what I wanted to achieve via the DIY project. The result sounds better to me.
Cheers, Duster
Duster:
For sure the Nichicon 50V units will work; it is more of a matter of how the exchange will affect the sound (if at all) in your circuit, and your taste in what constitutes an improvement.
DRS
Thanks, fastcat. I've implemented the particular upgrade for another unit before, with a substantial sonic improvement in all respects, but I want to make sure that the upgrade has long term stability, since I'm unfamiliar with the type of circuit involved. My first impression was that the two capacitors were a filter capacitor for each stereo channel, but the +/- configuration is over my head when it comes to an upgrade with a different capacitor value.
Cheers, Duster
Duster:
These are very good quality capacitors, so I see no problem with long term stability. Do remember to do a post about the changes you hear after you make the mod. I have been tinkering with audio equipment mods and build projects for many years (a very addictive hobby). I also find many of your posts to be interesting and insightful.
DRS
Hi fastcat, here's my findings (see link below).Regards, Duster
Edits: 07/18/18
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