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Thread: Current handling capability: big F&T power supply caps vs new design Nichicon

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    Current handling capability: big F&T power supply caps vs new design Nichicon

    If I compare the new design caps Nichicon: 500v 22uf 560ma ripple current etc

    https://www.mouser.com/ProductDetail...1z6jN6aA%3D%3D

    to the old style F&T

    https://www.tubesandmore.com/sites/d...t_ft-a_new.pdf

    am I reading the specs right, that the big heavy leaded F&T 500v caps are really 100ma, to 200ma, compared to the Nichicon? The little skinny lead nichicons have over 2x ripple current? Is this good or bad?

    Are the nichicon's really suitable for power supply caps in these old tube amps

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    Caps have followed the path of many electronic components in getting smaller along with increased performance. The physical size and lead diameter of pretty much everything is reduced. I have no problem at all with using this type of cap in older tube amps and they perform very well. The F&T cap leads are flimsy compared to the old Mallory caps in (say) silver face Fenders, now the Nichicons are thinner still.

    Ripple current becomes an issue either when designing a PSU or when replacing capacitors so that the PSU ripple current doesn't exceed the capacitor rating. A cap operated beyond it's ripple rating will have increased temperature and shortened lifespan. Ripple current is related to ESR, so low-ESR caps have better ripple figures - important in high-demand applications such as switch-mode power supplies. Fitting a capacitor with a higher ripple current rating than necessary doesn't harm things - you get a slightly more efficient capacitor that runs cooler, though perhaps not noticeable. I liken this to using 5W resistors in a circuit where 2W would be fine.

    There was a time where I never even looked at ripple and you'd have to dig out specs to find out what the value was for a certain cap. In my experience tube amps don't exhibit high enough demands on the power supply for ripple to be a real consideration. Having said that, If I'm shopping for caps at a given price I'll usually pick the ones that offer higher ripple figures - it can be a sign of better construction and durability and often a high ripple cap will have a better thermal rating, but not always.

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    Best cap does not mean the best sounding amp. F&T's have a good reputation among guitar amp repairers, builders and upgraders. If you look at the specs, they are not the best cap to make the best power supply, they have faults and weaknesses but "I" think they actually improve the sound without making it too sterile.

    I mentioned once before, there was a website where they had a good sounding Fender Bassman, they tested the power supply for a bunch of parameters. They then tried to duplicate this power supply with some lab equipment and subbed it into the amp. The sound changed.

    Look at some Valcos and Premiers, they used cheap disc coupling caps yet they sound great. You can get those F&T 22/500v for $3.95 or 4.95, i always keep at least 10 in stock.

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    Lifetime Member Enzo's Avatar
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    And I hate to repeat myself, but...

    It is only a guitar amp, tiny little differences in specs is not going to matter in the overall circuit.


    "Better" is an illusionary term. What does better mean? Better as in smooths ripple more completely? Better as in sags reliably? Better as in "sounds better"? And so on.

    To use another cliche, don't let the cap be a solution looking for a problem. In other words determine if the existing arrangement lacks anything a "better" cap can provide first, then consider replacements.

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    Thanks Everyone!!
    Well, for me, I don't know the physics well enough, so "better" means "it won't blow up in my face because I used new design caps that had a lower frammistan rating". Then, of course, there's the frickazoid adjustment.

    I have a friend who did electronics for years, don't get a chance to talk to him much. He said once in passing something about 105C caps ve 85c caps, that unfortunately stuck. So, Im thinking, geez, all these little projects Ive tinkered with, all have F&T caps, let me go look up the rating, and sure enough, they're all 85c.

    But then one of you guys on one of the blog posts, mentioned that, heck, compared to 1964 manufacturing technology, the F&T's are miles above, so just don't worry about that, worry about, e.g. lead dress. ...

    Cool, so, even not knowing the details of comparing caps, these will probably work fine in this little Supro mimicking project. Thanksa gain.

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    Lifetime Member Enzo's Avatar
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    Ever notice the doors in places like hotels or schools? The hinges are so much more heavy duty than ones in your home. Same for the latch and knob. That stuff is meant to last years under heavy use. Clearly they are "better" hinges and knobs than ones in your house. yet the home ones have worked just fine the life of the house in many cases 40-50-60 or more years. So what would my home gain if I replaced my lesser hardware with the better stuff? Nothing really. Just my opinion, but when we micro-analyze caps like this, it is a similar matter.

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    Quote Originally Posted by mikepukmel View Post
    compared to 1964 manufacturing technology, the F&T's are miles above, so just don't worry about that, worry about, e.g. lead dress.
    I was recently donated a shoe box full of ancient wax & paper caps. Maybe I'll offer 'em one of these days in our Flea Market. Or go for the big bucks on EepBay or Revoib. "Get that vintage sound at a price you can't afford!" Also have a box full of huge 400V electrolytic "beer cans" from 1966. They oughta make a big hit as they go kablooey when someone tries to charge 'em up, what fun. I'll have to give 'em a go, next 4th of July...

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    Double the ripple current rating infers 1/4 of the temperature rise and MUCH longer lifetime.
    I would perhaps use the F&T for repairs to replace F&T purely to keep an amp "original".
    I would use the Nichicon for new builds - actually I generally use Panasonic ED for new builds BUT not the F&T.
    JM2C
    Cheers,
    Ian

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    Bent Member Chuck H's Avatar
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    Nichicon convert right here offering his endorsement. I got tired of all the large diameter axial cap shenanigans (fakes on the market, small cap in big can, hiding mediocre specs from the general public and "exclusive" price point). I switched to Nichicon PW's many years ago and have never looked back. Better cap, lower price and easy to source. I think Nichicon makes a longer life cap than the PW, but I haven't tried it yet. Compared to what's in a typical guitar amp the PW's are already miles ahead. I don't even flinch when I have to shrink tube and zip tie things to safely use them in axial applications. Form follows function so it looks fine to me

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    Ian & Chuck,

    What are your views and experience on, electrolytics, whether 105C is better than 85C (or necessary) or that either will do the job fine?
    I have not found temperatures that high in amp chassis, but I tend to buy 105C caps anyway.

    I use Nichicon & Panasonic mostly, but also United Chemicon and Rubycon and I have used F&T once or twice.
    So far I have not had problems or failures with any of them, but I prefer the Panasonics and the 'cons for their size, over any of the axial caps.

    Cheers, Noel

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    Bent Member Chuck H's Avatar
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    "MY" opinion... Well, maybe you can state a spec of 105C no matter how mediocre it's performance at that temperature, as long as you state what it's actual performance is at that temperature. I wouldn't be at all surprised if some caps rated at 105C are no better under such conditions as many 85C rated caps. I think I've actually seen some of that in derate specs. But I don't actually know if there's any stringent criteria for being able to print a 105C rating outside of disclosing performance.

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    105 degrees C rating for tube amps and even then apply a bit of thought to physical placement - where possible place away from heat sources.

    Cheers,
    Ian

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    It isn't that the caps are intended to run at 105 degrees, it is that they will withstand that better.

    Your amps seldom get hot enough to boil water.

    A 105 will potentially be stressed less than an 85 by whatever heat levels you have.

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    Electrolytic Cap life is dependent on their internal temperature which has a drying effect on the paste electrolyte.

    Caps self heat according to Power = current squared x resistance, in this case the current is the ripple current and the resistance is their ESR (equivalent series resistance).

    They also absorb heat from adjacent components.

    To give some idea about this we see an equivalent idea in aircraft wiring standards, wire rating is based on temperature rise. If 2 wires are bundled together so they can heat each other then the current rating of each wire is reduced to 0.94, if 3 wires bundled to 0.86 etc. Source is Fig 11-5, AC43.13-1B Chapter 11 "Aircraft Electrical Systems".
    So don't bundle all your high ripple current caps together (like in Fenders "doghouse") and keep away from other heat sources.

    I said above that I use Panasonic ED but have also use Nichicon and Rubicon. Higher Voltage Caps, in general, have higher ripple current ratings. Don't be afraid to use a cap with much higher voltage rating than absolutely required.

    Cheers,
    Ian

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    Quote Originally Posted by Enzo View Post
    It isn't that the caps are intended to run at 105 degrees, it is that they will withstand that better.

    Your amps seldom get hot enough to boil water.

    A 105 will potentially be stressed less than an 85 by whatever heat levels you have.
    okay, here is how it works:
    It has to do with the manufacturers providing a published general "expectancy" of working life for the cap. This is usually stated in hours at it's MAX ambient operating temperature. Another factor which contributes to the working life is it's operating voltage, although less so than temperature.
    So, in general, a published working life of *** hours @ 105˚C (or 85˚C) can generally be expected.
    Two important things to consider:
    first, is that for every 10˚ lower, the capacitor life can be expected to extend by a factor of 2.
    Second, if the capacitor's internal temperature is increased more than 10˚ of it's max ambient temperature rating, then the capacitor's life is decreased by a factor as well. The main factor leading to this is caused by the capacitors ESR dissipation due to high ripple current.

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    Quote Originally Posted by Gingertube View Post
    Electrolytic Cap life is dependent on their internal temperature which has a drying effect on the paste electrolyte.

    Caps self heat according to Power = current squared x resistance, in this case the current is the ripple current and the resistance is their ESR (equivalent series resistance).

    They also absorb heat from adjacent components.

    To give some idea about this we see an equivalent idea in aircraft wiring standards, wire rating is based on temperature rise. If 2 wires are bundled together so they can heat each other then the current rating of each wire is reduced to 0.94, if 3 wires bundled to 0.86 etc. Source is Fig 11-5, AC43.13-1B Chapter 11 "Aircraft Electrical Systems".
    So don't bundle all your high ripple current caps together (like in Fenders "doghouse") and keep away from other heat sources.

    I said above that I use Panasonic ED but have also use Nichicon and Rubicon. Higher Voltage Caps, in general, have higher ripple current ratings. Don't be afraid to use a cap with much higher voltage rating than absolutely required.

    Cheers,
    Ian
    Good stuff Ian. Along with high ripple current ratings, aluminum electro's life can be extended as well by operating the cap at a lower voltage that it's max rating. Although, according to data published by Illinois, this is limited by a ratio of 2:1, even when the cap is run at 50% of it's voltage rating.

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    Quote Originally Posted by Chuck H View Post
    "MY" opinion... Well, maybe you can state a spec of 105C no matter how mediocre it's performance at that temperature, as long as you state what it's actual performance is at that temperature. I wouldn't be at all surprised if some caps rated at 105C are no better under such conditions as many 85C rated caps. I think I've actually seen some of that in derate specs. But I don't actually know if there's any stringent criteria for being able to print a 105C rating outside of disclosing performance.
    Good point and that is true; the temp rating doesn't tell the whole story.
    It could be a 105C rating with a lifespan of 100 hours or, of 10000 hours or, ?

    I guess that answers my question.

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    Quote Originally Posted by Gingertube View Post
    Electrolytic Cap life is dependent on their internal temperature which has a drying effect on the paste electrolyte.

    Caps self heat according to Power = current squared x resistance, in this case the current is the ripple current and the resistance is their ESR (equivalent series resistance).

    They also absorb heat from adjacent components.

    To give some idea about this we see an equivalent idea in aircraft wiring standards, wire rating is based on temperature rise. If 2 wires are bundled together so they can heat each other then the current rating of each wire is reduced to 0.94, if 3 wires bundled to 0.86 etc. Source is Fig 11-5, AC43.13-1B Chapter 11 "Aircraft Electrical Systems".
    So don't bundle all your high ripple current caps together (like in Fenders "doghouse") and keep away from other heat sources.

    I said above that I use Panasonic ED but have also use Nichicon and Rubicon. Higher Voltage Caps, in general, have higher ripple current ratings. Don't be afraid to use a cap with much higher voltage rating than absolutely required.

    Cheers,
    Ian
    Very informative Ian; about wire rating too.
    Maybe it would be good to measure the operating temperature of caps, as a gauge of their internal temp while working hard.
    Keeping them away from heat is always preferred.

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    Thanks to you all, for your replies.
    They tend to confirm that my approach, of using electros with manufacturer stated "Lifetime@Temperature" ratings of more than 8000 hours, is a good approach.

    Cheers, Noel

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    Given I'm usually building true PTP, I try to stay away from skinny-lead lytics, so it's F&T for the big guys for me for sure. I could go with Atoms, but quadruple the price is a bit of a deterrent...

    Justin

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    Quote Originally Posted by mozz View Post
    Best cap does not mean the best sounding amp.
    That is 100% true. It's CIRCUITS that affect the sound.
    F&T's have a good reputation among guitar amp repairers, builders and upgraders. If you look at the specs, they are not the best cap to make the best power supply, they have faults and weaknesses but "I" think they actually improve the sound without making it too sterile.
    I'll insert my standard complaint about anecdotes: reputation is interesting, but by no means definitive. You can't measure reputation, and that means you effectively can't figure out what to do to make it better or worse.

    I absolutely respect your opinion about what makes something sound better to you. But what, exactly, does "sterile" mean? Less distorted? Less 120hz ripple in it? Les subliminal 180hz or 240hz? "Sterile" is probably something like pure, unadulterated, absolutely true to the original, maybe. We know how to make that really dirty, but I suspect that's not what you're after either. What do we mix in to make it less sterile?
    I mentioned once before, there was a website where they had a good sounding Fender Bassman, they tested the power supply for a bunch of parameters. They then tried to duplicate this power supply with some lab equipment and subbed it into the amp. The sound changed.
    It is remarkably difficult to do unbiased A-B comparisons when you have to go muck around with components between tests. I have no doubt that the perception of the sound changed. The question is - how? And was it the parts or the people? This is a really crucial question for any attempt at engineering "betterness".

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    Bent Member Chuck H's Avatar
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    Quote Originally Posted by R.G. View Post
    It is remarkably difficult to do unbiased A-B comparisons when you have to go muck around with components between tests.
    +1
    You really do need an instant change facilitating an A/B comparison. That's why when my amp doesn't sound quite snuff I don't open it up and start changing values. I just cup my hands and box my own ears about five or ten times really hard. Very fast and almost always changes the tone.













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    Quote Originally Posted by Chuck H View Post
    +1
    You really do need an instant change facilitating an A/B comparison. That's why when my amp doesn't sound quite snuff I don't open it up and start changing values. I just cup my hands and box my own ears about five or ten times really hard. Very fast and almost always changes the tone.












    I prefer the 'drink a beer' mod. Sometimes it takes two or three before I'm satisfied that the amp sounds as good as it can. A funny side effect: my intonation gets better too (source: Joe's Garage, parts I and II)

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    Quote Originally Posted by Enzo View Post
    ...when we micro-analyze caps like this, it is a similar matter.
    I think Enzo makes a very good point. I woke up to this just last year, when we included another Led Zeppelin song into our repertoire ( What is and what should never be off the second album), and I started using one of my really old Valco amps miked up, instead of a more modern "cleaner" sounding distortion.

    If you listen to the guitar outro on that song, the amp has some horrific intermodulation breakup, and to me it's perfect for that song, as it adds a mysterious and brutal sounding guitar tone, in conjunction with a Big Mystical Gong Swell - (LOL, hey this is Led Zeppelin after all !). The Outro starts at 3:30 ---


    Take that same type of amp setup-(their live performance sounds very close so I think the breakup it's mostly from the amp), and use it to play some other stuff, as in say a later Zeppelin songs like "The song remains the same", and all of a sudden, the amp you loved before will now sound like crap, and you will be looking to "Fix" it, so it can now sound like the pristine Marshalls used later on... Go back to the early stuff again, and a Marshall would sound too clean, and it would lack the artistic impact the "dirty" intermodulation distorted sound adds.

    This is a good example IMHO of how context is very important when judging an amplifier's tone, so shooting for perfection in ripple reduction and hum may just well be the same as shooting your foot, in some instances.

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    Bent Member Chuck H's Avatar
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    Ok... On the subject of things that change the tone of an amp but can't be measured I'll nominate rainy days. My amps ALWAYS sound best on rainy days!?! Not like when rain starts, but really soggy days when the weather is already socked in. I'm not the sort that suffers mood changes with weather and it's consistent enough that I think there may be a physical reason, but I don't know what it is. About the only component that might change it's behavior under conditions of low pressure and high humidity would be the speaker/s. So that's always been my belief.

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    Quote Originally Posted by Chuck H View Post
    Ok... On the subject of things that change the tone of an amp but can't be measured I'll nominate rainy days. My amps ALWAYS sound best on rainy days!?! Not like when rain starts, but really soggy days when the weather is already socked in. I'm not the sort that suffers mood changes with weather and it's consistent enough that I think there may be a physical reason, but I don't know what it is. About the only component that might change it's behavior under conditions of low pressure and high humidity would be the speaker/s. So that's always been my belief.
    My guess is the speaker, as you already guessed ! there has to be some changes in absorptive materials based on high humidity, I would think. Add weight to a cone and you will change the tone !

    And as you stated, changes to barometric pressure. That sounds reasonable as well.

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    Mine sound better after sitting in the car on a sunny day for a few hours.

    Jusrin

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    "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
    "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

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    Last edited by catalin gramada; 09-26-2019 at 01:26 PM.
    "If it measures good and sounds bad, it is bad. If it measures bad and sounds good, you are measuring the wrong things."

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    Bent Member Chuck H's Avatar
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    Quote Originally Posted by catalin gramada View Post
    I wonder if the playback on the speakers for the before and after clips is done at a volume that might better exploit cone changes. It seems to me that a softened cone would demonstrate it's relative "softness" more when pushed harder? Anyway...

    IMHO the only way to properly break in a speaker is to play through it. I can hear the difference in the LF on the speakers in the video, but odd to me is that there is no difference in the HF. Odd to me because my own experience breaking in speakers by playing through them has demonstrated tonal changes in the HF that are more pronounced than those in the LF. This is part of why I've never jumped on the band wagon with the low frequency AC break in.

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    "Never bet your life on somebody else doing their job." SoulFetish's good friend

    "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

    "Being born on third base and thinking that you must have hit a triple is pure delusion!" Steve A

    "Back to the amp. It makes horrible sounds when I play my guitar thru it... because I suck at playing guitar." Mike6158

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    Yeah, same here: why "burn in" and not just play through it?

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    The only good solid state amp is a dead solid state amp. Unless it sounds really good, then its OK.

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    Quote Originally Posted by Enzo View Post
    Ever notice the doors in places like hotels or schools? The hinges are so much more heavy duty than ones in your home. Same for the latch and knob. That stuff is meant to last years under heavy use. Clearly they are "better" hinges and knobs than ones in your house. yet the home ones have worked just fine the life of the house in many cases 40-50-60 or more years. So what would my home gain if I replaced my lesser hardware with the better stuff? Nothing really. Just my opinion, but when we micro-analyze caps like this, it is a similar matter.
    Enzo, ah, ok so, we have these few brands that make electrolytic capacitors for these old tube amp applications. They look about the same, and specs, don't know. They have voltage rating, don't know about temp. Illinois, F&T, Sprague ($$$). These are huge can, thick leads. I wasn't so much trying to micro analyze, but compare the 'old style' big can, thick lead caps, with newer ones that look tiny in comparison, but that seem to have 'better' electrical specs. Not better from sound point of view, since I have no idea the impact on sound quality, but temp rating, voltage, ripple current. Was curious if something else in there would cause the new design caps to fail in a guitar amp. Or as Leo mentions above: charge them up and see what happens! Hoping for a non kablooey charging, here.

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    The only good solid state amp is a dead solid state amp. Unless it sounds really good, then its OK.

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    Quote Originally Posted by Leo_Gnardo View Post
    I was recently donated a shoe box full of ancient wax & paper caps. Maybe I'll offer 'em one of these days in our Flea Market. Or go for the big bucks on EepBay or Revoib. "Get that vintage sound at a price you can't afford!" Also have a box full of huge 400V electrolytic "beer cans" from 1966. They oughta make a big hit as they go kablooey when someone tries to charge 'em up, what fun. I'll have to give 'em a go, next 4th of July...
    Leo, my friend Steve's dad taught him the fine art of TV repair. This is late 60's through the 70's, when there were still many tube TV's in service. He has a standard joke, they have 2 x 100 foot extension cords. They put a tv after a repair, on an end table out in the back yard. stand 100 feet from the TV, and plug the two cords together, in case of a kaboom situation.

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    The only good solid state amp is a dead solid state amp. Unless it sounds really good, then its OK.

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    Old Timer Leo_Gnardo's Avatar
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    Quote Originally Posted by mikepukmel View Post
    They put a tv after a repair, on an end table out in the back yard. stand 100 feet from the TV, and plug the two cords together, in case of a kaboom situation.
    As our friends in UK say "stand well back." Often when lighting big firecrackers on Guy Fawkes Day. Coming up soon, only 5 weeks!

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    Enjoy. Every. Sandwich.

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    Senior Member trobbins's Avatar
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    I would suggest the query needs some more flesh with respect to the amps you intend to use the caps in. I'd anticipate that the ripple current in many valve amps is substantially below the ripple current of caps now typically available for retrofit. If that is the situation then ESR and internal temp rise is unlikely to be a concern compared to local ambient temp.

    What is more likely a concern is appreciating what ripple current the cap experiences. Pretty much the only cap that would experience significant ripple is the first filter cap, and the output stage filter cap (if those caps aren't one and the same) - any other filter cap would not have a ripple issue. Measuring the ripple current by temporarily inserting a 1 ohm resistor in the negative terminal to 0V may be pretty easy to do - similarly using something like PSUD2 can get you a reasonable estimate in a few minutes.

    That UCY Nichicon has a very long life rating, and at 105C.

    Of more concern is that the amp doesn't impose a peak voltage at turn-on that exceeds the cap rating - as in pretty much all modern caps, there is no +10% surge capability, so taking the time to measure the peak voltage achieved at turn-on is probably of most importance in choosing a suitable cap.

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    Quote Originally Posted by trobbins View Post
    I would suggest the query needs some more flesh with respect to the amps you intend to use the caps in. I'd anticipate that the ripple current in many valve amps is substantially below the ripple current of caps now typically available for retrofit. If that is the situation then ESR and internal temp rise is unlikely to be a concern compared to local ambient temp.

    What is more likely a concern is appreciating what ripple current the cap experiences. Pretty much the only cap that would experience significant ripple is the first filter cap, and the output stage filter cap (if those caps aren't one and the same) - any other filter cap would not have a ripple issue. Measuring the ripple current by temporarily inserting a 1 ohm resistor in the negative terminal to 0V may be pretty easy to do - similarly using something like PSUD2 can get you a reasonable estimate in a few minutes.

    That UCY Nichicon has a very long life rating, and at 105C.

    Of more concern is that the amp doesn't impose a peak voltage at turn-on that exceeds the cap rating - as in pretty much all modern caps, there is no +10% surge capability, so taking the time to measure the peak voltage achieved at turn-on is probably of most importance in choosing a suitable cap.
    Hope this doesn't end up a dupe, I wrote up a reply, and got "do you want to leave this page", clicked yes, and the reply disappeared.

    Re the intended amps: so far,just this one guinea pig Supro Thunderbolt S6420 ss rectified (6L6 cathode biased, simple circuit about 30watts).

    Re measuring ripple, just to confirm, I need a big (high wattage) 1R resistor, disconnect the negative side of the first filter cap, measure voltage drop across that. Can I use my old 'scope to do that?

    Re peak, turn-on, so, suppose amp has been sitting for some time, and the caps are "empty". Turn the on-off switch "on", its that first spike that comes across the transformer and hits the filter cap? Is this due to the on/off switch arc that occurs just as the contacts are about to close, or combination of that and power transformer charging?

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    The only good solid state amp is a dead solid state amp. Unless it sounds really good, then its OK.

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