Preferred Filter Cap Brands?

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Gainzilla
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Preferred Filter Cap Brands?

Post by Gainzilla »

Hey all,

Planning a new 20w Marshall style build with a pair of EL84m's. Still early in the planning stage, but so far I'm thinking it will be cathode biased 68 plexi style circuit with a switchable cascade gain stage and Solid State effects loop.

Any thoughts on power supply caps? Favorites? Cautionary tales? Hidden Gems?

Ive used Illinois in the past, but that was way in the past. Seems like they've got a bad reputation now? What about the Generic 450v caps available at cedist? Anyone tried those? The price looks appealing, but the old adage "you get what you pay for" comes to mind. I've also used JJ and they seem fine, if maybe a bit stiff? I'm looking for a tight low end but liquid lead in high gain mode.

Assuming there are no hidden gems you can recommend, am I looking at JJ and F&T. I would be willing to pay for something like Sprague Atom if they truly make a difference, but I've heard F&T are comparable.

Any thoughts here would be greatly appreciated.

Bonus question: I'm thinking the PS nodes will look like 47u --> 32u --> 32u --> 32u. Any thoughts here for a switchable 68plexi/JCM800 kind of circuit?

Cheers!

- Bryce
I know it's only rock and roll, but I like it!
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pompeiisneaks
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Re: Preferred Filter Cap Brands?

Post by pompeiisneaks »

I've not got miles of experience here, but from what I hear and what I've seen, I can't tell a difference between F&T and Sprague current line that is. I have also used Illinois and haven't had issues but they're still in new builds. Some people are adamant that Illinois are fine, it was just some lower cost requests by fender that got into some of their amps that ended up bad and it's not all of them, but I'm not sure. Most of this 'knowledge' is me reading things, though so take that with a grain of salt, hopefully some of the gurus that use them can confirm or deny with more authority.
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xtian
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Re: Preferred Filter Cap Brands?

Post by xtian »

Yeah, Illinois had a bad run, but that's old news. F&T are good.

I use radials when I can. Nichicon and Panasonic are very good, low ESR, and cheap, compared to axial.
I build and repair tube amps. http://amps.monkeymatic.com
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Gainzilla
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Re: Preferred Filter Cap Brands?

Post by Gainzilla »

Thanks guys, exactly what I needed.

Cheers!

- Bryce
I know it's only rock and roll, but I like it!
Bob S
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Re: Preferred Filter Cap Brands?

Post by Bob S »

Yup - F&T for axials & Nichicon for radials.
I've made quite a few amps with other brands (even Chinese) & never had a problem.
But that niggly doubt in the back of my mind persists. F&T & forget about it.
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mhartman
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Re: Preferred Filter Cap Brands?

Post by mhartman »

Tubedepot is having a 15% off sale right now. Go with the F&Ts. I'm not sure that they sound any better (I've used both), but they look more impressive, which doesn't hurt especially if you end up selling it in the future.
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Phil_S
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Re: Preferred Filter Cap Brands?

Post by Phil_S »

It depends on a few things. If you are building for yourself and no plans to sell, you can discard the cache factor that name brands carry. I've used all manner of inexpensive caps without any problem. You should, however, watch out for counterfeit caps that don't measure up to spec and that often come from the far east. I would look to minimize cost, but that doesn't mean the absolute lowest price. Also consider size -- don't go too big. I've long suspected that most filter caps come from the same few factories and are made with the same or very similar materials. I don't believe for a minute there is a difference in how they sound. OTOH, if your pockets are deep enough, go ahead and go for the guilty pleasure of a brand name. I would have no concerns about IC caps, and last time I looked, the price point was better than many other brand names.Don't hang them out to dry over an unintentional mistake that's in the distant past.
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Re: Preferred Filter Cap Brands?

Post by R.G. »

Here's a copy of a post I made over on Music Electronics Forum. It's a grim, but realistic view of choosing capacitor by brand and especially by mojo heritage from some or other "golden age".
=======================================

Let's play "Genetic Drift".

What's in an "Orange Drop" [or insert your favorite whatever here]? The folks who manufacture these go buy huge quantities of insulation materials, rolls of metalized film (or rolls of film and rolls of foil for that kind) from the cheapest supplier of such stuff they can find in today's market that also meets their quality needs. They buy lead wires, impregnating materials, and external epoxy dip, and then go run this stuff through their machines to make new [whatevers].

Are the results the same as a [whatever] that was made 20, 30, 40, 50 years ago?

No. First, the automated manufacturing machines are continuously updated as they wear out and/or are changed to produce more parts faster. The machines that are current are continuously tweaked to get the most good parts out of the incoming materials and labor time spent. So the [whatevers] are made on a continuously stepwise changing manufacturing line.

Are the materials the same?

No. You can't buy [whatever] today like you could decades ago. In most cases, you can't get materials that crude and/or wildly variable. In many cases you can't buy materials with the same environmental contaminants as decades ago. In fact, many of the suppliers from long ago are out of business, or they have been bought out by other companies and nothing but the brand name remains. This is much more common than anyone not involved in manufacturing realizes.

Are the factories the same? No. Clearly most of the workers have long since retired, as have the managers, and entire work force of the company. Factories weighed down by high-price work forces have been replaced by factories in low-cost labor places, or just newer, more modern factories.

It's important to realize that economic laws are as immutable as things like the law of gravity. If you can't stay out of bankruptcy making the [whatever] you used to make, you either go out of business or furiously find a way to cut costs and stay level with the competition.

Even in a relatively static manufacturing world, machines wear out, people retire, new laws make it illegal to use materials more dangerous than an ill-timed fart, all the little adjustments that we have to make.

The bottom line is that YOU CAN'T DEPEND ON A [WHATEVER] TO HAVE THAT MAGIC SOMETHING LIKE THE LAST ONE YOU HAD UNLESS THEY BOTH CAME FROM THE SAME MANUFACTURING RUN.

You have a much better chance of a huge manufacturer having some consistency across runs, but even huge manufacturers can and will change their processes with no notice to their huge customers, and they don't know you exist.

It is far, far worse with smaller manufacturers, especially little guys who make up small runs of very esoteric whatsits. It is possible they MIGHT be hand-building whatevers; in that case, they're either priced so high that they can afford to live on whatever gold-dust-covered clients believed their advertising. And their products are highly, high variable in quality, as everything done by hand is. By-hand is almost never repeatable. Did the winding-machine operator have the burrito grande for lunch? OK, we're getting bigger caps this afternoon.

Even worse is the small time guys who buy/contract for parts from the big makers, but re-label them as Platinum Eco-Caps, hand rolled on the soft thighs of Icelandic virgins. This might be OK, but (1) they're certain to charge you extra for their expensive advertising and business trips to Iceland, and (2) when their big-guy maker changes his process, well, you get more genetic drift.

Two last points. First: you can rely on the big guy makers of parts living up to the specs on their parts datasheets. No more, no less. If it's not on the datasheet, you'd be misguided to rely on it, because in most cases they don't even look for things not on the datasheet.

Second: you really, really can never go home again. Home changes out from under you. If you doubt this, go do a little research on who owns that trademark you are relying on.
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Gainzilla
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Re: Preferred Filter Cap Brands?

Post by Gainzilla »

Great insight, as always, guys! Much appreciated. I was leaning towards just getting the F&T's but maybe the Illinois would be fine for this build. I mean, they're just filter caps, right?

RG - Thanks for the in-depth reality check. This is something I've fundamentally known... We live in a mechanized culture, but value things like artisanal breads and craft brew for their unique qualities. However, With hand made components at scale you are sure to encounter the inconsistency you mentioned. What's that saying? Good, Fast, and Cheap: You can only pick two. Seems to apply here.

Cheers!

- Bryce
I know it's only rock and roll, but I like it!
FourT6and2
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Re: Preferred Filter Cap Brands?

Post by FourT6and2 »

For filter caps, I just go with whatever specs out the best. I don't look at the brand name, I look at the data sheet.
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pompeiisneaks
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Re: Preferred Filter Cap Brands?

Post by pompeiisneaks »

FourT6and2 wrote: Thu Jun 15, 2017 12:27 am For filter caps, I just go with whatever specs out the best. I don't look at the brand name, I look at the data sheet.
The only problem I could see with that is that you can't tell longevity or overall stability of a cap based upon a datasheet.

Does cap A last as long as cap B under the same conditions? The data on the datasheet are derived under lab conditions meeting the required expectations. I.e. 60 or 100degC, or voltage ratings at a constant level etc. In real circuits real spikes of heat and current and voltage happen at random, and some manufacturers are smart enough to account for this, and learn from failure states, others don't.

That's just my 2c on it, but I am weary of manufacturers trumping their stats when in reality they don't handle real world situations. BUT that may be less of an issue with caps, I'm no guru there... (yet)

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FourT6and2
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Re: Preferred Filter Cap Brands?

Post by FourT6and2 »

pompeiisneaks wrote: Thu Jun 15, 2017 12:38 am
FourT6and2 wrote: Thu Jun 15, 2017 12:27 am For filter caps, I just go with whatever specs out the best. I don't look at the brand name, I look at the data sheet.
...you can't tell longevity or overall stability of a cap based upon a datasheet.
Oh, but you can by looking at the fancy brand name and price tag?

Specs are derived under specific conditions. And with that, you can compare like for like. If all else is equal, I'm going to pick the cap with the longer hour rating or ESR or ripple or temp stability and so on.

Or, you know... if the cap is purple. Because purple just sounds better and that's a fact.
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martin manning
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Re: Preferred Filter Cap Brands?

Post by martin manning »

pompeiisneaks wrote: Thu Jun 15, 2017 12:38 amThe only problem I could see with that is that you can't tell longevity or overall stability of a cap based upon a datasheet.
Life in hours at rated operating conditions is often quoted on data sheets.
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Re: Preferred Filter Cap Brands?

Post by R.G. »

Translating data sheets into real knowledge is a learned skill. They are not as much advertising as they used to be, but the engineer's version of the very old statistic joke is "lies, damned lies, and datasheets". The

The numbers specified do actually have to be supportable in some fashion, because in an active competitive market, your competitors will go test your product to see if they really hold up. But some suspicion is called for.

On the other hand, a manufacturer that just doesn't want to talk about temp ratings and tolerances after X hours under Y conditions deserves every more suspicion.

Then there's the issue of: if you DID have absolutely rock-solid truth on datasheets, do YOU know what temperatures, voltages, surges, and power on hours you'll use the caps under? Ripple current ratings are almost an exercise in this aspect of the cap game. Sure, there's a ripple current rating on the cap datasheet. But what is the ripple current in YOUR application? And under min? max? medium? standby? conditions and how many hours of each? And how do the conditions add? Is two hours standby equal to 15 minutes of maximum warp output?

By the way, I'm not talking down to anyone on these issues, just stating my uncertainties. I did power supply design for some years, and predicting self heating by ripple current in ESR, and from that and the ambient temperatures a projected lifetime and failure rate was an exercise in futility. I did the math, concocted the reports, and then fervently hoped the stuff would live long enough in the field so I'd be in a new job by the time the smoke cleared. :lol:

My best advice is to buy caps from the biggest volume manufacturer you can. They have the most to lose if they turn out zillions of quick-failing units, so they'll put more money on getting them right. I shudder with horror at trusting a boutique capacitor maker.
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Re: Preferred Filter Cap Brands?

Post by norburybrook »

I suppose there's also the possibility that modern caps are in fact better than those of old 'because' of modern manufacturing processes. Look at cars, due to computers controlling a lot of the work they are now built to incredible consistency and reliability. A CNC machine can reliably churn out parts 24/7 with tolerances of a 1000th of an inch, which in turn means 1: it's cheaper to produce and 2; it's more reliable in it's intended 'machine' due to better tolerances.


the flip of this in guitar/amp world would be I suppose, the inconsistencies and poor tolerances of components are what give 'product X' it its 'mojo' :D


Marcus
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