Are Mallory caps essential?

[Ken Moon]

These are the good Vishay BC caps - available up to 68uF/450V:

[img:578:1020]http://webpages.charter.net/rmweb/Parts ... F-160V.jpg[/img]

http://www.vishay.com/docs/28329/041043as.pdf

Newark sells them in the US, but they add a $20 fee to each order that includes stuff from Farnell UK, like these caps.

I found a US supplier that sells them awhile back, but I can't remember who right now...

[Roe]

I can sell some BC 33s and 47s if you are interested

[Firestorm]

Can anybody hazard a guess as to who is making Gerald Weber's new line of caps for him? Supposedly have "non-etched plates", blah, blah, blah, and are the same physical size as old Spragues and Mallorys in the same values (except for the 220uFs, which are smaller).

[coolidge]

Here's a 6 pack of 220uf 450v BC's in a board I built recently

http://search.digikey.com/scripts/DkSea ... 349PHBK-ND

[img:700:611]http://www.coolidgeamps.com/pics/ps1.jpg[/img]

[C Moore]

Is there anything "bad' with Xicon or Nichicon.? All else being equal (capacitance and tolerance), what difference would the filter caps make. Is it just a matter of longevity, or as mentioned earlier, the ability to withstand some kind of vibration/abuse.?
Thanks

[Ken Moon]

Well, when you say "Nichicon", you're talking about at least 75 different series of caps, and that's just in the Miniature and Large Aluminum Electrolytic categories.

Here's a link to their website, that includes lists and parameter search tools, and from there you can get the datasheets:

http://www.nichicon.co.jp/english/products/index.html

The biggest differences between a "general purpose" cap and a higher quality cap, at least for guitar amp purposes, are temperature and long life. Caps are also rated for ESR, but that's not as important in the typical guitar amp power supply.

Other important considerations are voltage handling, physical size (especially if replacing an existing cap) and connection style (for radials, solder tab/lug is easiest).

Look at the Nichicon PW series, for example - this is, in my opinion, their best radial cap for guitar amps, and is as good as any electrolytic cap you can get for use as a filter cap:

http://www.nichicon.co.jp/english/products/pdf/e-pw.pdf

Since Nichicon doesn't make an equivalent 450V cap in the axial configuration, I use the Vishay BC caps in the pic above when I need an axial filter cap.

The Xicon caps are fine, but the high-quality Nichicons are cheap and available at multiple sources, so I've stuck with them, especially wth all the fake caps out there.

There is a cool-looking series of Nichicons that are made for automotive use (extreme temp and vibration), but they're hard to find in stock in the higher voltage ratings (the BX):

[img:320:240]http://www.sengoku.jp/fd/Nichicon_BX.jpg[/img]

[Ken Moon]

...and here's the equivalent web page for Vishay, which includes all the BC Components caps.

- as you can see, just saying "Vishay" or "BC" or "Nichicon" is pretty meaningless, unless you mention the series of caps you're talking about

http://www.vishay.com/capacitors/aluminum/

The most interesting Vishay caps to me are the 138 AML series for preamp cathode bypass duties, and the 041-043 ASH series I mentioned above, for axial filter caps.

[M Fowler]

I just want to know which ones to order for my jborders Dumble power supply board.

[Cliff Schecht]

http://www.nichicon.co.jp/english/products/index.html

The biggest differences between a "general purpose" cap and a higher quality cap, at least for guitar amp purposes, are temperature and long life. Caps are also rated for ESR, but that's not as important in the typical guitar amp power supply.

Other important considerations are voltage handling, physical size (especially if replacing an existing cap) and connection style (for radials, solder tab/lug is easiest).

ESR is important, but it typically isn't specified unless the caps are for SMPS applications where this is critical. Instead manufacturers give you the rated ripple current that the cap can handle safely and it is smart to follow this often ignored guideline. The rated ripple current is essentially how much RMS current the capacitor can deal with before it heats itself up to the point of failure. This is easy for tube stuff, just add up the B+ currents. I like some headroom with ripple current, at least a 1.5x overhead is necessary but I prefer at least a 2x overhead. This is the truly correct way to select the proper cap for what you are doing and staying within this parameter will guarantee longevity in your caps.

A talented power engineer (specializing in DC-DC stuff) once told me that you can essentially guess a caps ESR based on its size. Weirdly enough this hold pretty true for new caps and so I'll keep a few caps around with the ESR labeled so that I can know (at least roughly) what is going in my builds.

[C Moore]

Like this Xicon cap....I guess it operates to about 185 degrees Fahrenheit. Do we need better than that for amps discussed on this forum.?
I see the ripple current numbers. But I am not sure how to glean the info that Cliff is talking about.....

http://www.mouser.com/catalog/specsheets/XC-600179.pdf

[Cliff Schecht]

The calculation is based off of I=C*dV/dt where C is your capacitance, dV is the acceptable ripple voltage and dt is 8.33 ms for rectified 60 Hz. With 1V of ripple and a 22uF cap you are only looking at ~250uA of ripple. You can measure the ripple in your amp and calculate the ripple current off of this. Most likely it's fine but it's something to be aware of, especially when you go smaller in capacitance (smaller caps can handle less ripple current).

[Ken Moon]

Like this Xicon cap....I guess it operates to about 185 degrees Fahrenheit. Do we need better than that for amps discussed on this forum.?
I see the ripple current numbers. But I am not sure how to glean the info that Cliff is talking about.....

http://www.mouser.com/catalog/specsheets/XC-600179.pdf

If you compare this cap (a very popular series of Xicons) to the Vishay BC axial cap linked to above, you'll see that the max temperature is the same (up to 85 dgrees C), but the 450V Vishay BC caps are tested for 10,000 hours useful life, vs. 2,000 hours for the Xicon.

As Cliff said, this is closely related to the ripple current capability, as can be seen on the Vishay BC datasheet (last page), and this indicates a higher quality cap.

Since they are in the same price ballpark, I'd go with the one with longer life.

Now, if I was working for Fender/Marshall/etc, a price difference of a few cents would very likely drive the design decision to the Xicon.

[C Moore]

Like this Xicon cap....I guess it operates to about 185 degrees Fahrenheit. Do we need better than that for amps discussed on this forum.?
I see the ripple current numbers. But I am not sure how to glean the info that Cliff is talking about.....

http://www.mouser.com/catalog/specsheets/XC-600179.pdf

If you compare this cap (a very popular series of Xicons) to the Vishay BC axial cap linked to above, you'll see that the max temperature is the same (up to 85 dgrees C), but the 450V Vishay BC caps are tested for 10,000 hours useful life, vs. 2,000 hours for the Xicon.

As Cliff said, this is closely related to the ripple current capability, as can be seen on the Vishay BC datasheet (last page), and this indicates a higher quality cap.

Since they are in the same price ballpark, I'd go with the one with longer life.

Now, if I was working for Fender/Marshall/etc, a price difference of a few cents would very likely drive the design decision to the Xicon.

Yeah...the tested life span. I suppose that is something to consider
That is a factor of 5. A lot can happen during that time period. This has been a good education, some nice basic info to know about caps.
Appreciate It
Thank You

[rooster]

Thanks for this post, BTW. Mouser will be stocking the 22uf/450vdc Vishay BC types in about 5 weeks it seems. I ordered 6 to try and yeah, I can wait.

As to the Nichicon Muse series, the small voltage types really are very musical. Like say the 2.2uf/25vdc for a FuzzFace circuit or the 10uf in a tubescreamer - both in the audio path. Eh, FWIW, you know.

Also, in the FWIW catagory, I have used the Spragues and have never had a failure. Nor have I ever seen one first hand that has failed in a guitar amp. Whether they impact the tone/feel of the amp vs. the Mallorys is not for me to say either. Seriously someone needs to to some kind of unbiased shootout of the same amp with different caps for me to buy into the Mallory magic.

I like that most of you have an opinion, sure, so I will read what you have to say. However, till I run into the magic first hand I will remain sceptical. Just sayin.

[Roe]

the BCs have a warm and slightly dirty tone thats great for marshall, TW and Vox amps. I wouldn't use them in a BF fender though