Advantages of can capacitors?

[culturejam]

The only thing I don't like about cap cans is you cant wire the "individual" caps in series.

Right. I guess that would be sort of impossible.

[C Moore]

I agree and I have had no problems with grounding of can caps and no huming, buzzing or ghost notes using them. The 40/20/20/20 I have used in several builds the last being my Route 66 and that amps sounds great.

Thanks! I'm glad I'm not totally crazy for not understanding what the problem might be.

The problem is that with a can cap, all the caps have a common ground. Single, axial lead caps can be wired in series or parallel, whatever you need, wherever you need on the chassis. A can cap limits you in that manner. So you trade convenience for (potential) versatility.

[culturejam]

The problem is that with a can cap, all the caps have a common ground. Single, axial lead caps can be wired in series or parallel, whatever you need, wherever you need on the chassis. A can cap limits you in that manner.

I guess I just haven't worked on a project that required high-voltage, series-wired electrolytics. I'm still relatively new to amp building, though, and all my builds have been very simplistic.

[Andy Le Blanc]

It really is advantageous to have a separate ground for the first filter ground.

Cans are great other wise. There are other can styles besides the twist loc.

[paulster]

I like to have the preamp, PI (and NFB), screens and plates each with a distinct ground that's tied to their relevant filter cap to ensure the lowest possible source impedance and to minimise inter-stage interactions via the power supply, and from the cap grounds tie them to the star ground point.

With the dual-section cans you can usually get it to work out just fine, but I think that's where the 4-section can is potentially more limiting.

That's just my personal preference for grounding though, and other people make other schemes work just fine for them. Dana's had the Express working well with the JJ can, so it's eminently usable!

For certain builds with high voltage plates you also need to put the caps in series, so this can also be an issue.

[Andy Le Blanc]

I had an old WEST that had large cans with a threaded plastic mounts.
Only one had a card board sleeve. I reached in one day to check the
transformers for heat and found out the hard way they were in series and
the last tech put the sleeve on the wrong can.

[David Root]

One can for power tube plates and screens and a second for PI and pre tubes is I think a good compromise in the grounding scenario, especially for 50W and bigger amps.

I have heard that the JJs are a bit high in ESR compared with say the F&T dual radials, which are comparable to a two-cap can. Depending on your build that may or may not be a limiting factor.

Marshall guys say that the best current can cap for Marshalls is the ARS out of California. They are a relabel, origin unknown to me, but they sound good in the pre and PI of my 6SL7 Dumbleized 5F6A 100W. They can vary in capacity. I have two 16+16s in that amp, one is actually 16+16, the other is actually 20+20.

Maybe these would be good in real Dumble circuits too. That would be nice because there ain't a lot of free space in a Dumble sized chassis especially if you want four individual bias adjusts and DC heaters on the 12AX7s. If you put the can caps on top you then have all kinds of space below.

Now if there were 1000V cap cans I could do a Music Man iron 700V plate Dumble.........