cap can instead of 4 separate caps?

[pula58]

I'm building a 40W "ish" Blackface style amp (with reverb) in a Princeton reverb chassis. Due to space limitations I am thinking of using a CE distribution capacitor can with 40uF/20uF/20uF/20uF, rated to 525V. The princeton chassis already has an opening and mounting holes for a can cap like this.

In your experience, how do these cap cans compare in performance to, say, using discrete F+T or Sprague 40uF and 20uF caps?

And, in terms of layout, I may put the screen-supply choke where the Princeton's tube rectifier would normally be located ('cause I am using a solid state rectifier instead of a tube rectifier). Any caveats or bad experiences with putting the choke where I am intending to place it? Hum troubles?

[Milkmansound]

You can put a choke pretty much anywhere without needing to worry about hum.

The can caps work well - only complaint is that they all share a single ground so you can not isolate the ground on the reservoir cap from audio stages. In a low power amp you can get away with this - but anything over 20-25W you will be annoyed by the hum that causes.

One solution is to use the can for the audio stages, and put the 40uF from your rectifier to ground somewhere else.

[Bob S]

+++1 on using 2 cap cans.
The first stage definitely benefits from it's own ground.
Put some distance between the 2 grounds too - usually towards the input jack for the pre-amp filters. Grounding in general is a black art. Understood by few & shrouded in mystery.
Good luck with the build.

[gingertube]

Using multisection caps
These things are wound concentrically. The "outside" cap (closest to the can) is usually marked. That is the one which should be used closest to the rectifier as it handles heat due to ESR and ripple currents better.
Cheers,
Ian

[Colossal]

One solution is to use the can for the audio stages, and put the 40uF from your rectifier to ground somewhere else.

The "outside" cap (closest to the can) is usually marked. That is the one which should be used closest to the rectifier as it handles heat due to ESR and ripple currents better.

Very cool tips!

[pula58]

I may do this: Use a separate 47uF F+T for the first cap, and use a 20u/20u/20u/20u can cap for the next three....(I'll be not connecting one of the 20uF caps in the can...a little wasteful...oh well!).

[Firestorm]

What you may want to consider is using a 50/50 cap in the main filter position: one 50 for the plates, one 50 for the screens. This will ground the plate supply and the screen supply together as it should be. If you are using a choke, the additional capacitance in the screen supply shouldn't do anything noticeable. The other caveat with blackface reverb amps is location of the reverb driver cathode ground: since the B+ for the driver comes from the screen supply, that cathode ground should technically go to the same point (instead of with the rest of the preamps).