Can Caps in Express

[rooster]

FWIW, I've used the can caps, (non-VVR build), used one ground path for both caps, and also two separate ground paths, one for each can. No difference sonically, no added noise by using one ground path.

Also, let me be clear, to isolate the second can cap, I had to wrap the second can cap with clear packing tape, such that the can clamp did not ground the can. It was truly isolated, and then I attached one of the can grounds to the initial can that had it's can clamp grounded, along with a separate lug for the bleeder resistor.

[RJ Guitars]

One great reason to use can caps is that when you use a non US standard power transformer, it is common for them to have wires coming out of both end bells. This means you got wires coming up right into the Stack O' Caps. With can caps you free up a ton of real estate and to my ears, there is no penalty otherwise. For an Express I use the 50/50 JJ for the first filter cap and on the Rocket I use the 33/33 JJ so I don't hit the tube rectifier too hard.

I'm not sure why the TW trannies by Pacific and Heyboer have all the wires on one side... maybe they got that from the Stancors they copied. I know there are some old Triad transformers that are built that way... anybody know if the Stancor P-8378 is the same?

For the guys on the other side of the pond you also have the option of using a Vox AC-30 transformer for an Express or a higher voltage Rocket. These transformers can make a great power unit for an Express because the secondary specs are about right and they come in a variety of mains voltages. I used one on a Rocket so I could do some experimenting with voltages and layout. Because these are lay-down transformers, the can caps also worked great for this amp.

YMMV

rj

[Ken Moon]

Several builders have used the JJ 40-20-20-20 cap can on Express builds.

I built a couple Wrecks of this variation about 4 years ago, using the JJ cap can for the filter caps circled in red, and they were as quiet as an Express can get.

[img790]http://i514.photobucket.com/albums/t346 ... reckv2.jpg[/img]

[Curranproducer]

I finished my 1st express build a few weeks ago, and I used can caps on purpose to save space inside the chassis AND my basic fear of glue letting go and bolts being more secure. This amp is whisper quiet at full roar, O just need to chase down an oscillation that happens when NOTHING is plugged into the amp! HAHAHAHAHAHA the weirdest thing HUH!

[RJ Guitars]

... O just need to chase down an oscillation that happens when NOTHING is plugged into the amp! HAHAHAHAHAHA the weirdest thing HUH!

I think one of the best things you can do is to use a shorting jack on the input that kills the signal to the first gain stage until you plug in a guitar.

[M Fowler]

And if you did use a shorting jack make sure it is adjusted or working.

[Curranproducer]

yeah I always use those switch craft 12A jacks. So I hope that i just got a bum run of jacks instead of a mystery problem

[jelle]

Switchcraft changed the coating on these input jacks, and they seen to oxidize much faster.

The vintage 60s ones I have sometimes look better than the new ones.

Anyway, run a piece of paper with deoxit *for pots* between the contacts, and retighten. Done.

[M Fowler]

On my recent Rocket built I had to adjust the switch blades to get the jack to work properly on a new Switchcraft jack.

I suggest as others and myself have said clean and adjust the jack.