Can Caps in Express

[beasleybodyshop]

If I were to build an Express, could I use two of these:

http://www.tubesandmore.com/products/C-EC40-20X3-500

in lieu of the six 40/20uf stacked caps that were originally used? I had heard mention that can caps were a good alternative, just wanting to double check.

[cbass]

The bad thing about cap cans is that they have common grounds.
You might get away with using one for a and b
but your preamp grounds need to seperate from these.
I would stick with the plan Yous askin for trouble if you start monkeying around with the layout.

[beasleybodyshop]

The bad thing about cap cans is that they have common grounds.
You might get away with using one for a and b
but your preamp grounds need to seperate from these.
I would stick with the plan Yous askin for trouble if you start monkeying around with the layout.

What issue would common grounds cause? Sorry I am a luddite.

EDIT: I understand what you are saying now. Yes pre grounds would indeed have to be isolated.

[beasleybodyshop]

I was referring to this thread:

http://ampgarage.com/forum/viewtopic.php?t=9624

I was wondering if Ritchie was using a 50/50 cap and a 40/20/20/20 cap. That was my guess.

[cbass]

Typically You want your high current grounds away from the lower current ones.

Just copy what Richie did then.Pretty good guy to copy IMO

[Richie]

I was using the VVR in that amp. So I followed Dana's layout with the cap cans. Mine may be a little different than his, but pretty much its the same.
Hard to beat his amp work. The amps were quiet,and no problems using the can caps. here is a link to more info, and a pic of Dana's amp in the thread. And has the cap info,and parts used etc..

http://ampgarage.com/forum/viewtopic.ph ... ht=#113528

[beasleybodyshop]

I was using the VVR in that amp. So I followed Dana's layout with the cap cans. Mine may be a little different than his, but pretty much its the same.
Hard to beat his amp work. The amps were quiet,and no problems using the can caps. here is a link to more info, and a pic of Dana's amp in the thread. And has the cap info,and parts used etc..

http://ampgarage.com/forum/viewtopic.ph ... ht=#113528

Thanks for the reply Richie, This is exactly what im looking for. I am using a VVR in my express rig as well, and was kind of sweating the wire acrobatics around Mt. Electrolyte in the normal express build. This definitely makes life easier!

[beasleybodyshop]

Question: I noticed that there is only one CC 3W resistor off the power supply to ground in a cap can wreck. What is the reason for this?

[beasleybodyshop]

Disregard:I discovered through digging through old posts that I can sub in a 470K resistor.

[gingertube]

When using the multicap can electrolytics it is important to know that they are wound concentrically and to identify which of the caps is the outside one (closest to the can). This one will get rid of its heat the best and so will have the highest ripple current rating. It should be used for the first cap in the power supply, the one right after the rectifier. In a 40 + 20 + 20 + 20 (or similar) this will undoubtably be the 40, but sometimes you need to check closely.

I don't use these multicap cans. Separate caps are so much better AND in fact I use 22uF 450V Panasonic ED almost exclusively. It allows me to tune an amp sound. Start with 2 of these in parallel for the main filter cap (44uF) . Add one more (66uF) or 2 more (88uF) to see if its better or worse. It allows you to better tune the amp to your taste AND 2 off 22uF will have about half the ESR of a single 47uF.

Cheers,
Ian

[M Fowler]

Never had any issues using can caps and actually I prefer to use can caps when design allows.

[andrew]

http://ampgarage.com/forum/download/file.php?id=9797 what does the film cap across the grid resistor on pin 2 and 7 do? Thanks

[Tillydog]

http://ampgarage.com/forum/download/file.php?id=9797 what does the film cap across the grid resistor on pin 2 and 7 do? Thanks

Looks like it is an amp equipped with variable HT voltage, so they are probably blocking caps to prevent DC on the volume / guitar pots when operating at low voltage. The resistors would be grid leak resistors 'downstream' of the blocking cap.

/OT

[andrew]

Thank you Tillydog.

[Bruciep07]

I feel like we are skipping over one point. KF used common grounds in the real deal. Look at the layout, all 40uF's are tied together, and the last 2 20uF's are tied together, and they all terminate on one lug. I'm sure we all agree that they're are better ways to do it, (maybe not "better", possibly less noisy?) but nothing wrong with can caps in an express. Compared to the "stack-o-caps", I think can caps clamped to the chassis are a much better option than using silicone and weather stripping to keep them in place.