Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ncusack on March 08, 2012, 01:35:33 pm
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Hey Everyone,
I'm just looking for a bit of input on board layout design using radial filter caps. I'm thinking that sticking to a hoffman style layout will work fine using radial caps but I'm wondering if anyone has experience with them. What I'm specifically looking at is turret board design and laying the radials on their side like you would with an axial leaded cap. Any examples of boards done this way would be great.
Cheers,
Neill
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Here is how I do it. but Im just using them for the B+.
Bill
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Here's how I did it recently.
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Are those Nichicon PW Caps by chance?
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Are those Nichicon PW Caps by chance?
Yes, I used Nichicon VZ series, 22uF@ 450v, 105c., 115mA, 1K hours life.
But I recently found out about these, Panasonic ED series, 22uF@450v, 105c., 680mA, 10K hours life.
10x life rating, almost 6x the ripple current rating, only $0.25 more. I'm going to try these next.
Doug's caps are more than fine and if your going to use his turret board they fit perfectly cause that's what he used when he designed them. A _ lot _ of guys here (and on other sites) have used the Ill. caps with great results.
Brad :icon_biggrin:
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I like Willabe's way of doing it with the leads bent out to the sides so that they can be desoldered from the top rather than under the board, might mean more turrets but a lot less hassles and if height is a problem do the same but lay them down, great :thumbsup:
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Willabe would you mind sharing a few more pictures of your board layouts so I can get an idea of how you approach your builds with these caps?
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Here's a pic of radial filter caps located along the front edge of the board so that they're closer to their respective circuits. Otherwise the layout is very much the "Hoffman style".
(http://i222.photobucket.com/albums/dd298/Chipster457/PR%202008/PR2008boards.jpg?t=1242019501)
That thick copper wire is the preamp ground bus.
This approach works equally well with radial or axial caps:
(http://i222.photobucket.com/albums/dd298/Chipster457/Super%20Reverb/GutsPreamp.jpg?t=1250382952)
Hopefully it's obvious that the second photo is from a later & hopefully improved amp build. There's 1 hole in the board for each zip tie which I heartily recommend to keep those caps in place. This approach also puts caps where they can be replaced easily.
Cheers,
Chip
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Hey Fresh Start are you grounding only at the input with that design or is there a split style ground for the power section somewhere else?
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Hey Fresh Start are you grounding only at the input with that design or is there a split style ground for the power section somewhere else?
Three ground points actually. The long bus is for the preamp and is grounded at the input jack, one for poweramp and 3rd for heaters. Attached file shows full layout modified to show how I would build it if I had a "do over".
Cheers,
Chip
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Willabe would you mind sharing a few more pictures of your board layouts so I can get an idea of how you approach your builds with these caps?
I rebuilt my 5E3 and built a Fender stand alone reverb using the small radial e-caps. I wanted to try them and so far I like them. If you look at the top right corner of the pic you can see where I ran 1 cap vertical and another cap horizontal on the same pair of turrets.
Like Timbo said I bent out the legs a little and put them into the open end of the turrets. I did this to increase the distance between the turrets. It also allows you to run all the ground wires from each circuit that is fed from it's own cap to make a ground star point.
Doug, KOC (London Power TUT books) and Merlin use grounding like this.
Here's a link to Merlins site on grounding.
http://www.freewebs.com/valvewizard2/Grounding.html (http://www.freewebs.com/valvewizard2/Grounding.html)
Here's the scheme and layout drawings for my 5E3
Brad :icon_biggrin:
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Hey Guys,
Just wondering if I have the right idea here. This is a mock up for a 6v6 Lite iib using radial caps. Let me know if I'm on the right track as far as the layout goes. Both a rough schematic and layout are attached.