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Soft switch version 2 anyone?

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After the first group buy of the soft switch circuit, I continued to get emails from people interested in the kit. I've made a version 2 which includes the following improvements:

1. Replace the hard-to-obtain MAX6816 (debounce IC) with a CD4013.
2. Added a high current relay to switch up to 15A AC.
3. Added jumpers to make one board work with 115VAC and 230VAC.
4. Added an NTC thermistor for in-rush current limiting. The layout supports the popular CL-60 or larger CL-101 part.
5. Added a fuse (15A max) for the switched output.
6. Added an output for an optional current-limiting board.

You can find more info and pictures on my website: http://www.robcheng.com


Here is preliminary pricing:

$55 shipped (U.S.) includes everything.
$40 shipped (U.S.) minus the switch.
$15 shipped (U.S.) for PCB only.

International: add ~ $5-$10 depending on location.

The prices are higher than the previous GB because I'm including the transformer and high-current relay.

Please post or email if interested or if you have any comments, suggestions, etc. As interest grows I'll create a Wiki page.
dw8083 said:
Thought of combining the soft start and soft switch boards together in one circuit?

That might be popular.

Part of the problem with that idea is size. I don't doubt that there are folks who would want it all in one board, however I think some won't have room for a "large" board and not everyone needs the current limiting resistors. In smaller power amps the CL60 will work fine.

Got you down for 2 to 4.

Hi Robert,

You might consider adding a GB close date and and estimated ship date to the wiki page to help set expectations.

One other idea. What if the soft start board was combined with soft switch, but seperated with a scoring line. There could be jumper pads from one board to the other. The boards could be easily split if space is an issue, or the soft start is not wanted. Depending upon the PCB vendor, there might not be any additional cost for taking this approach. The soft switch parts could be included as planned, and the soft start parts are up to the buyer.

Just a thought,

I have updated the pricing on the Wiki page and I'm now accepting payments. I plan to start ordering parts on Aug 22, so this group buy will close on Aug 21. I will be ordering a limited amount of extra boards for those of you who procrastinate.

If you haven't yet, please send me an email directly so I can contact you directly if needed. Also check your info on the Wiki page and update any blanks (such as location).

I may be interested in a pair for my monoblock tube amps. Just a couple of questions.

I am on the wrong side of my mid forties :bawling: and find myself having a harder time working with the small stuff. I have never worked with the really small parts so just how hard is it to solder SMT components?

Also, can the "optional soft start kit" handle B+ of 450 to 500 volts at a 100 to 150 ma?

This is a reminder that I would like to close the group buy very soon.

There are still some folks who have expressed interest who have not paid:

David (DW8083)

Please check the Wiki page to verify your quantities, calculate amount due, and payment instructions.

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