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FS: Kit for amp power soft switch

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M

Maxhawk

Member
Joined 2002
robcheng.com
#1
I've designed a small board that's used as a soft power switch in my Leach amp. I had to order a minimum of five boards so I'd like to offer 3 of them for sale.

The PWB contains a PC mount AC transformer, JK flip-flop, switch debouncer, and relay to switch 115VAC to a device(s). I use the output to drive a solid state relay that powers the main torroid transformer.

I'd like to offer the kit for $20 shipped with all parts except for the switch, relay, and transformer. The switch I used is pretty fancy and has a built-in blue ring to indicate power is on.

Here is a list of parts you will need to order/provide. Vendor part numbers are in parentheses:
1. DIGIKEY: Relay (Z105-ND) $4.68
2. DIGIKEY: Transformer (TE70000-ND) $9.34
3. MOUSER: Switch (117-MPI002/28/BL) $19.40
4. MAXIM: Debounce IC (MAX6816) $0 -- free sample

You can choose to use a cheap momentary switch but this one gives a very high-end look.

I've got pictures on my webshots page: http://community.webshots.com/album/89459645dwnQjT


Rob
 

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#4
If there's really enough interest I can order more boards. The switch and transformer that I used makes this sort of expensive for what it is, but it's done in a very neat package and looks nice.

Since I didn't mention it before, the PWB measures 2.0" x 3.5".

If I can get a total of atleast 8 orders (3 PWB's that I want to sell + minimum order of 5 PWB's from vendor) then I'll order more boards. After the 3 are gone, I'll order more if there's enough interest.


-Rob
 
#5
I don't want to be a killjoy, but if switch-on thump is the problem, the Leach amp will power-up with no significant disturbance if the input is held at ground potential for two or three seconds after switch on. A 'normally closed' pair of relay contacts will do this,
relay operation being delayed and energised by a simple SCR/thyristor circuit with CR charging on its gate. This arrangement requires no significant additional power components, and leaves nothing attached to the signal path after power-up. The relay de-energises immediately on switch-off, and again results in no output disturbance as the power rails decay.

JTT
 
#6
Nope, that's not at all what this circuit is intended for. I wanted a momentary push button for my power switch with an LED "ring" to indicate that power was on. I was prepared to make a lightpipe around a regular push-button switch when I stumbled an off-the-shelf switch that did exactly what I wanted. I'm using a JK flip-flop to toggle power on and off, clocked by the switch. The switch needed to be debounced and I also needed some drivers for me LED. So to simplify things I made a PWB that contained all this as well as the power transformer.

Hence the name soft power switch.
 
#8
JTT

I have installed a Vellerman kit in my BOSOZ pre-amp to solve the turn-on thump problem. I have wired the output relay the way you have described it. I was wondering which circuit are you referring to. Can you post a schematic too?
 
#17
I've got enough orders to order another batch of 5 (or more) boards. I have interest from the following:

[res07ogj] qty 2 (paid)
[ipolykov] qty 3
[deewm] qty 1
[ac12-5dc] qty 2

If these numbers are incorrect, please email me. I'll wait until Friday morning to see if there's any more interest. When I order PWB's on Friday it will take 1.5 weeks to get the boards.
 
#19
JasonL said:
how much per board ? what comes with them ? what is the max curent that can be use.. I am assuming that depends on the relay ?
Click to expand...


$20 each shipped. Look at the first message in this post. I list the items that are included. The output of the board is the AC line voltage (115VAC) and is switched through a 1A relay. It is not suitable to switch a power transformer. You will need to use either a 115VAC input solid state relay (like I'm doing), or tap off a 5V switched output for the LED.
 
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