Power Supply Soft Start Board (V3)

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Here's a couple of pictures of a completed board.
I used the Keystone 30A screw terminals instead of the Fast-On connectors.


WP_20140110_001.jpg


WP_20140110_003.jpg
 
My Soft start board is built!

Hi Jason and ToeCutter

Just some comments about my build. Mouser in Europe (Germany) had run out of a couple of the resistors so I picked an alternative brand for R3-6 (Green Vishay) I tested all the resistors before soldering in.

I also picked a green LED, slightly different forward voltage, thanks for confirming it would be OK.
Really useful to refer to the photo of your built board ToeCutter esp for polarity of C3

Based on the post below I will remove the one thermistor (TH) and I guess just solder the leads from the primary together. Note UK 240v
http://www.diyaudio.com/forums/pass-labs/207103-f5-turbo-builders-thread-268.html
"If using the Soft-Start, you may omit the thermistors in the transformer primary"


Cost about £50. for parts, pcb and shipping.

Are there any basic checks I should make before connecting to my amp and turning on?

I will install and update you all by the weekend
 

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Can anyone provide the dimensions of the mounting holes of this board (v3)? I first assumed they were 40x80 but the store says the board outline is 55x110 and looking at the pictures posted here this doesn't look right to me. I'm also looking for the hole dimensions of the speaker protection board as well if you have them.
 
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I can measure tomorrow, but the measurements on the website look correct. I can tell you positively that the V3 board fits on the 10x10 grid. The 40 looks right on, I agree that a 110mm long board, with 80mm long spacing does not look to match the board pictured above.
 
Hi Rudy

I'm no engineer but I know that the Mundorf caps are expensive! I think its worth a little more to protect them. I can hear my transformer 'charging' and its only a small 300VA.

In terms of your load going through the soft start I don't know what it can handle.

Bones, do you want outside dimension or from centre of mounting holes?
 
Rudy, the main issue is relay current rating. While you are technically within spec at 8-9A, there isn't as much margin as we normally design into projects. You may find that the soft start works fine, although the mains switching relay may fail relatively early.

You might try to find a relay with a higher current rating that will fit the board, but In your shoes I'd just go ahead and use the soft start as is, knowing that someday I will probably have to pull the plug to turn the amp off. Every amp I have owned for more than 15 years has had that issue with its switch. They weren't pushed as hard as yours will be but that ought to give you some comfort.
 
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Bones, do you want outside dimension or from centre of mounting holes?

I have completed my soft start board, and its mounted on a plate with the momentary switch circuit, transformer for that, and the large solid state relay that the switch circuit controls.

I will have a chance this evening to get my ruler after the board, and give you the answers about size.

I am on call this weekend, but hope to get my left channel input/output wiring done, and start mounting the toroid, the cage over it holding the above circuits, and the stacked diode/cap boards for my PSU for my current Aleph J project. Most the stuff is the now easy to use DIYStore bought gear. Really enjoying the build, and hoping the sound measure up to the hype ;)
 
Yep. Before connecting the mains, Visually inspect that the joints are good and there are no shorts. Check for no continuity to the chassis from hot and neutral and from hot to neutral.

When ready to power the soft start, do it without anything connected to it downstream and ensure that both relays operate as expected. A voltmeter across the mains output will show mains voltage without the amp connected since there is no current draw.

Then, assuming that are powering your amp up for the first time, next just connect the transformer, again verifying operation of both relays. Repeat with the first PSU, then the first amp channel, the second channel PSU (if dual), then second channel. It doesn't take much time to do and makes troubleshooting much easier since you are isolating modules.
 
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I have completed my soft start board, and its mounted on a plate with the momentary switch circuit, transformer for that, and the large solid state relay that the switch circuit controls.

I will have a chance this evening to get my ruler after the board, and give you the answers about size.

I am on call this weekend, but hope to get my left channel input/output wiring done, and start mounting the toroid, the cage over it holding the above circuits, and the stacked diode/cap boards for my PSU for my current Aleph J project. Most the stuff is the now easy to use DIYStore bought gear. Really enjoying the build, and hoping the sound measure up to the hype ;)

I can confirm that the mounting holes are 100mm apart on the x plane and 40mm apart on the y plane.
The board dimensions are 110mm x 55mm
 
Question about wiring up the soft start board v3.0

Hi All

Please can you help me with wiring up this new board, I need it spelling out to me...:confused:

It seems obviois to put mains L and N from mains switch on left as per photo. Therefore Live mains brown wire to 'live/SW1' and blue neutral to 'neutral' board connector. However I can't figure what connector 'SW2' is for?

Does the primary of my transformer connect as follows, brown wire to XFR1 and blue/N to XFR2 ?

Once you share the answer with my I will update my hand drawn schematic and post for the benefit of others
 

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