Power Supply Soft Start V3

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The Power Supply Soft Start Board (V3) is available in the DIY audio store. This is an updated version of the Soft Start V2 boards, primarily to make them compatible with the 10x10 grid mounting pattern we've now standardized on (PCB=110mm x 55mm) so they can be easily mounted to Deluxe chassis baseplate, riser panels, front panels and/or heatsinks. Refer to the Soft Start V2 discussion thread for additional information.


This WIKI will attempt to provide instructions and/or guidelines to enable a properly working P/S Soft Start Board (V3).

Qty	Reference Designator	Value	Type	Mouser P/No	Lead Spacing	Notes
1	C1	0.01uF 1KV	Radial Ceramic	594-S103M47Z5UN63L0R	10mm	C1 should be X2 capacitor type for safety
1	C2	1uF 275V	Radial Polypropolene Snubber	80-PHE840MZ7100MF11R	20.3mm, 22.5mm, 23.4mm, 27.5mm	smaller value = longer delay
1	C3	1000uF 50V	Radial Aluminium Electrolytic	667-EEU-FC1H102	7.5mm
1	R1	220R	3W Metal Oxide	667-ERG-3SJ221A	18.4mm
1	R2	1M	3W Metal Film (1/4 W ok)	594-5093NW1M000J	26mm
4	R3, R4, R5, R6	180R	5W Wire Wound	280-CR5-180-RC	26mm
1	R7	2K2	0.5W Metal Film	273-2.2K-RC	9.5mm lead spacing
4	D1, D2, D3, D4	1N4007	Rectifier 1000Vr 1A	512-1N4007	11.05mm
1	D5	1N4749A	24V 1W Zener Diode	512-1N4749A	11.05mm lead spacing
1	LED1	Red	5mm Red diffused LED	78-TLHR6400	2.54mm lead spacing
1	K1	Relay	Relay SPDT 24VDC 15mA	653-G5LA-14-CF-DC24		poss. replace: G5LE-14-36 DC24, 769-JS1-24V-F
5		Terminal	30A PCB Screw Terminals	534-8197	5mm
	or
5		Terminal	TE Faston Connectors	571-624091

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XLS.ZIP

V2.0 - First Production Version
2.0.1 - Added board dimensions
3.0 - New Layout

• Double sided board

• Moved AC in and Txfrmr connections to ends of board

• Added Keystone connectors as option

• Conforms to 10mm mounting grid

For future changes:

• Add polarity markers for electrolytic capacitor

• Add optional fuse between SW2 & R1

Question 1:
Will there be any loss of dynamics or timing when playing music with the use of this circuit?
Answer 1:
Once the relay contacts shorts out the load resistors, the transformer will be effectively connected to the mains as if the soft start board ain't there at all so I doubt if any sonic difference will arise from it's use in any amp or preamp project. -Jojo
Question 2:
What is the maximum size toroid that can be started with this soft-start?
Answer 2:
I have been running a 1kva toroid with a combined filter capacitance of about 160kuf for about 3 years now. -Jojo
Question 3:
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Question 4:
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Question 5:
Answer:

Tip no. 1:
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Tip no. 2:
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Links:
Purchase this P/S Soft Start V3