I have a design, based off a bunch of soft starts out there. I have to test some of the circuit yet but I will post a schematic of the Proposed design tomorrow so you can see that you don't need a timer, though one would work the first time, I use a comparator a cap and a variable pot to adjust the timer to relay pull in.
softstart for you big amp
The soft start circuit still needs testing and any debugging and changes if necessary but here it is. It has the advantage of only switching 12-14vdc on the amp front panel. It has a connector J5 for a red LED, standby, and a blue LED, on. It uses an optocoupler as a zero crossing detector to trigger the Triac. A LM311 compares the input of the voltage divider with the input of a variable resistor and capacitor. the voltage divider is set for 2/10v, about 83% of full voltage. The pot controls how fast the cap reaches 12v. The LM311 output turns on the MOSFET which pulls in the relays bypassing the thermistor and changing the LEDs from standby to ON. Testing will determine if it will work consistently and properly when a power down then power up event occurs. I will post more when I have had time to test (already have the parts).
The soft start circuit still needs testing and any debugging and changes if necessary but here it is. It has the advantage of only switching 12-14vdc on the amp front panel. It has a connector J5 for a red LED, standby, and a blue LED, on. It uses an optocoupler as a zero crossing detector to trigger the Triac. A LM311 compares the input of the voltage divider with the input of a variable resistor and capacitor. the voltage divider is set for 2/10v, about 83% of full voltage. The pot controls how fast the cap reaches 12v. The LM311 output turns on the MOSFET which pulls in the relays bypassing the thermistor and changing the LEDs from standby to ON. Testing will determine if it will work consistently and properly when a power down then power up event occurs. I will post more when I have had time to test (already have the parts).
What is the wire size that people are using for their diyAudio F5T boards?
Is it really 20AWG?
If not, how are you connecting the wires to the boards? ( I my last iteration, I used harwin PCB mound solder cups, but that meant drilling out the boards....I'd rather not.)
Is it really 20AWG?
If not, how are you connecting the wires to the boards? ( I my last iteration, I used harwin PCB mound solder cups, but that meant drilling out the boards....I'd rather not.)
Cut some strands off the 14AWG. Mine is actually 14g Canare speaker cable.
I think the pcb will take 18AWG. My boards are the regular, much older F5 standard boards...I don't have the newer F5T boards.
Strip back a portion of the 14AWG wire. Cut of a resistor lead that fits nicely into your holes. Wrap 3/4 of the resistor lead around the outside of the 14AWG wire and solder. Cover that bit with heat-shrink tubing. Now the other end of the resistor wire goes into the hole.
What I do is to strip back the thicker wire and about 1/8” from the insulation I snip off some of the strands so that the end of the wire will fit in the hole. Then solder it and put enough solder on the top to have it flow up to the insulation, soldering the 14g portion of wire to the top of the board. This will make the wire a bit stiffer than typical. If your runs are short and you have multiple parallel output boards like in an F5V3 it may be overkill using larger wire. I can’t remember what gauge wire I used.
Neat idea ... but perhaps not the optimal solution for any wire that carries high current? 😕
I mean, you are reducing 14g wire to, say, 24g wire (the resistor lead). Whereas if you cut off some strands like Hikari1 suggested then you get down from 14g to, say, 18g - which is a lot thicker than 24g.
Andy
It should be 18 awg, although I cannot seem to fit the 18 awg stranded without losing a strand or two. Maybe solid core?
In a daisy chain the current in the wire feeding the first board is double.
With parallel you can run an independent wire from Power supply to each board
With parallel you can run an independent wire from Power supply to each board
A few inches of 14 gauge wire can handle all that current and more, so it doesn't matter either way.
If you prefer not to daisy chain, knock your self out. 🙂
Rush
I would argue that parallel is better although it probably won’t make much difference. What might make a difference is everything having a more central “star” ground. I started out with THHN house wire, I’ve used that, Teflon silver coated and speaker cable. Doesn’t make much difference.
If 14 awg would fit the boards, I would not care. My first implementation used 14 awg, but I messed up the boards drilling them out to fit a larger solder cup. This one may be 19 awg.
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You could connect 14 awg stranded wire by putting a 1mm pin into the center of the bundle of strands as a guide, then ensure that there is a solder bridge between the tips of the strands and the board.
You need to ensure that the wire is soldered in from the back of the board as well to make the circuit. For those connections you get maximum contact via 1mm wire.
Stranded is a must here for strain relief. I used solid core house wiring in the first version, which is too stiff.
You need to ensure that the wire is soldered in from the back of the board as well to make the circuit. For those connections you get maximum contact via 1mm wire.
Stranded is a must here for strain relief. I used solid core house wiring in the first version, which is too stiff.
Sometime at the beginning of this year, I bought the F5 kit from the diy store. I also bought the boards for the universal PSU. I had waded through the build guides at the time and put off buying the BOM for the power supply. I did buy the transformer but I don't recall if I needed the standard BOM for the PSU or if the parts values needed to be changed for the F5 specifically.
Can anyone answer this without me having to read back through all of where I went the first time? I would appreciate any help.
Can anyone answer this without me having to read back through all of where I went the first time? I would appreciate any help.