jims audio soft start module

[tinitus]

with this crude kind of softstart I think its the size(value) of power resistor
but Im not sure

but with 7watt resistor, that softstart must be designed for very small power, like preamps
for you a 20watt would be more like it

but my word is not really reliable here

 

[Lazy Cat]

SSA Soft Start universal utility module

 

[AudioSan]

cant find any info of how long delay time you have on your softstart
maybe its too long ?

I guess 2 sec would be good enough, and safe ?

2sec is way too much. that will burn the resistors. 200mS or so is better.
depending on current and resistors ofcourse
i like to use NTC bypassed by relè that takes the stress out of the relè

 

[quan]

I will try with 2+ CL60 thermistors and 24V zener across the relay and see what happens.
quan

 

[Lazy Cat]

2sec is way too much. that will burn the resistors. 200mS or so is better.
depending on current and resistors ofcourse
i like to use NTC bypassed by relè that takes the stress out of the relè

Here's the first second of a power on sequence with repetitive consistency. Diagram showing AC mains current from turn on moment (2 Ap - first relay switch current) to 0,68 s (3 Ap - second relay switch current). Serial inrush NTC is CL-90 (General Electric) managing to turn on 800 VA (two 400 VA toroids) with 90000 uF of smoothing capacitance.

 

[quan]

Here's the first second of a power on sequence with repetitive consistency. Diagram showing AC mains current from turn on moment (2 Ap - first relay switch current) to 0,68 s (3 Ap - second relay switch current). Serial inrush NTC is CL-90 (General Electric) managing to turn on 800 VA (two 400 VA toroids) with 90000 uF of smoothing capacitance.

Nice board and beautifully build. Do these available as kit or as module?
quan

 

[AndrewT]

Hi LC,
is that ~9Apk as a maximum?
What size of mains fuse passes this without nuisance blowing?
I'm wondering if T2A or T3A does the job?

 

[Lazy Cat]

Nice board and beautifully build. Do these available as kit or as module?
quan

Only PCB and parts list could be provided.

 

[Lazy Cat]

Hi LC,
is that ~9Apk as a maximum?
What size of mains fuse passes this without nuisance blowing?
I'm wondering if T2A or T3A does the job?

Yes 9 Ap is maximum between 0,14-0,16 s.

Just for turn on current capability T3A would do the job, but regarding to amplifier's Pmax I use T4A.

 

[quan]

Just to update , i swapped out the soft start kit to my other SS amp-500VA/40000uF. There is no smoke and the relay works fine. I gather then the new amp must be putting the kit under stress that it smokes. BTW the aussie amp soft start works perfectly with my new amp so all good. Pity i would like to know why it smokes in the first place.
quan