Oh nooo! should I post my concerns in confuse dot com?
soft start, no soft start, resistors, thermistors.... seems like there is no solution at all! it is just about try something and cross your fingers, isn't it??
I guess I'll turn on my PSU in 2024...
don't be frightened, it is really simple once you done it....we have been doing it for years with much success...
+1, i have turned on much bigger traffos than that.....mostly without soft start circuits...some folks took that 1980 Walter Jung article too seriously....
Nope
Probably in the 2 to 4 amp range for a typical domestic amp, or if you are testing at full power perhaps a little higher. No fuse will save a transistor, they just ain't quick enough. The fuse just keeps it all safe.
Well it is NOT an Amp, is a Modular Synth, the toroidal tranformer is 230volts (UK) there are two primary 115V I'll put in series to get 230V, it is 300VA, Two secondary 18-0 18-0 V rated 8.3Amps. The PSU is a dual LM338 IC, caps ar 10,000uF 50V, bridges are 400V 25Amp. and some small caps for filtering and protection diodes as you will expects from a regulated PSU with LM338.
So still no soft start, big switch and just slow blow (delay time) fuses in primary and secondary will do the job?
Thanks a lot Mooly!
Cheers.
being afraid is good...even today, powering up any equipment for the first time is so stressful and scary...being scared makes you alert all the time...
only you can make that decision based on inputs presented here....do that which inspires confidence in you....
i never tell people what to do....i just give them hints...
Yeah, it's what a forum means, right?, getting points of view and making your own decisions.
I did a huge research on the internet but more or less is the same as here, nobody can says exaclty wich solution is the best or at least nobody can be sure if there is only one way to go...
So, I'll put time delay fuses in primary and secondary, a massive switch and will see what happens...
I am very pleased of sharing it with you guys, AJT, Mooly and AndrewT, I really apreciate all your comments and info.
I guess in a week time I'm gonna have it sorted, then I'll post the results.
See you around!
Cheers.
Ok, a little bit more than a week...
Anyway it's done and working lije a charm.
There you have a pic of the time delay fuses and the Rifa cap.https://33.media.tumblr.com/53121a13f673f6e3a2b93b1e2d0d5ff3/tumblr_nc0dj4oMBD1rny58ho8_1280.jpg
Let's see how much it last
cheers guys! and thanks so much!!
Anyway it's done and working lije a charm.
There you have a pic of the time delay fuses and the Rifa cap.https://33.media.tumblr.com/53121a13f673f6e3a2b93b1e2d0d5ff3/tumblr_nc0dj4oMBD1rny58ho8_1280.jpg
Let's see how much it last
cheers guys! and thanks so much!!
Laziness?
I did it before (twisting pairs of trafo's in/out) and couldn't hear any difference, I'll do eventually, I guess.... but I was in a rush to finish it...I connected some VCOs to it today and works fantastically well, no noises at all, I'm very pleased with this PSU.
cheers.
Alternate Relay for the diyAUDIO Soft Start board
The Omron relay on the BOM was no longer available. I substituted an Omron # G5LE-1A4. Fits right, and works fine.
I wanted a long delay, so I used a 1uF MKT (X2 rated) 275V for C2, and a 4700 UF for C3 (with the above relay).
Using 120 VAC input power, I get a delay of 2.6 seconds.
Relay specs: 24VDC coil; 1 SPST N.O. contacts rated 10A 250VAC.
The Omron relay on the BOM was no longer available. I substituted an Omron # G5LE-1A4. Fits right, and works fine.
I wanted a long delay, so I used a 1uF MKT (X2 rated) 275V for C2, and a 4700 UF for C3 (with the above relay).
Using 120 VAC input power, I get a delay of 2.6 seconds.
Relay specs: 24VDC coil; 1 SPST N.O. contacts rated 10A 250VAC.
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