Thanks Buddy. So if I use 4 green 2,1 Vf leds (=8,4 V) and VGS over the fet is say 4,7 V over 250ish mA that leaves 3,7 for R101. That means I could start with a 15 ohm and some hooked up variable resistor in parallell to work my way down/up to 250 mA. Does that make sense?
Or would it be preferable to go with 3 leds and lesser voltage to drop over R101 and choose a smaller value?
Or would it be preferable to go with 3 leds and lesser voltage to drop over R101 and choose a smaller value?
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I have read the first 100 pages. Pure poetry. Fascinating how much energy some members can inject in a thread about a reg. I have also finished the load, an ESP 24dB LR two channel two way. It wants 51 mA per rail (+/- 15) with NE5532. I will also add one NE5532 output buffer and steal the signal from the lowpass to feed a miniDSP for sub management, so maybe 60 mA max.
I dug deep in my iron boxes and found a bunch of UI core type Tx:es. Probably as old as I and I suspect they were made for 220 mains cause they give slight vibrations to the table. Nothing to much though, and don't get hot. My guess is 80-100 VA aimed for 2x15 v at full load at 220 mains. Secondary 1 mm wire coil measures 0,32 ohm dcr with a DE-5000. They hand out 17 VAC at 300 mA load per secondary. Definitely not ideal but I think they have rested too long now and look cool, so I will give them a shot. Worst case I can feed the NE5532 unity gain 14 volts, I don't think they mind.
I have also started with some breadboard dummy cases that I could use for placing with the other stuff for listening tests if things behave in measurements. Making separate box for the Tx so it will be a mild C-R-C also.
So first test will be if the CSS is happy with 21,5ish to 15 volts. My mains seldom dips, very stable 235ish in the walls.
And yea, maybe one third of the posts were the mandatory cap roll magic and fairytails. For line, should I go with the Wima MKS4 10/63 or some lyt for both C101(2)/201(2) and C103(4)/203(4)? I have started a Mouser order so I can add to that. I think i have the other components.
I dug deep in my iron boxes and found a bunch of UI core type Tx:es. Probably as old as I and I suspect they were made for 220 mains cause they give slight vibrations to the table. Nothing to much though, and don't get hot. My guess is 80-100 VA aimed for 2x15 v at full load at 220 mains. Secondary 1 mm wire coil measures 0,32 ohm dcr with a DE-5000. They hand out 17 VAC at 300 mA load per secondary. Definitely not ideal but I think they have rested too long now and look cool, so I will give them a shot. Worst case I can feed the NE5532 unity gain 14 volts, I don't think they mind.
I have also started with some breadboard dummy cases that I could use for placing with the other stuff for listening tests if things behave in measurements. Making separate box for the Tx so it will be a mild C-R-C also.
So first test will be if the CSS is happy with 21,5ish to 15 volts. My mains seldom dips, very stable 235ish in the walls.
And yea, maybe one third of the posts were the mandatory cap roll magic and fairytails. For line, should I go with the Wima MKS4 10/63 or some lyt for both C101(2)/201(2) and C103(4)/203(4)? I have started a Mouser order so I can add to that. I think i have the other components.
Well, I half-baked a trafobox. I first had to do a reconfig on the trannys. They had CT-config so I separated the two secodarys. Then built two greatzbridges as per the SSLV config and put one 3900 uF after each and loaded circa 300 mA on each (70ish ohms). Happy with some things, not entirely with others. When I tested the tranny I had one greatz on CT-configed tranny. Now with two bridges it eats up another rectifier Vdrop. Vout can drop as low as 20,6 with some mains variations. I think I want 6 volts overhead nominal, with some margins so I might run the opamps on 14 volts instead. Trannys are superhappy with coming out of the closet though. Not sweating at all with the load. Runs cool.
I must say that I am a bit puzzled by the large drop. I did a new measure now, had 17,35 VAC from the tranny. Times 1,35 = 23,62. DC reading was 20,96. Thats a 2,66 v drop over a greatz. The FFPF08S60ST shall not drop this much over this small current. No time to investigate now though, family business for two days. Maybe poke around for some shottkys when I get back.
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