►► custom SBS20 supply TEST+

as the previous design had quite high input voltage and i'm not into storing the loads of various capacitors @ my place - i banned the design ... chk,chk 4700µF 35V =? 1.6€ ↔ 1.3£ ↔ 2.2$ ↔ 7 MYR ↔ 17$HK -- i expected 2.5 / 2.6€ (perhaps i should go sopping XD) anyway the Prj. SUM ::

1. too high difference in between I/O Vtg.-s = not a good trend = too low efficiency
2. switching design = good efficiency at Hi / Full loads = mystery work to prevent / block  RFI
3. since it's an audio supply that should be ready already and i found a suitable I/O difference TF -- i stayed at linear reg. design below 50% efficiency ~210mV / -33dB output noise REAL v. -79dB SIMULATED ??? . . . anyway you can't hear the supply over the 'puter fans background noise

Step.2 ::

here you should be aware of the 2-simulation shortcomings a) the real current gains (at low currents) may appear significantly higher than those of simulated , b) the real current gains (at high currents) may appear significantly lower than those of simulated , +the temperature rise & frequency rise lower the ß & all BJT-s are not "Const.- ß" 1-s e.g I_CE rise AND/OR microbe hour I_CE lowers the ß , ++ the Hi-Fq. performance/-response of even the Hi-Fq. transistors may occur a lot worse of the 1 simulated

so - the Step.2 is a nice promise but if it fails after a week of testing it in REAL - we're still nowhere - so ::

Step.3 ::

the transformer stays below 40°C and LM337 pretty much the same at below-/ medium volumes , cooled with Fe heat-sink::

┌┐┌┐┌┐┌┐┌┐┌┐ ─┬  ┬─ ┌┬┬┬┬┬┬┬┬┬┬┬┐
││││││││││││  │  │  │││││││││││││
││││││││││││  │  │ ┌┤│││││││││││├┐
││││││││││││       └┤│││││││││││├┘
├┴┴┴┴┴┴┴┴┴┴┴┐ W  H  │││││││││││││
└┬┬┬┬┬┬┬┬┬┬┬┤       │││││││││││││
 ││││││││││││ │  │ ┌┤│││││││││││├┐
 ││││││││││││ │  │ └┤│││││││││││├┘
 ││││││││││││ │  │  │││││││││││││
 └┘└┘└┘└┘└┘└┘─┴  ┴─ └┴┴┴┴┴┴┴┴┴┴┴┘
│           │       │           │
├──── L ────┤       ├──── L ────┤

Fig.1

Dim.-s	20	29	27	LWH(mm)
	L(mm)	N(×1)	H(mm)	S(mm²)
	11	24	27	7128
	9.818182	6	27	1590.545
	20	1	27	540
	20	2	3.5	140
	3.5	2	27	189
* the edge length of the double sided sq.		2		9587.545	single- sided
		1		19175.09
LE2(cm)	9.791601	0.01	10	191.7509	S(cm²)
LE2(in)	3.854961	0.00155	25.4	29.72145	S(in²)
Mass		1.76	m(OZ)	50	m(g)

-- whitch might be not enough for prolonged full load op.

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