alchemist Posted May 22, 2014 Report Share Posted May 22, 2014 Hello, Can I plug in parallel three 78xx regulators to get +5, +9 and +12V from the same 15V DC adaptor ? Is it better to do that in parallel or serial (+12, then +9, then +5)? (its for a full MIDIbox SID set-up, with 4 cores, 4 6581 and 4 8580, hence the 3 voltages). For now, I plug a 9V DC for +5V and 15V DC for +12, but I would like to minimize the AC adaptors. I don't see a problem, but I could say an heresy, and would be sure I wouldn't overload the 78xx with too high voltage or drained current. Quote Link to comment Share on other sites More sharing options...
freddy Posted May 22, 2014 Report Share Posted May 22, 2014 alchemist, You can plug them in series, that way the step-down and therefore temperature on the individual stages will be much lower but beware that the "earlier" regulator in the chain needs to be sized for the following stages as well! This might result in a 3A package (TO3) with a heatsink for the 12V stage, maybe even the 9V. Also, the transformer needs to be properly sized. Of course, this depends on the actual power you need. Htg, freddy Quote Link to comment Share on other sites More sharing options...
alchemist Posted May 22, 2014 Author Report Share Posted May 22, 2014 (edited) Hello, Thank you for the reply ! The power needed would be for - 4 x MBHP_CORE - 8 x MBHP_SID - 2 x MBHP_DOUT - 3 x MBHP_DIN - 4 x SID 6581 (+12V) - 4 x SID 8580 (+9V) - 1 x LCD display (20x2) - and about 80 LEDs for the Control Surface At term, I will use a C64 PSU, but this will come later, and I would like to use an other PSU before I get it. I will check the power needed by element, then compute the power consumed by each 78xx regulator. Edited May 22, 2014 by alchemist Quote Link to comment Share on other sites More sharing options...
Altitude Posted May 22, 2014 Report Share Posted May 22, 2014 Just use switching regulators for the 5 and 9V. I use Recom. I built a MB6582 with +5, +9, +12 all off a 1.5A 15V DC adapter Quote Link to comment Share on other sites More sharing options...
alchemist Posted May 23, 2014 Author Report Share Posted May 23, 2014 (edited) Thanks! What would be the recommended power for the convertors ? Are those OK ? http://www.reichelt.de/TSRN-1-2490/3/index.html?&ACTION=3&LA=446&ARTICLE=124099&artnr=TSRN+1-2490 http://www.reichelt.de/TSRN-1-2450/3/index.html?&ACTION=3&LA=446&ARTICLE=124097&artnr=TSRN+1-2450 There is also this, but 1W: http://www.reichelt.de/DC-DC-Inverters/SIM1-1209-SIL4/3/index.html?&ACTION=3&LA=3&ARTICLE=57502 http://www.reichelt.de/DC-DC-Inverters/SIM1-1205-SIL4/3/index.html?&ACTION=3&LA=3&ARTICLE=35028 Edited May 23, 2014 by alchemist Quote Link to comment Share on other sites More sharing options...
Altitude Posted May 23, 2014 Report Share Posted May 23, 2014 (edited) Yeah, those look very similar. The only high current one you will probably need is the 5V one. The traco will be drop replacements for the 78XX Edited May 23, 2014 by Altitude Quote Link to comment Share on other sites More sharing options...
ilmenator Posted May 23, 2014 Report Share Posted May 23, 2014 I am using this guy in my MB-6582. Almost the same specs (but only slightly lower input voltage levels allowed, 36V vs. 42V on the TSRN version) but only a little over half the cost. Quote Link to comment Share on other sites More sharing options...
alchemist Posted May 23, 2014 Author Report Share Posted May 23, 2014 that should be OK since I will use 12 V DC input ;) Quote Link to comment Share on other sites More sharing options...
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