kobus

i live in south africa.not exactly an electronics hub but we manage. any case, even $10 is a bit pricey for a student wanting to build 2 units for dual power supply purposes. i got the tle2141 which can handle 42V which will have to do for now. I can always upgrade later. hopefully the PCB will be done monday. in the case of overvoltage i will test the supply at first with a substantial load to reduce over-voltage and heat problems on the first run. but thats still laters worries. changes still include all listed except opamp including R14 and emittor connections. kobus

O.K im seriously sourcing components. Wil the LM343H replace the opa445AP?? If not the LM143 Id prefer the LM343H because he might be cheaper. Here the opa445 goes for about 25$US which is way above my price class.Also it's only available from one supplier.Must be because Burr/Brown was taken over a while ago or something?? Maybe its just me and it is that pricey??

sorry meant audioguru!!

Hello Kasamiko. I don't know about 0-30V 0-3A power supply but see under electronic forums-->project design/ideas-->modify 0-30V supply or something like that.On the last page is pretty much a summary of what audiophile thinks should be modified for a 5A supply.No-one knows yet if it works so no guarantees.I'm currently building the supply in my spare time and hope to have it done some time end of next week. Hope this helps.

I have also posted this reply on the modification thread. would just like a reply if this could be a working model. otherwise i'm starting building tommorow and see what i end up with. so far it seems that it will work. --------------------------------------------------------------------------------- after 2 hours of posts reading this is what i have for mods Transformer : 30VAC @ 5A = 30*5*1.5 = 225VA stepdown transformer Resistors : R2 & R3 --> 1/2 W R7 --> 10 W R1 --> 3 W Caps : C1 --> 4700 uF (prefer 10000 uF) @ 50V Diodes : Diodebridge : D1 - 4 --> Single chip diode bridge @ 8-10 A POTS : P1 --> many turns (10) P2 --> Cermet single turn OPAMP : OPA445 @ 100V Transistors : Q1 --> stays same BC548/547 Q2 --> TIP29/TIP30 (R15 becomes 100ohm) --> somebody also mentioned BD139/137?? Q3 --> Stays same BC557/BC327 Q4 --> stays same?? 2N3055 Heatsinks : Q2 & Q4 gets TO-220 package heatsink could someone please verify?? could this possibly be a workable mod or am i still missing something sorry if i left something out,had to decipher my own handwriting at 03:00. please correct me kobus.

Lets try again!!! Do not press enter accidentally while typing!! (and not on the type screen anymore) after 2 hours of posts reading this is what i have for mods Transformer : 30VAC @ 5A = 30*5*1.5 = 225VA stepdown transformer Resistors : R2 & R3 --> 1/2 W R7 --> 10 W R1 --> 3 W Caps : C1 --> 4700 uF (prefer 10000 uF) @ 50V Diodes : Diodebridge : D1 - 4 --> Single chip diode bridge @ 8-10 A POTS : P1 --> many turns (10) P2 --> Cermet single turn OPAMP : OPA445 @ 100V Transistors : Q1 --> stays same BC548/547 Q2 --> TIP29/TIP30 (R15 becomes 100ohm) --> somebody also mentioned BD139/137?? Q3 --> Stays same BC557/BC327 Q4 --> stays same?? 2N3055 Heatsinks : Q2 & Q4 gets TO-220 package heatsink could someone please verify?? could this possibly be a workable mod or am i still missing something sorry if i left something out,had to decipher my own handwriting at 03:00. please correct me kobus.

Hi all Im new to this forum Im attempting to build the 30 V supply 2 questions. 1 -> can i put a LED & R right after the diode rectifier bridge in parallel with the rest of the circuit or will the say 20mA reduction(parallel current flowing away) caused by the LED have an effect on the rest of the circuit?? If so any suggestions. 2 -> Has anyone started on the negative supply that can be connected in junction with this circuit with same specifications and which has a common ground? If so where can i find schematics. If not any suggestions on how this can be accomplished. Thanks