davenz

I'm in New Zealand and none of my usual component suppliers have those op-amps. Like I say, I can get them via mail-order but not in time for me to start building this weekend! I'll play around with the circuit as-is and see what happens while waiting for the op-amps to come from overseas. Cheers Dave.

Thanks again. I notice that earlier this year a guy named Ivan has added some suggestions to the bottom of the original circuit description page. He recommends adding a 7809 regulator and a zener to limit the voltage to the op-amps and connecting the relevant power pins and a couple of other circuit points to that new bus to reduce overhead voltage. In theory it sounds fine, though he also says to join 2 3055's with emitter resistors (which I have seen done in many other circuits) for current handling, because the single one got too hot. I don't recall anyone else mentioning this though. The only reason I am stuck on using TL081s is because I cannot source any of those other op-amps from any of the suppliers I deal with. I might bread-board one up over the weekend using the 7809 idea and see how that performs; I'm not after something whizz-bang, so this might be good enough for what I want to do. Thanks for your guidance and expertise. Dave.

Thanks for the prompt and efficient replies Holt and Audioguru. If I understand your post correctly AG, the original circuit is fine as long as the hardier op-amps (and transistor) are used. Or, are you referring to the latest version as being the modified circuit referred to by Holt with those chips instead or the frail ones? I might just be building this over Easter I think.... PS. Apparently I live in a first-world country but nobody supplies these chips locally (and we have some very good components stores). I can get them by mail-order but otherwise they are not easily obtainable. Guess I'll have to go in another direction. Thanks anyway.

Hi there. I have followed this project for some time and while I think it is one of the better power supply circuits around (hence 35 pages of forum discussion on it), I am still confused as to what the actual outcome of all this discussion has been. I built one based on the circuit on the original site and of course it blew the guts out of the op-amps and I threw the rest away in disgust. Months later I found this forum and have read as much as I can of it without my eyes watering. There appear to have been several mods to the original circuit to lower the voltage to the op-amps, therefore saving their lives, and the authors claim the supply works OK, but then there are other rewrites of the circuit to use different op-amps, many of which can't be found locally, so I am at a loss which one to go for. On top of that, so many parts lists and circuits are bandied about here I don't know which goes with what and what version is the one to build. Can someone please summarise for me what the upshot of everything is and, if I was to build one tomorrow, which circuit and parts list would I be best to use. Thanks and sorry for being so lame. Dave.