KevinE Posted May 5, 2009 Share Posted May 5, 2009 The centre tap goes down to chassis...they all work like this. Obviously the outer windings are symmetrical and can go either way. Link to comment Share on other sites More sharing options...
dave1foot Posted May 6, 2009 Share Posted May 6, 2009 So the 17v is AC? Link to comment Share on other sites More sharing options...
KevinE Posted May 6, 2009 Share Posted May 6, 2009 Its actually 34V with an earthed centre tap, this is expressed as 17-0-17. The desk has internal regulated power supplies to give the 15V split rails needed by the op amps. Link to comment Share on other sites More sharing options...
dave1foot Posted May 7, 2009 Share Posted May 7, 2009 Hey Kevin, I appreciate your replies, I just need that one more little piece of info: is the input AC or DC? Cheers Link to comment Share on other sites More sharing options...
KevinE Posted May 7, 2009 Share Posted May 7, 2009 Its AC..ie 17-0-17. You can't get DC at 17-0-17! Are you trying to make a power supply yourself? Link to comment Share on other sites More sharing options...
dave1foot Posted May 7, 2009 Share Posted May 7, 2009 Thanks for the info, I thought it must have been AC but I wanted to see it in black and white before hitting my unit with the wrong thing. Well, I was thinking of building a power supply myself but your question has made me nervous about it, I must admit I would have been happier building a dual rail DC supply, I've done those before and mostly know what I'm doing. My first thoughts were to use something like a Maplin N08CF (20VA mains transformer with two 15v secondary windings) or possibly the 18v version, the secondaries connected together would give the centre tap. The Thomann HB8051 looks too small to be a switched mode job so I'm guessing/hoping it can't be much more than a transformer, I suppose there could be some fuse/thermal cut-out arrangement and possibly some current limiting device but that's about it? This arrangement would not be tolerant to mains fluctuations but I would expect the on-board regulators to take care of that. The only thing in my hypothetical world that I'm less certain of is whether the phases at the two secondaries makes any difference. What d'you reckon? Will it fly, or should I swallow my pride and fork out for a new one? Link to comment Share on other sites More sharing options...
KevinE Posted May 8, 2009 Share Posted May 8, 2009 Just put a 17-0-17 transformer in a box and add a thermal fuse. Link to comment Share on other sites More sharing options...
dave1foot Posted May 10, 2009 Share Posted May 10, 2009 That's what I thought! Any idea where I can find one? Link to comment Share on other sites More sharing options...
dave1foot Posted May 15, 2009 Share Posted May 15, 2009 Bit too tricky that one eh? For anyone interested I bought a mains to 17-0-17 transformer from www.jmstransformers.co.uk - they make the transformer to your spec, very quick service, about double the price of an off the shelf item which is not too bad. I haven't got round to wiring it onto the notepad yet. Link to comment Share on other sites More sharing options...
KevinE Posted May 15, 2009 Share Posted May 15, 2009 Bit too tricky that one eh? No, I thought my contribution to the thread was enough, considering that the OP was after advice on a connector. Link to comment Share on other sites More sharing options...
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