Spyder Center Tap

[Primus]

I'm working on a lot of projects in parallel now... I go in spurts. I am finally finishing up my 12 legged spyder (R.G., I can't say enough about how great the steel stud is for an enclosure). Anyway, I've got all the transformers, IEC connector, fuse holder, etc etc mounted and wired up but I am not sure what the best way to deal with the center tap is. I have read recommendations to leave it floating and other recommendations to star groun them to the chassis and other recommendations to just attach them under each individual transformer lug. What's best? I should also mention that I am a novice, but this thing isn't going anywhere near mains power until I have it checked over by a pro : )

[R.G.]

Cool - it's always good to see people build this stuff.

OK, so center tap of the secondaries of the transformers?

Which transformers are/have you buying/bought? Are you trying to make +/- outputs from each one, or only a single isolated output from each one?

And thank you for being careful with AC power. It can be mysterious even to me and I've messed with it for over 30 years. Good tihnking on getting someone to check it out first.

[Primus]

R.G.

I've figured it out after reading your Basics of Power Supplies article. I've seen it referenced by you a million times, but I haven't been able to Google it or find it off yourmain page. Anyway, I'm dense, but I finally found it:

http://www.geofex.com/Article_Folders/Power-supplies/powersup.htm

I highly recommend reading this page. My query was regarding the center tap on the secondary side. I read now that the main purpose of this is for a reference (I think this is the right term) for a bipolar power supply. I see clearly now that since I just want +9V, this wire is NC or not connected. Should I connect it to the transformer mount or just put a little wire nut on it? I am using the recommended Mouser transformer for using many of the larger 115 V to 12 V transformers.

I've also been thinking of the best way to connect all of these transformers... This diagram describes what I am doing (R.G., Geofex):



As the mains move from the fuse holder to each transformer, you can see that there has to be a three way junction for incoming "hot", outgoing to transformer n and outgoing to junction n+1. Junction n+1 then is incoming from junction n, outgoing to transformer n+1 and outgoing to junction n+2. I thought about using a terminal strip, but then I thought it might be better to just solder the three wires necessary for this junction together and then seal them up w/ heat shrink tubing.

I have been thinking about what having all of these transformers on my pedal board is going to do... Did you have any noise come through in yours from interference, R.G.? Maybe I should have tried to spec toroidal transformers...

[Primus]

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