Total Recall DC Input Jack. Does it need to be plastic chassis ?

[cleaninglady]

I am thinking of using a metal chassis DC Input jack for my Total Recall builds. (Building two...)

Will this be an issue ? I vaguely remember reading somewhere the jack shouldn't connect with the chassis or something...can't find where i thought i read it.

Can anyone confirm ?

[m-Kresol]

you need one that is insulated against the enclosure since the enlosure will be grounded. If they're connected you've got an instant short circuit.

check out these lumberg jacks, I prefer them over all the others:
http://uk-electronic.de/onlineshop/product_info.php?cPath=50_22_23&products_id=2436&osCsid=2abab2b855c7b627f38ad898d3ed1ac0

[daleykd]

I second those thinline DC jacks.  Here they are in the USA:
http://bitcheslovemyswitches.com/#!/Thinline-2-1mm-DC-Power-Jack/p/18921807/category=5027592

[solderfumes]

I think OP is right, the Total Recall is positive ground so it would be OK, right?  I mean, you're probably going to have a dedicated 24V source for it, right?  So even if the chassis touches another neighbouring pedal's chassis it shouldn't be a problem.

That would be great for me as I bought some metal chassis DC jacks when I was first starting out and didn't know any better.

[solderfumes]

That assumes you're using a centre-negative 24V supply with the Total Recall.

[m-Kresol]

it's not about touching another enclosure. If the jack is connected to the enclusure, which will be grounded via the in/out jacks, you will have connected GND with V+. It doesn't matter which one is the positive voltage of those two, it will be a short circuit no matter what, so no current to your total recall board.

[solderfumes]

But for the Total Recall, your rails are GND and V-, so the positive terminal on the power supply should be grounded, no?  The concern would be if the negative terminal on the power supply were connected to ground.

[solderfumes]

And note that this would *not* work if you were using the same power supply for all your pedals, but with the Total Recall, assuming you have a dedicated 24V supply, then I think it should be fine.

[joesatch]

Definitely use a plastic power jack or your R57 will start smoking.

[solderfumes]

I think your power supply would be more likely to start smoking if there were a short!  In that situation I don't think any current would flow through R57.

I still stand behind what I said before, though.  Looking at the Total Recall schematic, the positive terminal on the supply is connected to ground.  Thus the metal jack should be fine, again assuming you have a centre-negative power supply.

Note that this means that you definitely need an isolated power supply for the Total Recall anyway, not just because it's 24V, but because it's positive ground (and this would be true of any positive ground fuzz pedal, for example).  If you didn't, then you'd absolutely have problems, as m-Kresol described.

[cleaninglady]

Thanks All , duly noted.