[OogeleyBoogeley]

Hey all-

I made a META42 earlier this year, and I made a custom case for it. I posted pictures on Imagestation, and you can search for that yourself. I used 2x 9V batteries to power it.

Last week, I ordered a switching DC jack and the 24V Elpac AC adaptor. I opened my case, changed the diode, rewired all the power switches and jacks. I remounted the old hardware, drilled a new hole for the power input and put that in. The second I put the power in, the LED turned on. I researched on Tangent's website and found out that the stainless steel was causing the circuit to bypass the virtual ground. Luckily, nothing was damaged except my cheap power capicitors (C2, C3) One of them actually popped, and squirted whatever stuff was inside.

Now for my real question: Tangent recommended buying insulated jacks, because cutting the mount from the V-, there will be no short. I looked up some Cardas jacks from Welborne Labs. The jacks in question are the GRFATHK connectors. Not the gold plated ones, but the silver and rhodium plated ones (gold and silver dont look too good together)

Are these jacks insulated enough to break the short caused in my mounting steel??? Does anybody have any other advice as to how to fix this problem? Because right now my solution was to leave the amp in a small cardboard box, with the DC input mounted in the cardboard

Thanks,
Dan

edit: spelling

 

[tangent]

Quote:

One of them actually popped

It appears someone thought I was kidding when I said not to use low-voltage caps in a META42....

Quote:

Are these jacks insulated enough to break the short caused in my mounting steel???

Yes. You don't need heroic insulation. Just a simple plastic shoulder washer does the trick. If you want to save money, Mouser carries some cheap nickel RCA jacks that come with insulating washers. I believe they're made by DGS.

A better path would be to get an insulated DC power jack. DGS also makes one of those. It isn't in the META42 parts list, but I believe I did use it in the PPA parts list. Or, dig through the catalog -- it's the one with the hole offset from the center.

 

[Voodoochile]

Yes, the jacks are tough enough to insulate from the chassis. Check also the output jack, pot shaft, and DC inlet. You might find it easier to insulate the inlet instead of everything else.

If you like the Cardas, also shop around (percy, handmade) for pricing. Percy also has Vampire, which is a bit less, and still very nice. But do shop around a bit.

Edit- tangent beat me to the punch while typing re: the DC inlet. Simplest way out for sure.

 

[binary_digit]

The Cardas jacks are supplied with nylon insulation washers. If correct mounting practices are used they will be insulated from the steel chassis. When you recieve the jacks you will see that the washers have a step or shoulder. this shoulder is for insertion into the mounting hole that you will drill keeping it centered and not allowing it to hit the inside edge of your chassis. The shoulder size is .445 inches or 11.3mm. You will want to get as close as you can with your drill size to ensure solid footing.

Good Luck
B_D

 

[OogeleyBoogeley]

Thanks for all of the help!

Tangent- when I was building this, I never planned on using 24V, so I bought a lower voltage rated set of caps. The replacements were rated at 25V.

So, if i just put a nylon washer in between, it should make all of my problems go away? I guess I will have to try that, but being a poor college student of 4 days, It might have to wait.

-Dan