XLR line out. Only spot left is next to power tube

[MickeyB]

Want to add a XLR line out and the only spot left on the back of the chassis is right next to one of the 6V6 power tube sockets. We're talking about a 1/2 inch away. Is this going to cause problems with the signal out if I do this? I have shielded cable to run off the xlr plug.

[olddawg]

Want to add a XLR line out and the only spot left on the back of the chassis is right next to one of the 6V6 power tube sockets. We're talking about a 1/2 inch away. Is this going to cause problems with the signal out if I do this? I have shielded cable to run off the xlr plug.

Why don't you just use a direct box. The Art tube mic/line preamp/direct box is available new from MF for $29. You can use it for a lot of things including your other amps with an effects send, pre out, or line out. It even has a VU meter and an overload limiter function It has adjustable voicing and works great. You won't have to worry about another hole, hum. Just keep one in your kit. They're small. http://pro-audio.musiciansfriend.com...amp?sku=180581

[Steve Conner]

While restoring my old Crown SXA power amp, I wanted to add balanced inputs on XLRs. And like you, the only spot I had available for them was right next to the power tube sockets. Since they were inputs, I was worried about feedback turning the amp into an oscillator.

I used shielded cable, and covered the whole back of the XLRs inside the chassis with electrical tape, and then with sticky-backed copper tape, the stuff you sometimes see used to shield guitar control cavities. The glue on this tape is conductive, so it gets grounded where it sticks to the chassis.

So between the tape and the shield on the cable, the input conductors were totally enclosed inside a grounded metal shell, and couldn't "see" the power tube pins electrostatically at all.

For an output, I'd be much less worried since it already picks up the amp's output signal by design. Stray capacitive coupling will just add a little more signal, or cancel a little of it out. Now if a loose wire touched the power tube's plate pin, frying the sound guy along with his PA, then I'd start worrying.

Can that ART tube thingy really take a speaker level input? You might be better with a regular DI box, which can also be had for about $29 if you can stand Behringer