Short Out Plugs

Radio Shack sells a bag of colored plastic RCA's; unscrew the cover, bend over the metal to short the plug, apply small amount of solder, screw cap back, and fill void with silicone. 8 plugs for about 5 bucks. Any cheaper ya gotta steal em!! Oh yeah...INPUTS ONLY!!!!!

Right on Notdigital !!! I have used this "trick" many times and reccomend it quite frequently. Since the specific circuit is shorted or "shunted" to ground, you don't have to use "high quality" connectors. The cheapest ones will more than suffice. Sean
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I almost forgot. Some preamps are not "stable" designs and may react adversely to installing "shunts" or "shorting plugs". If this is the case, using something like Cardas caps or "shield plugs" would be the next best thing. Sean
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Thanks guys. Dare I ask if these plugs would be useful in other parts of my system. Unused amp or dac inputs? Please let me know. I only want to make one trip to RADIO SHACK. Again many thanks for the money saving suggestion.

Sean, is there anyway to make a shield plug?

I read an article in Audio Amateur about potting circuits that the type of silicone that comes in caulking tubes is corrosive. According to this article, the vinegar smell comes from acetic acid. I'm no chemist, but I would find out before putting it on connectors. I guess it is no big deal on some 50 cent plugs, but I'd hate to ruin something expensive.

Wow, i didn't catch that part of "Notdigital's" post. Herman is correct. The acetic acid in MOST silicone is corrosive. If you were to seal the rear section of the shunts up, you might want to seek out some non acidic silicone or apply standard silicone and let it fully cure before installing them on the preamp. You can tell when it is fully cured because the smell is MUCH less pungent.

I really don't think that this step is necessary though, as the RCA's would normally be "open" and exposed to anything floating in the air as it is. Just putting the "shunts" on and covering the soldered area with the supplied caps should be more than enough. Since the shunts would basically seal the internals of the RCA plug, the only thing left to corrode or collect dust / dirt would be the "shorting strap" inside the shunt. At $3 for a package of 8, i think that we can afford to replace them once in a blue moon.

While i have never made "caps", i would assume that you could buy the same RCA's and simply ( and carefully ) pull the center pin out. Fold the ground lug over to the other side of RCA "ring" and solder away. While not nearly as glamorous or "high grade metal" as the Cardas pieces, it should be just as effective IF you fill in all of the rear gaps with solder. Hope this helps.... Sean
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Hi this is an interesting discussion but is there a difference in sound when using shorting plugs?

Thanks Sean. I'll take a look at the silicone I just bought. I may omit this step completely. Sws2 I don't know yet but I am going to find out. The engineer's at Theta thought enough of this procedure to mention it in the manual. Could someone tell me if it is safe to use these plugs on an amp or a dac before I try it? I do enough smoke testing at work. I'd like to avoid it at home if possible:~)

Since you asked here is a quote from my Theta Casa Nova
manual. " The Casa Nova can be susceptible to excessive RF. Shorting plugs in all unused inputs will improve the sound quality and may reduce the susceptibility to RF induced anomalies".

You can only "shunt" inputs, NO outputs !!! As to shunting the inputs on an amp, that might be tricky. They might be wired in parallel. Shunting one set would in effect short the signal going into the other input to ground. This could either result in a loss of sound or "bad things" depending on how the individual components were built.

As a matter of safety, i would strictly shunt inputs on a preamp. Since each input on a preamp is selected individually and none of them would share common signal paths, that SHOULD be safe ( so long as it was not an under-designed piece of junk ). As to shunting ANYTHING else, i would first contact the manufacturer and find out if it was "safe" in their opinion. Better to be safe than sorry.

As to Sws2's questions, it should lower your noise floor and help the sound to come from a blacker background. You might also be able to reduce crosstalk between sources, but this would depend on the device being used. Sean
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One quick continuity test and mission accomplished. Thanks everyone for the good advise on this thread. I built 12 short out plugs for under $12.00. I think I'll do my other pre-amp just for the Halibut. You know I even think I noticed a difference. That is my cheapest tweak to date. Thanks again.