Wait a Minute Do those Cardas Caps Work

sean...My point (FWIW) is that what Tandberg provided for their preamp was a dead short. Perhaps they knew this was OK for their particular circuit. What you say about other circuits being prone to oscillation may be true, although I have not seen such a problem with stuff I have used.

El: Due to variances in circuit design, especially with a high gain circuit like a phono stage, it is possible for a preamp to go into oscillation with a dead short at the input. Resistive shunts basically close the circuit and any "foreign signals" are resistively absorbed via the impedance of the resistor used for the shunt without loading down any other circuitry that may be connected through poor design / crosstalk. Then again, i know i'm preaching to the choir when talking to you about stuff like this. Others may not know how stuff like this works, hence the explanation.

Ross: I don't think i want to know what you were planning to do with the aluminum foil, but thanks for making mention of this anyhow. It made me think about the foil touching both the female and male part of the RCA, which would act as a shunt or short circuit rather than just a shield. While this might be okay for most inputs, it would definitely be a BIG "no-no" for any unused outputs. As such, one should check to see if their female RCA jacks as mounted on the chassis of a component have the center conductor recessed or if they are flush with the outer section. If they are recessed, this is not a big deal. If they are about even with the ground terminal, be careful if trying to make "Elizabeth shields" out of foil : ) Sean
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Hey Sean, I once put a tiny square of aluminum foil up against the backside of a female... and got the snot slapped out of me.

sean...FWIW..my Tandberg preamp came with shorting plugs for the MM and the MC inputs (not high R values). However this preamp has completely separate phono stages for the two inputs (all the circuitry is duplicated) so there really is no chance of crosstalk.

How about combining Elizabeth's idea with that of Dave's or Hepl's ? Put a tiny square of aluminum foil up against the backside of the female RCA and slowly push the plastic cap over the jack. This will "form-fit" the foil and no need for tape. Much easier to work with at minimal expense. Thanks !!!

El: I've recommended using shunts on unused inputs for a LONG time. While direct shorts are normally good, many components that lack the proper isolation between inputs respond poorly to this trick. In such a situation, one should solder a low value resistor ( 50 - 500 ohms ) across a cheap RCA plug and use it. This simulates the typical load that most inputs would normally have on them and keeps the jacks from getting pitted at the same time. Phono inputs should use a very high value resistor i.e. many, many Kohms. Sean
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LOL @ army of Woody Allens! Now you've completely ruined it for me Rosstaman. :•)

Are we talking about shorting plugs, or just plain dust caps. Shorting plugs are a good idea, not so much when the input is unused as when you sequence through that input with your selector switch, and may hear bad noises from the open circuit.

They look cool on my toy soldiers heads. Like an army of Woody Allens from Sleeper. But I don't notice any difference in the sound of my system.

If all you want to do is keep dust out, why not simply plug it with something (like a small piece of blu-tak over the end)?

If you want protection for unused female rca connectors at a
fraction of the cost go to a Linn dealer an order part number CONN-672. They are made of plastic and won't scratch
the gold plating, cost is around $0.15 each.

Neat looking audio jewelry. Great for keeping dog & cat hair out.

The most useful feature for me is to cover unused RCAs on preamp so when changing ICs behind rack with minimal clearance you instantly know where to insert new ICs........looks pretty cool to have two rows of shiny caps also.

As far as sound improvement, I have not noticed any real difference.

I use them on all my equipment especially Levinson 360s, 380s,DCS, and for the a relatively cheap price they just keeps dust out of these expensive components. A piece of mind! What is a few hundred dollars for 20,000+ dollars worth of componnets?

Here is a less expensive alternative to keeping dirt out
http://cgi.audiogon.com/cgi-bin/cl.pl?accstwek&1072541621&class&3&4&8
Dave

I use them too, can't say that I've heard a difference though.

Ditto. The RCA caps are pretty cheap, the XLRs too rich for my blood.

Yep, like Tireguy I use 'em too. Don't know if they do anything, but they do provide peace of mind and look kinda neat.

I've got them, and well...... they keep the unused inputs/outputs clean :)