Sieveking Sound RCA-Caps

Set of 10 RCA end caps in a green box.

Sieveking Sound RCA end caps are a useful accessory for all unused analogue RCA inputs and outputs of hi-fi components. The caps are made of copper and gold-plated by vacuum evaporation. Inside there is an additional Teflon insert. This unique combination provides excellent high frequency absorption.

The RCA end caps are placed over unused inputs and outputs of hi-fi components and perform three important functions.

1. protect the unused jack from corrosion, which is particularly useful for older equipment without gold-plated contacts.

2. prevent dust from entering unused sockets, which would reduce the conductivity of the contact surface in future use.

3. they prevent high frequency radiation from entering the unit, as the open sockets are now closed and do not protrude from the Faraday cage of the case like antennas. This means that electromagnetic radiation, which would otherwise be conducted directly into the unit via the positive contact of the RCA jack, is consistently shielded and diverted to the chassis ground. While functions 1 and 2 mainly affect the long-term durability of the unit, function 3 is actually audible. The reduced exposure to RF signals has the effect of reducing background noise. Music appears clearer and, surprisingly, the listener often has the feeling that the music signal has suddenly become quieter. This is a psychoacoustic illusion, as we initially associate the reduction in noise floor with a lower volume.

The before-and-after effect is particularly noticeable if you have listened for a few days with the end caps in place and then remove them.

The amount of improvement in the sound depends very much on the components used. Tube-based equipment and hi-fi systems with high efficiency loudspeakers will respond more noticeably than transistor amplifiers with high negative feedback and high current draw loudspeakers.

Regardless of the extent of the effect on your musical enjoyment, Sieveking Sound Caps are an enhancement to your system and an investment in long-term listening pleasure with your high-quality components.