Hi guys, it's been a while! I just picked up a Sirius tuner and need to feed the signal into the Empeg's aux input. Problem now (going straight from Sirius tuner's RCA out to Empeg's Aux in) is that there is too much distortion. Did some research and found that the tuner is putting out 2V RMS and the empeg takes 1V input.

What can I use to step down the voltage? I have a line level converter with wire inputs on one side and RCA outputs... should I retro-fit some Radio Shack RCA's to the other end and play with the level?

Thanks.

should I retro-fit some Radio Shack RCA's to the other end and play with the level?

No. The line level converter is only for speaker-level inputs, not the same as the Sirius output.

I don't know why the sirius unit is causing distortion, it shouldn't. Can you describe the distortion? Perhaps it's not related to the RCA voltage level.

To step it down manually, you can buy a radio shack stereo potentiometer and wire that to some male/female RCA sets. Once I had an amplifier which didn't have an adjustable input level, and this is what I used to step it down. Worked fine.

I called Terk since I thought it might be the antenna. They said that since this unit is meant to be used with an FM modulator, Panasonic stepped up the output voltage on the RCA outs. While the instructions said you could go from that out to an aux in, it is probably not meant to.

The distortion is almost identical to turning up your radio real loud. Bass, vocals "clip" and sound distorted, sorta like static. I knew it was some sort of gain issue. I'm just surprised that the Empeg can't handle 2V RMS in.

I will stop by "the shack" on my way home and see what they can do! Also, for wiring, which part of an RCA is (+/-)? Is the center pin positive of the outer ring?

Thanks again.

BTW, are you talking about something like this:

http://www.radioshack.com/category.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F010%5F003%5F005%5F000&Page=1

I think so. The stereo one, of course. Not completely certain about the exact part number of what I used.

I do remember that the one I used didn't have a very wide useful range to its travel. Because it was such a high-resistance pot, the area between "silence" and "full volume" on the potentiometer was about 1/8 of the turning radius of the knob.

Another thing you could do, which might save you another trip to The Land Of Blank Stares, is this: Just plug in one channel with a mono pot that you've got lying around. Fiddle with it until the volume is where you think you want it. Then measure the resistance on that pot and put fixed resistors on the connectors instead of making the system adjustable.

And yeah, the center pin on RCA jacks is the positive signal, the sleeve is the negative ground. And in many cases, the negative ground on the sleeve is common between both L and R, in case that simplifies wiring as you're working on this stuff.

Now you're getting too advanced for me Tony

What's the maker of the receiver? I'm looking at a Jensen (SSR2000) and am wondering if I'll run into the same issue.

Now you're getting too advanced for me Tony

Perhaps. I was just hoping to save you another trip to Radio Shack. If I were trying to install a tuner and ran into that problem, my situation would be:

- I have plenty of old "mono" potentiometers lying around amongst my electronics junk, just no stereo ones.

- I have plenty of fixed-value resistors lying around.

- I have RCA plugs lying around.

- I have a multimeter.

- I have a strong aversion to walking into Radio Shack stores, so I actively avoid doing so when I can.

- I know that there is an advantage to doing electronics modifications "solid-state", i.e., with no moving parts such as potentiometers which could get dirty/corroded, bumped, affected by temperature, etc.

The thing I was trying to describe was a quick way (assuming you have the equipment listed above) to create a solid-state solution to the problem. Essentially doing a quick rough measurement of the amount of needed resistance by playing with an extra mono potentiometer, then using solid-state parts to reproduce that resistance.

Using two identical resistors will drop the voltage in half. A couple of 10k resistors should be fine.

Okay, dodgy ASCII drawing follows:

Input -------+

             |

            [ ]  Resistor 1

             |

             +------------- Output

             |

            [ ]  Resistor 2

             |

Gnd   -------+------------- Gnd

- Trevor