Audio Systems: Receiver audio out to another receiver, onkyo receiver, rca jacks

Question
QUESTION: Mr. Tapia:  I have an older receiver in my main house that I have hooked up to many audio sources, and I play some great music. I want to be able to connect this receiver to another receiver in my guest house(Onkyo TXSR806)which supports my home theater room, so I can play the same music all over.  I ran L&R cables with RCA jacks from "tape 2 out" in the main house to an unused audio input on the guest house Onkyo. It didn't work. (The run is long -- about 150 feet). As a test, I connected a boom box to the guest house end of the run, and it worked fine.  I checked my Onkyo  receiver "source assignments", and they are correct.  I then unhooked another analog input, that I know works, from the guest house Onkyo and then hooked the cables from the main house to that input, and it still didn't work.  I called Crutchfield, where I buy all my stuff, and they agreed I had it set up right, and my testing was proper. They advised that due to the run length, the signal strength was too low for the Onkyo, but not for the boom box, due to the "simplicity of circuitry" in the boom box. They said all I needed was a pre-amp or signal booster that accepts RCA jacks in and out. (Replacing the cables with bigger ones is not an option, since I pre-wired this run when I built the guest house, all in-wall and underground, etc). The advice sounded good until I tried to find such a device.  Their are thousands of them, ranging in price from $12 to over $1,000 and I haven't a clue what I'm, looking for.  I don't need anything fancy, I just want to be able to play the same music all throughout my place.  Assuming I'm on the right track, will you please help with suggestions for brands, sizes, etc of appropriate "signal boosters"?

Thank you in advance for your help.

ANSWER: Woops. No model numbers.  We need the model numbers of both receivers in order to learn their technology and internal circuit characteristics.

For that cable run you may be placing a large capacitive loading on the output of the main receiver which is causing the no-signal condition.  The input impedance of the guest house unit may be causing part of the problem.  The boombox may have a different input impedance circuitry.

The signal booster is not a perfect solution because the long line may still cause a significant high frequency roll-off.  

What you really need is low capacity coax cable OR a low impedance balanced line feed OR a wireless transmission system.

ONE: Low capacity cable could be this Belden type video cable

http://www.bluejeanscable.com/store/shopbycable/index.htm

which is only 16pf/foot.

TWO: Low impedance conversion would allow you to use any good shielded coax cable.  You need two transformers on each end.  This is one which is built with plug connectors:

http://www.bhphotovideo.com/c/product/68084-REG/Audio_Technica_CP8201_CP8201_Low

The transformer at the output converts the signal to a low impedance; at the other end it is converted up to a higher impedance to feed the high input impedance of the guest house receiver.

THREE:  Here is an FM transmitter that will allow you to pickup the audio on the FM tuner in the guest house:

http://www.amazon.com/Crane-FMT-Digital-Transmitter-Adapter/dp/B0000E6I1N

And here is another solution with both transmitter and receiver:

http://www.datavis.com/cgi-bin/product.cgi?prrfnbr=448242&site=GOGL

Hope this helps you decide which way to go.

Wishing you the best.




---------- FOLLOW-UP ----------

QUESTION: Thank you so much for such a comprehensive answer, even though I didn't give you complete information.

It may not matter now, but here are model numbers:
Main house (sending# receiver - Onkyo TX-8511
Guest House - Onkyo TX SR-806

When I built the guest house, I ran 18 gauge outdoor speaker wire #direct burial certified)with RCA jacks on both ends between the houses.  It appears I should have used shielded coax.  Still, it works just fine in the boom box, but you may have explained that.  Replacing with with appropriate cables is just not a practical option due to what I'd have to go under and through (including my wife's iris bed - she'd kill me).

The distance, as the crow flies, between receivers is about 80 feet with 2 interior and 2 exterior walls in between.

If knowing the model numbers doesn't offer more or different options, do you think the FM transmitter can work over this distance?

Thanks again for your help.

Dan.

Answer
Why don't you try the fm transmitter and see if it works.  If you purchase from a local retailer - or someone like Amazon - you can return it if it does not do the job.  But, I have used them at 100 feet, but, as you suspect, the conditions are unique to each installation.  These low level fm transmitters work on Part 15 of the FCC rules and are limited to some low level of rf output so you will find a difference from unit to unit but I know they are used in stage productions where the distances are quite great also.  The two ended ones would be better where the receiver is dedicated to best receive the transmitted signal. Why?  Because the fidelity is usually better then in the single transmitter type.  You can find many if you go to google shopping.

Yes, the cable between the two receivers should be coax.  Speaker wires will be subject to hum and other interferences. If the speaker wires were twisted together along the way it would minimize the hum and interference but would also increase the capacitance - which is the problem, I think.

I wanted to know the model number of the main receiver to see if it had a low level output other than the tape outs.  It does not.  The low level out is usually a lower impedance than the tape out and may be a better source to feed your long line; but, alas it does not have it.

Well, best wishes.  Let me know if there is more.