I have a custmer that needs to convert speaker level out to analog rca out. I thought i saw a device that did it a while back, but can't remember who made it.

Nevermind, I found it. Xantech SLLC1. thanks anyways.

Gee, I hope your speaker level signal is analog already!

Smartass

I figured Ernie would say something.

What is the maximum speaker level distance these will work at?

I have a project where the client wants an audio source sent about 150ft to another system. The only thing I have to work with is a run of 16/4 going between the two places. Retro is not an option.

This looks like it would work much better then a speaker level A-B switch.

The SLLC1 is an awesome piece, so long as you get a decent signal, the maximum distance is less relevant. I'm sure someone could do the math on the 16/4 for added impedence/signal loss, but by converting back down to line level you can set the input gain to negate that loss...or just turn up the volume/reduce the attenuation on the output.

+1. Been there done that many times. If no twisted pairs available I would prefer to run high level long run and step down to low level...

No news there.


I'd say you should keep it under a mile.


You're almost set. Read on. And read the whole thing, because it kind of develops.

Here's the deal -- the amp output is nearly a zero ohm impedance, so running a speaker level wire A LONG WAY is very unlikely to introduce any kind of noise. You should use the 16-4 as is, connected directly to the amp (except for the resistor; keep reading), and put the speaker level to line level converter right next to the remote amp.

That line level converter has a pretty high impedance itself, so the wire will only carry a tiny amount of current to the converter. That means that you can do the same thing with a twisted pair from a CAT cable! That's right, connect a twisted pair directly to a power amp output, convert to line level at some distance, and all is well. The high input impedance of the line level converter swamps out any negative effects of CAT wire resistance.

However, if that pair of wires gets shorted, the entire output current of the power amp will try to go through that short. To protect against this, put a resistor in series with the hot output of each channel. 20 to 50 ohms will be good -- high enough to seriously limit the output current in case of a short, but low enough to have a tiny effect on a signal going to a high level to low level converter.

To figure out how many watts those resistors should be, take the power output of the amp and convert to volts using Ohms law. To write it out, voltage squared equals power in watts times load in ohms. Once you've got that voltage, convert to watts using the resistance you want to use. This boils down to, in words, my output power times eight ohms divided by my proposed resistance equals the resistor wattage. And since we hardly ever run power amps near their maxiumum output power, you'll be safe dividing that number by two or three.

Lastly, you'll do well to use a car stereo amp to line converter that ISLOATES GROUNDS between amp level and line level, because when you run a signal a long way, the chances for hum and buzz go up astronomically. Breaking the ground interconnection solves that.