Do they make 1/4" balanced pro jack to RCA converter plugs?

darkmoebius · 15th July 2005, 08:28 PM

I just bought a Samson Servo 550 pro amp to drive my passive subwoofers. It was just delivered and I realized that it only has professional 1/4" balanced input jacks (lower models include RCA's).

Do they make RCA to 1/4" converter plugs?

bigmike216 · 16th July 2005, 12:30 AM

Yes.

even thoug the input is balanced, you can still plug in an unbalanced cable will no ill effect.

Duo · 16th July 2005, 12:51 AM

In the case of sending an unbalanced signal to a balanced input, for non-inverting operation; one may drop the inverting(-) input to ground with a 10k resistor and feed the unbalanced input to the non-inverting(+) pin. Ground remains equivalent.

Higher end equipment may use a proper balun to actually 'convert' the unbalanced signal to balanced, but this is normally unnecessary since the good effects of balanced operation are lost because of an unbalanced source in the first place.

sam9 · 16th July 2005, 02:30 AM

There is more in this link than you want to know, but if you scroll through, near the end you will find how to make the connection.

http://home.comcast.net/~marcwhitney...g_whitlock.pdf

When faced with the same problem, I bought a balanced cable of twice the required length anf cut it in half. Then I terminated each end with an RCA plug.

darkmoebius · 16th July 2005, 03:21 AM

Thanks for the advice guys,

I picked up a 1/4" balanced to rca converter cord at Sam Ash music center. But, now I have another problem. Samson rates it's RCA inputs on it's amps as -10dBV as compared to +4dBV for balanced.

WHat I think this means is that normal home audio rca outputs don't put out enough voltage todrive the amp to full output. In order to get nearly decent power out of the amp (for subwoofers), I have to crank the volume controls on it full throttle and adjust the output on my sub crossover.

Although, this does push the sub amp into clipping territory(clip lights flash) at fairly low output. This sucker is 275wpc channel and should push these 88-90db subwoofers with relative ease, but that's not true.

I suppose I could look into some type of voltage stepup transformer.

Any suggestions?

Does anyone know what the standard max voltage output from pro/live gear is comapred to 2V for home audio?

sam9 · 16th July 2005, 03:43 AM

I may have this backwards, but I thought it was the other way around. Namely that balanced line drivers typically output at higher levels an commercial RCA output. Someone care to confirm or refute?

If I'm right, then maybe the balanced to RCA converter that some kind of attenuation built in. Anyway it sounds odd because in a similar circumstance, I've not had what you describe happen.

imix500 · 16th July 2005, 04:26 AM

+4dB balanced is broadcast, -10dB unbalanced is consumer (although in reality it is often much higher). Meaning if you want to connect it to the output of a mixing desk or a broadcast cart player or the like, the +4 input is best, but the -10dB can be used by most consumer gear.

bigmike216 · 17th July 2005, 05:52 AM

if you're driving it into clip range, you have enough input to drive it to full power.

15th July 2005, 08:28 PM	#1
darkmoebius diyAudio Member Join Date: Feb 2003 Location: Los Angeles, CA	Do they make 1/4" balanced pro jack to RCA converter plugs? I just bought a Samson Servo 550 pro amp to drive my passive subwoofers. It was just delivered and I realized that it only has professional 1/4" balanced input jacks (lower models include RCA's). Do they make RCA to 1/4" converter plugs?

16th July 2005, 12:51 AM	#3
Duo diyAudio Member Join Date: Jun 2002 Location: Victoria, BC, Canada	In the case of sending an unbalanced signal to a balanced input, for non-inverting operation; one may drop the inverting(-) input to ground with a 10k resistor and feed the unbalanced input to the non-inverting(+) pin. Ground remains equivalent. Higher end equipment may use a proper balun to actually 'convert' the unbalanced signal to balanced, but this is normally unnecessary since the good effects of balanced operation are lost because of an unbalanced source in the first place. __________________ -- Duo, W1ngs, VA7MON, and lesser known handles. -- -- http://www.w1ngselectronics.com -- My Work and Projects --

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16th July 2005, 12:30 AM	#2
bigmike216 diyAudio Member Join Date: Jul 2004 Location: BC, Canada	Yes. even thoug the input is balanced, you can still plug in an unbalanced cable will no ill effect.

16th July 2005, 02:30 AM	#4
sam9 diyAudio Member Join Date: Jun 2002 Location: Left Coast	There is more in this link than you want to know, but if you scroll through, near the end you will find how to make the connection. http://home.comcast.net/~marcwhitney...g_whitlock.pdf When faced with the same problem, I bought a balanced cable of twice the required length anf cut it in half. Then I terminated each end with an RCA plug.

16th July 2005, 03:21 AM	#5
darkmoebius diyAudio Member Join Date: Feb 2003 Location: Los Angeles, CA	Thanks for the advice guys, I picked up a 1/4" balanced to rca converter cord at Sam Ash music center. But, now I have another problem. Samson rates it's RCA inputs on it's amps as -10dBV as compared to +4dBV for balanced. WHat I think this means is that normal home audio rca outputs don't put out enough voltage todrive the amp to full output. In order to get nearly decent power out of the amp (for subwoofers), I have to crank the volume controls on it full throttle and adjust the output on my sub crossover. Although, this does push the sub amp into clipping territory(clip lights flash) at fairly low output. This sucker is 275wpc channel and should push these 88-90db subwoofers with relative ease, but that's not true. I suppose I could look into some type of voltage stepup transformer. Any suggestions? Does anyone know what the standard max voltage output from pro/live gear is comapred to 2V for home audio?

16th July 2005, 03:43 AM	#6
sam9 diyAudio Member Join Date: Jun 2002 Location: Left Coast	I may have this backwards, but I thought it was the other way around. Namely that balanced line drivers typically output at higher levels an commercial RCA output. Someone care to confirm or refute? If I'm right, then maybe the balanced to RCA converter that some kind of attenuation built in. Anyway it sounds odd because in a similar circumstance, I've not had what you describe happen.

16th July 2005, 04:26 AM	#7
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	+4dB balanced is broadcast, -10dB unbalanced is consumer (although in reality it is often much higher). Meaning if you want to connect it to the output of a mixing desk or a broadcast cart player or the like, the +4 input is best, but the -10dB can be used by most consumer gear.

17th July 2005, 05:52 AM	#8
bigmike216 diyAudio Member Join Date: Jul 2004 Location: BC, Canada	if you're driving it into clip range, you have enough input to drive it to full power.

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