ESP 101 with balanced/unbalanced input

Cloth Ears · 16th June 2006, 03:06 PM

Hi,

I've had a look through previous posts and haven't been able to find an answer that satisfies completely - although someone may be able to point out differently. So...

I'm building (eventually) a pair of P101 amps from the Elliot Sound Products site. I'm also using a soft-start circuit from the same place. But, as work sent me to Singapore for a month (yes, I know, poor me:-), I've had a chance to think - call the newspapers!!!

I've got some speakers that have passive cross-overs, that would need a full-range signal fed to the amplifiers - hence unbalanced (RCA) inputs. But I also have a pair of actively crossed speakers on the go (some parts built, some not yet). And the cross-over is the venerable (and not too bad) Behringer CX-3400 - with balanced XLR outputs.

I'd like to be able to feed these power amps with either feed. Should I just short the pins on the XLR plugs (or just get an adapter for $7), into an unbalanced (RCA) input. Or should I use both RCA and XLR inputs and feed the XLRs via a transformer and op-amp network and the RCA directly to the standard P101 input?

paulb · 16th June 2006, 10:26 PM

You may be able to modify the P101 to accept a differential input. Have you looked through the ESP forum? Or try posting the question there as well.

Cloth Ears · 17th June 2006, 11:12 AM

Hi Paul,

There's another project on the site (2 actually) for building a balanced receiver. Although, from careful reading of the crossover manual, it should be safe to use an XLR-RCA adaptor at the amplifier end.

So, no need to run both types of input. I'm still going to leave space in the box in case I want to put in XLR plugs as well.

What I was trying to get at last night (I'd been working on a problem at work and watching the football, so I may not have been clear) was whether it's simple to do both. The amp has an input and a ground, and the RCA has an input and a ground, and the receiver project has a + and - input and a ground, but has one output and a ground. Does this not mean that they could all just fit together (with a switch to allow you to decide which is input)?

16th June 2006, 03:06 PM	#1
Cloth Ears diyAudio Member Join Date: Dec 2001 Location: Melbourne, Australia	ESP 101 with balanced/unbalanced input Hi, I've had a look through previous posts and haven't been able to find an answer that satisfies completely - although someone may be able to point out differently. So... I'm building (eventually) a pair of P101 amps from the Elliot Sound Products site. I'm also using a soft-start circuit from the same place. But, as work sent me to Singapore for a month (yes, I know, poor me:-), I've had a chance to think - call the newspapers!!! I've got some speakers that have passive cross-overs, that would need a full-range signal fed to the amplifiers - hence unbalanced (RCA) inputs. But I also have a pair of actively crossed speakers on the go (some parts built, some not yet). And the cross-over is the venerable (and not too bad) Behringer CX-3400 - with balanced XLR outputs. I'd like to be able to feed these power amps with either feed. Should I just short the pins on the XLR plugs (or just get an adapter for $7), into an unbalanced (RCA) input. Or should I use both RCA and XLR inputs and feed the XLRs via a transformer and op-amp network and the RCA directly to the standard P101 input? __________________ Jont. "It is impossible to build a fool proof system; because fools are so ingenious."

17th June 2006, 11:12 AM	#3
Cloth Ears diyAudio Member Join Date: Dec 2001 Location: Melbourne, Australia	Hi Paul, There's another project on the site (2 actually) for building a balanced receiver. Although, from careful reading of the crossover manual, it should be safe to use an XLR-RCA adaptor at the amplifier end. So, no need to run both types of input. I'm still going to leave space in the box in case I want to put in XLR plugs as well. What I was trying to get at last night (I'd been working on a problem at work and watching the football, so I may not have been clear) was whether it's simple to do both. The amp has an input and a ground, and the RCA has an input and a ground, and the receiver project has a + and - input and a ground, but has one output and a ground. Does this not mean that they could all just fit together (with a switch to allow you to decide which is input)? __________________ Jont. "It is impossible to build a fool proof system; because fools are so ingenious."

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16th June 2006, 10:26 PM	#2
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	You may be able to modify the P101 to accept a differential input. Have you looked through the ESP forum? Or try posting the question there as well.

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