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I'm not an audio engineer, but I could sure use the help of one!

Recently I helped my church purchase a little box called an AutoHybrid by JK Audio. It basically takes a balanced line-level output and broadcasts it over a telephone line. This is useful for us because it allows church members who can't make it to a service one day to be able to "call in" and listen along. We just plug the box into the PA system, call into a number, and go.

I've verified that it's working. However, it's SUPER quiet... to the point that it's basically un-usable.

Here's an explanation of our set up. Most of this equipment is pretty old.

  • TOA Series A-506A Amplifier
  • Peavey 1/3 Octave EQ-31 Graphic Equalizer
  • Shure UT-4 Wireless Microphone
  • Gentner Assistive Listening FM Transmitter
  • JK Audio AutoHybrid

I actually drew up a diagram as best I could of how all this equipment is connected to each other, so take a look if you want all the specifics. But basically, there are two main (wired) microphones that plug directly into the amplifier, then the amp sends an output to the equalizer, which in turn sends an output back to the amplifier. And currently the AutoHybrid is plugged into the equalizer, because there was nowhere else to plug it in. And again, this actually does work in that it is broadcasting the signal over the phone... it's just far too quiet.

What do I need to do to make the AutoHybrid louder without breaking the current system? Someone I spoke with earlier had suggested adding either a mixer or a distribution amplifier to receive the microphone signals before sending it to the equalizer, but I'm not totally sure how I would have to re-wire everything to make that work.

Thanks so much in advance!

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2 Answers 2

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Using a pre-amp between the EQ and the AutoHybrid should handle your needs. I have personally used this tube pre-amp before, though I was using the unbalanced input to the balanced output, but I believe it should work for your needs as well. It isn't the best quality ever made, but it is a decent value for the money.

Seeing what your system layout is like now, this is probably your best bet. It would be preferable to branch off the audio from the amp prior to the 31 band, but it looks like the amp that is doubling as your mixer doesn't provide the outputs necessary without multiple steps or a major overhaul and modernization of the system, so the preamp should be good enough.

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I just made the purchase; I'll let you know how it turns out! And just so I'm clear: are the two XLR ports on this balanced? And would you recommend any particular setting for the "Preamp Mode" dial? Thanks so much! –  SoaperGEM Jun 11 '13 at 19:54
    
I recommend neutral, though you can adjust to taste. The XLR should be balanced. –  AJ Henderson Jun 11 '13 at 20:03
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Do the hard of hearing folk in the church pick-up the signal OK? If they do then you need to amplify the balanced signal from the graphic equalizer to the JK audio autohybrid.

That's probably what you need to do but i guess that doesn't get you much further so if you are in the UK call in to Maplin and ask them for help and if you are in the US call in at Radio shack and tell them what you need.

Don't forget to tell them you have a balanced output and this may require an audio transformer to give you an unbalanced output that is more suitable for a cheap audio amp found in these sort of retail outlets. You may also need an unbalced to balancing transformer to feed the hybrid - checks the specs of it and see what it says.

Possibly you'll be able to get a little amp that is balanced input and output.

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