2. amps-preamps
  3. 193485-41563

Mixing XLR and RCA outputs when biamping?

I’m about to introduce two new (to me) amps into my 2-channel system, and wondered about how to hook them up.

 

The amps are refurbished Adcom GFA555s1, and I plan to bi-wire them vertically.  My preamp (NAD C658) has both XLR and RCA outputs,  and it appears they output simultaneously.    However, the amps are RCA input only (no XLR input).          It would seem I have a couple of options:

 

1. use the RCA output of the preamp, and split each signal to feed both channels of each amp.    
 

2. Use both XLR and RCA outputs, with the two left channels going to the left speaker amp.

 

Would the voltage/sound level be the same for situation 2?    I was thinking running the left XLR into the low freq on the left speaker, and the right XLR not the low freq of the right speaker.

 

this is probably a dumb idea and I should split the RCA signal.

 

 

 

 

chessie

Showing 5 responses by erik_squires

erik_squires
16,564 posts
 

Yep,  a Y splitter is simple.

The issue with passive bi-amping (without a crossover) is that both amp channels still provide the same voltage swing, but with twice the power supply you used to have.

With a miniDSP you can do a couple of more advanced things:

  • Reduce the load on the mid/treble amplifier
  • Reduce the load on the woofer amp
  • Fine tune the bass to your room with DSP
  • Improve efficiency by removing level adjusting resistors since you can use miniDSP to set the relative mid/treble to woofer levels.

I think the Y splitter is the best place to start, and maybe look into getting into active a little bit at a time.  For instance, you could use the miniDSP strictly as an EQ and Y splitter first.  When you get more comfortable you can consider bypassing the woofer crossover. :)

 

erik_squires
16,564 posts
 

My suggestion was hybrid, keep the mid to tweeter cross and use a minDSP  for mid to woofer

erik_squires
16,564 posts
 

Also, didn't these speakers come with an "alignment filter" of some sort?  You can do away with it if you go fully active.  Replace the bass EQ in the filter box and use the DSP instead.

erik_squires
16,564 posts
 

Well if you were considering doing more work, those are good speakers to take semi-active.  Using a 2-way active crossover, and by passing the woofer low pass and mid high pass can increase your dynamic range and give you some powerful EQ capabilities.

erik_squires
16,564 posts
 

The levels are probably not going to be the same.  Use a Y splitter.

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