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
chessie OP
25 posts
 

Interesting, trying to understand how this would work.  

Is this what you mean?
--------------------------------------

1. Don't do anything to the existing (built-in) crossover.

2. send a regular signal to the "high" speaker input.
         (Source->Preamp->Amp->HSI)

3. use the miniDSP to process the signal that goes to the "low" speaker input.
        (Source->Preamp->miniDSP->Amp->LSI)

 

Thanks,

Ted

boxcarman
431 posts
 

I started out with Adcom separates in the 90's. MHO is that  Adcom was and is, starter equipment. You can and should go for something better.

tmortsd's avatar
tmortsd
37 posts
 

For the time being keep it simple get a good RCA Y splitter.  Check out Morrow audio, they custom make cables that I’ve been very happy with, you can get a quality cable at a reasonable price or really great ones for more…

curiousjim's avatar
curiousjim
4,983 posts
 

Bi-Amp good.

Bi-Wire, not so much.

erik_squires
16,442 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. :)

 

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