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
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. :)

 

barts's avatar
barts
736 posts
 

Using a Y will necessitate that you bi-wire (which for most systems is a waste of time and money in my opinion).

Considering that the amps are just refurbished I personally think your best bet is to bridge both of them.  Gives you plenty of headroom and your using the speakers as intended.  To any naysayers...if the amps are virtually as new or better and were designed to be bridged in the first place just go for it.

I ran ARC bridged amps for many years with no issues. 

Regards,

barts

  

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