Mixing XLR and RCA outputs when biamping?

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

Thanks Eric,

I had almost gotten to that point myself.   These amps are also bridgeable, but most people don't recommend it.   My speakers are 8ohm nominal, B&W 801S2.

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.

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.

There is/was an "alignment filter" but I don't have one.   I have looked for one but they are apparently made of solid gold.    How does one introduce an active crossover?   I assume there is some hardware to add somewhere.

I vertically bi-amp my speakers and found it to be a nice improvement.  I had BJC make a XLR cable that splits the signal from one XLR connector at the pre-amp output to two signal paths that run to the amplifier, each run is terminated with an XLR connector.  Works great.  You would not want to mix XLR and RCE.  

@chessie

alignment filter is the crossover network between woofer, midrange and tweeter. you would need 3 amps to run fully active and a good working knowledge of appropriate crossover frequencies, slopes and level matching the drivers as well as if there was an impedance flattener, notch filter, baffle step compensation and roll off filter. not for the uninitiated.

run the amps as you have planned using a splitter off one set of outputs. you should enjoy the difference assuming the adcoms are up to snuff.

@avanti1960

Thanks, yes... sounds like more than I am looking to do at this time.

The amps have been serviced/refurbished by an adcom specialist using new Hoppe boards.

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

Interesting, trying to understand how this would work.  

Is this what you mean?
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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

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.

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…

Bi-Amp good.

Bi-Wire, not so much.

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. :)

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

Thanks Barts.    Not sure why Y splitter necessitates bi-wire?   Can you explain?

Bi-wire to me is taking one output channel off of the amp and splitting it into two wires for the speaker inputs.   I agree, this doesn't make much sense as to why it would be beneficial.

What we are talking about is Y-splitting the output from the pre-amp so it can feed both channels of the amp with the same signal.   At that point you have of the two channels to feed each speaker (vertical bi-amping, not bi-wiring).