[cloudbaseracer]

Is this the best location for this thread? 

Here is my challenge:

I have Gedlee Abbey mains and four of his passive subs that require an external crossover. Most, including myself, use the Behringer DCX 2496 for this.  I will also have 2 Ncore amps for the main. My music is through a Squeezebox Touch which currently uses the stock analog out. I am looking to get something like the NAD M51 as it seems to have excellent reviews as a DAC and the pre-amp functionality is great.  The issue is that it does not have a sub out.  There are balanced outputs for the Ncore as well as L/R RCA outs. I have been told that I cannot sum the L/R because it will make the whole system mono. 

How do you guys suggest I handle this dilemma?


I do use my system for hooking up a Comcast DVR and Blu-Ray player via HDMI.  This is the main reason that I looked to the M51 - other than the great DAC reviews, it has HDMI inputs.

I prefer a single box as opposed to a separate DAC and pre unless there is a better option you guys know of.  The M51 is around $2k so that is a comparative budget.  I could go more if there was a better option.

Cheers,

James

[polishpowerlifter]

You need a NAD C390DD and could use the pre out but it is an amp also...

[JohnR]

Wouldn't you input L and R from the M51 into the Behringer, and do the summing in there? Then the "mono" will be only for the subs.

[cloudbaseracer]

Wouldn't you input L and R from the M51 into the Behringer, and do the summing in there? Then the "mono" will be only for the subs.

I do not think the DCX will sum L/R and then send to all output channels.  If you know that it will then that will be the way to do it.  I would use Input A for the Left and Input B for the right.  However, when I looked at the configurations page it looks like only Input A will send to all output channels.

Cheers,

James

[JohnR]

I'm not a DCX user but section 4.4 of the manual describes the SUM signal that can be the sum or A and B inputs. Then section 4.5 says that each output can be driven from the SUM signal.

[TomS]

That's exactly how I use it. XLR Y cable to amps and DCX. SUM within DCX to 4 outputs mono.

[cloudbaseracer]

I'm not a DCX user but section 4.4 of the manual describes the SUM signal that can be the sum or A and B inputs. Then section 4.5 says that each output can be driven from the SUM signal.

Thanks for that!!

I was looking at page 10 Section 4.2 of the manual and it seems to show a different configuration.  Here there is nothing shown that SUMS A+B to send to ALL of the 6 outputs.  At least by the way I read it.

Cheers,

James

[cloudbaseracer]

I am reviving this thread as I finally got my custom entertainment cabinet completed and now I need to get a DAC/Pre to make everything run.  The Ncores have been sitting and waiting till I can get something.

Any suggestions on a DAC/Pre?  Probably less than $3k total.  As I said before, I was looking at the NAD M51 and still may go this route unless you guys can give me a different direction. 

Is it better to get a separate DAC and Pre so I can upgrade the DAC as technology changes?  I do want balanced connections, remote capability and ability to run my Blu-Ray player through the Pre.

Cheers,

James

[JLM]

I use a Jaton Operetta RC2000S:  http://www.jaton.com/av/product_detail_ex.php?idx=4

MSRP $1500, Contact John Casler here at A/C. 

Has built-in DAC, multiple outputs, subwoofer output with several frequency cut offs, very high content value.

Here's a couple of good reviews: 

http://www.enjoythemusic.com/magazine/equipment/0112/jaton_operetta_rc2000p.htm

http://www.stereomojo.com/Jaton%20RC2000/JatonRC2000Preamp_DACReview.htm

Check out the other reviews, very neutral sound.  (Isn't that what a pre-amp should be?)

[jtwrace]

Any suggestions on a DAC/Pre?  Probably less than $3k total. 

Uh, Metric Halo LIO-8.

[TomS]

And you can find a very nice MH LIO-8 for sale at a great price right here 

http://www.audiocircle.com/index.php?topic=110698.msg1143571#msg1143571

[cloudbaseracer]

But I am always suspicious when Jason is selling something  . I mean how good can it be if he wants to get rid of it?

[cloudbaseracer]

So no one else has any suggestions?

[Russtafarian]

Back to the original question, if you can solder you can build a Y cable with resistors that will sum left & right to mono without messing up the stereo signal.  By including the resistors you are essentially building a fixed-value 2 to 1 passive mixer.

For the left and right pre-out RCAs, solder a 2000 ohm resistor between the center pin and the (+) lead of the cable.  For the mono input RCA connector, connect both left and right (+) leads to the center pin.  All ground leads are connected to the RCA barrels as usual.

For a balanced to balanced XLR summing cable, use a 1000 ohm resistor on pin 2 (+) and pin 3 (-) of the L & R pre-out XLRs and connect the ground lead directly to pin 1 (no resistor).  For the mono input XLR, solder both (+) leads to pin 2, (-) leads to pin 3 and ground leads to pin 1.

You can build single ended cable with XLRs on one end and RCAs on the other.  For the XLR use pin 2 for (+) and pin 3 for ground.  Use the same methodology as above soldering 2000 ohm resistors to the pre-out connector (+) pin and summing at the input connector (+) pin.  The XLR pin 3 ground lead may or may not need to be connected to pin 1.  I usually solder a bridge wire between pin 3 and pin 1 and plug everything in.  If the rig is quiet, then I leave it.  If I get a ground loop hum, I open the connector and snip off the pin 3 to pin 1 wire. 

Gear with XLR connectors should have specific wiring and ground instructions in the manual, so check that first before you do anything.

Russ