Behringer DCX2496 digital X-over

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mige0

mige0

Member
Joined 2005
members.aon.at/kinotechnik/DeepColor/DeepColor_clock.html
nonsub said:
Thanks Brett... no that is some other of NAIMS other amps that do that, 250s (old ones anyway) do not have a power supply out.
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But do they have XLR - IN then ? - IIRC "older ones" form NAIM always stuck to DIN connectors - non-standard pinout tho.

You know, NAIM always followed its own thoughts about how to best wire up non-symmetric gear (with excellent results one has to admit) - this caused a lot of head scratching among audophools back then.


Michael
 
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R

Radian

Member
Joined 2004
panomaniac said:
Ciao Paolo,

You seem to have a pretty good idea of what is needed. You should not have much trouble.

One thing that is important to know: There is 2.5 volts on the output pins of the DAC chip. That is 2.5V on both positive and negative. So somehow you have to block the DC before going to your volume control amps, etc. This can be done with a cap on each leg, or a transformer. Or some active circuit like the opamps in the DCX. But you can't leave out this part.

I don't think you will need the tube buffer stage, but it sure won't hurt to try. What you want is a buffer that delivers more current to drive the amplifier input stages. I doubt you will need more voltage.
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Hi panomaniac,
have you tried to go with no cap into the Tripath amps since they have a
2.5V DC bias ?

Greets,
Klaus
 
N

nonsub

Member
Joined 2010
mige0 said:
But do they have XLR - IN then ? - IIRC "older ones" form NAIM always stuck to DIN connectors - non-standard pinout tho.

You know, NAIM always followed its own thoughts about how to best wire up non-symmetric gear (with excellent results one has to admit) - this caused a lot of head scratching among audophools back then.


Michael
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Hey Michael yeah they are single XLR 3 pin in (from NAXO DIN out)


SQLGuy said:
Looking around it does look like Naim used a single XLR for unbalanced L/R/G. I guess this gives you the option of bridging it by plugging in a normal, balanced, signal.

For your setup, unless you want to bridge them, you'll need to make some custom cables. From the DCX, you'll want to use pin 1 for ground and pin 2 for phase+ signal. Pin 3 you can either leave open or connect to pin 1 for extra gain on pin 2.

On the Naim end, I have no idea. At a guess, I'd first try pin 1 for ground and then see whether 2 is left or right. A bit of trial and error and you should be able to figure it out.
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SQLguy I guess I can also do this by wiring inside the DCX itself? Either way I have issues with going from balanced to unbalanced? Thx!
 
Pano

Pano

Administrator
Joined 2004
Paid Member
Radian said:
Hi panomaniac,
have you tried to go with no cap into the Tripath amps since they have a
2.5V DC bias ?
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I have thought about it. But there would be 2 problems there:
  1. The 2.5V would have to match very closely on both. Any offset and you'll get large DC offset on the output of the Tripath amp. I may be possible to trim that, but I have not tried
  2. If you want attenuation, I don't see how you'd do it. So that means that the amp is running wide open. Easy to run into noise and clipping issues.

And RF noise between the units could also be a problem.

So it seems like a fun idea, but there would be problems to work out.
 
Pano

Pano

Administrator
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Legis said:
Is there some more versatile measurement tool? Preferably one that is free or available in "the other way".
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Try ARTA. That's what I used. The free version does not allow you to save files, but you can save graphics to the clipboard or do screen captures. I use Mirek's Free Windows Software to capture and save the graphs. It works great. (find a window size for ARTA that isn't too big). Save as GIF or PNG.

FYI, I won't be on the forum much for the next few days, so may not be able to comment.
 
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rikkitikkitavi

Member
Joined 2001
ergo said:
Kuei Yang Wang,

I just made an experiment a few weeks ago with LC filtering on DCX.

My conclusion was that it looks good on paper but was bad in reality. The problem is that there seems to be a lot of RF floating around inside DCX and the L part of the filter will pick it up like antenna.

I can post measurements later when I get home. I looked at the spectrum of 10Hz-40kHz and the LC type filter created a lot more dirt that raised above the noisefloor.

Thus I burried the idea of LC and now my setup will be

RC -> 6ch volume pot -> RC -> OPA2134 in simple gain mode -> output.


Regards,
Ergo
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well , it is not surprising that there is a lot of RF inside the box. Are you using the original power supply?
btw, I am doing similar output:

DCX motherboard => single ended passive RC => PGA2311 => passive RC => power amp.

All X 3 of course .

(only single ended signal is taken out, the other output from AKM DAC is grounded via 1,2 k)

if you fiddle around with the passive RC impedances it is equivalent with a 2nd order 80 kHz filter, and without to much impedance in series with the PGA (which degrades THD).

regards,
Rickard
 
S

sendler

Member
Joined 2004
mysite.verizon.net/vze4c5pt/id2.html
Peak

Gary P said:
For those interested I have added a transformer measurement section on my web page. Each transformer has frequency response/phase measured from 10Hz to 80Khz. Also distortion vs frequency from 10Hz to 50Khz at 3 voltages is tested. I will add transformers in the future as they pass by...

Gary
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Very nice job on the extended frequency range of your measurements. It is interesting to see the 6db peak at 60KHz that most of the transformers in the test tend to have. I have been working with modified output filters for the Sure 2X100 class D amp and have found that a filter that is flat at 20K and allowed to peak 6db at 70k sounds much more transparent than a text book slope that is flat at 20K and down 6db at 70K.
.
The original premise for the measurements was to see if a predominance of interjected third order distortion could explain why transformers can be preferred over capacitor and opamp coupling in listening tests but now I wonder if the just out of band peaking is also beneficial.
 
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peace brainerd

Member
Joined 2004
How many ways to skin this cat?

I have 2channel integrated amplifiers.

I'd like to introduce some degree of bass management.

I'd like to keep it pretty simple and low cost.

Is it possible to connect an active crossover between the CD player and the integrated amp?

I'm imagining the CD player connected to the crossover, and the crossover output sent to the signal level inputs on the subwoofer plate amplifiers and also to the integrated amp (now dedicated solely to the mains)

Both of my CD players have signal level volume control. Once the integrated amp volume is balanced with the subs it would no longer be used.
 
D

DougSmith

Member
Joined 2008
AR2 said:
Guys, check this out. Very cool. This is something we all wanted to have a long time. I2S in and out, between many other possibilities. And analog as well. They seems to be a start up, and product is an ideal experimenter board.
MiniDSP - Product Concept
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Someone pointed that out to me recently, It is kind of cool (I could easily have incorporated it into my 4 channel amp). However, it just has a graphic equalizer with preset frequencies, as far as I can see, instead of individually configurable PEQ filters, Not as useful for bass management.
 
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