Behringer DCX2496 digital X-over

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Indalhc

Indalhc

Member
Joined 2005
On upgrading the dac

Nothing new announced for the DCX at NAMM... Maybe there are some pleasant surprises in the coming series/backordered units then d:

PS With a good analog active crossover, and no need to tweak a lot (sweet spot dwelling). Couldn't I just add an inductor on each of the two top channels (in a three way system), to compensate for the timing delays? (remembering some Quad speaker model had a similar arrangement) Then how long is say 1262.5 Hz

;)
 
K

KBK

Member
Joined 2003
K5600 volume?!?

This is the puppy I've been waiting for! I don't want to try and design a unit, I jsut want to take apart andmodify somone else's! Far easier, far less time spent, the real key point.

I gotta get me afew of these. I found a link to this unit (K 5600) in Aussie land or NZ inthis case..and well, is that the only palce it's available? need soonest!

I suspect that if I buy two of these volume control units --- then the new behringer unit will come out with...remote level control. Such will be life. :rolleyes: :D
 
Indalhc

Indalhc

Member
Joined 2005
Thmartin said:


One thing bothers us though : there is a high pitched hum noise at intermediate volume settings :whazzat:

Noise completely disapears at full throttle or when muting is on. What could it be ? Defective cap in the power supply ? Bad decoupling somewhere ?

Thierry
Click to expand...

There might be a PWM based attenuation, with the duty cycle set within the audible spectrum...

I have a graphics card with similar behavior, emitting a tone while dimming the screen.
 
A

AnthonyPT

Member
Joined 2004
Hi

If we were to update the chips in the
K5600 down the track we could look at this
Wolfsonmicro solution if it is not too costly to do.
Get the evaluation board (US$100) then we make
our own group boards? I guess we would
have to decide what we can rescue and reuse too!
Also is the upgrade really audable?

Regards
AnthonyPT

http://www.wolfsonmicro.com/products/digital_audio/volumecontrol/WM8816Vol_EV1/
 
jan.didden

jan.didden

AX tech editor
Joined 2002
linearaudio.net
Paid Member
AnthonyPT said:
Hi

If we were to update the chips in the
K5600 down the track we could look at this
Wolfsonmicro solution if it is not too costly to do.
Get the evaluation board (US$100) then we make
our own group boards? I guess we would
have to decide what we can rescue and reuse too!
Also is the upgrade really audable?

Regards
AnthonyPT

http://www.wolfsonmicro.com/products/digital_audio/volumecontrol/WM8816Vol_EV1/
Click to expand...


Anthony,

I have the Wolfson board and find it quite good, very little or no coloration. The changes in level are completely silent in my application.
However, I have been reading an AES report of the guys who developed that CS3310 I think it was. The difference between the WM8816 and the chip in the K5600 versus the CS3310 is that the 3310 has on-board buffer amps. Now, initially I thought that was Not Good, because those opamps probably were not the hottest ones and with the Woffson and the K5600 chip you have the flexibility to play with the opamp and / or final gain.
But, reading the CS3310 AES report it became clear that there is more than meets the eye. The onboard opamp allows modulation of the semiconductor wells under the ladder switches on the chip. These switches have a resistance that is signal dependent and ultimately are the limiting factor to the distortion of those switches and the rising distortion with frequency. So, having the onboard opamp allows for the well modulation which can to a large extent cancel the level-dependency of those ladder resistors.
Is it audible? Don't know, but it probably is measureably better.

Jan Didden

PS If you want to give the WM board a spin sent me a private email

PPS: http://www.mhennessy.f9.co.uk/preamp/analogue_research.htm
 
T

Thmartin

Member
Joined 2004
Hello Jan

Did you have a chance to evaluate the K5600 ? - well, if it has flown back from Perth at last ;)

I have repaired the first I built which was faulty : a 7906 regulator in the power supply board was shot and was feeding the volume control ICs with +6V and -3V :eek: hence the humming noise.

Everything is back to normal now.

At the same time I have replaced all the electrolytics on the PS board and signal board with BlackGate and Elna Silmic caps for the sake of silence.

Thierry
 
jan.didden

jan.didden

AX tech editor
Joined 2002
linearaudio.net
Paid Member
Thmartin said:
Hello Jan

Did you have a chance to evaluate the K5600 ? - well, if it has flown back from Perth at last ;)
[snip]Thierry
Click to expand...


No not yet, although it has arrived finally. The Altronics staff were quite helpful to talk to the EMS courier to speed up delivery. My first dealing with them, they seem a competent and responsive outfit.

Maybe I'll complete the kit this weekend.

Jan Didden
 
Indalhc

Indalhc

Member
Joined 2005
ezkcdude said:
Just noticed this thread has a lot of DIYers. So, here's my question. I've looked at the specs for the Behringer x-overs and several other brands. Most seem to have built-in D/A without the ability to pass a digital output. The only one I know of is the very expensive DEQX crossover, which can have a digital out added as an option.

The idea is that it would be nice to use a separate D/A converter for the different channels, after they've been digitally filtered. For example, the Lavry Blue with 2 or 3 different channels could be used to do the D/A for a 2- or 3-way system. The advantage is that the D/A in the Lavry is much higher quality than the onboard Behringer D/A. I also thought about using PC cards, but then I would have to write a bunch of software. Anyway, if the DIY community here has a cheaper solution, I'd love to hear about it.
Click to expand...

The six channel DA from Lavry Blue is about similar in price as the DEQX :xeye:

My take on the DCX, I plan to buy one - wishing at the same time that the manufacturer have listened to this thread over the years, and done at least some of the improvements accordingly ;)

Else if not, I plan maybe to modify with transformer outputs à la AR2 on four of the channels (mid and high), and then possibly some other more affordable? mod like those Thierry and Ergo are working on for the low frequency. This is all prelimnary though. I might as well be satisfied with the unit as it is, since I mostly listen to 'internet radio' these days anyway :)
 
jan.didden

jan.didden

AX tech editor
Joined 2002
linearaudio.net
Paid Member
Thmartin said:
Hello Jan

Did you have a chance to evaluate the K5600 ? - well, if it has flown back from Perth at last ;)[snip]Thierry
Click to expand...


Hello Thierry,

Finished the boards this weekend, now assembling the unit.
Had some issues with the kit contents though: the 10k resisitor (9 or 10 are needed) were missing (but I have a lot of extra pcb-stakes I don't need ;) ), some of the hardware (stand-offs) were of the wrong size or number.
There is a resistor in the ps of 330 ohms 5W which in all the text, diagrams and parts lists is called 33 ohms 5W. However, the kit had the 330 ohms, which is also shown on the pictures, so I guess 330 ohms is OK? Not a big deal anyway as it's use is only to avoid on/off thumps I guess.

Jan Didden
 
T

Thmartin

Member
Joined 2004
Dear Jan Didden

The two K5600 I have assembled had the 330R resistor on the PS board, so there's no worry about that.

One of them had a non working 7906 regulator, hence a strange humming noise and the culprit regulator running bloody HOT :hot:

Apart from this, very good stuff.

I must confess that I already replaced all of the electrolytic capacitors with Black Gate and Elna Silmic II caps :rolleyes:

Let me know what you feel about the sonics of the kit. I'm very tempted by trying different opamps like the LT1361...

Cheers

Thierry
 
K

kepa1

Member
Joined 2004
Hello there,

I finally upgraded 2 outputs on my unit, following Thierry's schematics and I must say that it has improved upon the stock output, especially in term of smoothness.

Nevertheless, I expected a bit more refinement, that proves that the DCX as it is sounds rather good.

And I worry about the loss in db, the passive out gives about -21db / active. In fact it's even -9db compared to the analog out of my TEAC player.

Anyone noticed that too?
 
jan.didden

jan.didden

AX tech editor
Joined 2002
linearaudio.net
Paid Member
kepa1 said:
Hello there,

I finally upgraded 2 outputs on my unit, following Thierry's schematics and I must say that it has improved upon the stock output, especially in term of smoothness.

Nevertheless, I expected a bit more refinement, that proves that the DCX as it is sounds rather good.

And I worry about the loss in db, the passive out gives about -21db / active. In fact it's even -9db compared to the analog out of my TEAC player.

Anyone noticed that too?
Click to expand...

The DCX output as-is has about 10.8dB gain IIRC. Going passive means you lose that; going from balanced to single-ended again means a loss of 3dB (or was it 6dB?).
But my experience is that it is OK because the stock gain was too high for domestic use. Easy compensated by turning the level control up a bit.

Jan Didden
 
seppstefano

seppstefano

Member
Joined 2004
Thmartin said:


Funnily enough even after removing all the **** by cutting off circuitry between X13 connector and the XLRs, the Mute function is still working ! (transistors T1 to T6)

That proves if needed how un-necessary was that stuff for our use.

Did I say each on his own ? Yes I did :rolleyes:

Thierry




.
Click to expand...

Hi Thierry, all,
many thanks for sharing those great info! Would you eventually know whether the DCX shares the ouput stage with the older DSP8024 (which I happen to use in order to eq. my DIY subs)?

Or where I might look for DSP8024 schematics?

Thanks again,

Stefano
 
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