Hello,
Some questions to Ian Didden concerning your active output card - Congrats for the hard work !
- what is the output impedance?
- what is the range of volume attenuation? can I lower channel 1 to 45db and raise channel 6 by 3db? The issue is that I plug my tweeters directly on the DCX outputs
( and they need almost no attenuation).
- is the BOM available somewhere (are XLR connectors included)?
- as far as I understand, the board accepts balanced connectors but works SE (?), will I benefit from transformers to have a real balanced signal?
Some questions to Ian Didden concerning your active output card - Congrats for the hard work !
- what is the output impedance?
- what is the range of volume attenuation? can I lower channel 1 to 45db and raise channel 6 by 3db? The issue is that I plug my tweeters directly on the DCX outputs
( and they need almost no attenuation).- is the BOM available somewhere (are XLR connectors included)?
- as far as I understand, the board accepts balanced connectors but works SE (?), will I benefit from transformers to have a real balanced signal?
Originally posted by kepa1
Hello,
Some questions to Ian Didden concerning your active output card - Congrats for the hard work !
Hi Kepa, thank you!
- what is the output impedance?
130 ohms
- what is the range of volume attenuation? can I lower channel 1 to 45db and raise channel 6 by 3db? The issue is that I plug my tweeters directly on the DCX outputs ( and they need almost no attenuation).
The range is -60dB to +6dB. That is set in software. +6dB gives 3.4VRMS which should be enough to drive any poweramp to max level. For specific purposes I could set it anywhere between -112db to +22dB. I guess you have a power amp between the DCX and the tweeters, no?
The issue with the level offset is that if you set one at -45dB and the other to +3dB, which is a 48dB difference, you have only 18dB range between -60dB and +6dB, so in that case I can set the larger range for you in the software. But are you sure about that direct connection of the tweeter??
- is the BOM available somewhere (are XLR connectors included)?
everything is included, including the screws and stand-offs for the display/control pcb, XLR's, all parts, cable, connectors, pcb for the RS232 remote connection, absolutely everything. You need nothing more.
- as far as I understand, the board accepts balanced connectors but works SE (?), will I benefit from transformers to have a real balanced signal?
The output is impedance balanced for max common mode interference, hum and noise supression. You can use it with XLR as well as RCA (but without the balancing of course). You can use transformers after it, and retain the balanced operation, but why not try it first without xformers? There may be no need for balanced operation; I retained it because some users have power amps with balanced inputs. You need to trade of the extra cost and sound coloration from a xformer against a possible benefit from balanced interconnects.
Jan Didden
Hello,
Some questions to Ian Didden concerning your active output card - Congrats for the hard work !
Hi Kepa, thank you!
- what is the output impedance?
130 ohms
- what is the range of volume attenuation? can I lower channel 1 to 45db and raise channel 6 by 3db? The issue is that I plug my tweeters directly on the DCX outputs
( and they need almost no attenuation).The range is -60dB to +6dB. That is set in software. +6dB gives 3.4VRMS which should be enough to drive any poweramp to max level. For specific purposes I could set it anywhere between -112db to +22dB. I guess you have a power amp between the DCX and the tweeters, no?
The issue with the level offset is that if you set one at -45dB and the other to +3dB, which is a 48dB difference, you have only 18dB range between -60dB and +6dB, so in that case I can set the larger range for you in the software. But are you sure about that direct connection of the tweeter??
- is the BOM available somewhere (are XLR connectors included)?
everything is included, including the screws and stand-offs for the display/control pcb, XLR's, all parts, cable, connectors, pcb for the RS232 remote connection, absolutely everything. You need nothing more.
- as far as I understand, the board accepts balanced connectors but works SE (?), will I benefit from transformers to have a real balanced signal?
The output is impedance balanced for max common mode interference, hum and noise supression. You can use it with XLR as well as RCA (but without the balancing of course). You can use transformers after it, and retain the balanced operation, but why not try it first without xformers? There may be no need for balanced operation; I retained it because some users have power amps with balanced inputs. You need to trade of the extra cost and sound coloration from a xformer against a possible benefit from balanced interconnects.
Jan Didden
130 ohms -> very close to the stock DCX specs!
The range is -60dB to +6dB. That is set in software. +6dB gives 3.4VRMS which should be enough to drive any poweramp to max level. For specific purposes I could set it anywhere between -112db to +22dB. I guess you have a power amp between the DCX and the tweeters, no?
-> I actually don't, tweeters are driven by the DCX; these are high efficiency. Sounds ok to me!
The issue with the level offset is that if you set one at -45dB and the other to +3dB, which is a 48dB difference, you have only 18dB range between -60dB and +6dB, so in that case I can set the larger range for you in the software. But are you sure about that direct connection of the tweeter??
-> Does that mean I can decrease/increase volume by 18db steps? I think I'll take the original settings anyway, the numbers I gave you are a little exaggerated.
The output is impedance balanced for max common mode interference, hum and noise supression. You can use it with XLR as well as RCA (but without the balancing of course). You can use transformers after it, and retain the balanced operation, but why not try it first without xformers? There may be no need for balanced operation; I retained it because some users have power amps with balanced inputs. You need to trade of the extra cost and sound coloration from a xformer against a possible benefit from balanced interconnects.
-> I have a mix of unbalanced and balanced amps, one of each kind.
Thanx
The range is -60dB to +6dB. That is set in software. +6dB gives 3.4VRMS which should be enough to drive any poweramp to max level. For specific purposes I could set it anywhere between -112db to +22dB. I guess you have a power amp between the DCX and the tweeters, no?
-> I actually don't, tweeters are driven by the DCX; these are high efficiency. Sounds ok to me!
The issue with the level offset is that if you set one at -45dB and the other to +3dB, which is a 48dB difference, you have only 18dB range between -60dB and +6dB, so in that case I can set the larger range for you in the software. But are you sure about that direct connection of the tweeter??
-> Does that mean I can decrease/increase volume by 18db steps? I think I'll take the original settings anyway, the numbers I gave you are a little exaggerated.
The output is impedance balanced for max common mode interference, hum and noise supression. You can use it with XLR as well as RCA (but without the balancing of course). You can use transformers after it, and retain the balanced operation, but why not try it first without xformers? There may be no need for balanced operation; I retained it because some users have power amps with balanced inputs. You need to trade of the extra cost and sound coloration from a xformer against a possible benefit from balanced interconnects.
-> I have a mix of unbalanced and balanced amps, one of each kind.
Thanx
kepa1 said:
No, silly ;-)
The volume and balance can be changed in 0.5dB steps. But if the max = +6dB and the min = -60dB, and you have one channel at -45dB and another at +3dB, the RANGE you have available is 18dB. At min level, one is at -60dB and the other is at -12dB; at max level one is at +6dB and the other at -42dB.
Jan Didden
I just found this thread I’m a total newbe and mostly self taught so go easy on me. I have only made it through about 20 pages of this thread so far so this question may have already been answered. If so please point me in the right direction.
So here goes. I am hooking up the DCX2496 to a Sunfire 5200.
My amp specs are:
Input sensitivity for rated output (Balanced): 0.65 vrms
XLR Input impedance 10k each leg balanced to ground.
DCX2496:
XLR Output impedance 160
Output level +22 dbu
I convert 0.65 to dbu and I get -1.5. This leads be to think that I need a 23.5db pad on the DCX outputs to achieve optimum gain structure. Is this correct so far?
For a ‘U’ pad with a 23.5db loss my calculations are:
dbLoss=23.5db
rShunt = 160ohms
rSeries=rShunt*(10^(dbLoss/20)-1 = 2100
rEachleg = rSeries/2 = 1100ohms
Have I got this right? The Impedance to the Amp is only 2260ohms which is far lower than the 20k shown by the amp.
Any help will be greatly appreciated.
Scott
So here goes. I am hooking up the DCX2496 to a Sunfire 5200.
My amp specs are:
Input sensitivity for rated output (Balanced): 0.65 vrms
XLR Input impedance 10k each leg balanced to ground.
DCX2496:
XLR Output impedance 160
Output level +22 dbu
I convert 0.65 to dbu and I get -1.5. This leads be to think that I need a 23.5db pad on the DCX outputs to achieve optimum gain structure. Is this correct so far?
For a ‘U’ pad with a 23.5db loss my calculations are:
dbLoss=23.5db
rShunt = 160ohms
rSeries=rShunt*(10^(dbLoss/20)-1 = 2100
rEachleg = rSeries/2 = 1100ohms
Have I got this right? The Impedance to the Amp is only 2260ohms which is far lower than the 20k shown by the amp.
Any help will be greatly appreciated.
Scott
I think your calculations are right on target.
But the impedance seen by the amp is not 2260. The amp 'sees' the shunt (160) in parallel with 2200, which will be something like 135.
BTW You should stop bragging that you are a newbie. You're ahead of a lot of so-called "pro's" here
Jan Didden
But the impedance seen by the amp is not 2260. The amp 'sees' the shunt (160) in parallel with 2200, which will be something like 135.
BTW You should stop bragging that you are a newbie. You're ahead of a lot of so-called "pro's" here
Jan Didden
Hi Scott,
This is the problem with pro stuff. To get things right you should have less circuitry after the DACs, not more. A good option could be to invest in Jannemans passive outputcard, http://www.linearaudio.nl/Documents/dcx passive article.pdf , as this has the right output levels. Max out directly from the DACs is, if I have done the math right, ca 1,6Vrms balanced. It also has a provision to attenuate the signal to suit your needs on the PCB.
This is the problem with pro stuff. To get things right you should have less circuitry after the DACs, not more. A good option could be to invest in Jannemans passive outputcard, http://www.linearaudio.nl/Documents/dcx passive article.pdf , as this has the right output levels. Max out directly from the DACs is, if I have done the math right, ca 1,6Vrms balanced. It also has a provision to attenuate the signal to suit your needs on the PCB.
After some quick tests with LL1676 at the output and some discussion with a few of you guys, Jan and AR2, I have ordered six Lundahl LL1544A, some Mundorf silver/oil caps and smallparts. Neutrik A and B-series XLR fit directly to the holes in the chassie. Neutrik RCAs needs some minor adjustments to fit.
Will also rebuild my tube-preamp to balanced out, so I go for XLR in but unbalanced RCA out.
As I mostly use analog sources I will not modify the digital parts at this time. Digital input will be placed where the Link ports are now. I will also keep the mic input C to be able to use the auto-align function.
See schematic below:
http://www.eflatjump.se/pre2496H30.pdf
Will also rebuild my tube-preamp to balanced out, so I go for XLR in but unbalanced RCA out.
As I mostly use analog sources I will not modify the digital parts at this time. Digital input will be placed where the Link ports are now. I will also keep the mic input C to be able to use the auto-align function.
See schematic below:
http://www.eflatjump.se/pre2496H30.pdf
revintage said:This question maybe been up before but the thread is to long and I am to lazy.
If fed digitally with a CD-drive: Will the DCX run in 16bit/44.1k mode internally all the way through the processors and into the DACs?
I am not sure, but I believe that DCX will just convert what is given to it. It is not upsampler. SRC would upsample and DEQ would do it if you allow it, so than you could send 24/96 further, but I believe that DCX will just deal with what is given to it. I would appreciate if someone could confirm my reasoning.
Hello to all,
I do not wish to disrupt the current flow of the thread but I have an anomaly on my radar screen that I just can't resolve without some help from the resources of great talent evident on this forum.
I have a dcx2496 and have just recently discovered all the upgrade potential for making improved sound so bear with me for what I don't know. I have decided what modifications I think I want to make but I'm not sure what road to take. From what I've learned in a week's time I want to upgrade the clock, voltage regulation, and the analog output stages. I'm not replacing the power supply just yet and I don't need 6 channel level control.
Currently I use aes input, home made xlr to rca cables on output, and rs-232 for PC control. All my music comes from an XP PC in the form of Flac or Ape audio format played thru M-Audio hardware floating point digital volume control bypassing kmixer.sys using direct kernel streaming. The signal from the M-Audio Delta DIO2496 sound-card's optical output feeds an M-Audio CO3 toslink to aes/ebu converter box which in turn sends the signal to the dcx.
I've narrowed my choices down to two as to what I think is the best route to go. A) The clock/src kit, vreg kit, and passive i/o kit from Pilgham audio website. Or B) The digital input module w/ 24MHz clock kit and I/O board kit from Selectronic.
So to help me decide, I guess the basic question that requires a multi part answer is: What are the advantages and disadvantages of the two choices above? A or B?
I do not wish to disrupt the current flow of the thread but I have an anomaly on my radar screen that I just can't resolve without some help from the resources of great talent evident on this forum.
I have a dcx2496 and have just recently discovered all the upgrade potential for making improved sound so bear with me for what I don't know. I have decided what modifications I think I want to make but I'm not sure what road to take. From what I've learned in a week's time I want to upgrade the clock, voltage regulation, and the analog output stages. I'm not replacing the power supply just yet and I don't need 6 channel level control.
Currently I use aes input, home made xlr to rca cables on output, and rs-232 for PC control. All my music comes from an XP PC in the form of Flac or Ape audio format played thru M-Audio hardware floating point digital volume control bypassing kmixer.sys using direct kernel streaming. The signal from the M-Audio Delta DIO2496 sound-card's optical output feeds an M-Audio CO3 toslink to aes/ebu converter box which in turn sends the signal to the dcx.
I've narrowed my choices down to two as to what I think is the best route to go. A) The clock/src kit, vreg kit, and passive i/o kit from Pilgham audio website. Or B) The digital input module w/ 24MHz clock kit and I/O board kit from Selectronic.
So to help me decide, I guess the basic question that requires a multi part answer is: What are the advantages and disadvantages of the two choices above? A or B?
Seems you have an awful lot of digital stuff in your input chain (I don´t understand much of the digital mumbojumbo you mention) I think the first choice should be to cut down the equipment there. I also have learned that digital volumes are a no-no but I admit I am a novice in this field.
The anolog part of the DCX is the worst so begin with that one.
As you already have narrowed down I would suggest you go for Jans (Pilgham) solution on the output side. It uses the differential outputs from the DACs when used balanced and one when unbalanced. Selectronics uses only one side of the two outputs of the DAC and must be a looked upon as a compromise as it also only have provision for unbalanced.
But.... for my personal taste six Lundahl transformer is the ultimate solution. This is the only passive way to use the differential outputs of the DAC and also to get unbalanced out. Have not compared what happens but it must be better to use both outputs from the DAC. It is an easy fix and there is no problem to find RCAs or XLR chassis-connectors as Neutriks are drop-in replacements. Anyway I am sure you can adopt transformers to Jans card later if you want to upgrade.
The anolog part of the DCX is the worst so begin with that one.
As you already have narrowed down I would suggest you go for Jans (Pilgham) solution on the output side. It uses the differential outputs from the DACs when used balanced and one when unbalanced. Selectronics uses only one side of the two outputs of the DAC and must be a looked upon as a compromise as it also only have provision for unbalanced.
But.... for my personal taste six Lundahl transformer is the ultimate solution. This is the only passive way to use the differential outputs of the DAC and also to get unbalanced out. Have not compared what happens but it must be better to use both outputs from the DAC. It is an easy fix and there is no problem to find RCAs or XLR chassis-connectors as Neutriks are drop-in replacements. Anyway I am sure you can adopt transformers to Jans card later if you want to upgrade.
revintage said:
Lars,
Just a small addition: my active output board uses both phases of the DAC output, balanced, both when you ultimately use the board output balanced or unbalanced. In both cases you have the advantages of noise and distortion cancellation that comes with using the balanced DAC outputs.
Jan Didden
Jan,
I know about the active board solution, but squarewaves asked specifically about A or B, not C .
You are so right that the differential/balanced outputs from the the DACs are an important issue and should always be used.
So for unbalanced either active or, from my point of view the best, transformers must be used.
If going balanced, passive is also an option.
I know about the active board solution, but squarewaves asked specifically about A or B, not C
. You are so right that the differential/balanced outputs from the the DACs are an important issue and should always be used.
So for unbalanced either active or, from my point of view the best, transformers must be used.
If going balanced, passive is also an option.
squarevawes:
Thought about it and isn´t so that it will not help whatever volume control you have before the DACs in the DCX?
I have no insight in the digital domain, but I thought the AKM DACs lost dynamic range as soon as the max signal level was lowered.
This is interesting and as you seem to know, please explain!
Thought about it and isn´t so that it will not help whatever volume control you have before the DACs in the DCX?
I have no insight in the digital domain, but I thought the AKM DACs lost dynamic range as soon as the max signal level was lowered.
This is interesting and as you seem to know, please explain!
Lars,
it's quite simple, I would say: the less bits are used the less resolution you have.
A while ago I tried feeding an analog volume controlled signal into dcx2496 - was great as long volume was high, but was ugly as soon as volume was reduced to night level listening.
I would be surprised if this wouldn't apply to a digital volume controlled signal.
I've done Jan's active analog -> great! both, sound and useability.
I've added 2 Vregs (analog is still one of my sources) -> I'm really impressed you much music was improved by such a 'simple' mod.
Passive PSU and src/clock will be next.
Ulli
Jan,
is there an option to have mute-off when active board is switched on?
it's quite simple, I would say: the less bits are used the less resolution you have.
A while ago I tried feeding an analog volume controlled signal into dcx2496 - was great as long volume was high, but was ugly as soon as volume was reduced to night level listening.
I would be surprised if this wouldn't apply to a digital volume controlled signal.
I've done Jan's active analog -> great! both, sound and useability.
I've added 2 Vregs (analog is still one of my sources) -> I'm really impressed you much music was improved by such a 'simple' mod.
Passive PSU and src/clock will be next.
Ulli
Jan,
is there an option to have mute-off when active board is switched on?