AndrewT said:
I stupidly assumed the OP meant that the noise appeared when the laptop was plugged into the DCX (as in the RS232 cable). If that is not the case I find that rather odd. I suppose all systems are different.
Bricolo said:
There was reports of the 'egg-frying' sound on these. It was directly attributed to the crappy ribbon cable between the DSP and IO boards. A simple replacement, apparently, is a proven fix. This appears to have manifested itself on units that were manufactured before the major shortage recently.
See this topic for more info
Thanks
Gert
What I meant was that if I plug my laptop's switching power supply into the outlet, I hear considerably more noise coming out of the DCX. My laptop's power supply is probably pretty darn noisy. On the other hand without the DCX, I do not detect any audible inceases in noise, so the power supplies of my B&K units filter the noise out considerably better (which I would hope considering their price difference).
Anyway, the noise was not a real problem as it is non audible during music playback.
Philip
Anyway, the noise was not a real problem as it is non audible during music playback.
Philip
Selling his DCX
It is normal for passive speaker designers to tweak the crossover to hide the drivers' weaknesses. You probably failed to do this with your DCX. However, the DCX has the potential to do this better than the passive crossover. However, you need to fully analyse and understand your individual driver units and the bass system (driver and cabinet).
I noticed you used room eq software, what frequency response did you aim for.... flat? That would not sound good. You need to understand what you want. Look again at the room eq your passive crossover provides. Is that what you want?
It is up to you if you have given up. We only have a certain amount of time for our hobbies. But the DCX would certainly overtake the passive crossover if done properly. However, that is no guarantee you would prefer it, even when outperforming the passive. It is simply a fact that many audiophiles prefer the sound of lesser performing systems.
pgruebele said:
It is normal for passive speaker designers to tweak the crossover to hide the drivers' weaknesses. You probably failed to do this with your DCX. However, the DCX has the potential to do this better than the passive crossover. However, you need to fully analyse and understand your individual driver units and the bass system (driver and cabinet).
I noticed you used room eq software, what frequency response did you aim for.... flat? That would not sound good. You need to understand what you want. Look again at the room eq your passive crossover provides. Is that what you want?
It is up to you if you have given up. We only have a certain amount of time for our hobbies. But the DCX would certainly overtake the passive crossover if done properly. However, that is no guarantee you would prefer it, even when outperforming the passive. It is simply a fact that many audiophiles prefer the sound of lesser performing systems.
I can only say that I 100% believed what you are saying and still do so for DIY projects. All digital seems to be the way to go. I analyzed the frequency response of the passive and active crossover setup and tried to make them as close as possible. I'm no analog expert, but now I think that the passive crossover components can affect more than just the frequency response. Transients and dynamics could also be affected and this is not measured... Of course we all know that the technically "perfect" system does not necessarily sound better. In the end I can only say that I tried REALLY hard to make it sound better and REALLY believed that it should. Although it did sound slightly different, it was not better by enough to be worthwhile. I use my system for surround and stereo and no processors seem to put out front L/R PCM from a DTS/DD input. To make this all work seamlessly I would have had to hack my preamp to extract Front LR PCM from the DACs in order to feed the DCX (ironically they are the same AK4393 DACs). This was just not worthwhile...
I am now switching from a B&K Ref 30 preamp to a Primare SP31.7. Someone else who made the same switch had large increases in sound quality. It's a lot of money but we must sacrifice in the search for audio nirvana
Wish me luck.
Philip
I am now switching from a B&K Ref 30 preamp to a Primare SP31.7. Someone else who made the same switch had large increases in sound quality. It's a lot of money but we must sacrifice in the search for audio nirvana
Wish me luck.
Philip
Hi to all DCX2496 owners,
Is there anybody who is interested in the Oehlbach mod:
http://freerider.dyndns.org/anlage/Behringer-Input-Stage-E.htm
I bought 4 of them, 2 for a friend of mine and 2 for me. Due to a misunderstanding my friend doesn’t want to have the mods any more. So there are two left. I’m pretty happy with the mod. You can hear noticeably more details.
The price for one PCB plus all components is 75 Euro. Assembled and tested you can have one mod for 85 Euro plus shipping costs.
Please send me an Email when you are interested.
Is there anybody who is interested in the Oehlbach mod:
http://freerider.dyndns.org/anlage/Behringer-Input-Stage-E.htm
I bought 4 of them, 2 for a friend of mine and 2 for me. Due to a misunderstanding my friend doesn’t want to have the mods any more. So there are two left. I’m pretty happy with the mod. You can hear noticeably more details.
The price for one PCB plus all components is 75 Euro. Assembled and tested you can have one mod for 85 Euro plus shipping costs.
Please send me an Email when you are interested.
Oehlbach PCB
Thank for your news about the Oelbach PCB offer Oettle! Are you happy with the way the Oehlbach modification sounds in your system?
I would be interested in your Oelbach PCB mod in its assembled and tested state. Please PM me to let me know if you have any of the PCB left.
Craig Goff
Camarillo, CA
USA
Thank for your news about the Oelbach PCB offer Oettle! Are you happy with the way the Oehlbach modification sounds in your system?
I would be interested in your Oelbach PCB mod in its assembled and tested state. Please PM me to let me know if you have any of the PCB left.
Craig Goff
Camarillo, CA
USA
I have finally finished reading all 108 pages of this thread. My friend and I have each purchased DCX2496's for the purpose of loudspeaker measurement and crossover design. I am more electronically inclined than he is and have read with great interest the mods available. The one hting I have gained from reading this whole thread is that matching levels at input and output is critical for good SQ from this unit. I also cannot see spending more than I paid for the unit in mods. So I have decided that for the input the Canare transformer will work well for feeding a digital signal into the unit. The passive modifications described here are what I am going to pursue as far as taking care of the output section. I don't need balanced outputs so SE is OK. I have acquired a 6 section Alps motorized pot that I will build into an interface box to control the level post 2496. That takes care of the hardware end of it. Now I have to learn how to emulate crossovers with it. Thanks ofr all the work you have all done.
Chuck
Chuck
DCX update
Hi All,
Just want to report something that I feel is important to users of this group.
A while back I made some posts explaining that I stopped using the DCX because for all the trouble it did not give me sufficient sound quality improvementl. I was using the DCX through a sevel channel B&K 200.7 amp to drive my speakers. This is supposed to be an excellent amp although it is not a monoblock design. I thought it would be perfect for the DCX and my speakers.
After stopping DCX use I recently upgraded to B7K 200.1 monoblock amps and they made a HUGE difference in my system. The sound stage is much deeper and wider. The monoblock design allows each speaker to be driven more accurately since there is no crosstalk between amp channels. I believe that better phase coherence is making the sound stage much deeper.
Anyway, in conclusion, I cannot stress the use of the amp enough. Based on my experience, if you want good sound you might be better off using 2 monoblock amps with passive crossover instead of DCX with a 6 channel amp. Therefore, if you go the DCX route, and you actually want better sound than what you can achieve with passives, you really need to use monoblock amps! I know a lot of people use pro-series mono amps so they are OK.
I hope this realization, although obvious to some, will help other...
Philip
Hi All,
Just want to report something that I feel is important to users of this group.
A while back I made some posts explaining that I stopped using the DCX because for all the trouble it did not give me sufficient sound quality improvementl. I was using the DCX through a sevel channel B&K 200.7 amp to drive my speakers. This is supposed to be an excellent amp although it is not a monoblock design. I thought it would be perfect for the DCX and my speakers.
After stopping DCX use I recently upgraded to B7K 200.1 monoblock amps and they made a HUGE difference in my system. The sound stage is much deeper and wider. The monoblock design allows each speaker to be driven more accurately since there is no crosstalk between amp channels. I believe that better phase coherence is making the sound stage much deeper.
Anyway, in conclusion, I cannot stress the use of the amp enough. Based on my experience, if you want good sound you might be better off using 2 monoblock amps with passive crossover instead of DCX with a 6 channel amp. Therefore, if you go the DCX route, and you actually want better sound than what you can achieve with passives, you really need to use monoblock amps! I know a lot of people use pro-series mono amps so they are OK.
I hope this realization, although obvious to some, will help other...
Philip
Re: Using a pair of DCX2496 together
Hi tnargs,
I had the same problem and I purchased a ready made box
that I've tested for the last 6 months as part of a new stereo I'm in the middle of designing.
http://www.henryeng.com/hedigimatch.html
I thought it cost ~250-275 bucks but in my app it was worth it.
It does all of the proper loading required perfectly.
I feed it a 24/48 s/pdif signal and it will support up to
three independent AES/EBU outputs.
It can be matrixed multiple ways as well. Good luck with your projects.
tnargs said:
Hi tnargs,
I had the same problem and I purchased a ready made box
that I've tested for the last 6 months as part of a new stereo I'm in the middle of designing.
http://www.henryeng.com/hedigimatch.html
I thought it cost ~250-275 bucks but in my app it was worth it.
It does all of the proper loading required perfectly.
I feed it a 24/48 s/pdif signal and it will support up to
three independent AES/EBU outputs.
It can be matrixed multiple ways as well. Good luck with your projects.
World première, Selectronic mod repport
In case if some of you guys are not subscribed to the Yahoo DCX group I posted that and the follow up :
Hi DCX owners and groupies. I want to share my experience with the assemblage of the Selectronic I/O and analogue supply boards. Please excuse my basic English, it is my third language. My comments are for the French version of the documentation.
A little bit of background so you can better judge my comments. I would qualify myself as an intermediate DIY guy but do not know a lot about modern electronics. I have built my own tube SET amplifiers and tweaked some amplifiers and CDP. I've also tweaked my DCX.
I installed a Tentlabs clock, some BG capacitors in the power supply and replaced DAC's decoupling caps with os-con ones. I`ve installed a passive output mod à la T. Martin with first order filter (r = 900 ohm) and DC blocking audiophile caps. The last tweak was a 6x10 k gang Alps potentiometer. Of course all these tweaks have improved the sound a lot, but you know this is a hobby….
I bought the Selectronic boards because I wanted the I/O tweaks to look more professional and maybe sound better with the new analogue PS. I hoped also to obtain some gain on the signal strength due to the summing of both halves of the signal.
As you know the Selectronic boards are not cheap. I paid around 200 euros including shipping to Canada. The PCB seems to be of good quality but I'm not an expert. The kit is nicely packed and comes with some documentation. Components are of good quality ex 1% resistors, mica capacitors, BB opamps etc. Some parts were missing like cables and adhesive pads (minor but annoying).
This is my first experience with a kit so I cannot compare but I must say that though I assembled it I didn't liked "the making off".
This kit is not for beginners. You have to know at least the basic of electronics, the parts identification, soldering (opamps!) and be rather a wise guy because you have to handle the lack of clear instructions.
The main problem is the poor documentation. I will have a lot to say but will limit myself to some examples:
the list of components furnished is for the complete kit (with analogue inputs) so it is impossible to verify if the kit is complete if ones bought the basic version;
the schematic is not supplied;
the implementation scheme is supplied but only the numbers of the parts are given ex R107; the value are only written in the parts list; BTW the PS board is supplied with the opposite the values are given on the implementation drawing, confusing;
the parts numbers are not printed on the PCB, the right place has to be found following the pictures (color) or the implementation scheme, it is very painful to find the right position at the beginning and I made some mistakes (I love to desolder !). Some dozens of holes on the PCB are not used. Not easy.
despite the two voltage regulators used on the board no instructions are given for some voltage verification on finished board. You have to solder and pray!
no information about the output voltage levels, input or output impedances, not a word of the DC offset. There is an option with BG blocking caps but nothing is explained.
What I disliked most was the feeling of being treated like a semi intelligent monkey. You have to follow the pictures and don't have the right to know what you are doing. The reverse engineering is of course possible but I would much prefer to be fully informed for 200 euros! You follow me guys: I'm not saying that it is a bad product but I was expecting more.
I just finished the assemblage and haven't installed the boards in the DCX yet. I will post a follow-up as soon as the boards are functional.
Chris
In case if some of you guys are not subscribed to the Yahoo DCX group I posted that and the follow up :
Hi DCX owners and groupies. I want to share my experience with the assemblage of the Selectronic I/O and analogue supply boards. Please excuse my basic English, it is my third language. My comments are for the French version of the documentation.
A little bit of background so you can better judge my comments. I would qualify myself as an intermediate DIY guy but do not know a lot about modern electronics. I have built my own tube SET amplifiers and tweaked some amplifiers and CDP. I've also tweaked my DCX.
I installed a Tentlabs clock, some BG capacitors in the power supply and replaced DAC's decoupling caps with os-con ones. I`ve installed a passive output mod à la T. Martin with first order filter (r = 900 ohm) and DC blocking audiophile caps. The last tweak was a 6x10 k gang Alps potentiometer. Of course all these tweaks have improved the sound a lot, but you know this is a hobby….
I bought the Selectronic boards because I wanted the I/O tweaks to look more professional and maybe sound better with the new analogue PS. I hoped also to obtain some gain on the signal strength due to the summing of both halves of the signal.
As you know the Selectronic boards are not cheap. I paid around 200 euros including shipping to Canada. The PCB seems to be of good quality but I'm not an expert. The kit is nicely packed and comes with some documentation. Components are of good quality ex 1% resistors, mica capacitors, BB opamps etc. Some parts were missing like cables and adhesive pads (minor but annoying).
This is my first experience with a kit so I cannot compare but I must say that though I assembled it I didn't liked "the making off".
This kit is not for beginners. You have to know at least the basic of electronics, the parts identification, soldering (opamps!) and be rather a wise guy because you have to handle the lack of clear instructions.
The main problem is the poor documentation. I will have a lot to say but will limit myself to some examples:
the list of components furnished is for the complete kit (with analogue inputs) so it is impossible to verify if the kit is complete if ones bought the basic version;
the schematic is not supplied;
the implementation scheme is supplied but only the numbers of the parts are given ex R107; the value are only written in the parts list; BTW the PS board is supplied with the opposite the values are given on the implementation drawing, confusing;
the parts numbers are not printed on the PCB, the right place has to be found following the pictures (color) or the implementation scheme, it is very painful to find the right position at the beginning and I made some mistakes (I love to desolder !). Some dozens of holes on the PCB are not used. Not easy.
despite the two voltage regulators used on the board no instructions are given for some voltage verification on finished board. You have to solder and pray!
no information about the output voltage levels, input or output impedances, not a word of the DC offset. There is an option with BG blocking caps but nothing is explained.
What I disliked most was the feeling of being treated like a semi intelligent monkey. You have to follow the pictures and don't have the right to know what you are doing. The reverse engineering is of course possible but I would much prefer to be fully informed for 200 euros! You follow me guys: I'm not saying that it is a bad product but I was expecting more.
I just finished the assemblage and haven't installed the boards in the DCX yet. I will post a follow-up as soon as the boards are functional.
Chris
Attachments
Selectronic mod, part 2, conclusion
This is the part 2 as posted on yahoo group forum:
Hello anybody. After two days of intense work I finished the implementation of the Selectronic cards – I/O and analogue PS. A lot work to do since the DCX must be taken completely to pieces. I insist: this is not a beginner kit. I had some apprehensions (see my previous post) about the rightness of my assemblage since it is not easy to verify it without installing it in the DCX.
I put everything in the chassis, soldered the last supply connections and fired the power switch – not connected to the amps of course. No explosion, no smoke, no noise, the only apparent glitch: the C input shows a full strength signal. I made some checks and one of the decoupling capacitors was soldered in the wrong position (exactly like on the photo, thanks Selectronic for the clear instructions !), both legs were connected to ground. I switched it but it hasn't changed anything. I will have to take the whole card out to verify but don't know where to start.
Despite this bug I decided to install it in my system. First I had to modify my cables which were XLR to RCA since the card uses RCA connectors. I tried first on the midband amplifier and it worked, the sound came from the speakers. In fact all 6 channels worked. Alleluia ;-), it was Easter after all.
I know that everyone is dying to hear about the sound and can not retain myself:
THIS IS A MAJOR UPGRADE. The sound is very good, much better than I expected. All of you know that very often the tweaks or even new components make some changes which are on the threshold of the perception and how the "happy father" or placebo syndromes can be powerful. But I swear the difference is huge compared to stock unit (I have one) and my previously tweaked one with passive but single ended mod. There is more of everything in the sound. The biggest improvement is RESOLUTION. Now the DCX really sounds like a very good DAC. The sound is very vivid, live like (I use high efficiency horns). Improvements are particularly clear I the mids (voices) and highs maybe less in the bass (this can be an issue of impedance matching with my amplifier).
I cannot tell the part due to the PS but both the I/O card and the PS should be used together.
Congratulation to the Selectronic team and last but not least the enthusiastic participation of Thierry Martin who started these mods. Thanks guys.
Chris
PS : Somebody has an idea what is the problem with the C input? BTW I discovered another one the RS 485 link seems not work.
This is the part 2 as posted on yahoo group forum:
Hello anybody. After two days of intense work I finished the implementation of the Selectronic cards – I/O and analogue PS. A lot work to do since the DCX must be taken completely to pieces. I insist: this is not a beginner kit. I had some apprehensions (see my previous post) about the rightness of my assemblage since it is not easy to verify it without installing it in the DCX.
I put everything in the chassis, soldered the last supply connections and fired the power switch – not connected to the amps of course. No explosion, no smoke, no noise, the only apparent glitch: the C input shows a full strength signal. I made some checks and one of the decoupling capacitors was soldered in the wrong position (exactly like on the photo, thanks Selectronic for the clear instructions !), both legs were connected to ground. I switched it but it hasn't changed anything. I will have to take the whole card out to verify but don't know where to start.
Despite this bug I decided to install it in my system. First I had to modify my cables which were XLR to RCA since the card uses RCA connectors. I tried first on the midband amplifier and it worked, the sound came from the speakers. In fact all 6 channels worked. Alleluia ;-), it was Easter after all.
I know that everyone is dying to hear about the sound and can not retain myself:
THIS IS A MAJOR UPGRADE. The sound is very good, much better than I expected. All of you know that very often the tweaks or even new components make some changes which are on the threshold of the perception and how the "happy father" or placebo syndromes can be powerful. But I swear the difference is huge compared to stock unit (I have one) and my previously tweaked one with passive but single ended mod. There is more of everything in the sound. The biggest improvement is RESOLUTION. Now the DCX really sounds like a very good DAC. The sound is very vivid, live like (I use high efficiency horns). Improvements are particularly clear I the mids (voices) and highs maybe less in the bass (this can be an issue of impedance matching with my amplifier).
I cannot tell the part due to the PS but both the I/O card and the PS should be used together.
Congratulation to the Selectronic team and last but not least the enthusiastic participation of Thierry Martin who started these mods. Thanks guys.
Chris
PS : Somebody has an idea what is the problem with the C input? BTW I discovered another one the RS 485 link seems not work.
