Frank
You re quite right. In the course of removing and reinstalling the VReg, I created a problem with the solder on the output pin. It is now properly connected to the 3.9K resistor. Fixing that gives an output of 4.9V instead of 5.7V and pin 3 on the BC517 of 5.8V instead of 5.9V. All other values are the same.
Thank you for your input.
Todd
You re quite right. In the course of removing and reinstalling the VReg, I created a problem with the solder on the output pin. It is now properly connected to the 3.9K resistor. Fixing that gives an output of 4.9V instead of 5.7V and pin 3 on the BC517 of 5.8V instead of 5.9V. All other values are the same.
Thank you for your input.
Todd
janneman said:So, now my DCX2496 has my active output/volume control board, Frank's digital input and +5V analog reg mods, and the replacement linear supply. And each step was an improvement. So, what should I do next?
Jan Didden
I haven't been here for a while, and look all this great activity! Congrats Jan, it is a great feel having it all done. I was very happy to hear that there is not much difference between modified DCX and stock DEQX. My feeling is that it will take a lot to beat modified DCX even for standalone DACs. Than if you think that we have three DACs ...
For your next project - few suggestions: Tube analog balanced output (this will take you a while) or switchable digital outs so you could plug any other DACs.
Enjoy!
ergo said:When I get it I will surely poke around inside DCX as I have wanted to "see above 45kHz" for a long time. It would be really interesting to see what is going on on power supply lines and also what sort of "crap" the DAC outputs in addition to audio signal. All this can hopefully lead to some new tweak ideas also
Ergo
Great idea - I am all ears, waiting for another great ErgoReport. I think there is a big mystery of what is coming out of DACs in terms of HF garbage. How much filtering is really needed ?
Stay well
AR2
Yes, all is fine. Just been more occupied with other things... work, kids, house. But also once I was done with my DCX I got the same dilemma - what now? Realistically, the sound coming out from DCX is so good that it discourages you to change anything, but that feels weird to me
That situation best describes my personallity - It is nice to be there, whatever goal I set, but once I am there I realized that I have enjoyed much more going there than being there.
By the way, great article in AudioXpress
That situation best describes my personallity - It is nice to be there, whatever goal I set, but once I am there I realized that I have enjoyed much more going there than being there.
By the way, great article in AudioXpress
AR2 said:Yes, all is fine. Just been more occupied with other things... work, kids, house. But also once I was done with my DCX I got the same dilemma - what now? Realistically, the sound coming out from DCX is so good that it discourages you to change anything, but that feels weird to me
That situation best describes my personallity - It is nice to be there, whatever goal I set, but once I am there I realized that I have enjoyed much more going there than being there.
By the way, great article in AudioXpress
Yes, it's the journey that is the reward
Jan Didden
kepa1 said:
Very true and very Buddhist bye the way,
Ha, that would be me, only considering my roots clinched between Greek and Roman cultures, strongly leaning toward peaceful Greeks currently seeded in hippie birthplace of San Francisco. Now, with contemporary linguistics locals would call this mental profiling.
For those who asked about my linear supply for DCX2496 : I have just finished the construction guide and put it on my site. Pilgham Audio has kits available including the custom transformer.
Jan Didden
Jan Didden
Just finished Jan's active output/preamp board and I am quite pleased with the sound improvements it gives, including:
* Improved Dynamics
* Reduced 'grain' in the sound
* Tighter bass
* improved 'air'
* improved detail
* oh yeah and did I say remote volume!
It hasn't been transformed into a high end killing machine but even if you include the price of
the original DCX and the cost of the kit, there is still nothing to touch it IMHO for the money.
The only other (-ive) points were:
* Slight tonal change (esp on the analog inputs) which took a bit of getting used to.
* No input buffer for the analog C input.
* not ideal for the first time builder, making the IDC cables and the high component density made the legend difficult and hence pick correct component placement.
But all in all a positive move and worth the effort.
* Improved Dynamics
* Reduced 'grain' in the sound
* Tighter bass
* improved 'air'
* improved detail
* oh yeah and did I say remote volume!
It hasn't been transformed into a high end killing machine but even if you include the price of
the original DCX and the cost of the kit, there is still nothing to touch it IMHO for the money.
The only other (-ive) points were:
* Slight tonal change (esp on the analog inputs) which took a bit of getting used to.
* No input buffer for the analog C input.
* not ideal for the first time builder, making the IDC cables and the high component density made the legend difficult and hence pick correct component placement.
But all in all a positive move and worth the effort.
IMSTOOPID: Before I say anything I’d just like to make it clear that in no way did any aspect of the sound after the upgrade was ‘worse’.
From my small experience in modify equipment, the sound only seems to change slightly, such as improved detail. But with this mod the ‘tone’ of the DCX has changed. I guess because the analog section has been completely changed and as I don’t have another DCX so I can’t do an AB comparison. If I had to take a wild guess I would say it sounds less ‘forward/pushy’ because the ‘grain’ in the sound has been greatly reduced, so this would be noticeable on any of the mods that remove the original input/output section.
I now no longer use the analog input for my music listening because of the built-in preamp facilities in Jan’s kit and have moved to the digital input. The analog input will now only be used for AV use, where (to me) the sound quality is less critical.
From my small experience in modify equipment, the sound only seems to change slightly, such as improved detail. But with this mod the ‘tone’ of the DCX has changed. I guess because the analog section has been completely changed and as I don’t have another DCX so I can’t do an AB comparison. If I had to take a wild guess I would say it sounds less ‘forward/pushy’ because the ‘grain’ in the sound has been greatly reduced, so this would be noticeable on any of the mods that remove the original input/output section.
I now no longer use the analog input for my music listening because of the built-in preamp facilities in Jan’s kit and have moved to the digital input. The analog input will now only be used for AV use, where (to me) the sound quality is less critical.
From a technical point, I can give at least two reasons for the change in the analog input.
- In the stock situation, the analog input signals goes through 3 not-so-hot opamps. In my active mod, that trio has been replaced by a single very high performance fully balanced opamp (OPA1632);
- In the stock situation, Behringer slightly rolls UP the mid/high frequencies (up to +6dB at 20kHz) as shown in the simulator pic. I don't know why, possibly to improve the subjective 'presence'. For me it sounded a bit unnatural, though. My new analog input is ruler flat.
Jan Didden
- In the stock situation, the analog input signals goes through 3 not-so-hot opamps. In my active mod, that trio has been replaced by a single very high performance fully balanced opamp (OPA1632);
- In the stock situation, Behringer slightly rolls UP the mid/high frequencies (up to +6dB at 20kHz) as shown in the simulator pic. I don't know why, possibly to improve the subjective 'presence'. For me it sounded a bit unnatural, though. My new analog input is ruler flat.
Jan Didden
Attachments
The in stock situation also has some Cs in the output section (e.g. 220p || 2k32 at IC1B). I didn't do a simulation - just a guess: could be a kind of preemphasis (just do have some more bits & less noise in a range with usually lower levels).
This theory doesn't fit well to the obeserved balancing problems... hmmm...
Ulli