Hi all,
The regulators on the SRC/clock and Vreg PCBs need a minimum voltage of 8.5V to work properly. That's because there are two different regulators in a row to realize the high PSRR @ 10 Hz to 100 kHz.
The original DCX supply has a regulated 9VDC output which works fine. Also any supply built with a 7809 would be OK. Be aware that max current draw is about 500 mA for all DACs and ADCs together.
I assume a supply built with a 7VAC transformer, a bridge rectifier, a cap and no further regulator won't stand a worst case calculation even when using standard 7805 regulators which have a typical dropout voltage of 2-3V.
Here some further fresh ideas for PSU modding for all who use active outputs (opamps). Add two 100µH(~0.5ohm) coils on the +/-15V rails between PSU and DSP to reduce HF noise and use two Hypex +/-12V regulators close to the opamps: http://www.hypex.nl/docs/hxr.pdf I fear it’s nearly impossible to improve this combination.
Frank
The regulators on the SRC/clock and Vreg PCBs need a minimum voltage of 8.5V to work properly. That's because there are two different regulators in a row to realize the high PSRR @ 10 Hz to 100 kHz.
The original DCX supply has a regulated 9VDC output which works fine. Also any supply built with a 7809 would be OK. Be aware that max current draw is about 500 mA for all DACs and ADCs together.
I assume a supply built with a 7VAC transformer, a bridge rectifier, a cap and no further regulator won't stand a worst case calculation even when using standard 7805 regulators which have a typical dropout voltage of 2-3V.
Here some further fresh ideas for PSU modding for all who use active outputs (opamps). Add two 100µH(~0.5ohm) coils on the +/-15V rails between PSU and DSP to reduce HF noise and use two Hypex +/-12V regulators close to the opamps: http://www.hypex.nl/docs/hxr.pdf I fear it’s nearly impossible to improve this combination.
Frank
Ryssen said:
The trafo is 937-02.
I do not know if 9V is regulated or not, but my trouble was that I couldn't use power trafo that you guys are using - which was I believe custom made for various voltages, but 220V. I got the one from Digy Key for 120V that was 2x7V. In that configuration I wasn't getting enough voltages for Frank's board that needs 9V. If you are not using Franks board, than anything is good since 9V is used only to supply enough voltages for 7805 regulators to operate and to supply 5V for DACs and ADCs. That is why Stephane doesn't regulate 9V supply on his board.
And yes, 15V from Stephane's supply will work, but for myself that meant another trafo that I neded to get and to fit in the case. In your case that will be no issue.
You can use a 2x8v transformer without problem. You'll get 9v (around) after the diode/caps. You can try with a 9v transformer but you will need to check if not too high for the digital filter caps (4700uF/10v) and also for the Franck's boards.
Don't forget that transformers are not all the same (quality, loss, etc.). Some printed for 7v, will not give 7v or others will give 8v. I've at home 3 differents 2x15v toroid printed 15v/20va, and each one give a different (loaded) voltage.
Dropout for regulator is often given at full load (2v at 1A for the 7805).
But have you tried if your current transformer works with the psu connected to the dcx AND also with the Franck's board?
.
Don't forget that transformers are not all the same (quality, loss, etc.). Some printed for 7v, will not give 7v or others will give 8v. I've at home 3 differents 2x15v toroid printed 15v/20va, and each one give a different (loaded) voltage.
Dropout for regulator is often given at full load (2v at 1A for the 7805).
But have you tried if your current transformer works with the psu connected to the dcx AND also with the Franck's board?
.
Thank you Stephane,
I will try that since I like your board a lot, but I would need to figure out some transformer that will do all that instead of having two. I would prefer that.
Stay well
AR2
I will try that since I like your board a lot, but I would need to figure out some transformer that will do all that instead of having two. I would prefer that.
Stay well
AR2
Sorry for that but when I ordered the batch of dedicated transformer, I was not thinking that people outside (France, Europe) will like to have it. The 20 transformers are close to be sold out. I'll ask the suppliers how will cost to have 2x120v primary instead of only one 230v.
I tested the small regulator I built (less sophisticated that the Frank's one). Still waiting for the Franck pcb. The noise on the speaker have been lowered (very difficult to ear now, ears slicked to the speaker). I very recommend people to upgrade the 7805 with their preferred low noise mini regulator.
I tested the small regulator I built (less sophisticated that the Frank's one). Still waiting for the Franck pcb. The noise on the speaker have been lowered (very difficult to ear now, ears slicked to the speaker). I very recommend people to upgrade the 7805 with their preferred low noise mini regulator.
Finally found some time to mount the DSP board with Frank's digital input board and the low-noise replacement regulator. The output board is my own active output / level control board, but in RCA version.
My first impression is that this is another step up in sound quality. Not a difference of day and night, but definitely there. The highs are even more clear and, how shall I say, as if cut out with a sharp knife (sorry, I don't know how else to say this). It's sharp and in focus yet not shrill or tiring. Not much difference in the lows I can hear (which was pretty good to begin with!). But there are also imprevements in the mid range. More quiet, more easy, less stress. I have tried several replacement clocks in this unit but this mod is the best I have tried and will stay in! And absolutely no noise from the speakers, even close up.
This was the 2nd DCX I have, which had some intermittent problems with the CS8420 (loss of highs). I'm happy now that these problems are all gone, that alone was worth it.
Summary: a great mod for a very reasonable price, well done Frank!
Pic: the replacement board on the DSP board, the low-noise reg can just be seen at the right behind the existing other reg.
Jan Didden
My first impression is that this is another step up in sound quality. Not a difference of day and night, but definitely there. The highs are even more clear and, how shall I say, as if cut out with a sharp knife (sorry, I don't know how else to say this). It's sharp and in focus yet not shrill or tiring. Not much difference in the lows I can hear (which was pretty good to begin with!). But there are also imprevements in the mid range. More quiet, more easy, less stress. I have tried several replacement clocks in this unit but this mod is the best I have tried and will stay in! And absolutely no noise from the speakers, even close up.
This was the 2nd DCX I have, which had some intermittent problems with the CS8420 (loss of highs). I'm happy now that these problems are all gone, that alone was worth it.
Summary: a great mod for a very reasonable price, well done Frank!
Pic: the replacement board on the DSP board, the low-noise reg can just be seen at the right behind the existing other reg.
Jan Didden
Attachments
Who is this Frank and how do i contact him? I missed about 50 pages in the middle of this thread??
Zc
Zc
Hi Jan,
I'm glad to hear that's not only me who is able to hear some improvement and that it's not all placebo
I was afraid that after Vladimirs threads expectations are too high. It’s not a miracle mod, but based on my personal experience it’s the most valuable after the output mod.
I hate audiophile talking and it’s very hard for me to find the right wording because it’s not my mother tongue. My impression is that frequencies become more accurate. It’s like some sonical mud has gone and you can hear in between. Might be Jan is right that this is true primarily for the highs and mids but I can also hear clear difference when someone e.g. is hitting a base drum. That’s because a base drum is not only a 20Hz signal but a mixture of various frequencies. So my feeling is that even these kind of lows become more realistic. Due to better accuracy also stereo imaging seems to get better. You don’t hear two speakers playing different things but e.g. one voice in the mid between. When listening to music unconscious I sometimes lift my head because I heard a detail which my brain obviously hasn’t heard before. But as already said it’s not a miracle mod.
Hi Zero Cool, it’s me. Please click on the email button down here.
Frank
I'm glad to hear that's not only me who is able to hear some improvement and that it's not all placebo
I was afraid that after Vladimirs threads expectations are too high. It’s not a miracle mod, but based on my personal experience it’s the most valuable after the output mod.
I hate audiophile talking and it’s very hard for me to find the right wording because it’s not my mother tongue. My impression is that frequencies become more accurate. It’s like some sonical mud has gone and you can hear in between. Might be Jan is right that this is true primarily for the highs and mids but I can also hear clear difference when someone e.g. is hitting a base drum. That’s because a base drum is not only a 20Hz signal but a mixture of various frequencies. So my feeling is that even these kind of lows become more realistic. Due to better accuracy also stereo imaging seems to get better. You don’t hear two speakers playing different things but e.g. one voice in the mid between. When listening to music unconscious I sometimes lift my head because I heard a detail which my brain obviously hasn’t heard before. But as already said it’s not a miracle mod.
Hi Zero Cool, it’s me. Please click on the email button down here.
Frank
Hi Oettle,
i would like to email to you also! 🙂
Unfortunately it is not possible for me to send emails, as i haven´t made any posts here before this one - hopefully modes will lift up my "beginners-ban" soon.
Any other option to contact you, if there is possibility to do business..?
BR, tussi
i would like to email to you also! 🙂
Unfortunately it is not possible for me to send emails, as i haven´t made any posts here before this one - hopefully modes will lift up my "beginners-ban" soon.
Any other option to contact you, if there is possibility to do business..?
BR, tussi
Hi tussi,
I think there should be a way that I can send an Email to you. Please edit your user cp -> edit options -> Hide email address: no.
Frank
I think there should be a way that I can send an Email to you. Please edit your user cp -> edit options -> Hide email address: no.
Frank
Impressive mods, AR2! Have you considered running the coax all the way to the input transformer and terminating it properly? I'm not sure how much it really matters, but the extra stretch of ribbon cable, connectors and PCB traces aren't of the good kind.
oettle said:
Frank - Could you also email back to me how to obtain the clock module? I am on noob probation too ;-) Thanks! Tom
Stephane, that would be great...
... if the next batch of custom transformers supported 115v volt primaries. I'd like to upgrade the power supplies of my DEQ and my DCX.
... if the next batch of custom transformers supported 115v volt primaries. I'd like to upgrade the power supplies of my DEQ and my DCX.
novec said:
Thank you Novec,
Yes, I was thinking of going directly to the board, but board is so fragile, and coax cable is rigid and thick (even the one that I got from monster that is about 1/2 the size of regular coax and is very flexible comparing to the typical coax) There is really no room on the board to secure and connect the cable. Even if I connected it, it would most likely lift the trace or damage DSP board in some way first time I would want to do some work on the board. Comparing to what was the layout before the mod, it will now be quite fine with very short run through ribbon cable.
Even that is better than lifted trace off the board.
Ar2
I used a hot glue gun and also a thinner coax cable - has stayed put for years now - even though I move the DSP board out for mods every now and then.
Check
http://esken.net/ergo/dcx2496_spdif_in.html
Ergo
Check
http://esken.net/ergo/dcx2496_spdif_in.html
Ergo
Yes it could be done with much thinner cable, but the only thinner cable I was finding was 50 ohm coax, not 75 ohm (whatever that means).
I'm listening again to my DCX with Frank's digital input mod, comparing it with the other one that has the Tent clock. Frank's mod sound to me better than the other one. Again I noter a more clear and detailed mid/high, but also a better soundstage. Both DCX'es have my modified active output remote level control. The Tent clock in itself did already improve matters but this is another step forward, I presume because it not only replaces the clock but the whole digital input receiver section. And I always thought 'bits is bits'.....
This is a very good mod, almost as good as my own active output mod😀
Jan Didden
This is a very good mod, almost as good as my own active output mod😀
Jan Didden
I am glad that I am not the only one! That is exactly what I noticed - soundstage. Voices are nicely centered and instruments are far on the edges. Even listening the web radio gives different experience! I would say, very important upgrade.
Hi all,
Due to further request I decided to make a final V1.0 version and to produce some more PCBs for the SRC/clock and 5Vreg mods.
I implemented some minor improvements and shrunk the PCB to about ¾ of the previous size.
To simplify installation the single wires for the SMD connector are replaced by only one pin header.
The SRC/clock mod includes the following mods plus improved power supplies (2++ in 1 mod).
Main features are: 1. Fixed problems of CS8420 (dull sound), 2. Improved 2nd generation SRC and 3. Low jitter (0.5ps) synchronous master clock (for DACs, DSP, SRC and PLL).
http://freerider.dyndns.org/anlage/Behringer-Input-Stage-E.htm
http://www.dcx2496.fr/upsamp.php
http://www.tentlabs.com/Components/XO/index.html
http://www.dcx2496.fr/selectro3.php
The 5Vreg mod is a high PSRR (>>100dB@10Hz-100kHz) and low noise (18µV) voltage regulator for the DAC and ADC devices which replaces the on-board 7805 regulators (IC7:ADCs and IC8😀ACs).
The picture shows DCX-DSP board (blue) with SMD connector (and pin header) assembled instead of CS8420. You also see two SRC/clock PCBs and two 5Vreg PCBs (both sides each).
Frank
PS: Vladimirs pictures are much better. Do you have an idea of an optical mod?
😉
Due to further request I decided to make a final V1.0 version and to produce some more PCBs for the SRC/clock and 5Vreg mods.
I implemented some minor improvements and shrunk the PCB to about ¾ of the previous size.
To simplify installation the single wires for the SMD connector are replaced by only one pin header.
The SRC/clock mod includes the following mods plus improved power supplies (2++ in 1 mod).
Main features are: 1. Fixed problems of CS8420 (dull sound), 2. Improved 2nd generation SRC and 3. Low jitter (0.5ps) synchronous master clock (for DACs, DSP, SRC and PLL).
http://freerider.dyndns.org/anlage/Behringer-Input-Stage-E.htm
http://www.dcx2496.fr/upsamp.php
http://www.tentlabs.com/Components/XO/index.html
http://www.dcx2496.fr/selectro3.php
The 5Vreg mod is a high PSRR (>>100dB@10Hz-100kHz) and low noise (18µV) voltage regulator for the DAC and ADC devices which replaces the on-board 7805 regulators (IC7:ADCs and IC8😀ACs).
The picture shows DCX-DSP board (blue) with SMD connector (and pin header) assembled instead of CS8420. You also see two SRC/clock PCBs and two 5Vreg PCBs (both sides each).
Frank
PS: Vladimirs pictures are much better. Do you have an idea of an optical mod?
😉
Attachments
Frank
I am also a total nuB here also and cannot send email. I have a DCX and ordered Jans active kit.
I am very intrigued by your mods. Please contact me via my email
Thanks
Carlton
I am also a total nuB here also and cannot send email. I have a DCX and ordered Jans active kit.
I am very intrigued by your mods. Please contact me via my email
Thanks
Carlton