No filter
I install AK4395 or AK4396 dac chip and run with no filter to keep the output impedance low. Just a high quality coupling cap. Sounds better with no filter.
I install AK4395 or AK4396 dac chip and run with no filter to keep the output impedance low. Just a high quality coupling cap. Sounds better with no filter.
Hy!
I started to modify to my deq2496. I killed the analog power line from the original psu. The original psu just give the 3,3V and the 5V to digital circuits. Both digital power line has got new bigger caps. Replaced the original two 1000uF and the two 470 uF to four 2200 uF.
The new analog psu have two traditional transformers. One is for the +/- 15V opamp power, and one is for the DACs and ADCs analog 5V power.
Every tansformer have dedicated rectifier bridge and many big buffer elkos. The original 7805 which was on the main panel, jumped out to the heatsink around the psu with the 7815 and 7915.
The two analog devices chip, and the ADC chip has got som extra heatsink, because their temperature was high.
This is the current state!
I will rebuild the total analog and digital inputs and outputs. The original backboard put the trash, except the RTA/MIC input and the auxiliary input, because this part is cut out of it!😀
I'll be back soon!
I started to modify to my deq2496. I killed the analog power line from the original psu. The original psu just give the 3,3V and the 5V to digital circuits. Both digital power line has got new bigger caps. Replaced the original two 1000uF and the two 470 uF to four 2200 uF.
The new analog psu have two traditional transformers. One is for the +/- 15V opamp power, and one is for the DACs and ADCs analog 5V power.
Every tansformer have dedicated rectifier bridge and many big buffer elkos. The original 7805 which was on the main panel, jumped out to the heatsink around the psu with the 7815 and 7915.
The two analog devices chip, and the ADC chip has got som extra heatsink, because their temperature was high.
This is the current state!
I will rebuild the total analog and digital inputs and outputs. The original backboard put the trash, except the RTA/MIC input and the auxiliary input, because this part is cut out of it!😀
I'll be back soon!
Attachments
Very interesting kalmi79.
Look forward to your updates as you venture into modding the DEQ2496!
🙂
Look forward to your updates as you venture into modding the DEQ2496!
🙂
Awesome! Soooo... How about a schematic for the less gifted. I need to replace a blown PS in one of my DEQs.
Thanks tony
Thanks tony
Using DAC output through a coupling capacitor is a fairly common audio mod
Hi,
Just a couple of comments upon carefully reviewing this thread.
The idea of taking the output from a DAC directly through an output capacitor is a fairly common and successful audio mod.
It was initially known in 2004 as the 'Swenson' mod and can be found at a link on Page 2 of the included Squeezebox Mods Detail.doc which is contained in the attached SBox Mod Detail Word97 doc + Audio Pass Calcs Excel97.zip file.
There was a lot of discussion of this when the Slimserver Squeezebox V2 first appeared. The general consensus was that the DAC output capacitor bypass was a reasonably useful audio quality improvement. The attached zip file reports on my experience doing that mod. That attached zip file also usefully contains an Excel spreadsheet called High Pass Filter.xls which shows that for a 50K Ohm input amplifier even a 0.47 microFarad cap should work reasonably well.
Some of the links in the above document no longer work. Thus, also attached as squeeze audio mod overall view .jpg and slim install closeup high resolution.jpg are what that particular DAC output bypass looked like.
There does not appear to be any reason why the same kind of DAC output capacitor bypass would not conceptually work equally well with the DEQ2496.
Regards,
Dick
Hi,
Just a couple of comments upon carefully reviewing this thread.
The idea of taking the output from a DAC directly through an output capacitor is a fairly common and successful audio mod.
It was initially known in 2004 as the 'Swenson' mod and can be found at a link on Page 2 of the included Squeezebox Mods Detail.doc which is contained in the attached SBox Mod Detail Word97 doc + Audio Pass Calcs Excel97.zip file.
There was a lot of discussion of this when the Slimserver Squeezebox V2 first appeared. The general consensus was that the DAC output capacitor bypass was a reasonably useful audio quality improvement. The attached zip file reports on my experience doing that mod. That attached zip file also usefully contains an Excel spreadsheet called High Pass Filter.xls which shows that for a 50K Ohm input amplifier even a 0.47 microFarad cap should work reasonably well.
Some of the links in the above document no longer work. Thus, also attached as squeeze audio mod overall view .jpg and slim install closeup high resolution.jpg are what that particular DAC output bypass looked like.
There does not appear to be any reason why the same kind of DAC output capacitor bypass would not conceptually work equally well with the DEQ2496.
Regards,
Dick
Attachments
Hello:
First, say sorry for resurrect this old thread, but I need some help.
I would like to make a capacitors upgrade on the DSP board (AKM chips, etc). I have several Sanyo OSCON SEPC 470uf 16V in my drawer. Do they have too much capacitance? The actual DSP capacitors are 10uf.
Would I have some problem with the experiment?
I'm new in the DIY, so sorry if the question it's very basic.
Best Regards
First, say sorry for resurrect this old thread, but I need some help.
I would like to make a capacitors upgrade on the DSP board (AKM chips, etc). I have several Sanyo OSCON SEPC 470uf 16V in my drawer. Do they have too much capacitance? The actual DSP capacitors are 10uf.
Would I have some problem with the experiment?
I'm new in the DIY, so sorry if the question it's very basic.
Best Regards
DEQ2496
Hi
Excuse me for just hopping in here, I need some advice:
The Didden article describes a balanced output.
I've read as much as I can on the direct output mod: For single ended output, do I put a series cap in the +ve output and use it as the centre contact of the RCA socket, and the -ve as the sleeve? I imagine the RCA sleeve must be insulated from the chassis.
Is is necessary to put a capacitor on both +ve and -ve wires, or just one (+ve).
Alternatively, how would one use the Didden circuit for single ended output?
Thank you.
Hi
Excuse me for just hopping in here, I need some advice:
The Didden article describes a balanced output.
I've read as much as I can on the direct output mod: For single ended output, do I put a series cap in the +ve output and use it as the centre contact of the RCA socket, and the -ve as the sleeve? I imagine the RCA sleeve must be insulated from the chassis.
Is is necessary to put a capacitor on both +ve and -ve wires, or just one (+ve).
Alternatively, how would one use the Didden circuit for single ended output?
Thank you.
No. Just use one leg for output. The RCA outer conductor is always audio ground. I let the other leg float open or you can cap couple it to ground through a 20k resistor if you think that is better
Hi Scott
Thank you. I have some big, old 6uF oil caps that I plan on using. May even try a transformer output - I have a pair in an old studio phono stage that has balanced outs.
Thank you. I have some big, old 6uF oil caps that I plan on using. May even try a transformer output - I have a pair in an old studio phono stage that has balanced outs.
I run transformer output and love it. I can swap between Onetics, Cinemag, Altec, Edcor, Sowter and Jensen if I want.
If you use a transfo out of a phono stage, be sure it's a 1:1 or close. Also be sure that it can handle line level without distortion. It will be fairly large if it can.
If you use a transfo out of a phono stage, be sure it's a 1:1 or close. Also be sure that it can handle line level without distortion. It will be fairly large if it can.
I'll post pics of my output transformers later. They will be salvaged off a phono stage that has transformer-coupled balanced outputs.
Studer. size approx. 30mm x 25mm x 20mm - unpotted.
I hope you guys can assist with the other required components once I get started.
Studer. size approx. 30mm x 25mm x 20mm - unpotted.
I hope you guys can assist with the other required components once I get started.
Here is the photo of the transformers. They are centre-tapped. The resistance on one side is twice that of the other.
Attachments
I need Coax out for my home DAC
"I want spdif (75 ohm) digital out from the DEQ2496" I found this topic on page 15
I red manual for ak4114 and see on p.22 some sircuits with even 75 om transformers.
So could you clean this topic: what exactly I need to take coax spdif out (75om) from pin 15 and 16? Should I add resistors + transformer 75om or just use direct connecting through coax 75om cable to my DAC?
"I want spdif (75 ohm) digital out from the DEQ2496" I found this topic on page 15
I red manual for ak4114 and see on p.22 some sircuits with even 75 om transformers.
So could you clean this topic: what exactly I need to take coax spdif out (75om) from pin 15 and 16? Should I add resistors + transformer 75om or just use direct connecting through coax 75om cable to my DAC?
Cool! I just finished fixing the power supply and thought to share some tips:
- the Vishay 146 RTI caps have similar size to the big value originals in the power supply; these are 125C rated and should hold for a while 😀 the usual suspects such as Nichicon BT and Nippon Chemicon GXE won't fit.
- when used as a plain DAC, the single point that makes the biggest difference in sound is the interstage coupling capacitors (C20, C29 for Main out and C7, C23 for Aux out). There's 0V DC across them and as expected, bi-polars were performing best; Panasonic SU 47u/25V gave the most balanced, fluid, non-fatiguing, pleasant sound; I didn't try film though as there's not enough space there.
- the Vishay 146 RTI caps have similar size to the big value originals in the power supply; these are 125C rated and should hold for a while 😀 the usual suspects such as Nichicon BT and Nippon Chemicon GXE won't fit.
- when used as a plain DAC, the single point that makes the biggest difference in sound is the interstage coupling capacitors (C20, C29 for Main out and C7, C23 for Aux out). There's 0V DC across them and as expected, bi-polars were performing best; Panasonic SU 47u/25V gave the most balanced, fluid, non-fatiguing, pleasant sound; I didn't try film though as there's not enough space there.
Just ansuwering about if there is someone reading this tread
🙂An enthusiastic YES!
I am reading this again, making some modificatons in mine.
I have access to Audio precision test equipment and 2 months ago I made some measurements in the DEQ2496, and most important! ->listened it as a pre-amplifie in a high end sound system ( BW 802Diamonds, Classe Power amplifier, Tascan professional CD player, connected to the DEQ through AES EBU) and compare it to a US$ 8000 DAC...
If there is interest I will post the measurements I made , I am postponing it just because will be a long post, lots of Audio precision test results print screen.
Flavio
🙂An enthusiastic YES!
I am reading this again, making some modificatons in mine.
I have access to Audio precision test equipment and 2 months ago I made some measurements in the DEQ2496, and most important! ->listened it as a pre-amplifie in a high end sound system ( BW 802Diamonds, Classe Power amplifier, Tascan professional CD player, connected to the DEQ through AES EBU) and compare it to a US$ 8000 DAC...
If there is interest I will post the measurements I made , I am postponing it just because will be a long post, lots of Audio precision test results print screen.
Flavio
It is fun to see peoples still modifying those units. I still use mine in my main system every weeks. The mods I did so far :
- Remove the internal switching power supply and used Acopian linear power supplies that I had on hand in an external case. Since I had not the exact voltage values with 2 modules, I added very low noise regulators to get the exact voltage (3.3V and 9V)
- I took the AK4393 output signal from the nap cable and I used Jensen JT-11-EMFC transformers for the analog output
- I replaced the stock clock with a DCXO clock
- Replaced all voltage filtering caps for the digital chips by Sanyo Os-Con caps
- Remove the internal switching power supply and used Acopian linear power supplies that I had on hand in an external case. Since I had not the exact voltage values with 2 modules, I added very low noise regulators to get the exact voltage (3.3V and 9V)
- I took the AK4393 output signal from the nap cable and I used Jensen JT-11-EMFC transformers for the analog output
- I replaced the stock clock with a DCXO clock
- Replaced all voltage filtering caps for the digital chips by Sanyo Os-Con caps
Attachments
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