Hello guys. I want to change my denon dvd2900, and my idea was to bypass the stage I / V Original and opamp. This stage I / V Pass can I use it on my Denon? I would have the idea of adding a valve buffer after stage I / V, it would be a good thing? or can I get the output directly from the stage I / V? Thanks to those who can help me out.
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I found the datasheet for the dsd1792 which should be the same as 1790, at least from the pin, 1790 should be an amended version of 1792, or so I read on the web.
http://www.ti.com/lit/ds/symlink/dsd1792.pdf
http://www.ti.com/lit/ds/symlink/dsd1792.pdf
I consulted the service manual at HiFi Engine and it contains the DSD1790 DAC.
NJM2068 opamps used at I/V stage.
NJM2068 opamps used at I/V stage.
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As can be seen the differential outputs from the DAC goes via opamp I/V stages to single ended conversion via a OP275 opamp. Filter via BA15218 opamps and OP275 output buffer. Output caps back to bacl el-lyts and parallelled with something presumably better.
I once planned to modify an universal player, but ended up ripping all my physical disks to FLAC and bought a decent DAC. Now playback is from a silent PC via the DAC to a B-1.
I once planned to modify an universal player, but ended up ripping all my physical disks to FLAC and bought a decent DAC. Now playback is from a silent PC via the DAC to a B-1.
Attachments
I did not find any DSD1790 datasheet at Analog, Embedded Processing, Semiconductor Company, Texas Instruments - TI.com, I only found that Service Manual hinting at the DVD2900's DAC being current out.
So, Mr. Pass can use its circuit with my dvd player, exploiting it to the maximum, or will I have any restrictions? Her I would you recommend?
The dac dsd1790 was built on specific denon, so there is no datasheet on the net, they should denon and TI. But the pin, it would seem a modified dsd1792.
Yes, according to the DSD1792 datasheet the pin out is identical.
Thank you for that information.
Well, I expect you may use the Zen I/V then. The DSD 1792 has Differential Current Output: 7.8 mA p-p, so if the DSD 1790 has this specification identical, it shpuld be easy to implement the Zen I/V in a correct way.
Good luck.
Hi,
afaik all HiFi-DACs of TI with current output are of the current sourcing type with an DC offset current.
This leads to an voltage offset at the output pins of IC213 and IC215.
Due to the differential input to IC216 and IC217 the offset cancels out.
When replacing the original output stage You must consider the DC-offset current of the DAC.
I/V converters like the original or the ZEN would require a dedicated current sink at their inputs towards the negative supply to be Offset-free, or some means of Offset cancelling/blocking at their outputs.
A single ended grounded Base circuit based for example on the JockoHomo or OPC´s includes the current sink, requires very few parts and is sonically absolutely top notch.
If it weren´t for the DSD compatibility You could omit with the post filter stage (IC218, IC219) also.
As is the whole stage looks like a simple copy and paste from app-notes design .... it leaves quite alot room for sonic improvement.
jauu
Calvin
ps.
afaik all HiFi-DACs of TI with current output are of the current sourcing type with an DC offset current.
This leads to an voltage offset at the output pins of IC213 and IC215.
Due to the differential input to IC216 and IC217 the offset cancels out.
When replacing the original output stage You must consider the DC-offset current of the DAC.
I/V converters like the original or the ZEN would require a dedicated current sink at their inputs towards the negative supply to be Offset-free, or some means of Offset cancelling/blocking at their outputs.
A single ended grounded Base circuit based for example on the JockoHomo or OPC´s includes the current sink, requires very few parts and is sonically absolutely top notch.
If it weren´t for the DSD compatibility You could omit with the post filter stage (IC218, IC219) also.
As is the whole stage looks like a simple copy and paste from app-notes design .... it leaves quite alot room for sonic improvement.
jauu
Calvin
ps.
Just not in Your reach .... mine are dead quiet in every regard.
Hi,
afaik all HiFi-DACs of TI with current output are of the current sourcing type with an DC offset current.
This leads to an voltage offset at the output pins of IC213 and IC215.
Due to the differential input to IC216 and IC217 the offset cancels out.
When replacing the original output stage You must consider the DC-offset current of the DAC.
I/V converters like the original or the ZEN would require a dedicated current sink at their inputs towards the negative supply to be Offset-free, or some means of Offset cancelling/blocking at their outputs.
A single ended grounded Base circuit based for example on the JockoHomo or OPC´s includes the current sink, requires very few parts and is sonically absolutely top notch.
If it weren´t for the DSD compatibility You could omit with the post filter stage (IC218, IC219) also.
As is the whole stage looks like a simple copy and paste from app-notes design .... it leaves quite alot room for sonic improvement.
jauu
Calvin
ps.
Just not in Your reach .... mine are dead quiet in every regard.
Thanks for the answers, ultimately you what would you advise me to do? I would have also taken into consideration, an output tube, but do not know what could be done for me. Some idea?
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