Thank you Oliver & Lucas for your help, I found the problem!
It was what we learned on our first day of electronics 101.
Make sure your GROUNDS are tight!!!
The input gnd to the converter was loose.
We're back in buisness, and sounding good, but still have a long way to go.
Best Regards,
Ned
Ahh ok
So have much fun! I am looking forward to your ready build DAC
Best regards,
Oliver
I must admit I was surprised by his findings. I found that using simple aligator clips to connect and reconnect caps realtively quickly made it fairly simple to check out the differences. I do suspect there is a lot of snake oil being sold at rediculous margin. I did on the other hand find differences in cap sound in this application even among the modestly priced units.
TDA1541A DAC V3.0 module progress report
A short intermediate result to the TDA1541A DAC V3.0 module.
The 1st testings with the module are finished.
Everything works perfect and i could tell you,
that also the SQ benefit from the new design and modifications.
Now the 2nd test with -ecdesigns- MK7 Onboard Grounded-Gate MOSFET Current Buffer I/V Stage will start.
To be continued...
The 1st testings with the module are finished.
Everything works perfect and i could tell you,
that also the SQ benefit from the new design and modifications.
Now the 2nd test with -ecdesigns- MK7 Onboard Grounded-Gate MOSFET Current Buffer I/V Stage will start.
To be continued...
New TDA1541A DAC Module
The evolution brings the following changes
- Direct shunt voltage inputs with shortest onboard traces
- I2S In-/Outputs with shortest onboard traces
- Upgrades DEM Synchronizer
- Onboard Grounded-Gate MOSFET Current Buffer I/V Stage
(-ecdesigns- MK7 version)
- Compacter design
Still on the module
- Separate GND-Trace for DEM-Synchroinizer
- Master/Slave connectors for parallel DAC module usage
and external I/V Buffer stages e.g.
Tube-I-zator & DDNF Stage
- Groundplane
- no SMD Design
If you want to use the onboard Grounded-Gate MOSFET Current Buffer I/V Stage,
you need additionally the DC-Reference Module
Description
Because the Grounded-Gate Buffer is connected between the DAC output and the passive I/V resistor,
normally the I/V resistor is connected between the DAC output and GND,
you must get rid off the approx. 4V DC on each I/V resistor.
Therefore we must get a new reference GND for each channel.
The circuit is connected to the ref.+5V at the output of the buffer and GND,
with a decoupling cap for each channel.
By trimming each voltage so it exactly matches DC voltage on the I/V resistor,
the DC voltage between I/V resistor and reference becomes zero.
In other words, the DC component is removed without using a coupling cap.
The Red Baron
aka TDA1541A DAC V3.0
aka TDA1541A DAC V3.0
An externally hosted image should be here but it was not working when we last tested it.
The evolution brings the following changes
- Direct shunt voltage inputs with shortest onboard traces
- I2S In-/Outputs with shortest onboard traces
- Upgrades DEM Synchronizer
- Onboard Grounded-Gate MOSFET Current Buffer I/V Stage
(-ecdesigns- MK7 version)
- Compacter design
Still on the module
- Separate GND-Trace for DEM-Synchroinizer
- Master/Slave connectors for parallel DAC module usage
and external I/V Buffer stages e.g.
Tube-I-zator & DDNF Stage
- Groundplane
- no SMD Design
An externally hosted image should be here but it was not working when we last tested it.
If you want to use the onboard Grounded-Gate MOSFET Current Buffer I/V Stage,
you need additionally the DC-Reference Module
Description
Because the Grounded-Gate Buffer is connected between the DAC output and the passive I/V resistor,
normally the I/V resistor is connected between the DAC output and GND,
you must get rid off the approx. 4V DC on each I/V resistor.
Therefore we must get a new reference GND for each channel.
The circuit is connected to the ref.+5V at the output of the buffer and GND,
with a decoupling cap for each channel.
By trimming each voltage so it exactly matches DC voltage on the I/V resistor,
the DC voltage between I/V resistor and reference becomes zero.
In other words, the DC component is removed without using a coupling cap.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
Here you see the two configurations.
1st without the onboard I/V buffer stage and in parallel mod
The shortest connection between the two modules
for the I2S signal and the analog output.
2nd with -ecdesigns- MK7 onboard I/V buffer stage
Because of a small failure in my pcb design program it is necessary,
that you switch the source and drain of the MOSFET like in this picture
1st without the onboard I/V buffer stage and in parallel mod
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The shortest connection between the two modules
for the I2S signal and the analog output.
2nd with -ecdesigns- MK7 onboard I/V buffer stage
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Because of a small failure in my pcb design program it is necessary,
that you switch the source and drain of the MOSFET like in this picture
An externally hosted image should be here but it was not working when we last tested it.
The Red Baron - Setting Points
Here are the setting points, if you use the onboard I/V stage.
All further informations in my Blog.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Here are the setting points, if you use the onboard I/V stage.
All further informations in my Blog.
onbard i/v
Look's good
Question: 2 DAC = 2 onbard I/V with output coupled and
the same values???
Look's good
Question: 2 DAC = 2 onbard I/V with output coupled and
the same values???
Hi Antonio,
if you would like to use 2 DAC modules with the onboard I/V stage,
you must build 2* the I/V stage with one I/V resistor and halve the value to 250R to get 2Vpp output voltage.
From my subjective side, the onboard I/V has a quite similar sound signature to the DDNF I/V stage.
Perhaps not that dynamical, but keep in mind you don't need any additional parts or modules.
If space and more investment is not the problem, i would go with the DDNF or Tube-I-zator I/V stage.
In my rig the tubes stays with a different tube rectifier.
Interesting conclusion oliver... Have you put this forward to ecdesigns yet? Technically speaking, the onboard iv stage is more elegant (by routing currents back into +5v).
But if it doesnt sound as good... Well... I'd go for ddnf anyway.
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I am here: http://maps.google.com/maps?ll=58.921263,5.597345
But if it doesnt sound as good... Well... I'd go for ddnf anyway.
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I am here: http://maps.google.com/maps?ll=58.921263,5.597345
Well, as written that is my personal poit of view. It would be interesting to hear more statements.
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