Re: Anybody used a tune output on this DAC
I tried using a tube output stage similar to lampizator. But transformers sounds way better than tubes when you use tube amplifier. And when you use solid state amplifier, transformers may sound even horrible. I'm going to add a cathode followers after transformers and test it with solid state amp. To be honest, I'm soldering it right now
shuggi67 said:
I tried using a tube output stage similar to lampizator. But transformers sounds way better than tubes when you use tube amplifier. And when you use solid state amplifier, transformers may sound even horrible. I'm going to add a cathode followers after transformers and test it with solid state amp. To be honest, I'm soldering it right now
Re: Anybody used a tune output on this DAC
I tried lampizator, AiKido balanced, Fet, balanced fet, Burson op amps. For me, nothing beats transformers in all systems transistor or tube based.
I modified 7 of these dacs with transformers . Before modding them with transformers, peoples used them with different circuits I made. When modded with transformers, everybody asked me to transform their dacs with transformers. They are really happy in all their setups.
shuggi67 said:
I tried lampizator, AiKido balanced, Fet, balanced fet, Burson op amps. For me, nothing beats transformers in all systems transistor or tube based.
I modified 7 of these dacs with transformers . Before modding them with transformers, peoples used them with different circuits I made. When modded with transformers, everybody asked me to transform their dacs with transformers. They are really happy in all their setups.
McGyver, your finding should be interesting as I would imagine some of us on this thread just use solid state amps and AV receivers, I myself am using a AV receiver and though content with the Sound of the Marantz its probably more electronically engineered for 7.1 sources i.e movies, hence the external DAC solution.
please post your results after you perform your listening tests.
Thanks
please post your results after you perform your listening tests.
Thanks
Regarding audio Transformers
Couple more questions regarding Audio Transformers.
1, Should we be trying to source "Shielded" transformers ? or for this application it does not matter.
2, I'm a bit confused as a general rule is that you should not use a transformer to increase signal level by more than 25 dB, what does this mean exactly based on this project as 25dB is not very loud and how will this effect volume levels on AMP/receiver, its probably a dumb question but I had to ask
Couple more questions regarding Audio Transformers.
1, Should we be trying to source "Shielded" transformers ? or for this application it does not matter.
2, I'm a bit confused as a general rule is that you should not use a transformer to increase signal level by more than 25 dB, what does this mean exactly based on this project as 25dB is not very loud and how will this effect volume levels on AMP/receiver, its probably a dumb question but I had to ask
Shuggi
Unshielded transformers are obviously working fine in this application. Shielding is essential for low level signals.
When using 1:1 transformers there is no gain, just a very little bit of loss, depending on the transformers quality.
An increase of the signal level of 25dB means using a 1:18 transformer.
Franz
Unshielded transformers are obviously working fine in this application. Shielding is essential for low level signals.
When using 1:1 transformers there is no gain, just a very little bit of loss, depending on the transformers quality.
An increase of the signal level of 25dB means using a 1:18 transformer.
Franz
I have a couple of these..
http://www.sowter.co.uk/specs/5069.htm
will they be suitable for this mod?
http://www.sowter.co.uk/specs/5069.htm
will they be suitable for this mod?
Grounding
I have been away in DAC tweaking nirvana for a couple of days. I love this DAC, with the Tamura GA80080s and legarem's primary filter and secondary loading setup.
Having initially got grounding wrong (and getting awful sound) I have been trying lots of combinations of grounding connections - that is mains ground with RCA shield, Tamura black lead and the 12V-0-12V centre tap on the board.
One thing I have noticed is that it sounds fantastic with none of these three grounds connected, but only after system is warm.
I am new to this, so am not really sure what is going on. I guess the secondary is getting a ground connection anyway, from my amplifier via RCA shield. But the only thing connected on primary side are the 8V feeds (from power transformer) and the optical signal lead (which is electrically isolated), so there is no external grounding there. Does the a.c. to d.c. conversion provide it?
Or maybe my ears need grounding?!
I have been away in DAC tweaking nirvana for a couple of days. I love this DAC, with the Tamura GA80080s and legarem's primary filter and secondary loading setup.
Having initially got grounding wrong (and getting awful sound) I have been trying lots of combinations of grounding connections - that is mains ground with RCA shield, Tamura black lead and the 12V-0-12V centre tap on the board.
One thing I have noticed is that it sounds fantastic with none of these three grounds connected, but only after system is warm.
I am new to this, so am not really sure what is going on. I guess the secondary is getting a ground connection anyway, from my amplifier via RCA shield. But the only thing connected on primary side are the 8V feeds (from power transformer) and the optical signal lead (which is electrically isolated), so there is no external grounding there. Does the a.c. to d.c. conversion provide it?
Or maybe my ears need grounding?!
work in progress
According to my observations if the solid state amp has low input impedance, the sound of our DAC with trafos alone sometimes becomes "dead". So I'm soldering Version with cathode followers after trafos. There is a picture of my test setup built into CD player. There is mini SMD version of our DAC:
shuggi67 said:
According to my observations if the solid state amp has low input impedance, the sound of our DAC with trafos alone sometimes becomes "dead". So I'm soldering Version with cathode followers after trafos. There is a picture of my test setup built into CD player. There is mini SMD version of our DAC:
Attachments
Here is what I have learned from my research and experience.
The CS439x dacs are differential output, meaning they have plus and minus out. No ground connections are needed, they do not need a ground reference.
Transformers are differential input and output, they also do not need a ground reference.
Amplifiers using RCA inputs use the shield lug to reference the signal to the amp circuit ground to provide a return path for the signal.
Amps using balanced XLR inputs do not need a ground reference, the shield is used only for shielding and is not in the signal path.
You can feed a transformer output to either type with the two secondary wires only, RCA- one to center and one to shield lug, XLR- one to pin two and one to pin three- pin one is the shield ground.
The old adage applies, KISS. You do not need or want to connect anything to ground on the dac board or to the chassis ground.
Choice of transformers is wide open.
1/1 ratio means 1V in 1V out, 1/2 means 1V in 2V out.
Rated impedance is proportional to the dc resistance, usually 10/1 or less. Example 600 ohm impedance winding will be 60 ohms or less of DC resistance.
From research done, excellent quality 600 ohm transformers are vastly easier to manufacture than say 10Ks because of the volume of materials that are used and winding techniques that have to be used for the higher impedance units.
Using 600 ohm units is ideal as long as the dac chip is protected from the low DC resistance by using series resistors.
The DB rating of the transformer is important at the low end of the frequency spectrum, so higher ratings like +15 or 20DB ratings tell you they can handle bass well. 5 Volts would be a pretty good number looking at it voltage wise.
If anyone has any corrections to any of my ramblings please speak up, otherwise I'm going to shut up now.
The CS439x dacs are differential output, meaning they have plus and minus out. No ground connections are needed, they do not need a ground reference.
Transformers are differential input and output, they also do not need a ground reference.
Amplifiers using RCA inputs use the shield lug to reference the signal to the amp circuit ground to provide a return path for the signal.
Amps using balanced XLR inputs do not need a ground reference, the shield is used only for shielding and is not in the signal path.
You can feed a transformer output to either type with the two secondary wires only, RCA- one to center and one to shield lug, XLR- one to pin two and one to pin three- pin one is the shield ground.
The old adage applies, KISS. You do not need or want to connect anything to ground on the dac board or to the chassis ground.
Choice of transformers is wide open.
1/1 ratio means 1V in 1V out, 1/2 means 1V in 2V out.
Rated impedance is proportional to the dc resistance, usually 10/1 or less. Example 600 ohm impedance winding will be 60 ohms or less of DC resistance.
From research done, excellent quality 600 ohm transformers are vastly easier to manufacture than say 10Ks because of the volume of materials that are used and winding techniques that have to be used for the higher impedance units.
Using 600 ohm units is ideal as long as the dac chip is protected from the low DC resistance by using series resistors.
The DB rating of the transformer is important at the low end of the frequency spectrum, so higher ratings like +15 or 20DB ratings tell you they can handle bass well. 5 Volts would be a pretty good number looking at it voltage wise.
If anyone has any corrections to any of my ramblings please speak up, otherwise I'm going to shut up now.