So, I have reinstalled the fourth board, switch the chokes, now I have:
Transformer -> Diodes -> LL1694 in parallel -> 2200uf -> LL1638 in common serial mode -> 2200uf -> 100R in parallel -> Dac modules feeds with 12.5V.
I still have a big issue, like it miss a ground somewhere. So after some tests, the situation seems much better if I connected the ground of DDDAC boards with one mono block's ground but... I feel that it is worst than yesterday with only 3 boards.
How do I have to connect the cinch plug for output? Now I have dac's POS to cinch's center and dac's EG to cinch's outside. Do I have to connect cinch's outside to dac's ground ?
Transformer -> Diodes -> LL1694 in parallel -> 2200uf -> LL1638 in common serial mode -> 2200uf -> 100R in parallel -> Dac modules feeds with 12.5V.
I still have a big issue, like it miss a ground somewhere. So after some tests, the situation seems much better if I connected the ground of DDDAC boards with one mono block's ground but... I feel that it is worst than yesterday with only 3 boards.
How do I have to connect the cinch plug for output? Now I have dac's POS to cinch's center and dac's EG to cinch's outside. Do I have to connect cinch's outside to dac's ground ?
Hello,
Of course 2× 18 ohm will give much more voltage drop than 2×0,9 ohm especially because it is used for choke Input!
It might be even to high.
Just try. The previous regulator will get warmer, maybe even hot depending how much the input voltage to the boards will be . If I am right 13 volts is still OK without heats ink. If it rises to 17 volts switch off QUICKLY and find a way to make it go down.
Greetings, eduard
Of course 2× 18 ohm will give much more voltage drop than 2×0,9 ohm especially because it is used for choke Input!
It might be even to high.
Just try. The previous regulator will get warmer, maybe even hot depending how much the input voltage to the boards will be . If I am right 13 volts is still OK without heats ink. If it rises to 17 volts switch off QUICKLY and find a way to make it go down.
Greetings, eduard
Hello,
I would use ll1694 in serial common mode too. Use the bleeder across the first cap so you will have less voltage drop. If to big you could use one 100 ohm.
I don't have the manual here but it will show how to do the earthing correctly. Of course separating power supply left and right makes things more complicated.
Greetings
I would use ll1694 in serial common mode too. Use the bleeder across the first cap so you will have less voltage drop. If to big you could use one 100 ohm.
I don't have the manual here but it will show how to do the earthing correctly. Of course separating power supply left and right makes things more complicated.
Greetings
Hello Billy,
Take a look in the manual. The negative terminal says nc so not connected.
You are using output Cap?
I am using the special sowither from Doede and I had to ask him too just to be sure.
Better wait for Doede to wake up. With these kind of things it can cause big problems if you do it wrong.
Greetings
Thank you Eduard ! 🙂
What a stupid mistake ! I'm connected by POS and NEG... I will fix it tomorrow as you have suggested, now it's time to go to bed 😉
I don't have any cap or cinemags, I have removed them, I use Dave Slagle's autoformer directly.
Thanks again and have a good night 😉
What a stupid mistake ! I'm connected by POS and NEG... I will fix it tomorrow as you have suggested, now it's time to go to bed 😉
I don't have any cap or cinemags, I have removed them, I use Dave Slagle's autoformer directly.
Thanks again and have a good night 😉
Hello,
With cap you are not using negative terminal and with transformer the common terminal is not connected.
Better sleep before study the manual.
Maybe with autotransformer ( like mcintosh solid state power Amps? ) connection could be Different? I don't know. Doede will Know!
Greetings eduard
Morning !
I fixed this morning the connection to the auto transformer, it is better but there is still an issue, a kind of distortion at the end of the pianol's chords for example. This is what I have today:
After I have a pair of mono block tube amps, Williamson's schematic, the RCA's center feeds the first triode's grid, outer connected to amp's ground star.
I fixed this morning the connection to the auto transformer, it is better but there is still an issue, a kind of distortion at the end of the pianol's chords for example. This is what I have today:
An externally hosted image should be here but it was not working when we last tested it.
After I have a pair of mono block tube amps, Williamson's schematic, the RCA's center feeds the first triode's grid, outer connected to amp's ground star.
Yes, the fourth decks are connected as it should be except for VB+, the connection to the mainboard is cutted.
Have you tried cutting all power to one of the dacs on the fourth board, say the left dac off and the right dac on, I would also remove the digital power and music signal supply too, this may show the issue, sounds like a power supply issue, perhaps you have generated a tank circuit with the caps and inductors and it is oscillating at the current required for 4 decks but not at 3, perhaps measure the current at 4, remove deck 4, then load supply to same current as 4 decks via load resistance, see if this changes things.
Thank you, I'll will try tonight, currently it is 14.30PM, I am at work 😉
I haven't indicate that now, after inversing the chokes, 1694 in // mode, I have 12.8V to the dac 😉
Also, is it possible to do your test without removing digital and analog links, just power supply connections ?
I haven't indicate that now, after inversing the chokes, 1694 in // mode, I have 12.8V to the dac 😉
Also, is it possible to do your test without removing digital and analog links, just power supply connections ?
Another point, I have noticed that I can hear "ploc" (since I started last week my "final verison") when I turn the switch, so I have measure the DC between POS and NEG, I didn't remember how many I had in the past but it seems to be a little too much to work without cap or transformer ?
Hello,
I would put the 100 ohm across the first cap and put in the ll1694 in serial common mode. I think you will get about the right voltage out.
Maybe your connections between main board and dac boards are to Long?
I would wait for Doede to answer.
Maybe the answer is very Simple!
Greetings, eduard
I would put the 100 ohm across the first cap and put in the ll1694 in serial common mode. I think you will get about the right voltage out.
Maybe your connections between main board and dac boards are to Long?
I would wait for Doede to answer.
Maybe the answer is very Simple!
Greetings, eduard
Hello,
It looks like you did do something the wrong way but we don't know what. If you have to make a ground connection between dac and one of your amps something is wrong too..
Maybe some part was destroyed by just trying Things! When I was building my dac I always did ask here or Doede personally if I had a strange idea or if the manual was not clear.
This kind of digital gear is not like a tube amp which can be misused severely before something breaks down.
Better wait for an expert or Doede to react.
Maybe there is a bad solder joint connecting the boards and main Board?
Greetings, eduard
P.'s I remember reading about a strange kindof distortion here Before!
It looks like you did do something the wrong way but we don't know what. If you have to make a ground connection between dac and one of your amps something is wrong too..
Maybe some part was destroyed by just trying Things! When I was building my dac I always did ask here or Doede personally if I had a strange idea or if the manual was not clear.
This kind of digital gear is not like a tube amp which can be misused severely before something breaks down.
Better wait for an expert or Doede to react.
Maybe there is a bad solder joint connecting the boards and main Board?
Greetings, eduard
P.'s I remember reading about a strange kindof distortion here Before!
You have quite some DC across the input of the autoformer. This may saturate the core, and cause distortion. Could this be your problem?
A cap might work, but the complex impedances of the cap and the autoformer might also cause a resonance. But it should be okay for debugging. Or just try a cap without the autoformer to make things simple?
Tonight I modified analog PS as Eduard suggested, both chokes in common rejection mode, R between the choke, I have 13V at the final, but the resistor become very very hot.
Anyway, I did some measure with scope which I will show you tomorrow then I would like to test it but no sound came from the DAC... I immediately checked the voltage and the analog was 20V !!! Nothing at the output of the LF80 so I thought it was dead. I plugged it again on my test's table and everything seems to be come back normal.
It is too late now, and I would like to avoid big mistake so I will try it tomorrow.
Thanks everybody for your contribution, I really appreciate.
I'm sure that I will find the solution 😉
Anyway, I did some measure with scope which I will show you tomorrow then I would like to test it but no sound came from the DAC... I immediately checked the voltage and the analog was 20V !!! Nothing at the output of the LF80 so I thought it was dead. I plugged it again on my test's table and everything seems to be come back normal.
It is too late now, and I would like to avoid big mistake so I will try it tomorrow.
Thanks everybody for your contribution, I really appreciate.
I'm sure that I will find the solution 😉