Re: Re: cd 63se and ezdac
Just remember guys, the PCM1794 is current output. So, there are two things you may or may not want to bypass. 1) The onboard I/V is done passively (via resistor) and 2) the op amp performs differential-to-single ended conversion and voltage gain. Just thought I'd make that clear. Anyway, I will be shipping the boards on Monday. I just didn't have the time today (you know, the customs forms alone are a huge PITA for me, and almost all the ezDAC buyers so far are Europeans).
rowemeister said:
Just remember guys, the PCM1794 is current output. So, there are two things you may or may not want to bypass. 1) The onboard I/V is done passively (via resistor) and 2) the op amp performs differential-to-single ended conversion and voltage gain. Just thought I'd make that clear. Anyway, I will be shipping the boards on Monday. I just didn't have the time today (you know, the customs forms alone are a huge PITA for me, and almost all the ezDAC buyers so far are Europeans).
I managed to squeeze my S-Power reg into the dac analog today. I have sat for the last three hours listening. I must admit I was skeptical before whether the improvement of my Invisus would be as good as you said Brent. But it was.
I know some of the benefits are from splitting the dac & decoder analog from each other, but still. Those little regs are very impressive. There's no wonder Simon likes them so much. I can't imagine how good your player must sound Brent.
Cheers,
Lee.
It won't need a heatsink here will it?
I know some of the benefits are from splitting the dac & decoder analog from each other, but still. Those little regs are very impressive. There's no wonder Simon likes them so much. I can't imagine how good your player must sound Brent.
Cheers,
Lee.
It won't need a heatsink here will it?
Os Con
Hi Ray
I have two OsCon Sprague 220uF 10V and would like to experiment them...
Can I swap C124 on Servo VREF output with one OsCon?
After I replaced C135 / 138 (Q105) Sled + LD and C153 / 154 (QM01) Disc Motor Driver with 120uF 16v Pana FC, I noticed an increase of detail and low end power, but now the player tends to skip sometimes....
Can you help ?
Regards
Ricardo
Hi Ray
I have two OsCon Sprague 220uF 10V and would like to experiment them...
Can I swap C124 on Servo VREF output with one OsCon?
After I replaced C135 / 138 (Q105) Sled + LD and C153 / 154 (QM01) Disc Motor Driver with 120uF 16v Pana FC, I noticed an increase of detail and low end power, but now the player tends to skip sometimes....
Can you help ?
Regards
Ricardo
RCruz said:
Hi Lee
Why do you keep the tx if the digital and analog are supplied by an exterior tx ?
What lines do the stock tx feed ?
Ricardo
Hi Ricardo. At the moment the original tx feeds everything but the clock and dac/decoder. I have a spare 100va tx housed in my preamp, which I am going to use for the output stage supply. With 10,000uF caps.
Lol. After fitting that S-Power reg, my missus walked in and asked me if I'd fixed my subwoofer. I have but it wasn't switched on!
Lee.
Thomo said:
Thanks Lee
Hours of design and testing showing its worth. I really should be charging £99 like Audiocom shouldn't I LOL
Glad you like them. Now just imagine your opamps running off them
cheers
Brent
SPOWER REGS
rowemeister said:
Good girl, give her a big kiss from me
Brent
Lol. Sorry to disappoint. She was ready to have a go, she hates the thing!
And yes, the bass really has improved that much. Those regs are great, there's just so much more detail and dynamics. I'm sure Simon can vouch for this also.
Lee.
Thomo said:
Sure can Lee! The dynamics really come out when using the regs on the output stage, and the detail comes out using it on the DAC and from using a C1 on the servo.
Overall, more good regs and separation of psu rails gives detail, impact and a very natural sound.
The value for money is terrific too. Compare to changing speaker cable: I just changed my Kimber 4PR to double-8TC (16x the price new) and the change is pleasant but very subtle. One well-placed £35 regulator makes a lot more difference.
Simon
Re: Os Con
If you leave out all the parts around and including the CS8416, and the 100 ohm resistors that feed data to the ASRC (R18...R21), you can use those pads to connect the I2C signal from the player's decoder. Should work o.k., i'm going to try this too with my next PCB in a CD67, see how that sounds.
The output stage is another thing, it's made for voltage output DACs, and as Evan already explained the 1794 is current output. You could experiment a bit and use the two 25 ohm resistors to do the I/V conversion and then connect this signal to both inputs of the output stage. You don't need the passive filter.
Yeah, why not, experiment all you want I would say. I don't think there will be much effect from the Vref though, but who knows...
I can't explain the skipping, as those caps should be ok over there. Maybe it's a coincidence caused by handling the transport. Try refitting the flatcables and cleaning & lubricating the metal slider-rod.
Regards,
Ray
reddish75 said:
If you leave out all the parts around and including the CS8416, and the 100 ohm resistors that feed data to the ASRC (R18...R21), you can use those pads to connect the I2C signal from the player's decoder. Should work o.k., i'm going to try this too with my next PCB in a CD67, see how that sounds
.The output stage is another thing, it's made for voltage output DACs, and as Evan already explained the 1794 is current output. You could experiment a bit and use the two 25 ohm resistors to do the I/V conversion and then connect this signal to both inputs of the output stage. You don't need the passive filter.
RCruz said:Hi Ray
I have two OsCon Sprague 220uF 10V and would like to experiment them...
Can I swap C124 on Servo VREF output with one OsCon?
After I replaced C135 / 138 (Q105) Sled + LD and C153 / 154 (QM01) Disc Motor Driver with 120uF 16v Pana FC, I noticed an increase of detail and low end power, but now the player tends to skip sometimes....
Can you help ?
Regards
Ricardo
Yeah, why not, experiment all you want I would say. I don't think there will be much effect from the Vref though, but who knows...
I can't explain the skipping, as those caps should be ok over there. Maybe it's a coincidence caused by handling the transport. Try refitting the flatcables and cleaning & lubricating the metal slider-rod.
Regards,
Ray
i/v conversion with a resistor
hi ray thanks for your answer, i dont see any potential problems using a resistor for i/v conversion (but i am very new at this) as long as all the voltages are correct, however do you think that this will affect soung quality?
Plus its only a concederation as i dont really like using op-amps
thanks
chris
hi ray thanks for your answer, i dont see any potential problems using a resistor for i/v conversion (but i am very new at this) as long as all the voltages are correct, however do you think that this will affect soung quality?
Plus its only a concederation as i dont really like using op-amps
thanks
chris
Re: i/v conversion with a resistor
Hi Chris,
The ezDAC sounds very good in its current configuration, with the opamps. But I don't see any reason why you couldn't use the discrete output stage. Sound quality should at least be the same or better, especially the mid-high region will become more fluid. But you need a good separate supply though, because the output stage is single ended. Any noise on the power lines will be directly transferred to the output. You may have to adjust the gain by changing the emitter resistors of the differential input. The two I/V voltages will be summed, just as with the opamp, and the rest should be ok.
Ray
reddish75 said:
Hi Chris,
The ezDAC sounds very good in its current configuration, with the opamps. But I don't see any reason why you couldn't use the discrete output stage. Sound quality should at least be the same or better, especially the mid-high region will become more fluid. But you need a good separate supply though, because the output stage is single ended. Any noise on the power lines will be directly transferred to the output. You may have to adjust the gain by changing the emitter resistors of the differential input. The two I/V voltages will be summed, just as with the opamp, and the rest should be ok.
Ray