Not 100% decided yet! I've run several types on various incarnations of 1541 output!
I have a resitor IV into a tube stage option that I got at the same time as the other PCB's in the pic.
My CD960 currently uses a single burson IV with a feedback filter and an adjustable CCS to offset any DC on the output (removing the need for DC blocking caps on the output)
I really like the fully discrete, zero feedback with a DC servo (again removing the need for DC blocking caps on the output) used in meridian stuff.
What I'll probably do is use a basic opamp IV (single ended with 1.8k and 2n2 feedback) and DC blocking caps to start then when I've built the tube stage, have a go at that but if I'm honest, fully discrete zero feedback is probably the way that I will go! I know Simon and Lee have had some really good results with Pass Labs D1's and if i'm honest, i'll end up having a play with that too>
Attached is a basic opamp IV which will pretty much outperform anything you'd find in a comercial player (unless its discrete!) If you add a ccs before the opamp, you can tune the DC voltage to 0 then remove the blocking caps and then you are starting to talk......
I have a resitor IV into a tube stage option that I got at the same time as the other PCB's in the pic.
My CD960 currently uses a single burson IV with a feedback filter and an adjustable CCS to offset any DC on the output (removing the need for DC blocking caps on the output)
I really like the fully discrete, zero feedback with a DC servo (again removing the need for DC blocking caps on the output) used in meridian stuff.
What I'll probably do is use a basic opamp IV (single ended with 1.8k and 2n2 feedback) and DC blocking caps to start then when I've built the tube stage, have a go at that but if I'm honest, fully discrete zero feedback is probably the way that I will go! I know Simon and Lee have had some really good results with Pass Labs D1's and if i'm honest, i'll end up having a play with that too>
Attached is a basic opamp IV which will pretty much outperform anything you'd find in a comercial player (unless its discrete!) If you add a ccs before the opamp, you can tune the DC voltage to 0 then remove the blocking caps and then you are starting to talk......
Attachments
Not 100% decided yet! I've run several types on various incarnations of 1541 output!
I have a resitor IV into a tube stage option that I got at the same time as the other PCB's in the pic.
My CD960 currently uses a single burson IV with a feedback filter and an adjustable CCS to offset any DC on the output (removing the need for DC blocking caps on the output)
I really like the fully discrete, zero feedback with a DC servo (again removing the need for DC blocking caps on the output) used in meridian stuff.
What I'll probably do is use a basic opamp IV (single ended with 1.8k and 2n2 feedback) and DC blocking caps to start then when I've built the tube stage, have a go at that but if I'm honest, fully discrete zero feedback is probably the way that I will go! I know Simon and Lee have had some really good results with Pass Labs D1's and if i'm honest, i'll end up having a play with that too>
Attached is a basic opamp IV which will pretty much outperform anything you'd find in a comercial player (unless its discrete!) If you add a ccs before the opamp, you can tune the DC voltage to 0 then remove the blocking caps and then you are starting to talk......
Same here, I will try the tubizator one, but will probably end up with this http://bgaudioclub.org/gallery/albums/userpics/11518/discrete_I-V.pdf, powered by another 3 salas shunts (so that means 7 salas regs in the dac).
Sorry for the offtopic
I am not sure what you meant on your first line.... I am using Spowers on the analog DAC side as well as in the DOS with great results.
I also use spowers in my Meridian 101 preamp....
Salas shunts are too big and generate too much heat for these purposes.... otherwise I would try them to evaluate the differences.
Apart from size and heat there are other big differences .... I can build them p2p (I have built 20 of those).... Salas shunts respond very well to component changes anabling me to tune them to fit the rest of the system.
I can not build Spowers
1 amp? Is it an oscillator with an oven?It will need an external power supply, this current is too high to draw from the original tranny.
Or you could get yourself a Flea
I've asked the seller how I to reduce the power consumption down to say 200mA. It uses a TL431 in the power supply stage, so I guess a simple resistor change is all thats needed. I would like to use it if I can, but have ordered a flea PCB in case. This clock has a /2 and /4 output as well, which is the main reason I bought it as I believe I can re-clock the servo with it as well...?
I've got the Salas shunt working at 5V, which are the sound-critical 5V lines to add the reg to? I believe U200 and U174 are the DAC 5V lines, but which other links do I need to tap in to?
You should start to isolate all the 5v supply rails accross the player thats why most of us run multiple regs. 2 on the DAC, 3 on the decoder, 1 for the HF amp area...........the list goes on. Even loads of 7805's is a massive improvement!
On the DAC, there are 4 Analogue supply pins (17,21,22,26) these can be fed from a single point (U200). Pin 16 is the digital psu line and can be traced back to RD04. If you are running multiple devices from the same regulator, you should use a small resitor in line with each supply (thats exactly what RD04 is). If you look at the 1st few posts in this thread, you'll see the mods list from Ray with suggestions for inductors with ferrite beads instead. Personally I prefer separate regs for everything then you can do away with the resistor/inductors. Remember, the more lines you add to the single reg, the more noise transfered between all the connected devices.
As the CPU is noisy, a good mod will be to get that onto its own 7805 just to get it off the other rails.
Spend some time familiarising yourself with the manual, you'll soon pick out the 5v rails and see where you can start to seperate.
RE U200 -For the analogue supplys, use something like Rubycon ZLG or ZA (or Black Gate if you fancy) to replace the decoupling caps CD15 & CD16
RE RD04 - For the Digital supply, use an Oscon SEPC or Nichicon solid polymer to replace CD07
Dont worry about increasing the values to either!! I run 470uF for most local decoupling!
On the DAC, there are 4 Analogue supply pins (17,21,22,26) these can be fed from a single point (U200). Pin 16 is the digital psu line and can be traced back to RD04. If you are running multiple devices from the same regulator, you should use a small resitor in line with each supply (thats exactly what RD04 is). If you look at the 1st few posts in this thread, you'll see the mods list from Ray with suggestions for inductors with ferrite beads instead. Personally I prefer separate regs for everything then you can do away with the resistor/inductors. Remember, the more lines you add to the single reg, the more noise transfered between all the connected devices.
As the CPU is noisy, a good mod will be to get that onto its own 7805 just to get it off the other rails.
Spend some time familiarising yourself with the manual, you'll soon pick out the 5v rails and see where you can start to seperate.
RE U200 -For the analogue supplys, use something like Rubycon ZLG or ZA (or Black Gate if you fancy) to replace the decoupling caps CD15 & CD16
RE RD04 - For the Digital supply, use an Oscon SEPC or Nichicon solid polymer to replace CD07
Dont worry about increasing the values to either!! I run 470uF for most local decoupling!
Last edited:
One other thing! The large benifits of running a decent reg on the DAC analogue (U200) will be lost if you start adding everything else to the new reg.
You should listen and make your own mind up but in my experience, digital rails are noisy. When you add a nice clean supply just to the analogue DAC rail, things will improve, if you then add the DAC digital with its noise to the same reg, you will transfer that noise the the analogue side.
Dont take my word for it!!! try both and see what you think.....
You should listen and make your own mind up but in my experience, digital rails are noisy. When you add a nice clean supply just to the analogue DAC rail, things will improve, if you then add the DAC digital with its noise to the same reg, you will transfer that noise the the analogue side.
Dont take my word for it!!! try both and see what you think.....
But still, 1A is a lot, even for a few TL431's, it can sink 100mA itself and is mostly used at 10mA. Is there a power transistor behind it?
Your Flea board is in the mail btw!
Ray
If you only have one 5v reg at the moment, the best place to put it is powering the entire dac. I've done this quite a few times myself, and it's definitely the best use for one good reg imho.
Cut U164 and tag the output of the reg onto the dac side of that link. Connect the gnd to the gnd plane and job done.
Of course what Ian said is correct, the more regs, the more improvement, but if you only have one at the moment, I recommend trying this as you'll be impressed.
Cheers, Lee.
Cut U164 and tag the output of the reg onto the dac side of that link. Connect the gnd to the gnd plane and job done.
Of course what Ian said is correct, the more regs, the more improvement, but if you only have one at the moment, I recommend trying this as you'll be impressed.
Cheers, Lee.
It will never die
Well not until another format comes out that is actually better and does not run off a smps. They way its been going the last 5+ years we are defo going backwards imhoBrent
Yes, they do. Take a look in the datasheet, an MC7805 has 50uV output noise. So this would make the high-quality reg in front of it totally useless
Allthough, that's -100dB, seems quite reasonable... Ok, only bad if your low-noise reg is better than -100dB
These specs can easily be made worse by bad wiring, poor GND lay-out etc.
Ray
Allthough, that's -100dB, seems quite reasonable... Ok, only bad if your low-noise reg is better than -100dB
These specs can easily be made worse by bad wiring, poor GND lay-out etc.
Ray
Last edited:
Yes 7805 add their own noise. This is why we remove them. Running lots of 7805 instead of one does isolate all the V rails and the improvements are there to hear.
Running a load of 7805 after a low noise reg won't work. Shunt regs and the SPower like to shift current quickly and efficiently where the demand is needed and a 7805 etc just holds it back.
Once you have all the 7805 fitted you can then overtime easily swap these for low noise types
Brent
Running a load of 7805 after a low noise reg won't work. Shunt regs and the SPower like to shift current quickly and efficiently where the demand is needed and a 7805 etc just holds it back.
Once you have all the 7805 fitted you can then overtime easily swap these for low noise types
Brent