On CS8412 and DIR9001, UV101 wrote
Now at the time I used an USB-SPDIF/DAC.
I now use the SB Classic. I intend to use a quality clock on the DAC PCB(any need for external clock like Valab in this build?).
I'm a bit tired now and on painkillers for my bad foot, so please excuse stupid questions.
In this build, considering equipment used etc...what would be the best way to go between CS8412 and DIR9001?
I'm not really comfortable modding the SB Classic beyond building a better PS for it at this point.
No....its not the same chip. The main advantage of using the CS chip is that you can choose an external clock within the DAC. With the DIR, its a better chip but you can only use the SPDIF recovered clock. There are advantages either way. You can buy and adapter kit on ebay to utilise the DIR on a pin connection for the CS chip. With respect to SPDIF jitter, yes it can be a problem but I've never seen anyone argue the case for SPDIF properly. IMHO if you use the best PSU and regulation for the device generating the SPDIF and a high quality clock with its own PSU and do exactly the same at the receiver end, you will end up with something that to a very large extent flies in that face of those who dont like SPDIF. I have spent considerable time and effort messing with I2S and SPDIF. Personally, I would choose SPDIF every time with the right PSU's for digital connectivity between separate devices. However, if you were to add a USB receiver internal to a DAC or CDP, I'd not convert to SPDIF and back, I'd you the 3 internal bus lines of I2S (or similer). The only time you may have a problem is if there are differing clock speeds. With modern chips, its fairly common to run at 24.xxMhz so this makes interfacing easy. With older chips like the TDA, they run 11.xxxMhz so interfacing to a moder USB receiver would be problematic. SPDIF will overcome this at the clost of converstion (twice) and therefore the cost of multiple PSU's and clocks
Now at the time I used an USB-SPDIF/DAC.
I now use the SB Classic. I intend to use a quality clock on the DAC PCB(any need for external clock like Valab in this build?).
I'm a bit tired now and on painkillers for my bad foot, so please excuse stupid questions.
In this build, considering equipment used etc...what would be the best way to go between CS8412 and DIR9001?
I'm not really comfortable modding the SB Classic beyond building a better PS for it at this point.
Hopefully I'll get some more work done on the DAC tomorrow, I expected parts to arrive today...they should be here tomorrow. The parts I thought I'd get today is 99% of the restistors, all the inductors and all the trimpots.
Really happy I got a hold of good Wima MKP's for all the 100nF caps, those might arrive tomorrow as well with a bit of luck.
EDIT: found a cheap place to get custom made toroids, so I'll order one 50VA 16-0-16Vac(1A) + 0-15Vac(1A), this with the 9Vac 1200mA I've got is all I need for the DAC-PCB, I'll probably build a separate regulated supply for the B1 buffer.
For TDA1541A decoupling I thought I'd follow the PDF:
pin 13,18, 2mA, fDEM /2, 1uF
pin 12,19, 1mA, fDEM, half current (13,18), twice the frequency of MSB, 250nF
pin 11,20, 0.5mA, fDEM / 2, half frequency, half current (12,19), 125nF
pin 10,21, 0.25mA, fDEM, half current double frequency (11,20), 31.25nF
pin 9,22, 0.125mA, fDEM / 2, half current, half frequency (10,21), 31.25nF
pin 8,23, 0.0625mA, fDEM, half current (9,22), 7,8nF
pin 7,24, 0.0625mA, fDEM, equal current (8,23), 7.8nF.
In practice, 1uF (MSB), 220nF, 120nF, 33nF, 33nF, 8.2nF, 8.2nF. This would give equal ripple currents
on all MSBs.
Closest I found was:
1uF, 220nF, 150nF, 33nF, 33nF, 10nF, 10nF. All x2 of course.
Really happy I got a hold of good Wima MKP's for all the 100nF caps, those might arrive tomorrow as well with a bit of luck.
EDIT: found a cheap place to get custom made toroids, so I'll order one 50VA 16-0-16Vac(1A) + 0-15Vac(1A), this with the 9Vac 1200mA I've got is all I need for the DAC-PCB, I'll probably build a separate regulated supply for the B1 buffer.
For TDA1541A decoupling I thought I'd follow the PDF:
pin 13,18, 2mA, fDEM /2, 1uF
pin 12,19, 1mA, fDEM, half current (13,18), twice the frequency of MSB, 250nF
pin 11,20, 0.5mA, fDEM / 2, half frequency, half current (12,19), 125nF
pin 10,21, 0.25mA, fDEM, half current double frequency (11,20), 31.25nF
pin 9,22, 0.125mA, fDEM / 2, half current, half frequency (10,21), 31.25nF
pin 8,23, 0.0625mA, fDEM, half current (9,22), 7,8nF
pin 7,24, 0.0625mA, fDEM, equal current (8,23), 7.8nF.
In practice, 1uF (MSB), 220nF, 120nF, 33nF, 33nF, 8.2nF, 8.2nF. This would give equal ripple currents
on all MSBs.
Closest I found was:
1uF, 220nF, 150nF, 33nF, 33nF, 10nF, 10nF. All x2 of course.
Last edited:
For a one off, the DAC pcb looks familiar....
Didn't know I was sitting such a fortune...
I bet UV will know - I certainly don't - sorry.
I thought you'd appreciate seeing it - nearly fell of my chair when I read the price and thought immediately of you.
You can comfortably replicate that with the effort your putting in.
Bit of encouragement there for you to keep going.
Hey, there's a TCXO on it - did you notice that ?
Nice case though - not sure about the transparent top lid.
.
Thanks!
All inspiration/encouragement is welcome
I figure I might as well build this with the best components that I can afford and get the most out of it. I really like the way TDA1541A sounds with a few mods so this DAC will probably stay in my stereo for years.
Yeah, the TCXO is also in the BOM for this kit, thought I'd go with Valab or maybe Tent. There's little point in using an external clock in this build right?
74HC4040N, does reclocking or am I way of base here?
I'm actually putting more effort into this build than any before, I don't even trust the labels of resistors etc, I measure each one before soldering it in.
Waiting for the 100nF Wima MKP's to arrive from germany now. There's also some os-cons coming, but those will take longer I think.
I'll use a Cd-player as a case but with a oak front or something like that.
Have you seen the .3 ppm TCXO on E Bay ?
I'm trying to think who sells it now...
I'll check it and let you know - I want one too for my Valab.
I think I've also seen gold ones.
I'm sure that people will say the Tent is better - they're probably right too.
There's only so much ££ I can justify in my head for this hobby which eliminates the expensive clocks for me.
Sure, they'll be better but will I hear it ?
Like you - the TDA for my ears is very nice and it responds so well to the mods we are all doing.
I just hope your replacement caps come soon for the CD so we can hear your reaction to the step you are about to make
I'm trying to think who sells it now...
I'll check it and let you know - I want one too for my Valab.
I think I've also seen gold ones.
I'm sure that people will say the Tent is better - they're probably right too.
There's only so much ££ I can justify in my head for this hobby which eliminates the expensive clocks for me.
Sure, they'll be better but will I hear it ?
Like you - the TDA for my ears is very nice and it responds so well to the mods we are all doing.
I just hope your replacement caps come soon for the CD so we can hear your reaction to the step you are about to make
Have you seen the .3 ppm TCXO on E Bay ?
I'm trying to think who sells it now...
I'll check it and let you know - I want one too for my Valab.
I think I've also seen gold ones.
I'm sure that people will say the Tent is better - they're probably right too.
There's only so much ££ I can justify in my head for this hobby which eliminates the expensive clocks for me.
Sure, they'll be better but will I hear it ?
Like you - the TDA for my ears is very nice and it responds so well to the mods we are all doing.
I just hope your replacement caps come soon for the CD so we can hear your reaction to the step you are about to make
I remember seing something similar to the TCXO you described..
So do I mate, but shipping can vary from a few days to several weeks...it's a bit of a lottery when it arrives it seems.