DAC build TDA1541A/SAA7220P/B *will take som time*

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
T

Torchwood421

Member
Joined 2011
Dwight, I am all wired up on the second build. Have to get up the nerve to flip the switch. Did all except the ground to the IEC power connector. I like to make sure I have no noise first. Tonight is ASM, audio club night so I have to test the build when I can. PM me with your full address so I can get a postage quote from the Post Office. Once I check everything I'll test that CS8414. That way you know you have a tested part. Dave :)
 
T

Torchwood421

Member
Joined 2011
8414

Hi msmart2b, Dwight I am listening to the dac with the 8414. Sounds good. It works. When I fired up the dac yesterday after putting it in an enclosure, it didn't work! All voltages were OK. I touched the digital filter and it came to life. My adapter has low profile sockets and I guess the chip was loose. I had the board top side down to inspect the pins a day ago. What a relief. :eek: I'll get over to the PO this morning. ;) Dave
 
C

ctef

Member
Joined 2011
Well. I'm going better and better:cool:
Now I'm checking everything, and try to change the Analogmetric PCB to that Not Reclocked Mod, and next and NOS mod. But hate to cut the traces:mad:
Any way.
At both schemes, is big difference with the analog and digital grounds. Is this so important?
 
T

Torchwood421

Member
Joined 2011
DGND and AGND

Hi ctef, From the CS8414 datasheet. " DGND should be connected to same ground as AGND". That means they tie together so not an issue. The pin 16. "SEL- Select 16. Control pin that selects channel status information (SEL=1) or error and frequency information (SEL=0) To be displayed on six of the following pins 2-6 and 27." The Analogmetric DAC doesn't use the reporting capability in the CS8414. It doesn't matter if tied to ground or +5. Has to be one or the other. So I would leave it alone unless you want to access pins 2-6 and 27. I hope that helps. :) Dave
 
A

AudioLapDance

Member
Joined 2003
Torchwood421 said:
.... The ECDesign's thread has lot's to say and I'm glad it made it into the Red Baron board. :) ...
Click to expand...

EC (John) did have a lot to say but the way it's implemented on the Red Barron won't work out (not SMD, too far away, poor ps bypass ...)

It's still one of the better boards out there (better grounding for DEM decoupling) but as Thorsten used to say, it's still a bit "horror show."

Cheers,
Jeff
 
A

AudioLapDance

Member
Joined 2003
Since someone will probably ask, what's "horror show"?

Here's Thorsten's evaluation of Raindrop's 8805/dual 1541:

8805 dual 1541.jpg

DAC Kit WM8805 + TDA1541 2.0C parallel output OS/NOS | eBay

ThorstenL said:
Folks,



Okay, lets do some analysis of the kit from pictures, shall we?

First, one quick look suffices to note that this "kit" is mostly a "cut'n'paste" job from a number of sources, not something that I would call a "design".

Let's start at the beginning. The WM8805 circuitry is "bog standard". But the decoupling, instead of following best practice, is based on audiophoolish notions of using through hole film cap's with arrangements that produce long loops on chips that run at frequencies of 10's of MHz all the way to around 100MHz (WM8805 internal operation). The powersupply are generic 3-Pin regulators, including for the critical reference clock for the DPLL in the WM8805.

The "Os-Con's" may look similar to the best series from Sanyo but are the cheaper Nichicon alternative. I have tested these myself and they perform anywhwere between three times (resonance frequency) and twenty times (minimum impedance) worse than real Os-Cons.

So the WM8805 section will work after a fashion, but there is no way it is ever going to offer anything like the phase-noise / jitter levels the WM8805 is capable of. In fact, I think despite all it's shortcomings, a well applied Cirrus Logic CS-8412/14 will have lower jitter.

Okay, the SAA7220 is a MASSIVE noise generator. It's decoupling matches that of the rest of the digital section, that is it has for all intents grassmudhorse all decoupling. The single ferrite bead between the SAA7220 PSU will help, but likely not remotely enough, especially as the "far side" of it is not decoupled...

Just poking a 'scope around the PSU pins on this PCB will be feast for the eyes, I'd predict noise levels in the 100's of mV around the filter and probably no better for the rest.

Okay, now our heavily jittered signal goes to our TDA1541.

This has the same kind of decoupling arrangements on the supplies as the rest of digital section, that is grassmudhorse incompetent and the DEM decoupling is about as bad as can be.

By the looks of it the regulators for the TDA1541's are some discrete ones, does not like shunts though. No matter how good or bad they are, they are too far from the IC's to do much good no matter their nature.

Overall the level of "engineering" around the TDA1541's seems an attempt to recreate the 1980's Philips/Marantz approache and getting an epic FAIL at even that task (I would recommend these players primarily as a lesson in "how not to do it").

Okay on to the analogue stages. These seem a mixture out of one of the common base I/V's we have seen here (there where numerous variation on these all with noisy LEDS's as references), I'd probably rather have a CEN or SEN, but they are probably the part of the whole circuit, thanks to the Chinese Kopy-Mao that calls itself "Engineer" having used a rather decent source to Kopy.

Sadly the Kompetence of the Kopy-Mao did not extend to kopying a discrete diamond buffer to place after the I/V so we find an Op-Amp.

I think almost anyone can build a better TDA1541 DAC on a piece of veroboard and using some copper foil, using what can be learned in the forums here.

Certain the "Reference" DIYA Groupbuy project would be a better choice, wretched as it is...

That's not just a trainwreck, that's an epic, high speed, Wenzhou level trainwreck, complete with completely clueless Wang Yongping style apologists saying "This is all very good and proper, whether or not you believe, I believe it."

CAVEAT EMPTOR MONITUS ES

Ciao T
Click to expand...

from:
http://www.diyaudio.com/forums/digital-line-level/203511-any-good-tda1541a-dac-kit-4.html

:eek:
 
Last edited:
A

AudioLapDance

Member
Joined 2003
Here's a summary of T's suggestions for getting the most out of the 1541:

AudioLapDance said:
Joshua_G, it's too bad you didn't ask this question a few months earlier:

Raindrop was selling a WM8805 to NOS TDA1541 with no I/V. Although a train-wreck like T says, there's less to go off the track and for $90 it will be a fun thing for me to play with. I emailed him/her and they aren't offered anymore.

Anyway, let's try to get this thread back on track:

T's first hints:
http://www.diyaudio.com/forums/digi...-any-good-tda1541a-dac-kit-4.html#post2854098

T's veroboard:
http://www.diyaudio.com/forums/digi...any-good-tda1541a-dac-kit-13.html#post2862125

Pics of T's 1541 DAC
http://www.diyaudio.com/forums/digi...-any-good-tda1541a-dac-kit-5.html#post2854719

Decoupling on T's DAC
http://www.diyaudio.com/forums/digi...-any-good-tda1541a-dac-kit-6.html#post2854945
...
Click to expand...

from:
http://www.diyaudio.com/forums/digi...any-good-tda1541a-dac-kit-36.html#post2887893

Lots of good 1541 info in there (some of which contradicts advice given in this thread) but my post is a good summary.

Cheers,
Jeff
 
Last edited:
T

Torchwood421

Member
Joined 2011
1541A dac's

Hi AudioLapDance, Thanks for posting all that great data. It looks like the Red Baron's I ordered are lost in the mail or maybe never shipped? Don't know. I may have no choice except to do a Veroboard times 2. I'll give it a little more time. I am looking at a balanced version of the TDA. Doing it a way that I have never seen here or on the forums. Not perfect but 1 way to do it. I'm always surprised about the claims of building balanced dac's yet I see no circuits. Hmmmmm? Well moving on. My second build the Mark II Analogmetric is up and running in a new enclosure. I swapped in a NPC SM5814BP for an AP. I think it sounds better with a BP part. The Mark II uses a EC designs style daughter board under the chip with PPS smd caps. I used a starch plastic socket (plastic dissolves) leaving standing pins. Most of the decoupling is under the chip now. It is a very clear clean detailed sound. I recommend doing ECDesign's decoupling scheme. The Pedja DDNF is doing a great job. Hope to find time to look at the AD844 again from the other thread. :xfingers: Dave
 
A

AudioLapDance

Member
Joined 2003
Torchwood421 said:
... It looks like the Red Baron's I ordered are lost in the mail or maybe never shipped? Don't know. I may have no choice except to do a Veroboard times 2. I'll give it a little more time...
Click to expand...
He seems like a nice guy, I got my board promptly. Tell him and he might express post you some replacements.

Torchwood421 said:
... I am looking at a balanced version of the TDA. Doing it a way that I have never seen here or on the forums. Not perfect but 1 way to do it. I'm always surprised about the claims of building balanced dac's yet I see no circuits. Hmmmmm? ...
Click to expand...

T would say to get a single 1541 running optimally and then worry about a dual or balanced. [And he would be chuckling to himself because once you fully understand the complexities of the unique 1541 and mixed-signal design, you'd realize it is very difficult to do two. ]

Torchwood421 said:
...Mark II Analogmetric is up and running in a new enclosure...
Click to expand...

This one?:
TDA1541A 16-Bit DAC Kit (Stereo)_DAC/USB DAC_Analog Metric - DIY Audio Kit


Torchwood421 said:
...I swapped in a NPC SM5814BP for an AP. I think it sounds better with a BP part...
Click to expand...

Careful with the digital filters. T mentions they're very noisy and must have excellent ps decoupling. Otherwize, sometimes it's best to bypass them and go from receiver to 1541


Torchwood421 said:
...The Pedja DDNF is doing a great job. Hope to find time to look at the AD844 again from the other thread. :xfingers: Dave
Click to expand...

http://www.diyaudio.com/forums/grou...-diamond-non-feedback-i-v-stage-tda1541a.html

Do you have a good layout?



Radio Amateur? Nope. But, I'm curious why you ask?

Cheers,
Jeff

PS If you mention stuff, it's good to link to it. It makes things more clear and ... rich! The beauty of the Internet and hyper-linking, no?
 
Last edited:
T

Torchwood421

Member
Joined 2011
AudioLapDance said:
He seems like a nice guy, I got my board promptly. Tell him and he might express post you some replacements.
I will give him a little time maybe stuck in customs.


T would say to get a single 1541 running optimally and then worry about a dual or balanced. [And he would be chuckling to himself because once you fully understand the complexities of the unique 1541 and mixed-signal design, you'd realize it is very difficult to do two. ]
I agree with you. Just thought it's odd as to the numerous comments that they did it. Maybe there is no advantage to balanced. I do have old S1 Crown dac's They predate the fake fade. They are quite alright.


This one?:
TDA1541A 16-Bit DAC Kit (Stereo)_DAC/USB DAC_Analog Metric - DIY Audio Kit
That is the beast. Warts and all.



Careful with the digital filters. T mentions they're very noisy and must have excellent ps decoupling. Otherwize, sometimes it's best to bypass them and go from receiver to 1541
Actually my Cousin started this in about 1990. That is why I am using such an old obsolete NPC filter. Like the true 18 bit coefficients. We started out with old Magnavox CD players.



http://www.diyaudio.com/forums/grou...-diamond-non-feedback-i-v-stage-tda1541a.html

Do you have a good layout?
I have Oliver's last garage sale board with Mundorf Supreme capacitors. :D


Radio Amateur? Nope. But, I'm curious why you ask?
I remember hearing Hamilton on the air. Thought it was worth asking. I have been licensed since 14 years old. AB0N
Cheers,
Jeff

PS If you mention stuff, it's good to link to it. It makes things more clear and ... rich! The beauty of the Internet and hyper-linking, no?
Click to expand...
I am still learning how to do it. Sorry! :eek:
 
A

AudioLapDance

Member
Joined 2003
Torchwood421 said:
I am still learning how to do it. Sorry! :eek:
Click to expand...

As if to prove your point! Ba-dum, tish! :D

Where are my manners, I assumed the worse! :eek:

When you hit the "quote" button in the bottom right corner, the text editor pops up and the post is enclosed in tags

blah said:
I 'select all' (cntr a) and then make a bunch of copies. Now using highlight and '...' I cut up your posts so each set of quote tags contains just the sentence I want to respond to. Then I put my comments inbetween these mini quotes.

To link to websites, just copy/paste their www.blahblah web address directly into your post and they get converted to links with nice descriptive titles!

I hope that's clear?!?

Cheers,
Jeff
Click to expand...
 
Last edited:
T

Torchwood421

Member
Joined 2011
Computer illiteriate

Hi Jeff, Yes it's true. I am pretty much self taught on all things computer. :eek: I will try your suggestions. The odd thing is I figured out things at work that they never taught. How to recover a failed log on and all that kind of thing. So sometimes I am ahead of the curve usually a little behind. That is why my post tend to be simple. I thought my cheat was slightly clever. Doah.... If not a bit Homer Simpson. :D I do need to do some picture hosting somewhere to. I'll look into that soon. Dave ;)
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom