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-   -   Signalyst DSC1 (https://www.diyaudio.com/forums/digital-line-level/254935-signalyst-dsc1.html)

Signalyst 22nd November 2016 08:47 AM

Quote:

Originally Posted by carlsor (https://www.diyaudio.com/forums/digital-line-level/254935-signalyst-dsc1-post4889573.html#post4889573)
I received a bunch of 74AHCT595 chips made by Diodes Inc. instead of by TI. Same problem. I am doing only careful hand soldering and have had more fail than survive. One that survived the soldering had a channel fail later.

The 74AHCT595 chips I'm using are by NXP.

How do you do the soldering? I'm using RoHS compliant SMD soldering paste and hollow head / cup tip soldering iron, and IIRC the Weller solder station is set to 350C. Then I just pull the iron over each pin and clean solder flux with cleaning spray. Very small amount of solder paste is enough, otherwise it easily gets under the chips/behind the pins. And the paste must be at the outer tips of the pins to avoid residuals left in any improper place.

Signalyst 22nd November 2016 08:49 AM

Quote:

Originally Posted by Fabrizio72 (https://www.diyaudio.com/forums/digital-line-level/254935-signalyst-dsc1-post4893367.html#post4893367)
For sure SN74AHCT595 from TI, available also in PDIP package, appears more realiable.
But I don't know if operating frequency (max 110 MHz) or other features are appropriate

Where do you source PDIP variants? I would have used PDIP instead of SOIC if I would have been able to ensure supply of needed chips, because soldering PDIP is much easier...

kukynas 22nd November 2016 09:51 AM

Quote:

Originally Posted by Signalyst (https://www.diyaudio.com/forums/digital-line-level/254935-signalyst-dsc1-post4893987.html#post4893987)
Where do you source PDIP variants? I would have used PDIP instead of SOIC if I would have been able to ensure supply of needed chips, because soldering PDIP is much easier...

SN74AHCT595N TEXAS INSTRUMENTS, Shift Register, AHCT Family, Serial to Parallel, 1 Element, DIP, 16 Pins, 4.5 V, 5.5 V | Farnell element14

carlsor 22nd November 2016 05:58 PM

74AHCT595 Chips Still Failing
 
My guess is that all 74AHCT595 SOIC chips come from the same Chinese factory no matter the company. I suspect a bad batch coming through both Diodes Inc and TI. All 16 of the chips that came with the Chinese kit survived my soldering. I am only about 6 out of 20 with chips that I ordered recently. I replaced two bad 74AHCT595 chips two more times and had some output channels fail each time. The NXP 74AHCT595 is not available in SOIC.

I redesigned my PCB's to provide only 5V input signals so that I can use 74VHC595 chips which I was successful with in the past. These PCB's will also accept the 74AHCT595 chips. I will try both in my recalibrated reflo oven in a couple of weeks when the PCB's arrive.

Nic.M 22nd November 2016 06:52 PM

74AHCT595N DIP availability
 
Signalyst,

I have been using the Dip version of the Texas Instrument 74AHCT595N in my version of your DAC without any problems. I got them from Digi-Key,
P/N 296-33695-5-ND.

See Page 13, post 128 of this forum above for a picture of the beast.

N.

Fabrizio72 23rd November 2016 11:37 AM

... also available at mouser:

http://www.mouser.it/ProductDetail/T...ZxstehaqGUk%3d

Signalyst 6th December 2016 08:59 AM

Quote:

Originally Posted by carlsor (https://www.diyaudio.com/forums/digital-line-level/254935-signalyst-dsc1-post4894421.html#post4894421)
My guess is that all 74AHCT595 SOIC chips come from the same Chinese factory no matter the company. I suspect a bad batch coming through both Diodes Inc and TI. All 16 of the chips that came with the Chinese kit survived my soldering. I am only about 6 out of 20 with chips that I ordered recently. I replaced two bad 74AHCT595 chips two more times and had some output channels fail each time. The NXP 74AHCT595 is not available in SOIC.

I redesigned my PCB's to provide only 5V input signals so that I can use 74VHC595 chips which I was successful with in the past. These PCB's will also accept the 74AHCT595 chips. I will try both in my recalibrated reflo oven in a couple of weeks when the PCB's arrive.

Strange, here's the DigiKey packaging label for my NXP 74AHCT595 (from Thailand) batch:
https://www.sonarnerd.net/tmp/shift-reg.jpg

I'm using soldering iron and not oven, so the chips don't really get hot. But of course shouldn't make difference, reflow is supposed to be OK.

4est 7th December 2016 03:09 PM

1 Attachment(s)
Does anyone have a version of this running? I have mine bread boarded, but have an issue. It plays music just fine, but there is an annoying clicking low in the background as if the shift registers aren't summing to silence or something. FWIW, my output transformer is my TVC pre. Anybody else experience this and/or have any ideas?

Quote:

Originally Posted by nautibuoy (https://www.diyaudio.com/forums/digital-line-level/254935-signalyst-dsc1-post4806745.html#post4806745)


carlsor 7th December 2016 08:30 PM

16-bit Sine-wave DSD Working!
 
2 Attachment(s)
See pictures of my latest differential 16-bit sine wave weighted DSD and Amanero Interface-Mute boards.

First listening impressions are promising. I first connected the outputs to my Cinemag transformers. Very nice sound, but lacking a bit in bass and musical energy. No noise that I can hear. Much more detail than the Chinese 32-bit version.

Next I sent the output to a JFET buffer board and then through the Cinemags. Bass is powerful and deep - best I have ever heard. I use this same JFET buffer circuit on the outputs of my reference DDDAC NOS PCM1794 DAC which gave a similar sonic improvement. Lots of musical energy and detail resolution. Also, lots of new parts sound which is very bright and edgy. In a few days of continuous play I will know how good this DSD NO-DAC can sound.

nautibuoy 7th December 2016 08:51 PM

Good to see your progress Carlsor, it looks very promising.

I've been short of time to progress my projects after I got frustrated at damaging my Chinese diff board and I've been waiting to see how you're project progressed.

Assuming it all works out, are you willing to share your boards/schematics?

What DSD rate are you able to run your Amanero at? As I have had some success at running my Buffalo 3SE DAC at DSD512 via a Beaglebone/Botic/NAA I will be looking to develop that input interface.

Cheers

Ray


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