I'm more interested in modding it into a DAC. I've yet to try out feeding in directly 96kHz upsampled on my PC (the interface on the board is limited to 48kHz). I do now have a CM6631 and an SA9023 which can handle that, so might be time to have a play with an extremely steep output filter...
It is, in effect, a high current/voltage output DAC so I'm not sure what the end purpose of turning into a low voltage/current DAC would be - as DAC for a better amp stage? Or into a buffer for huge currents? Definitely the CM108 is the drawback but I've played with one before and so I know it's possible to get decent i2s out of it by replacing the pierce oscillator with a low jitter/phase noise xo. I saw earlier on the thread that the STA333W PLL can also be modified to lower jitter. For me, it's these features that make it worth playing with - it's so cheap to buy it's really whether it's worth my time to mod.
Yeah - to get a better DAC, meaning one with nice drive capability, low OOB noise and without opamps in the OPS. When I've played with these chips for speakers I always end up being limited by the PSU, particularly on bass. The STA333 is also rather low voltage, not enough swing for my tastes into normal speaker impedances (8ohm).
Yeah, I guess that's why it's discontinued with no replacement and the other STA DDX chips live on.
The board just arrived so I hooked it up to a 19V netbook psu - the sound was a bit rough at first and the front volume/mute buttons on the board didn't do anything- it seems they don't control the STA333W I2C but rather they control the CM108. That's a real shame.
I couldn't get the CM108 to run anything more than 16 bit so that means a PC based (on the target machine, its Win 7 64bit) 16 bit volume control. I'm having flashbacks to the 1990's and Win XP! I'm decimated....
I also tried the CM108 Vista driver and although it worked, when I opened up the driver in Control Panel, my laptop crashed. I tried to install the CM108ah Win8 driver but it wouldn't install. So then I let windows update find a driver for "USB pnp headphone set" and that works - in that it allows the front buttons to control the Windows volume control but there's no other driver control, so I can't get the headphone output to work. That's another shame - I hoped to use it as a simultaneous output for a subwoofer.
So, a bit disappointed really, except it was US$3. I won't be spending anytime modding it given it simply must have a better USB receiver, and why bother doing it to this because it clearly isn't as good as the STA326 and there'd still be no volume control for the STA333.
I might still use it for computer speakers but with no mods for me. It's saving grace is the tiny size, low cost and no need to press a button to turn it on so it can hide in a box unseen. It's certainly better than many of the options, just not as good as I had hoped. But then, US$3. How silly a price is that.
The board just arrived so I hooked it up to a 19V netbook psu - the sound was a bit rough at first and the front volume/mute buttons on the board didn't do anything- it seems they don't control the STA333W I2C but rather they control the CM108. That's a real shame.
I couldn't get the CM108 to run anything more than 16 bit so that means a PC based (on the target machine, its Win 7 64bit) 16 bit volume control. I'm having flashbacks to the 1990's and Win XP! I'm decimated....
I also tried the CM108 Vista driver and although it worked, when I opened up the driver in Control Panel, my laptop crashed. I tried to install the CM108ah Win8 driver but it wouldn't install. So then I let windows update find a driver for "USB pnp headphone set" and that works - in that it allows the front buttons to control the Windows volume control but there's no other driver control, so I can't get the headphone output to work. That's another shame - I hoped to use it as a simultaneous output for a subwoofer.
So, a bit disappointed really, except it was US$3. I won't be spending anytime modding it given it simply must have a better USB receiver, and why bother doing it to this because it clearly isn't as good as the STA326 and there'd still be no volume control for the STA333.
I might still use it for computer speakers but with no mods for me. It's saving grace is the tiny size, low cost and no need to press a button to turn it on so it can hide in a box unseen. It's certainly better than many of the options, just not as good as I had hoped. But then, US$3. How silly a price is that.
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There's a new FDA on Taobao now, more expensive (around $23) but it has the significant advantage of having an S/PDIF input which means it can accept a 96kHz stream. The advantage of this is it bypasses the internal up/down-sampling digital filter. The chip itself is STA350BW which has a higher upper voltage limit (30V). I've been experimenting with using the STA350 as just a modulator, connected to an STA508 as output stage, this works well but the STA508 needs a seriously low impedance supply to get best results - running on my bench supply the subjective effect is rather bass-light. I'm in the process of identifying the best bang for the buck capacitors to build a 1F supply for it.
This new board has a real volume control (encoder) and an LCD to show the volume setting (0.5dB steps). Pretty much all the niggles with the earlier board have been solved
STA350?????? ??? ?? USB?? ??2.1??/ 2.0??-???
This new board has a real volume control (encoder) and an LCD to show the volume setting (0.5dB steps). Pretty much all the niggles with the earlier board have been solved
STA350?????? ??? ?? USB?? ??2.1??/ 2.0??-???
I tracked down Richard's blogs on the new forum...
https://www.diyaudio.com/archive/blogs/abraxalito/
https://www.diyaudio.com/archive/blogs/abraxalito/
Today I've resurrected this project and I'm listening to my unmolested STA333BW board as I type this - considering it's just temporarily hooked up with croc leads and the speaker is a naked 4in unit that is my test/sacrificial unit, it actually sounds OK!
I have a second board that I've already started stripping down to prepare it for utilisation as per Richard's headphone amp experiments and he's kindly offered to help me out with the stepdown transformers.
Studying the STA333BW datasheet I can see that the STA chip has an I2S input so, assuming I get the basic HPA function working, I'm looking to replace the onboard USB interface with something like a JLSounds I2SoverUSB board - this should allow higher rate material (the onboard interface is limited to 44/48KHz), which the STA can handle, and give the benefits of isolation and reclocking. I can see some vias that will serve to connect an I2S input, the only thing that I need to get my head around is the relevant register setting - see section 7.1.1 of the STA333BW datasheet
file:///C:/Users/Ray/AppData/Local/Temp/sta333bw.pdf
I have a second board that I've already started stripping down to prepare it for utilisation as per Richard's headphone amp experiments and he's kindly offered to help me out with the stepdown transformers.
Studying the STA333BW datasheet I can see that the STA chip has an I2S input so, assuming I get the basic HPA function working, I'm looking to replace the onboard USB interface with something like a JLSounds I2SoverUSB board - this should allow higher rate material (the onboard interface is limited to 44/48KHz), which the STA can handle, and give the benefits of isolation and reclocking. I can see some vias that will serve to connect an I2S input, the only thing that I need to get my head around is the relevant register setting - see section 7.1.1 of the STA333BW datasheet
file:///C:/Users/Ray/AppData/Local/Temp/sta333bw.pdf
Finished stripping and cleaning-up the STA board, ready for replacement parts now - they're on the way from Richard and Mouser.
and here's a proper link to the STA datasheet.
https://www.digikey.ch/htmldatasheets/production/864699/0/0/1/sta333bw.html
and here's a proper link to the STA datasheet.
https://www.digikey.ch/htmldatasheets/production/864699/0/0/1/sta333bw.html