Hello again fellow DYI-ers!
I've been using LM3886 hybrid amplifier for quite some time now and am thoroughly pleased with it. However some of my friends claim these have nothing on the STA575 which in their opinion is the absolute best sounding chipamp.
So the question is: how do i provide the proper voltages for it? I know from the datasheet that Vs+ and Vs- are fixed voltages that are used for all but the power transistors. However we also find the CD+ and CD- voltages which are supposedly used for the power stages and here's the confusion: These rails are "tracking" rails and the voltage for the power transistors is supposed to follow the signal voltage so that the transistors operate at their optimal efficiency point. But i cannot understand if the IC produces these voltage variations internally or i have to provide the adaptive voltage myself.
If it requires variating voltages, then what would the impact be of feeding it fixed voltages? I imagine the efficiency would be lowered and it would not be able to attain maximum output because of over dissipation.
What are your thought on this? Has anyone attempted to use that chipamp???
I've been using LM3886 hybrid amplifier for quite some time now and am thoroughly pleased with it. However some of my friends claim these have nothing on the STA575 which in their opinion is the absolute best sounding chipamp.
So the question is: how do i provide the proper voltages for it? I know from the datasheet that Vs+ and Vs- are fixed voltages that are used for all but the power transistors. However we also find the CD+ and CD- voltages which are supposedly used for the power stages and here's the confusion: These rails are "tracking" rails and the voltage for the power transistors is supposed to follow the signal voltage so that the transistors operate at their optimal efficiency point. But i cannot understand if the IC produces these voltage variations internally or i have to provide the adaptive voltage myself.
If it requires variating voltages, then what would the impact be of feeding it fixed voltages? I imagine the efficiency would be lowered and it would not be able to attain maximum output because of over dissipation.
What are your thought on this? Has anyone attempted to use that chipamp???
No takers? Ok, i understand this is called envelope following and it works as i described it. Apparently the IC does NOT produce it's voltages internally so it's more or less useless without auxiliary circuitry. The IC outputs a signal that from what i could gather is digital and tells a microcontroller to adjust the voltage to a certain level and it does that very quickly. I could build an analog circuit to replicate that behavior but it would be nowhere near as accurate... I guess i'll leave this one on the sidelines for now.
Sorry, my bad. I just assumed that the people here would know what those are. Anyway, the LM3886 is not in question, but the STA575.
This is the datasheet for it:
http://www.st.com/web/en/resource/technical/document/datasheet/CD00002481.pdf
The STA575 is a BTL stereo power amplifier chip capable of 100W per channel output, but only under the prescribed conditions, which in my opinion are not available to any DIY-er. But i could be wrong.
There was only one other post that i could find using search and there wasn't any relevant information there so that's why i made this thread.
This is the datasheet for it:
http://www.st.com/web/en/resource/technical/document/datasheet/CD00002481.pdf
The STA575 is a BTL stereo power amplifier chip capable of 100W per channel output, but only under the prescribed conditions, which in my opinion are not available to any DIY-er. But i could be wrong.
There was only one other post that i could find using search and there wasn't any relevant information there so that's why i made this thread.
The STA575 is an obsolete product, according to the watermark on the datasheet. In order to use it you need the power supply controller chip, the STABP01, which is also obsolete. Neither chip is available from Digikey or Mouser. And the first line of the STABP01 data sheet should raise some concerns: "BASH® LICENCE REQUIRED".
There are probably many other IC amps from ST that will offer the same performance without the availability and licensing issues.
The STA575 chip itself wouldn't be a problem since i already have it and it's guaranteed to be in working condition, but the controller... that's another story entirely.
Not sure what you mean with the licence but if it means the controller needs to have some code programmed that only they have... then it's like Don Quijote fighting the windmills.
Edit: furthermore i can't seem to find a schematic on how i would even use these if i had both so i should ask the guy who gave me the STA575 if he has the service manual for whatever device it was in.
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