Searching for a quality amp for single 12V supply

Otherwise · 27th September 2004, 02:34 PM

Title says it all.. I'm designing an amp which would be placed in the 3,5" rack of my computer and alternatively sometimes used as is with a separate power supply. I already have a case of a diskette drive, some heat sinks and a fan to suit the application.

The main restriction seems to be the supply available; the amp should work with a single supply of +12v (or 5v). The power supply of the computer should be adequate for connecting an extra current eater to it (350W). The TDA 7xxx series from ST could be a solution but I'm not feeling very confident of their sound quality

And sonic quality is the main thing in here. Power needed is only a couple watts. I'm currently using a pair of sensitive Philips fullranges near the computer, in the future maybe some fullrages from Monacor, Visaton or Tang Band. And of course listening levels are low.

A very small class A amp could be an option (cool

) or the TDA 2040, it apparently should operate with single 12v supply, which means a couple watts output power.

Any suggestions?

Otherwise · 28th September 2004, 04:28 PM

Found an alternative for the TDAs, the ta8225h chip from Toshiba. -datasheet- Experiences about that? THD and gain vs freq seem to be a little better compared, for example, to tda7386 etc.

cm961 · 8th October 2004, 02:07 PM

Phillips has a bunch but I haven't found a source for them yet.

Like TDA5871 etc.

They're ment for car audio amplications, so 12V would be fine.

Pete

Just check Phillips I'm not sure if that part number is right. TDA8571 I think, or something.

thespeakerguy · 10th October 2004, 03:52 AM

Put class D in there, as computer cases already have a tremendous thermal load.

Maxim, Ti, Tripath, whatever.

Otherwise · 11th October 2004, 01:30 PM

I have now decided to use two ta8225h chips since I already bought them last week, but thanks for replying anyway. I did search for projects with ta8225h, but found zero, so this is a sort of experimenal project (not again

).. I'll let you know how they sound. Project is about to start during this or next week.

It's a challenge to get all the stuff in.. Estimated running temperature: hot

mateo88 · 11th October 2004, 05:17 PM

Why not use an lm1875 or an lm3875 and use both the +/- 12 volt rails?

Nasse · 11th October 2004, 05:51 PM

Always wanted to know what audiophile gurus think about TDA7370 chip amp. Maybe it is not perfect but has nice power and is easy to use, and reliable too. Works nice with available 12 V power supplies

Otherwise · 11th October 2004, 06:04 PM

Quote:

Originally posted by mateo88
Why not use an lm1875 or an lm3875 and use both the +/- 12 volt rails?

Because it would be nice if the amp worked without a dedicated ps, for exaple in the car. But the main reason is that AFAIK computer power supplies can only provide about 0,5A from the -12V rail.

zykegun · 2nd September 2006, 02:20 PM

Can anyone have build the TDA8571J ic amplifier? I build one based on the datasheet given circuit, when i turn on the circuit the diagnostic output pin goes low and there is noise on the speaker.
Anybody can help me?

TIA.

elaar · 4th September 2006, 11:54 PM

Wouldn't the sound quality of any of the possible chipamps be questionable with both the fairly unstable 12v voltage rail (i've seen it move up around 0.4v depending on what your computer is going), and also the number of nasty devices connected to this rail, such as perhaps 3 fans, the motor spinning up in the dvd drive etc..

Also won't proper grounding be a problem?

Alex

27th September 2004, 02:34 PM	#1
Otherwise Account disabled at member's request Join Date: Jun 2003 Location: Finland	Searching for a quality amp for single 12V supply Title says it all.. I'm designing an amp which would be placed in the 3,5" rack of my computer and alternatively sometimes used as is with a separate power supply. I already have a case of a diskette drive, some heat sinks and a fan to suit the application. The main restriction seems to be the supply available; the amp should work with a single supply of +12v (or 5v). The power supply of the computer should be adequate for connecting an extra current eater to it (350W). The TDA 7xxx series from ST could be a solution but I'm not feeling very confident of their sound quality And sonic quality is the main thing in here. Power needed is only a couple watts. I'm currently using a pair of sensitive Philips fullranges near the computer, in the future maybe some fullrages from Monacor, Visaton or Tang Band. And of course listening levels are low. A very small class A amp could be an option (cool ) or the TDA 2040, it apparently should operate with single 12v supply, which means a couple watts output power. Any suggestions?

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28th September 2004, 04:28 PM	#2
Otherwise Account disabled at member's request Join Date: Jun 2003 Location: Finland	Found an alternative for the TDAs, the ta8225h chip from Toshiba. -datasheet- Experiences about that? THD and gain vs freq seem to be a little better compared, for example, to tda7386 etc.

8th October 2004, 02:07 PM	#3
cm961 diyAudio Member Join Date: Jun 2001 Location: Peterborough, Ontario	Phillips has a bunch but I haven't found a source for them yet. Like TDA5871 etc. They're ment for car audio amplications, so 12V would be fine. Pete Just check Phillips I'm not sure if that part number is right. TDA8571 I think, or something.

10th October 2004, 03:52 AM	#4
thespeakerguy diyAudio Member Join Date: Feb 2001 Location: Silicon Valley	Put class D in there, as computer cases already have a tremendous thermal load. Maxim, Ti, Tripath, whatever.

11th October 2004, 05:17 PM	#6
mateo88 diyAudio Member Join Date: May 2004 Location: Argyle, Texas	Why not use an lm1875 or an lm3875 and use both the +/- 12 volt rails?

11th October 2004, 05:51 PM	#7
Nasse diyAudio Member Join Date: May 2004 Location: Scandinavia	Always wanted to know what audiophile gurus think about TDA7370 chip amp. Maybe it is not perfect but has nice power and is easy to use, and reliable too. Works nice with available 12 V power supplies

2nd September 2006, 02:20 PM	#9
zykegun diyAudio Member Join Date: Jul 2006	Can anyone have build the TDA8571J ic amplifier? I build one based on the datasheet given circuit, when i turn on the circuit the diagnostic output pin goes low and there is noise on the speaker. Anybody can help me? TIA.

4th September 2006, 11:54 PM	#10
elaar diyAudio Member Join Date: Oct 2005	Wouldn't the sound quality of any of the possible chipamps be questionable with both the fairly unstable 12v voltage rail (i've seen it move up around 0.4v depending on what your computer is going), and also the number of nasty devices connected to this rail, such as perhaps 3 fans, the motor spinning up in the dvd drive etc.. Also won't proper grounding be a problem? Alex

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