high-voltage chip amp

xplod1236 · 30th May 2004, 09:42 PM

is there a high-voltage chip amp? I'm looking for something that will run off +/- 50-75v rails. I'm not worried about current handling, because I can always parallel the chips.

till · 30th May 2004, 09:48 PM

http://focus.ti.com/docs/prod/folders/print/opa445.html

but you would need to parallel 100 of them or so - better to make a current gain stage with transistors behind it. (see datasheet)

paulb · 30th May 2004, 09:59 PM

You'll find something here:
http://eportal.apexmicrotech.com/mainsite/index.asp

soundNERD · 31st May 2004, 02:22 AM

well when i bought a set of logitech z-680 speakers, the first one had an annoying rattling sound so i had them send me a new set. so, the first thing i did was tear apart the old one. the amps inside it, according to the datasheet can run off of 120V (+/-60V) supplies, and also produce 100W at that voltage (i think)

i also forgot what chip it is.

djk · 31st May 2004, 01:32 PM

The power supply is in the subwoofer and each of the sats is powered by 53W RMS

soundNERD · 31st May 2004, 01:44 PM

Quote:

Originally posted by djk
The power supply is in the subwoofer and each of the sats is powered by 53W RMS

yes, the trafo is 26.2-0-26.2V. There is also a 14V single output. . I am not sure what voltage it is after the voltage boost from the rectifiers.

I know that the chips aren't running at full power, since there is no way its getting +/-60V

But that is still pretty high voltage.

bradleyGT · 1st June 2004, 11:15 PM

The Z680 uses TDA7294 amp IC's. Absolute maximum rating for this chip is up to +/- 50V according to the data sheet, but it's much happier below 40V. Keep in mind this is also assuming single-ended into 8 ohms. If you want to use a standard 2-chip BTL config you should not exceed 35V into no less than 8 ohms (basically same constraints as LM series).

I have a Z680 and it has 8 ohm sats in SE config, subwoofer is 8 ohm BTL config. The voltages listed above from the data sheet are consistent with a 26.2-0-26.2 VAC transformer since this would essentially yield ~35VDC unloaded. 35V into 8 ohms according to the IC data sheet yields 70W typical. My Z680 spec says 62W into 8 ohm sats, 188W into 8 ohm BTL sub, so these ratings make sense given the transformer and the IC specs.

The 14V winding on the transformer is sent to the digital control pod and is used to create the low voltage DC for the digital circuits.

Cheers

soundNERD · 2nd June 2004, 03:09 AM

yes, i didn't know that, all i knew was that when i looked up the datasheet it said it was +/-50

30th May 2004, 09:42 PM	#1
xplod1236 diyAudio Member Join Date: Dec 2003 Location: On the couch	high-voltage chip amp is there a high-voltage chip amp? I'm looking for something that will run off +/- 50-75v rails. I'm not worried about current handling, because I can always parallel the chips.

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30th May 2004, 09:48 PM	#2
till Banned Join Date: Apr 2002 Location: Germany, Clausthal	http://focus.ti.com/docs/prod/folders/print/opa445.html but you would need to parallel 100 of them or so - better to make a current gain stage with transistors behind it. (see datasheet)

30th May 2004, 09:59 PM	#3
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	You'll find something here: http://eportal.apexmicrotech.com/mainsite/index.asp

31st May 2004, 02:22 AM	#4
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	well when i bought a set of logitech z-680 speakers, the first one had an annoying rattling sound so i had them send me a new set. so, the first thing i did was tear apart the old one. the amps inside it, according to the datasheet can run off of 120V (+/-60V) supplies, and also produce 100W at that voltage (i think) i also forgot what chip it is.

31st May 2004, 01:32 PM	#5
djk diyAudio Member Join Date: Feb 2001 Location: USA	The power supply is in the subwoofer and each of the sats is powered by 53W RMS

1st June 2004, 11:15 PM	#7
bradleyGT diyAudio Member Join Date: Feb 2003 Location: USA	The Z680 uses TDA7294 amp IC's. Absolute maximum rating for this chip is up to +/- 50V according to the data sheet, but it's much happier below 40V. Keep in mind this is also assuming single-ended into 8 ohms. If you want to use a standard 2-chip BTL config you should not exceed 35V into no less than 8 ohms (basically same constraints as LM series). I have a Z680 and it has 8 ohm sats in SE config, subwoofer is 8 ohm BTL config. The voltages listed above from the data sheet are consistent with a 26.2-0-26.2 VAC transformer since this would essentially yield ~35VDC unloaded. 35V into 8 ohms according to the IC data sheet yields 70W typical. My Z680 spec says 62W into 8 ohm sats, 188W into 8 ohm BTL sub, so these ratings make sense given the transformer and the IC specs. The 14V winding on the transformer is sent to the digital control pod and is used to create the low voltage DC for the digital circuits. Cheers

2nd June 2004, 03:09 AM	#8
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	yes, i didn't know that, all i knew was that when i looked up the datasheet it said it was +/-50

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