| xplod1236 |
| 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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| soundNERD |
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. |
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| djk |
| The power supply is in the subwoofer and each of the sats is powered by 53W RMS |
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| soundNERD |
| 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. |
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| bradleyGT |
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 |
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| soundNERD |
| 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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