| sith |
Just finished, PA100 using Alexw schematics and layout, and Carlosfm snuberized regulated PSU.
Testing one chanel (board) everything is beautiful, rail voltage is steady +/-27V, dc-offset 15mV, testing other the same thing... Absolutely beautiful...
Now the funny part, when I connected both channels(boards) to a PSU I got massive voltage drop and negative LM388 got too hot to touch... I used a single power tranny (separate windings), a single PSU, two rectifiers (ready made, rated 7A) LM388 regulators... So, every board works perfectly, but when they are both in system sh.. hits the fan... :hot: :bawling:
Alexw amp.
http://shine7.com/audio/pa100.htm
Regulated psu , nuuk's pages http://myweb.tiscali.co.uk/nuukspot...gainclone6.html |
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| sith |
:bigeyes: what??? No one??? :bigeyes:
C'mon ppl help me out with this one!!!!:bawling: |
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| tiltedhalo |
| LM3886 insulated or non-insulated, is the heat sink grounded and no insulator? PS properly connected for each channel?? Could you give more details?? |
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| Eva |
| I built a similar symmetrical regulated power supply around LM338K eight years ago, it was intended to power four TDA7294 ICs. I had planned to put both regulators in the same heatsink, but that caused parasitistic oscillation issues that by that time I did't know how to solve. The only working solution that I found was to put each regulator in a separate heatsink, without any electrical coupling between them, and also without any coupling to to the case or to the heatsinks of the chip-amps. |
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| sith |
| quote: | | LM3886 insulated or non-insulated, is the heat sink grounded and no insulator? PS properly connected for each channel?? Could you give more details?? |
Insulated, separate heatsinks, sure is connected properly, only one amp board in system, works perfectly, together they make problems.... |
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