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Old 27th March 2010, 05:50 PM   #7551
Yunick is offline Yunick  Sweden
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Thanks guys.
I'll order a few to try.
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Old 27th March 2010, 06:48 PM   #7552
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couple noob biasing questions:

1. do I bias one side at a time or do I have to bring up both sides together?

2. I hooked up a 25w lightbulb in series with the mains and it glowed dimly after settling. After bringing up the bias on the right side, the bulb started glowing brighter and brighter. This sounds normal (since its drawing more current), but want to check. I then put a 75W bulb in when the 25W got to "normal" brightness. The 75W was alot brighter. This is normal as well, right?

Am I safe to wire the amp to my power strip without the lightbulb limiter?

thanks,
kevin
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Old 27th March 2010, 06:59 PM   #7553
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Go back with your settings untill the bulb slight glows.
Take out the bulb and start again your settings..
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Old 27th March 2010, 07:07 PM   #7554
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I got it to dim lightly by setting the pots to a minimum, so I can now plug it into the power strip, and then adjust bias?

Can I adjust one side at a time, or do I have to go back and forth between channels?
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Last edited by acold7dusta; 27th March 2010 at 07:14 PM.
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Old 27th March 2010, 07:13 PM   #7555
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It is ok too.
The bulb allows to check there is no big issue at first powering on but must be out when setting.

Last edited by bobodioulasso; 27th March 2010 at 07:16 PM.
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Old 27th March 2010, 07:17 PM   #7556
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ok, thanks for the clarification
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Old 27th March 2010, 08:55 PM   #7557
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Ummmm connected it to the power strip and I got some smoke?! I checked the obvious, there are no shorts, I had proper voltage at the boards with the bulb in series, and my pots were at a minimum. The only things it COULD be are bad capacitors or rectifiers. The only reason I say that is because the PSU is recycled from my previous attempt that had the V- and gnd reversed at one rectifier.
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Old 27th March 2010, 09:42 PM   #7558
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Quote:
Originally Posted by acold7dusta View Post
Ummmm connected it to the power strip and I got some smoke?! I checked the obvious, there are no shorts, I had proper voltage at the boards with the bulb in series, and my pots were at a minimum. The only things it COULD be are bad capacitors or rectifiers. The only reason I say that is because the PSU is recycled from my previous attempt that had the V- and gnd reversed at one rectifier.
I always start with the bulb with series, and if everything is ok I put the pots again to zero (by measuring the R3 and next R4 across their legs, the voltometer shows zero ohm).
If the fuse blowed after sometime, then you burnt the 0.47R resistor together with some of your mosfets...
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Old 27th March 2010, 10:28 PM   #7559
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pots read 0.3R, the fuse is fine, and my 0.47R resistor reads 0.5R. not sure why my other resistors are all now out of wack though...
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Old 27th March 2010, 11:23 PM   #7560
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Disconnect one channel from the PSU.
Check the pots are at min. measuring almost 0 ohm across R3 and R4.
Short circuit the input.
No speaker wired.
Insert the bulb again.
If OK, the bulb glows while the caps are charging and then stops glowing.
Check and set one channel at a time.

Last edited by bobodioulasso; 27th March 2010 at 11:29 PM.
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