voltage

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voltage

Postby chingon » Sat Mar 17, 2007 6:48 pm

I just finished building the J99 kit rev 3.3 and have a question. U1 & U2 at pin 3 I get a voltage reading of 28.6v and pin 5 gives me -14.6. According to the assembly instructions I've done something incorrectly because i'm not get -+14v.
At U3 on pin 4 I get a voltage of -11.9 and pin 8 gives me 12.1.

I also check if it passes signal and it does. The problem is when I adjust the gain I will get pop at each increment.

Anybody have any Idea on any of my problems?
Thanks
chingon
 
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Postby chingon » Sun Mar 18, 2007 9:36 pm

Anybody?

I tracked some guitar and it sounds good. How much of a sound difference is the with the hardy 990C?
chingon
 
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Re: voltage

Postby dkatz42 » Sun Mar 18, 2007 11:07 pm

chingon \$m[1]:I just finished building the J99 kit rev 3.3 and have a question. U1 & U2 at pin 3 I get a voltage reading of 28.6v and pin 5 gives me -14.6. According to the assembly instructions I've done something incorrectly because i'm not get -+14v.
At U3 on pin 4 I get a voltage of -11.9 and pin 8 gives me 12.1.

I also check if it passes signal and it does. The problem is when I adjust the gain I will get pop at each increment.

Anybody have any Idea on any of my problems?
Thanks

Looks like you're getting unregulated voltage on the +B rail. I'd look for a short across U4, or U4 or D6 being installed backward or anything else along the path from the +27 power input up to the opamps (follow the schematic.) Having wildly unbalanced voltages might explain the pops when you switch stuff.

BTW, the whole point of the voltage check before plugging in the opamps is to not burn them up if you've got power problems, which you do. It's probably not a good idea to plug in the opamps if the voltages are way off.

Disclaimer--my last EE class was during the Carter administration.
dkatz42
 
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Postby chingon » Tue Mar 20, 2007 12:08 pm

D6 was installed backwards...oopps.... Gool call dkatz42, you da man!
Thanks a lot broham
chingon
 
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