Green Pres Finished...almost

pxpx83

Active member
Joined
Jun 3, 2004
Messages
44
Location
Orlando, FL
Finally finished up my pair of green pres. Tested them with an sm57 earlier today, and they sounded great. Everything works perfectly except for the led meter. I get a steady glow on 2 of the green leds on ch. 1 and both green and yellow on ch. 2. This does not change with the input signal (i.e. no input signal still shows lit leds). Any ideas on things to check? I'm not sure I connected the jumper correctly to make the led monitor input gain. Thanks Peter for a great project and Ptownkid for the parts kit.

green1.jpg

green2.jpg

green3.jpg
 

pxpx83

Active member
Joined
Jun 3, 2004
Messages
44
Location
Orlando, FL
Is this the correct spot for the input metering jumper? I'm still troubleshooting my led metering problem.

jumper.jpg
 

fucanay

Well-known member
Joined
Oct 18, 2005
Messages
478
Location
Hayward, CA
Check out this pdf.

http://www.nrgrecording.de/green_pre.pdf

This will show you the correct place to wire it to.

Matt
 

pxpx83

Active member
Joined
Jun 3, 2004
Messages
44
Location
Orlando, FL
Ok. So the jumper is right on both preamps, and I still cant find out what the problem is with the meters. Adjusting the meter trimpot has no effect and even without signal present, the same leds stay lit. Here is what I am seeing:

ch 1.
green -10.93
green -12.89
yellow -14.83
red -14.97


ch 2.
green -9.06
green -11.02
yellow -12.96
red -14.83


Does anyone have voltages for the TLO72 and LM339? I'm gonna pull both preamps out of the box tomorrow, and recheck component placements and orientation.

Thanks.

-Mike
 
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