wmb
Well-known member
Hello,
This is the first of two that I'm building. I got everything together tonight and so far it passes audio and is generally not making any unusual noises but it is not working correctly. There are a number of things that may have one root cause or possibly more.
1. The gain control has no effect other than adjusting the level of noise present in the signal. When it's turned to maximum the unit is very quiet and passes audio. If I turn it down even a little the output level does not change but it seems to hum more.
2. The meter switch seems like it's working backwards. In the gain reduction postition the meter is hyperactive. Just about any signal will cause the meter to jump to maximum output. In the +4 Output position the needle is responsive to the Zero Adjust. I was pretty careful to follow the wiring diagram in the drip opto manual. I will check this tomorrow.
3. Touching the Gain, Peak Reduction and Compress/Limit switch cause the unit to hum.
4. Did not demonstrate any gain reduction with T4B (drip version) installed.
All of these volume/hum symtoms sound like a grounding problem. I am using a case made by Purusha that has a powder coated front panel. I did not grind off the powder coat around the pots but I'm thinking this is the first thing I should check. I'm also wondering if I should connect all the panels with a grounding strap of some kind.
Also one of the pots I got from digikey just spins continuously without any stops. Do they have an exchange policy? Is it worth it to send it back or should I just order another before I start on the second unit. Kind of annoying that I didn't notice this until now.
Any ideas would be very helpful.
Thanks, Wm.
This is the first of two that I'm building. I got everything together tonight and so far it passes audio and is generally not making any unusual noises but it is not working correctly. There are a number of things that may have one root cause or possibly more.
1. The gain control has no effect other than adjusting the level of noise present in the signal. When it's turned to maximum the unit is very quiet and passes audio. If I turn it down even a little the output level does not change but it seems to hum more.
2. The meter switch seems like it's working backwards. In the gain reduction postition the meter is hyperactive. Just about any signal will cause the meter to jump to maximum output. In the +4 Output position the needle is responsive to the Zero Adjust. I was pretty careful to follow the wiring diagram in the drip opto manual. I will check this tomorrow.
3. Touching the Gain, Peak Reduction and Compress/Limit switch cause the unit to hum.
4. Did not demonstrate any gain reduction with T4B (drip version) installed.
All of these volume/hum symtoms sound like a grounding problem. I am using a case made by Purusha that has a powder coated front panel. I did not grind off the powder coat around the pots but I'm thinking this is the first thing I should check. I'm also wondering if I should connect all the panels with a grounding strap of some kind.
Also one of the pots I got from digikey just spins continuously without any stops. Do they have an exchange policy? Is it worth it to send it back or should I just order another before I start on the second unit. Kind of annoying that I didn't notice this until now.
Any ideas would be very helpful.
Thanks, Wm.