Page 1 of 1
T15 built and working, but ?s about pops and +48
Posted:
Thu Mar 26, 2009 1:01 pmby radrobot
Had fun building the T15, especially now that it works.
Question 1: When I turn the gain knob, it sends a pop noise through the monitors when clicking to each gain stage. Is this normal? Have I done something wrong?
Question 2: My phantom power readings are +45.4 when on and .4 when off. Is this normal?
Thanks for your help.
Posted:
Thu Mar 26, 2009 9:14 pmby tpryan
What voltage do you measure between U1, pins 1 and 8?
Your phantom voltages are fine.
Posted:
Fri Mar 27, 2009 1:26 pmby radrobot
Voltage from pin 1 to 8 on U1 is .023
I'm assuming the pin configuration is:
notch
1 8
2 7
3 6
4 5
I'm placing the black (-) lead on the DMM to pin 1 and the red (+) lead to pin 8.
Posted:
Mon Mar 30, 2009 12:42 pmby radrobot
I've edited the above reply a couple of times because of my ignorance.
Posted:
Tue Mar 31, 2009 7:30 amby tpryan
Does the voltage between pins 1 and 8 change as you switch gain?
Posted:
Tue Mar 31, 2009 8:00 amby radrobot
Today I'm getting a reading of .026 to .027.
No, voltage does not change when switching gain.
Posted:
Sun Sep 06, 2009 7:28 pmby mikew
What is the acceptable range for the phantom power? I usually get about 46.5 or so as well.
Thanks,
- Mike
Posted:
Wed Sep 09, 2009 6:59 amby tpryan
46.5V is perfectly OK.
Re: T15 built and working, but ?s about pops and +48
Posted:
Sun Sep 27, 2009 2:35 pmby evolver
radrobot \$m[1]:Had fun building the T15, especially now that it works.
Question 1: When I turn the gain knob, it sends a pop noise through the monitors when clicking to each gain stage. Is this normal? Have I done something wrong?
hey there i am in the same boat. i just finished building a T15, all measurements checked out and when i plug in a mic it sounds clear and has plenty of gain, however when i turn the gain knob i get a loud popping that i don't get from my A12 and N72 modules.
did you resolve this ?
Posted:
Mon Sep 28, 2009 10:39 amby tpryan
Measure the voltage between U1, pins 1 and 8. It should be very close to 0V. If it isn't, check your soldering around U2, R22, R23, R6, R7, C8, and C9.
Re: T15 built and working, but ?s about pops and +48
Posted:
Thu Apr 29, 2010 10:59 pmby Joel C
evolver \$m[1]:radrobot \$m[1]:Had fun building the T15, especially now that it works.
Question 1: When I turn the gain knob, it sends a pop noise through the monitors when clicking to each gain stage. Is this normal? Have I done something wrong?
hey there i am in the same boat. i just finished building a T15, all measurements checked out and when i plug in a mic it sounds clear and has plenty of gain, however when i turn the gain knob i get a loud popping that i don't get from my A12 and N72 modules.
did you resolve this ?
Same pop sounds over here.
Anyone solved the issue?
Posted:
Fri Apr 30, 2010 7:00 amby tpryan
Measure the voltage between U1, pins 1 and 8. It should be very close to 0V. If it isn't, check your soldering around U2, R22, R23, R6, R7, C8, and C9. If it is close to 0V, the circuit is working properly and whatever pops you're hearing are normal.
Posted:
Sat Jan 14, 2012 12:09 amby dblair
I had the same issue of sounding fine but getting pops when switching gain. My Conn 1 readings were also low around 25v. So I re-soldered U2, R22, R23, R6, R7, C8, and C9. When I powered back up. the gain switch popping was gone But now everything is distorted on any setting whether it by phantom or dynamic mics. Totally unusable sound.
To be more specific it goes between almost clear to distorted sound to cutting out completely at random intervals of a couple of second between.
Conn 1 readings are still low at about 27-29v, when off about -55 mv. And measuring across U1 pin1-8 I get -6 to -8 v sometimes more.
I then unsoldered and resoldered the above mentioned connections with the same results. Except now the popping on the gain switch is back.
My other T1 that I built right after this one works perfectly.
What would cause this type of problem?