Please please help me figure out my problem with my precious MarkIV:
It sounds perfectly fine in all channels when the volume knob on my guitar is way down (say 3) - but when I turn it up, there is a loud crackle that is made along with the guitar notes... Interestingly, as I describe below, I can set create a situation where no signal should possibly get through to the power amp stage, but the crackle is still made at the same volume as if I had a guitar signal getting through.... I have tried swapping tubes out and there is no change when new tubes are put in.
1. USING CHANNEL 1 with
effects loop OPEN (so no signal should get through),
output level to zero (again, making it so no signal should get though), and
master1 to zero (again, making it so no signal should get through)
The crackle still is made just as loud once the channel 1 gain goes past 7
(the position of the Master1 makes no difference regarding the amp's sensitivity to crackle...)
2. Using CHANNEL 2 with
effects loop open
Output level set to zero
Crackle is made if the sum of channel2 gain + channel2 Master exceeds 15
(So for example, it will crackle if channel2 gain at 10 and channel2 master at 5)
3. USING CHANNEL 3 with effects loop open
Output level set to zero
Crackle is made if sum of Gain + Drive + Master settings is greater than 18
for example Gain 10, Drive 0, Master 8
THANKS!!!!
It sounds perfectly fine in all channels when the volume knob on my guitar is way down (say 3) - but when I turn it up, there is a loud crackle that is made along with the guitar notes... Interestingly, as I describe below, I can set create a situation where no signal should possibly get through to the power amp stage, but the crackle is still made at the same volume as if I had a guitar signal getting through.... I have tried swapping tubes out and there is no change when new tubes are put in.
1. USING CHANNEL 1 with
effects loop OPEN (so no signal should get through),
output level to zero (again, making it so no signal should get though), and
master1 to zero (again, making it so no signal should get through)
The crackle still is made just as loud once the channel 1 gain goes past 7
(the position of the Master1 makes no difference regarding the amp's sensitivity to crackle...)
2. Using CHANNEL 2 with
effects loop open
Output level set to zero
Crackle is made if the sum of channel2 gain + channel2 Master exceeds 15
(So for example, it will crackle if channel2 gain at 10 and channel2 master at 5)
3. USING CHANNEL 3 with effects loop open
Output level set to zero
Crackle is made if sum of Gain + Drive + Master settings is greater than 18
for example Gain 10, Drive 0, Master 8
THANKS!!!!
