Yes, another Maggie 8802 low volume thread

[Patrick620]

I have researched this to death, did the 390 ohm balance pot mod, rolled tubes, chop sticked it, resoldered a few joints that probably did not need it, checked to schematic, etc. etc. etc and still the V1 channel has very low volume. Any thoughts or obvious to you mistakes? Here are the measurements taken without the power tubes.:



V1 6EU7: Cathode to ground R=1.9k ohms
p1 2 6.6V
p4 2.4V
p5 0v
p6 223V
p7 147V
p8 -4.5mV
p9 1.4V

V4 6EU7 Cathode to ground R=2.1k ohms
p1 to 2 6.6v
p4 2.7v
p5 0v
p6 232v
p7 176v
p8 +.3mv
p9 1.6v

p7 and 8 seems to be the trouble spot?

 

[Patrick620]

Looks OK. How about back end?

To me the back end is easier than the front. I try not to get too drunk doing this and will walk away. All of the voltages on the output tubes were ok. What about the differences between the voltages on pins 7 and 8 on the preamp tubes? For some reason it will not let me add a detailed photo at this point. The 2nd photo shows most of it. Beyond that it is just speaker stuff. Maybe I have a bad resistor somewhere. Ugg, this thing is driving me nuts. It has to be on the front end somewhere

 

[Patrick620]

To me the back end is easier than the front. I try not to get too drunk doing this and will walk away. All of the voltages on the output tubes were ok. What about the differences between the voltages on pins 7 and 8 on the preamp tubes? For some reason it will not let me add a detailed photo at this point. The 2nd photo shows most of it. Beyond that it is just speaker stuff. Maybe I have a bad resistor somewhere. Ugg, this thing is driving me nuts. It has to be on the front end somewhere. I know that print helps a lot when it can not be seen

 

[Patrick620]

https://community.klipsch.com/uploads/monthly_10_2013/post-17845-13819321803902.jpg schem link for better viewing pleasure. Hell, even I can see this one, lol.

 

[Patrick620]

I might add that is was working fine at one point when I first thought that I had it wrapped up and feeling good, then not.

 

[xwarp]

Are you sure the 6v6's are good? How about checking the pot mod wiring again just to make sure all is good with that.

 

[Blast]

How about swapping those 6EU7's? Will the low volume transfer to the other channel?