[mik000000]

I have my steps/PPA v2 running now finally. I am listening to it as i type and it sounds great. I have not yet put in the bias transisters or the bass boost and yes, I have c6g installed.
I measure the output offset and get
OL-OG .3mv
OR-OR 1.8mv
both of which look good
to check the opamp offests i am measuring from pin 6 on the opamps to IG and get:
L- -12mv
G- -8.5mv
R- -12.9mv
the offset values look ok, but i don't understand why i am getting negative voltage on the offset.
any ideas? or is this normal?

 

[mik000000]

am looking for some help here... It boils down to 2 questions.

1) Is the 12mv at the opamp normal, or within noermal parameters?
2) Is the fact that the offset is a negative voltage normal?

need some input people!!!

 

[Polaris111688]

12mV seems fine. What opamps are you using?

 

[mik000000]

I am using opa627's on all 3 channels. Any opinion on the fact it is a negative voltage? or is this normal?

 

[mik000000]

I am using opa627's on all 3 channels. Any opinion on the fact it is a negative voltage? or is this normal?

I want to be sure all is ok before adding the bias transistors and the bass boost parts

 

[joe_cool]

The numbers you are reporting are so small that you could be measuring the opposite ends of a short piece of wire next to a video monitor.

No one is responding because your post is confusing. I think I see two typos in the descriptions but I'm not sure.

Basically if you see less than 10mv across the headphones then it's OK.

 

[MisterX]

Quote:

I measure the output offset and get OL-OG .3mv OR-OR 1.8mv

Those are the only reading you posted that really matter and they are both Ok.

 

[tangent]

There's nothing wrong with a negative offset. You basically have a 50/50 chance with any chip that its offset will be negative or positive. It's random.

EDIT: Thinking more about it, there is a bias towards one direction or the other. But the main point is, it doesn't matter which direction it goes. It just needs to be reasonably close to 0.

 

[mik000000]

thanks for the input. I was not aware they offset could be a negative value.

will probably be back with more dumb questions on the bias transistors