The other was still allowing over a half volt of DC pass (0.68v), not acceptable when there are no blocking caps on the input of my amp....or is it?
Still might dive in and see if I can get them out, luckily It's Sunday so may not be difficult or messy
But with my plans, and these being 1.5uf I doubt I'll use them unless I go with a SS player or DAC.......not likely for myself.
Edit: Ah bugger it, can't bring myself to dumpster dive to get them back.
Data,
You should really just get a tech to check it out, anyone who knows what they are doing will have the problem diagnosed very quickly.
If you are measuring DC on the OP of the pre amp this can be purely because there is no ground reference resistor at the OP to pull it to ground.
There should be a resistor -after- the OP cap going to ground but some equipment don't always have one, they rely on the gear that the
pre is feeding to have an IP ground ref resistor which will pull it to ground.
If there is no resistor to ground after the OP cap, solder a 1 meg R there to gnd and re measure.
If you have a decent size OP cap and the OP resistor is also large say >1.0uF and 1 Meg R then you may measure some
DC there that is constantly slowly hunting around because of very low frequency drift. But it will be 'hunting' around zero going + and -
to some small degree - this is normal.
Other causes of DC offset are a leaky grid on the IP tube that connects to the 'wiper' of the volume pot - assuming the vol pot
is right at the IP feeding the first tube.
There are some cases where a high frequency oscillation can measure as a DC offset with a multi meter and where the oscillation can
actually cause some DC offset, however this is not common and since you don't have an oscilloscope lets doubly hope so.
In the end you are better off just getting someone who knows what they are doing to check it out, you will save a lot of time.
cheers
Terry