channels not balanced

[Mmaxed]

The right channel is not as strong as the left.  Swapping 2 pairs of tubes left to right makes no difference.

 Brought it up to the shop to test voltages.   The readings that should be 70-90v are higher on the left side.  Left side runs 74-75v, right 70-71v.  Is this enough to cause the problem?  If so where would I look to find the trouble spot?

The other strange thing is that all the terminals that should read 180v will sometimes read 180 and sometimes down to 160.  Once or twice the meter would change over that range in a few seconds.  Same result with 2 different meters.

Thanks for any guidance.   

[Paul Birkeland]

The right channel is not as strong as the left.  Swapping 2 pairs of tubes left to right makes no difference.
 The readings that should be 70-90v are higher on the left side.  Left side runs 74-75v, right 70-71v. 

Lower voltages indicate stronger emission, so there isn't an issue here.  The difference of a couple of volts on the plate isn't enough to worry about.

The other strange thing is that all the terminals that should read 180v will sometimes read 180 and sometimes down to 160.  Once or twice the meter would change over that range in a few seconds.  Same result with 2 different meters.

This would tend to suggest that you may have a cold solder joint in the circuit that isn't quite conducting properly.  I would reheat all the joints on the offending channel to see if that restores the output level.

-PB

[Mmaxed]

Thanks for the quick reply.  I kind of wondered about the joints as I had some problems early on with the build that were all my lack of soldering skill or knowledge. 

Is it possible for a bad joint to get worse over time? 

Iron warming up soon.

[Paul Birkeland]

Is it possible for a bad joint to get worse over time? 

Oh yes, absolutely.  Sometimes you'll have a connection that is mechanically crimped pretty well to the terminal in question, but not soldered well.  Over time, that connection will get jostled and potentially pushed-pulled around (when you remove and install tubes), and this can loosen up that mechanical connection and give you problems down the road.