09-08-2012, 08:45 AM
I have finally confirmed that the inter-stage transformer is bad in this set and my idea about using a separate output transformer to drive the tweeters won't work.
Below are a couple of pictures of the swept response of the 6L6 grid windings and the tweeter output winding:
[Image: http://www.myvintagetv.com/posts/690_trans.jpg]
On the left is the 6L6 grid winding response, the loss through the transformer is only 2dB, but the loss through the tweeter winding is between 14 and 18dB! The left side loss is the crossover loss.
I tried about 10 different output transformers, but every time I loaded the output winding the level dropped to virtually 0.
So unless I can find a replacement transformer, this one has beat me.
Chuck
Below are a couple of pictures of the swept response of the 6L6 grid windings and the tweeter output winding:
[Image: http://www.myvintagetv.com/posts/690_trans.jpg]
On the left is the 6L6 grid winding response, the loss through the transformer is only 2dB, but the loss through the tweeter winding is between 14 and 18dB! The left side loss is the crossover loss.
I tried about 10 different output transformers, but every time I loaded the output winding the level dropped to virtually 0.
So unless I can find a replacement transformer, this one has beat me.
Chuck
