Fisher X-101-they clean up nice - part 2 The X-101-C

[audiodon]

More time has passed and the regular use of this X-101-C has continued.
For a time I changed it out for a partially restored X-1000, but the X-101-C won hands down. That being said, the X-1000 will get the audiodon treatment soon. I haven't replaced the coupling caps though the big can caps were done by the former owner, and I haven't tried rolling tubes.
So, this is the First Fisher that has remained my go-to unit for more than a year.

Every once in a while it'll run out of steam, but that's rare and only on truly dynamic recordings. I'm using it with 87 dB efficient speakers and I'm using a powered sub in a near-field monitoring situation.

 

[audiodon]

Here's a link to my cross-forums postings about how I shellacked the transformer and how, over time, the hum diminished and is now gone.
Hopefully this will help someone else with a transformer hum someday. Click the links within the referenced thread to find out more. Pictures are included in the threads.
http://www.audiokarma.org/forums/showthread.php?t=280008&highlight=shellac

 

[Fisherdude]

Interesting that the hum didn't go away as soon as you shellacked it, but that it diminished over time. I wonder if the shellac that soaked into the interior didn't completely cure right away, but continued to migrate a bit under the influence of vibration and warmth, until it finally made it into the gaps.:scratch2:

Definitely a fix to add to the memory list.

 

[audiodon]

My impression is that, aside from heating the outside by baking, it was the repeated heating from the inside by using it that finally dried it out fully and set the shellac properly.
This is one thing that there was no quick fix for.
The solution was more like performing an operation and healing a wound rather than an isolate the problem and replacing a component to fix a problem electronics repair.

Considering that the half-dozen or dozen that have sold on that auction site in the past year were not parts units, this shellacking seems like a good approach, whereas with other tube gear, a quick replacement from a parts unit from someone's damp cellar might have been the best solution.

The only time it ran out of steam was on a DMM vinyl record through an outboard phono stage into the tape play input so it coulda saturated the phono stage and not the amp.