The Mercury has all of the same sounds, but I think it sounds a little more "Open," or natural sounding. To me, it sounded like the amp was working less and breathing more if that makes sense. It shouldn't change your overall sound much since it is basically a clone of the original but made with much better materials.
To test the OT:
http://www.geofex.com/ampdbug/outtrans.htm
http://www.google.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=how+to+test+an+output+transformer
Just make absolutely sure that you drain the filter caps.....
For a DC, you can simply turn the amp off and turn the Standby to the Play position and let it sit for about 20-30 minutes. It usually only takes about 3-5 minutes, but hurts badly if you are careless!
I always check the voltages with my meter before reaching in to make absolutely sure that they are drained.
Also.....make absolutely sure that the amp is not plugged in when you reach inside! That hurts too......
Basically, you are looking for the continuity/ohms between the following wires:
Red - Blue and Brown (these will be slightly different but pretty close)
Blue + Brown - should be roughly twice the resistance as the Red to either the Blue or the Brown
You should also have some continuity between the Black and Yellow and Black and Green wires.
There should be almost no resistance between the Yellow and Green.
Electronically, your transformer should be pretty similar to this one:
https://taweber.powweb.com/store/404248sch.jpg
With the exception of the White wire.
The ohm readings on the drawing are not accurate in terms of resistance. They are impedance readings which take into account the inductance created when the transformer has signal flow and the resistance.
Resistance measurements are not always accurate though. I had a DC-2 that measured good, and sounded good at lower volumes, but had a shorted winding that would arc to the housing at higher volumes and make the most awful farty noises!
Hope this helps! You can call me and I can walk you through it over the phone if you want.
808-214 five seven four six
I have a mint condition DC-3 Mercury Magnetics output transformer!
