Hi Guys,
I have an older Modwright 9.0 Pre that was upgraded one year ago by the previous owner to the current Signature edition with all mods. I used it happily for three months. Now in the last week, the following has happened.
1. A hum started from the pre on the left side and lasted for about two seconds on power up.
2. Then also maybe a few popping sounds coming from the right side for a second or two.
I changed all the tubes, put new ones in, and nothing changed, it even got worse:
1. After a few days, I noticed all of a sudden a loss of 80% of my volume in my right channel. I isolated it to my DAC, replaced the DAC, and then 2 hours later, guess what, blown channnel again in the second DAC.
2. I took out the DAC, added a CDP, and the channel came back to life.
Now all is good for a day or two until,
1. I install new Coincident Frankenstein 300's and get a very loud, oscillating
hum through one channel (this time the left). It comes and goes and is not dependent on volume. I change power cables, sockets, interconnects, etc. And no change. Brand new tubes in the 300. Change the tubes, and no change in the hum. Change PC, outlet, etc. And no change.
2. I install an Uber Buss and no change.
3. I exchange the RCA input going into the amplifier (reverse left to right) from the Modwright, and the hum changes sides.
4. I them remove the modwright and connect the amp directly to the cdp and the hum is gone.
So what do I do now?
All the problems started with a hum coming from the pre on power up followed by some popping noises that sometimes were loud and sometimes not so loud. Then the DAC blew x 2 , and now the loud hum that sounds like a ground loop hum......
Can anyone help? I have asked many their opinion and no one knows.
Thanks,
Morgan