Bad Feedback and Hum From Crate GFX30 Resolved

[BaronvonStumpf]

Hello,

I am a new member. I apologize if this subject has already been addressed in the past.

I am a new guitar player. I just received a Gretsch G5420T, for my first guitar, from my wife. I was looking to buy an amplifier. Then I found a Crate GFX30 in my attic (oldest son is in the Air Force, his amp) abandoned and dirty. I cleaned it inside and out. I energized it and it was nothin except loud squeals and a really bad hum. I tried to find schematics, and I did, after I accomplished my repair of the system.

Apparently, from the forums I visited, the Crate system is notorious for this type of issue. I am a biomedical electronics engineer and I applied my skills to investigate. There were a couple of obvious issues when I looked closely. First, incoming power wires crossed over and touched the speaker wires. I rerouted those and eliminated the squeal. However, I still had the hum and brrrrrrr. Then I used magnetic chokes on the power wires. The rest of the issues disappeared.

The sound is amazing. My son, a great guitar player, could not believe the sound. He originally received the amp from a friend and he said it never worked.

Anyway, I joined this forum after the repair. I thought this information might help some others with the same amplifier. I am impressed by the helpfulness of the other members.


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