[aljordan]

Hi Rick,

Many years ago I bought a pair of subs from you that use KG-5230 plate amplifiers. They have both developed an annoying transformer hum. From web searches it appears these are no longer made. Do you know of a suitable replacement that would fit into the subs?

Thanks,
Alan

[Rick Craig]

Hi Rick,

Many years ago I bought a pair of subs from you that use KG-5230 plate amplifiers. They have both developed an annoying transformer hum. From web searches it appears these are no longer made. Do you know of a suitable replacement that would fit into the subs?

Thanks,
Alan

Sorry to hear that. It might be just a matter of tightening the mounting screws for the transformer. If that doesn't work it could be a ground loop. Try looking at those items first and let me know the results.

[tkp]

Not sure if this is the same issue I ran into with the 1000 W Keiga amp. but here it is.  I had the humming issue with my Keiga amplifier many years ago and debugged that down to the cold solder joint on the speaker level input of the amp.  What happened was that the speaker level input connector is a heat sink hence much the solder did not bond with it that well.  Over time, the solder that connecting the amp. GND to the negative (black color) binding post detached from the post causing the speaker level (red color) to float resulting a constant hum.

The solution is to open the amp. up and use a high heat soldering iron to touch up the solder.  One way to verify if this is the issue is to use the line level input (RCA connector) to see if the humming went away.

Good Luck!