Khornukopia

Using unshielded speaker wire from the pre-amp to the amps might cause some unwanted noise. Best to use the proper type of interconnect cables.

Just in case someone with a PA5 needs this info, (1) Topping PA5 fix - D01 Module Replacement for everyone | Audio Science Review (ASR) Forum

LarryC, Rest In Peace

We would enjoy viewing pictures of your Belles. (downsize your picture files for easier attachment to the forum)

One look at the plastic tubs as speaker stands and I'm not interested in watching the video.

I sometimes visit larger than average homes with loudspeakers in (almost) every room, wired to a central music player. Walking from room to room lets you observe how furnishings and room shapes have a big influence on the sound. Acoustic treatment is definitely worthwhile for people who want the best sound from their loudspeakers.

I agree with you also but, it seems strange that 3 different amps have the same problem.

I agree, and yes, taking it to a house in a different neighborhood would be a more effective test. Almost any speaker should work for this purpose.

@MT1086 hasn't been back since, but for anyone else with a similar condition, I say double-check your speaker wire polarity.

Everything you have stated seems to indicate an amplifier problem, but 3 different units with the same hum makes me continue to wonder about the house wiring or the power from the street transformer. It is only fair to Decware that you become certain that your house is not the problem. While we all think about the possibilities, can you post some picture of your amps? (This forum has picture file size limits, so it is best to downsize the pic file.)

Have you swapped back to one of those other amps since this problem started, plugged into the same wall outlet?

Well, that is helpful information.

Because all 3 amplifiers exhibit the same hum, I would still suspect something like a bad light dimmer somewhere in the building.

@HenningO if you have another tweeter to connect, that would be a really good test. Can you show some pictures of your tweeter next to a tape measure or ruler, after you remove it from the housing.

Learning what works best is a good thing. I saw where you enclosed the backs of your K-Horns. Removing the top should be very easy for you.

Just to acknowledge my awareness that the Klipsch forum does not permit open discussions about modifications to Klipsch speakers, the procedure to remove the top panel would be applicable to anyone who needs to easily repair their original K-77 tweeter in a K-horn.

Remove the screws at the top of the 2 vertical rear supports. Next remove the screws (2 on each side) that attach the side panels to the underside of the top panel. Lift off the entire top panel and you will have a wide open space. Do NOT mix up the 6 screws, as 2 of them may be longer than the other 4 screws.

Very impressive. Can you tell us about the space behind the wall and subs.

Nice speakers! What amplifiers are in your picture?

Are those built-in subwoofers?

Is it good?

At this point, I would remove the silent tweeter and connect it to the good La Scala for a listening test.

Can you take a picture of the board (and downsize the picture file) and post it here?

Just build your enclosure to fit your K-horn. Should not need to match the tail board dimension of a different speaker. As I recall, volti had a very detailed explanation of his procedure.