Mechanical Hum

[RJ Guitars]

One more note from Phil at Heyboer. He confirmed the steel was M6 so we shouldn't have anything weird happening because of the 50 Hz.

He did say that sometimes it can make a difference to swap the polarity on the AC line in. He said he knows it doesn't make much sense but has seen it change the hum.

His primary inclination is that there is something physically loose and rattling... I would guess rattling at something like 60 Hz.

rj

[loupy31]

Hi All,
Sorry its taken a while to report back. Ok, Rj supplied a new PT for me and I managed to finish installing it last night, Oh By the way, if you put your filter Caps over the top of the Pt mounting bolts, Prepare others around you for some serious language when you need to remove the PT, It was a nightmare and a half,
but got it in,
There is still some humm but nowhere as much as the other PT.
Some noise in the pots
V is very noisy
T a little quietter
M no noise
B some
P some noise as well

in stanby I get hum from the PT as well as through the peakers
Standby off (Play) hum and hiss both increase as V is turned up



. . Is there a way of checking the OT?

I will take the time and post up the voltages I am getting so you can see if I need to change anything.

Thanks to Every one that helped me so far, special thanks to RJ, his after sales service is second to none.

Regards Peter

[loupy31]

Voltage chat

[Richie]

disconnect the standby switch, or wires going to that switch,make sure they are out of the way, then power the amp,and see if it hums in standby.

[loupy31]

Hi Richie,
I disconnected the wire to the ST/BY switch, it made no difference sorry to say, I am still getting hum through the speakers.
I hope its not the OT.

Peter

[marcoloco961]

Loupy, Usually the only thing that will cause a hum in standby mode is the coupling of electromagnetic fields of the transformers. You did try the "headphone trick" to make sure it is not just the placement of the trannys in relation to each other, correct? I doubt it is a bad transformer. It sure sounds like the placement to me. Sometimes just the smallest of movement will fix it.

[loupy31]

Hi,
I moved both the transformer as far apart as I could, But I still get speaker hum, I am not sure what to try next, There are some other small problems, like noisy pots, but was hoping to solve the hum prob before I tackle any other issues.

Regards Peter

[marcoloco961]

Hi,
I moved both the transformer as far apart as I could, But I still get speaker hum, I am not sure what to try next, There are some other small problems, like noisy pots, but was hoping to solve the hum prob before I tackle any other issues.

Regards Peter

Moving them further away from each other might now stop the hum. Try a more side to side motion, or twisting them slightly. You would be surprised how little of a movement can reduce the hum of the fields coupling.