TRL Dude or Joule 150 MKII for Major Pre Upgrade

Hi Grannyring, if the the chassis is grounded to the middle pin of the IEC, but there is no resistance (open) between the RCA ground and the chassis, then the chassis can act as a sort of antenna- and thus can can buzz.

A resistor of about 100 ohms (1/2 watt) between the RCA shield and chassis should take care of it if this is the problem. If it were me this would be the next thing I would try, based on the measurements you have reported.

Keep posting...

Atamasphere, if Grannyring's Dude is like mine when I first got it, the chassis is not grounded to the middle pin of the IEC.

Mine preamp's chassis is indeed grounded to the middle pin of the iec. Again, the buzz comes when the preamp is off and unplugged even. I have an amp issue. I called Aesthetix today and they gave me some other things to measure on the amp.

I will report back on how this ends up so all can learn. Thanks to all for the help.

Okay, I read through the whole threads and come up with another theory and idea to try. I simply cannot stand a fellow Dude owner not happy with his setup. ;-)

I still think it is a grounding issue. If I understand it correctly, it did not hum with the previous set of speakers which are electrostatics. My theory is that the set of electrostatics provided proper grounding through their AC plugs.

So, Bill, can you try the following and see if it fixes the hum? The idea is to provide grounding at the source. So find any of your source equipment that has the signal ground wired to the ground pin of the AC plug. I don't know what source equipment you have. But you can measure the source's output RCA ground and the the ground pin of the AC plug. If it reads close to zero ohm (meaning there is a connection), then the signal is grounded to the AC line. You can use that equipment as the source.

Then connect the source to the Dude and select the right input. Connect the Dude to the amp. Turn them on and see (or hear) if you still get a hum.

Please let us know. Thanks.

Bill, in your earlier post today, you said that the chassis was not wired to anything, which was similar to my experience. Then you said it in your most recent post that the chassis was wired to the middle pin of the IEC. So I am a bit confused. Can you use your ohm meter to measure the chassis and the ground pin of the IEC socket?

Did you send your Dude back for re-work? I got my Dude after reading your review a few years back. Being an engineer, I opened it up to review its design as soon as I received it. I found that the chassis was NOT wired to the AC ground. I sent it back to Paul and specifically asked him to do so later on.

I still think you should try my latest suggestion: find a source equipment that has its signal ground wired to the AC ground pin. Then see if it still hums...