TRL Dude or Joule 150 MKII for Major Pre Upgrade

The Dude is not the issue at all. I have tried three preamps in the system and one of them was a passive. As soon as ANY of these 3 pre's are hooked up by ic's only - the buzz starts. Just an FYI. The preamps don't even have to be plugged into the wall.

My issue has nothing to do with the Dude. I seem to have a strange room or total system issue. The system was dead quiet with every other amp I have used with the same Dude as well as my last set of active ESL speakers. Please understand this is not a preamp issue. The Dude is properly ground and built to the highest standards and like a tank.

Thanks to all for the help thus far.

Atmasphere, I will take the measurements you point out and post the results.

Well the amp seems to be the issue after more testing. I tried using Blue Jean cables that are well shielded, but the buzz continues. Again, with the preamp off and unplugged the buzz continues.

I measured as Ralph stated and could not get any reading on my ohm meter (too low) when testing for ground on the RCA 's and the middle (ground) on the AC inlet of the amp. My meter measured too low to read on the (m)ohm setting.

I tried shorting out all 4 xlr inputs between pin 1 & 3 and still have the buzz. This Buzz was not there when my previous Soundlab speakers were in the system. The buzz came for the first time when I replaced the Soundlabs with a passive speaker.

I am at a loss. I spoke with Aesthetex and they had no answers. I will try them again now, but they also seem stumped.

I meant to say I measured no ohms. I assume getting no ohms means there's no connection from the signal ground as measured at the RCA socket to chassis. Same with the power cable ground to chassis. The chassis has no resistive connection and seems isolated from everything.

This does not seem good to me.

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...