2. amps-preamps
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TRL Dude or Joule 150 MKII for Major Pre Upgrade

Thinking of either of these for what I view as a huge pre upgrade in my system. Current system is:

-Celestion A3
-Krell KAV250a (500 wpc/4 ohms).
-Nohr CD-1
-Rotel 995 preamp

I am looking to pickup warmth, depth and much more soundstage. Quality bass is also important to me. I want to keep the Celestions and feel that my current pre is the weakest link. Will also will update my digital source and ss amp down the road.

My thinking is that it will be worth paying up a bit for a higher quality pre that I can grow into.

Also I have a small naive question...with either of these pre amps will the sound difference be that great compared to the Rotel.

Thanks...any comments are appreciated.

-Iggy
iggy7
grannyring's avatar
grannyring
4,637 posts
 
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.
atmasphere's avatar
atmasphere
7,068 posts
 
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...
vett93
205 posts
 
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.
grannyring's avatar
grannyring
4,637 posts
 
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.
vett93
205 posts
 
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.
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