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
I just read this in my Aesthetix Atlas's manual. " each channel is a balanced bridge amplifier, thus the negative speaker terminal is not a ground, and cannot be connected to a system ground or loudspeaker system with a common ground. Consult your speaker builder to confirm that your speaker does not have internal circuitry with a common ground."

Well, my speaker is passive - Nola Viper Reference. As for what this means above, I have no clue. I can't imagine a passive speaker would have this sort of grounding issue however?
Sounds like Vett93 gave you some excellent suggestions. One additional experiment I would suggest is that besides shorting the two pins on the XLR connectors, you also short the center pin and ground sleeve of the two RCA connectors for the high passed inputs of the amp. If you don't have shorting plugs, you could again use IC's with something conductive inserted at their other end to provide the short.

I would add to your summary, btw, as you mentioned in the other thread where this was discussed, that the noise is present if the preamp is connected to the regular inputs of the amp and the high passed inputs are selected, but disappears if the preamp is connected to the high passed inputs and the regular inputs are selected (while being present if the preamp is connected to the high passed inputs and the high passed inputs are selected).

And yes, the caution about not grounding the negative output terminals of the amp is not applicable if all that is connected is a passive speaker. It shouldn't be applicable with an electrostatic, either.

Best regards,
-- Al
Thanks Al. I just inserted two shorted RCA jacks on the unused crossover inputs on the amp. Still have the buzz however.

Wonder if my extra preamp inputs should be shorted?
I wouldn't expect that shorting the preamp inputs would make any difference, since the problem occurs even when the preamp is turned off and unplugged from the AC.

Sure is a baffling problem :-)

Best regards,
-- Al
Grannyring, what kind of speaker cables are you using, and how long are they? If by any chance they are one of the kinds that has extremely high capacitance, such as Goertz or Ocos, and you are using them without a Zobel network, I'm wondering if that may be resulting in the amp being on the edge of having some sort of low level oscillation, that could somehow be put over the edge by conditions at the inputs.

Also, did the positioning of the speaker cables change significantly when you changed speakers? Perhaps they are picking up rfi/emi which is entering the feedback loop of the amp, if it has one.

Just some shots in the dark.

Best regards,
-- Al