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.


In case it is not clear to you, I modded the amp to get rid of the ground loop. I opened the chassis and found the designer wired the signal ground, the AC ground, and the chassis all together. So I diconnected the signal ground from the AC ground/chassis.

Hope it is clearer....

PS. If you have a high voltage amp, be careful of what you are doing....
Gentlemen, once again let me emphasize that Grannyring's issue arises even when the preamp's power cord is not plugged into an AC outlet, and when no components are connected other than the preamp, power amp, and speakers. Therefore I don't see how the problem could be due to a ground loop, because there is no loop in that situation.

The facts that the problem is not present when nothing is connected to the inputs of the amp, but is present when the preamp and interconnects are connected to the amp, would seem to suggest an issue involving emi/rfi pickup. However, as Grannyring indicated in his thread that I linked to earlier, in addition to its normal RCA and XLR inputs his amp provides separate RCA and XLR inputs that are processed through high pass filter circuitry. And when the preamp is connected to the normal RCA inputs the problem exists even if any of the other three inputs are selected on the amp. Which leaves me totally baffled, unless perhaps something is defective in the amp's input select circuitry. But that, in turn, would not seem to explain why the problem wasn't present with the previous speakers.

Vett93, regarding your otherwise excellent posts it should be pointed out that with many designs isolating signal ground from chassis and AC safety ground may involve considerably more than minor modification. For starters, the ground sleeves of RCA connectors may not be isolated from chassis. Also, it would seem possible that in many cases changing the component's internal grounding scheme might result in unpredictable sonic side-effects.

-- Al
Hi Grannyring,

If the power cord is not plugged in to your Dude and you have a hum already with just the interconnect, it is not a ground-loop induced hum then. Have you tried a shileded interconnect like the one from Blue Jeans cable?

What amp do you use these days?
Grannyring, Have you tried connecting the cd player to the amp with and without pc in the cd player? If same buzz noise, then narrowed the problem to the amp.

Have you check the tubes in the amp? Once I had a bad input/driver tube in my tube monos and it produced a buzz humming noise.

You can always ask Paul to convert or add pseudo XLR outputs to your Dude.
Al, I am very sorry that I did not see the previous posts.

Bill, you mentioned that you shorted the pin 1 and pin 3 of the XLR connectors and it would still hum. Did you just short 2 of the 4 XLR connectors? If that is the case, can you try to short all 4 XLR connectors? I mean shorting the pin 1 and pin 3 for all 4 XLR connectors.

The design of your Atlas amp looks similar to my Counterpoint/AltaVista NP100 amp by Mike Elliot. They both use 6SN7 differential gain stage and don't use switches in that area.

Let me know if that fixes your problem.