New Preamplifier Testing (Poor sound)


Looking for help...

I got a new preamplifier to replace my integrated amplifier, but the sound is extremely underwhelming. Biggest issues are sound distinction and clarity (sounds dull) and field depth (sounds narrow/flat) with less depth and width regarding the sound field when listening to stored digital music.

Old set up:
Innuos Zenith -> (USB) Gustard X26 Pro -> (XLR) Cambridge Azur 851a -> (RCA) Cambridge Azur 851w -> KEF LS50 Meta's and Kube 12b subwoofer.

New set up:
Innuos Zenith -> (USB) Gustard X26 Pro -> (XLR) Rotel 1590MKii Preamp -> (XLR) Cambridge Azur 851w -> KEF LS50 Meta's and Kube 12b subwoofer.

I'm really surprised this new preamplifier was such a drop off in sound quality compared to my older, cheaper integrated amp, but wondering if there are any tests I could do to maybe change something to better figure out if its the preamp, or rather something I'm doing. Looking at all the extra digital inputs in the Rotel that my 851a doesn't have makes me think that maybe the 851a is just a more adept component at passing along my DAC's signal, where the Rotel is geared towards using it's internal DAC.

The Rotel is run in a "Tone Bypass" mode via the XLR connections to bypass the internal DAC.

Just wondering why the Rotel would choke off the sound so much while the older integrated amp make things sound so deep and bright when paired with the power amp?

A friend suggested running my DAC straight to my power amp and see if the sound was back to old (or at least better).

Any other suggestions I should try before I send the preamplifier back?
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@douglas_schroeder 

That's a great article, and sadly I was trying for months to track down a Azur 851e, but sadly they're impossible to come across and I lost out on bidding on a used one that sold for over $2,200 and was many years old.

But yeah, I'm really impressed with the bulk of Cambridge Audio's stuff.

Excited to run my851w amps in monoblock mode and just trying to sort out the "pre" portion of the system, but maybe I'll just stick with the 851a.

Just need to give the Rotel a little more time and attention. Also gonna look at Yamaha and Technics out of my own curiosity after doing some reading and you-tubing.
"...the sound is extremely underwhelming. Biggest issues are sound distinction and clarity (sounds dull) and field depth (sounds narrow/flat) with less depth and width...".

OP, these are very serious defects.  Break-in time is not going to fix them.

Next time, insist on an extended home audition of a previously broken in piece.
I would make sure you try plugging the Pre amp strait into the wall no power conditioners,same for amp.
Take the USB output of Zenith into the USB input of the 1590. if you can source a pair of Audioquest Red River RCAs between pre and amp are neutral . 
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I ordered two other units to try out, and we'll see.

Gonna have a 4 way shoot out winner take all. I just need a little time with the Rotel and then give the old iAmp a try again and see.

I've been working so much lately I finally got to listen to like 15 minutes of music the other day before my wife told me to "knock it off".

Just need a solid music listening day for each unit.