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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: April Music Stello CDT-100/DA-100 Signature [on review]
Preamp/Integrated: Red Wine Audio Isabella, Red Wine Audio Signature 30.2 [on review]
Amp: Red Wine Audio Signature 30.2 [on review]
Speakers: Acoustic System Tango R
Cables: Acoustic System Liveline interconnects and speaker cables; Crystal Cable Ultra power cords
Stands: 2 x Ikea Molger with Ikea butcher block platforms and Acoustic System footers
Powerline conditioning: 2 x Walker Audio Velocitor S
Sundry accessories: Furutech RD-2 CD demagnetizer; Nanotech Nespa Pro; full-house installation of Acoustic System resonators, noise filters and phase inverters
Room size: Sound platform 3 x 4.5m with 2-story slanted ceiling; four steps below continues into 8m long open kitchen, dining room and office which widen to 5.2m with 2.8m ceiling; sound platform space is open to 2nd story landing and 3rd-floor studio; concrete floor, concrete and brick walls, converted barn with no parallel walls nor perfect right angles; short-wall setup with speaker backs facing the 8-meter expanse
Review Component Retail: Isabella starts at $4,000 ($5,500 as reviewed); 30.2 Signature $3,000 as integrated, $2,600 as stereo amp

Halleluja. No golden eeriness for once.
As a follow-up to our feature reviews of Vinnie Rossi's preamp and integrated, this assignment ended up with dead obvious outcomes. This mandated wit. Or better, the easier part called brevity. The header already hints at sonics that wouldn't require gilded ears to hear loud and clear. The job today was to determine what the tubed Isabella preamp adds over the Signature 30.2 integrated when

a/ the integrated is run solo vs preceded by the pre;
b/ when the integrated is compared to the pre+power combo; and
c/ when the pre+integrated goes against the pre+power. Upgraders within the RWA line wanted to know what additional funds would buy; and whether the stepped attenuator on the integrated would be an audible deficit when adding the preamp (thus putting two pots in series).

Reductionism
If a critic's job is to apply negativity -- what faults can I find -- an assignment like this works best in reverse. Start out with the best-case scenario, then see what goes away, falls apart or diminishes when you remove or downscale bits. To set the gussied-up stage, I wired up the April Music two-box Stello source combo (it's attractively priced at $1,500 to be a realistic stand-in for what actual RWA customers might own) to the Isabella, from there to the stereo amp into my customary ASI Tango R speakers with all ASI cables. Then I swapped in the integrated with its pot fully opened to see whether I could hear an additional resistor in the signal path. Because that's what it boils down to. Vinnie's stepped attenuator on the 30.2 INT is a passive device which trims volume with a single resistor per setting.

No
The answer is nein. Had I endlessly labored and sweated, perhaps I might have talked myself into a tiny difference. But my sense of self isn't wrapped up in any wishful abilities to hear things that aren't there. Unless your hearing is simply a lot more astute than mine, I think you'll not hear a difference either. Which means that if you presently own the integrated and wish to add the Isabella (or any other) preamp, you're not compromising things one wit. Brevity, remember?


Yes
The real question is, does it make sense to add the Isabella? How much does it buy? Can one easily hear the difference - and, is it squarely better or just different? Yes times two. Just remember that adding a $4,000 preamp (that's what the Isabella costs without the DAC and headphone option) to a $3,000 amplifier (integrated in your case but the math works out very similarly if you owned the stereo amp version), you won't get twice+ the performance. That's not how things work with something as dialed as the Signature 30.2 platform is these days. The improvements from adding this tube preamp are significant and easily audible but only you can decide whether they're enough to warrant the expense.

What
Take the absolutely stunning Melos by Vassilis Tsabropoulos and Anja Lechner on ECM. It's my favorite disc-overy of 2008. With the Isabella, the piano's left end has more weight and meat. The tinkly right-handed notes too flesh and round out. Particularly the harmonic halos around them that flare up so briefly are rather more developed. The con-arco cello is more voluptuous, the bow action on the string clearer. You can hear the horse hairs scraping before the string sets off the wood. The triangle strikes resonate just a bit longer before they drop below the noise floor.


30.2 solo, things compact and flatten out. This is most easily observed on the piano. Its very rich harmonics should suggest a complex aroma like a good spirit or perfume where layers of flavors and notes compete for attention. Without the Isabella, that diminishes. More obvious still is Hector Zazou's In the House of Mirrors [Crammed Disc]. Superbly mastered, this meditative album sports exotic stringed instruments like the Uzbek Tanbur, East-Indian slide guitar and Arabian oud and violin. There's a lot of semi-flageolet action when a player deliberately invokes specific overtones to produce a dirty hoarse sound. Any losses of harmonic data here spell disaster. The entire recording is about tones "ricocheting and reflecting within a house of mirrors for endlessly subtle interplays". Remove a few mirrors and all you've got left are some explorative, not very melodic improvisations over drones and percussive ambiance. Now bore me - for a new spin on bite me.

With an expansive tonal palette, House of Mirrors is very trancy however. You've rarely heard exotic strings so raw, virile, sweet, buzzing, metallic, sinuous... well, mysteriously rich and even goose-pimply alien at times. Without an Isabella, such exploits are wasted. You'd of course never know. With House of Mirrors in particular though, the eventual awakening is rather rude. It's of the aghast "you mean I've put up with just this all along" sort. Naturally, if you're not keyed into tone modulations, it mightn't bother you terribly. But it's true on any album that the Isabella, on integrated and stereo amp alike, adds body, weight and substance. To an extent, there's also some dynamic expansion whereby phrasing becomes more emphatic, inflections more pronounced. This adds to the overall sense of greater fullness even if you don't dissect the effect into its apparent constituents.


The Big One
What if you're already stoked with the Signature 30.2 integrated? Would you find the Isabella worth more than twice your initial investment? On resolving speakers, I'd expect 80% would be affirmative. The trouble for Vinnie is simply how relatively high he has priced the preamp. There's very little inside and the batteries are chump change. You'll thus also want to know about other good valve preamps like the Eastern Electric MiniMax. That sells for $1,100 and functionally only removes the remote. Its only snafu in this context could be high gain. The T-amp platform makes lots of it already. Hence Vinnie's lo-gain choice for the Isabella, including its gain option toggle. It's very sensible.


Ultimately, reviewers take the 5th on matters of price. To invoke the reductionist approach again, if we focus purely on performance and the high-fidelity context, the Isabella is an eventual must for Sig 30.2 owners. The only qualification resides in the choice of albums I picked. Where the improvements occur is in the field of the secondary finer stuff. If all you want is more fullness, just play it louder. But if you want such fullness at lower levels, it'll have to come from elsewhere. Brute SPLs can't fake it. It's about sophistication. That's where the preamp comes in. You can get even more harmonic elucidation, air and speed but there Vinnie's particular voicing of his amps becomes the bottleneck. And, considering other T-amp competitors from Firenze Audio to Passion &ound and Sutra I've heard, there's clearly a limit as to what Tripath can realistically deliver in ultimate HF sophistication. That's just added to keep it realistic. It takes nothing away from the very canny balancing act Vinnie Rossi has accomplished with his components to make them unfussily musical, a satisfying and fun listen and, from what I can tell, supremely reliable as well.

Red Wine Audio website