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At first, I ran the INT-150 against the F5 off the ModWright DM 36.5 preamp. The 150's attenuator trimmed its higher gain by hovering around 47 on the display. Now the valve pre's volume control setting tracked both amps the same. I just swapped leads and compared. Naturally, the whole integrated notion is to decommission preamps as a breed. Hence later sessions removed the ModWright. That was the scenario our Swede wanted tested, that was the scenario most readers would want to read about.

To set the stage, Critic's Corner on the Audio Asylum netted a telling bit by Morricab, former Positive Feedback reviewer: "...One name that Stereophile tends to drool over that leaves me far from impressed is Musical Fidelity. Another is Pass Labs (at least the X series amps). I have a lot of respect for Nelson's ideas and writing but the sonics of his current products IMO don't live up to the ideals. I haven't heard the First Watt stuff but I think it could be a lot better sounding..."

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For 'approved' electronics, we get KR Audio, Lamm, Convergent, BAT, Vacuum Stage, Acoustic Plan, Silvaweld, Einstein (CDP excepted), Antique Labs' Hurricane, Edge NL Reference amps and battery preamp, Weiss digital and Monarchy Audio amps and DACs. Morricab, for amplifiers, thus favors full-on valve designs or as with Acoustic Plan and Monarchy, hybrids. He hasn't heard the Pass Labs XA amps but allows them chances. Translation, they're class A. He hasn't heard the FirstWatt amps but thinks they could be closer to his tastes. Again, most the Fs are As. Plus, FirstWatt is esoteric niche stuff, Pass Labs muscular mainstream. Serious audiophiles could thus exclude the INT-150 from consideration for being "mainstreamish, proletarian A/B and without valves". We're back to Hans' opening gambit.

Without at this stage knowing whether the ModWright preamplifier compromised or upgraded the INT-150's performance with redundant circuitry or commendable signal conditioning, there was a distinct sonic family resemblance to the F5. But the smaller, lighter and far cheaper amp booked a sonic lead. With hi-rez 24/96 DVD-A source material compliments of Aix Records and Laurence Juber's Guitar Noir played back via 20 paralleled 32-bit AKM converters per channel, this played out as

More tonal substance or inner warmth
More elucidation of the percussive background accompaniment
A more suave top end on metallic ring-outs
A soundstage that had moved farther behind the speakers by a few feet
A cooler, thinner, sharper and 'bluer' overall gestalt for the INT-150 in turn

Extricating the ModWright from the chain, the INT-150 lit up. Its innate bluishness didn't really change but it became more robust, substantial and immediate. It suggested quite conclusively that the signal detour through the preamp had been detrimental to prevent the 150 from fully opening up.

Resolution improved. An interceding filter or block had been removed, stalled energy liberated. In musical terms, the focus now was on crispness, precision, separation and focus. This was a highly optimized, undiluted but civilized 3
rd-order sound. That's how Nelson Pass references amplifiers whose remaining low THD is mostly 3rd and some 5th as opposed to SETs and other critters which are 2nd order (and up) machines.

The sound now had one essential core quality from the SET camp: Unmitigated directness. Very un-SETish remained the absence of inner radiance. That's a triode effect some relate to as warmth; others as higher color temperature; other as saturation and others again as ripe tone or wet textures. It also telegraphs as spatial suchness. That isn't so much holographic from a sight/eye sense as it is 'deep space' from a feeling dimension. Whether such qualities are ultimately FX tricks, colorations or unpredictable distortion interactions remains irrelevant. Triode lovers recognize and fancy them. The 150 is texturally far leaner, drier and more 'matter of fact'. It doesn't cater to that big part of the triode gospel.

Neither does the F5. Fully. But it comes a bit closer. And then of course there is deliberate seasoning with a valve preamp. For perhaps the ultimate La Triode dose I've come across in that sector, think Thorens TEP 3800. Such preamp seasoning will certainly shift the balance. Another way to differentiate Inty's gestalt from premium SETs -- many lesser SETs are very sloppy -- is inner flexibility or buoyancy. Superior triode amps perform a tangibly breathing, wave-lapping action. The Pass is unwavering and solid. Factual. That's different. It celebrates what perhaps might be called a more cerebral sight-based clarity. There everything is assigned its proper place to be well-sorted, accurate, defined and precise. Unfazed. Crystalline nearly. With that, a cool temp reading. And great transparency.

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Morricab-type listeners will miss the minor sweetness and a certain inner redolence of enhanced tone compared to my DM-36.5/F5 combo. Or, they could snub their noses altogether and call anything less than my Yamamoto A-09S insufficient. Conversely, I also appreciate Hans I Jonsson tiring of lesser triode sound especially if he failed to arrive at an amp/speaker combo that truly meshed to compromise the stuff he wants to listen to. So I can appreciate why he likes the INT-150 but I favor what I already have more - on the Tango R.

The intermediate scoop.
One definite strong suit of the INT-150 is dynamic brio. Its reflexes are very well oiled. If you need close-miked hammer falls of a Cuban piano ace to thunder with appropriate percussiveness; rim shots to crack; popped power bass strings to go pow; you're home. In fact, think 'fast sound' in general. It's very decisive, direct and to the point in all regards. Those adoring harmonic padding will find this kind of directness a bit too stripped down, bare-boned or clean. (That their preference would then be dirtier by implication is just one of many hi-end peculiarities, syntax and otherwise.) But even those folks would have to admit that such non-abrasive, non-bracing clarity moves volumes needed for clarity downward. One can listen later into the night without stirring those already asleep.