ModWright In­stru­ments KWA 100 Am­pli er and LS 100 Tube Pream­pli er

NOVO - - PRODUCT REVIEW - Suave Ka­jko

Ear­lier this year, in the April/May 2012 is­sue of CANADA HiFi, Phil Gold re­viewed the ModWright In­stru­ments KWA 150 Sig­na­ture Edition Am­pli er. He was so im­pressed by this am­pli er that it ended up nd­ing a per­ma­nent spot in his au­dio sys­tem. His high praise of the am­pli er also in­spired us to bring in a cou­ple of the more af­ford­able pieces from ModWright, the KWA 100SE Am­pli er and LS 100 Tube Pream­pli er. If you’re not fa­mil­iar with the ModWright In­stru­ments brand I in­vite you to read Phil’s re­view as it does a great job of in­tro­duc­ing the com­pany. All ModWright In­stru­ments com­po­nents are de­signed and hand-made in the USA.

So how did these two en­try-level ModWright com­po­nents fair? Let’s start at the very be­gin­ning. Both com­po­nents were dou­ble-boxed for ship­ping. But I was sur­prised that the in­ner box of the LS 100 preamp was signi cantly larger than the preamp it­self. Inside, the sty­ro­foam in­serts were smaller than the box and hence could not fully pre­vent the LS 100 from mov­ing inside the box dur­ing ship­ping. The ve tubes in­cluded in the box were scat­tered loosely inside the box, three of them had fallen com­pletely out of their pa­per boxes. Luck­ily none of the tubes were bro­ken. I con­tacted the man­u­fac­turer to make them aware of these is­sues and was told that as long as the tubes worked when I rst power on the LS 100, then I shouldn’t have any prob­lems. There were no is­sues with the pack­ag­ing of the KWA 100SE amp on the other hand. Let’s look at each com­po­nent in de­tail.

The LS 100 preamp has a sin­gle-ended tube de­sign and strives to im­prove many of the qual­i­ties of­fered by the 9.0SE model, de­signed some seven years ear­lier. The brushed alu­minium en­clo­sure gives it an at­trac­tive in­dus­trial ap­pear­ance, if you’re into this sort of thing. The front panel fea- tures two large di­als (bal­ance, vol­ume), a se­ries of sunken-in but­tons for power and in­put se­lec­tion (with cor­re­spond­ing LEDs above each) and 1/4 inch head­phone jack. It is topped off by a large, blue back­lit ModWright logo that’s anked by large ModWright In­stru­ments let­ter­ing on the top and the LS 100 des­ig­na­tion on the bot­tom. Its de­sign fea­tures in­clude a sin­gle gain/buf­fer stage, phase in­vert­ing and an up­grade slot for an op­tional in-board DAC or phono stage. The base LS 100 preamp re­tails for $3,700, or $4,500 with the built-in phono stage or DAC. My re­view unit was equipped with the phono stage. The LS 100 of­fers a bank of ve in­puts (4 RCA, 1 XLR), three out­puts (2 RCA, 1 XLR), one mon­i­tor in­put and tape out, as well as a home the­atre by­pass in­put. Two re­mote trig­ger out­puts and an IEC socket, for a re­mov­able power cord, round out the rear panel. The sup­plied re­mote has a com­pact form fac­tor, sim­i­lar to re­motes sup­plied with mini stereo sys­tems, but of­fers nearly all the same func­tion­al­ity as the front panel but­tons. Frankly, the re­mote looks and feels a bit cheap.

Like some of the other tube-based com­po­nents on the mar­ket, the LS 100 preamp re­quires some assem­bly – namely plac­ing the tubes inside the sock­ets. It’s a fun, en­gag­ing process that gave me the op­por­tu­nity to get to know the com­po­nent a lit­tle bet­ter. To get the tubes into place, the top cover of the LS 100 needs to be com­pletely re­moved, which means undoing 20 hex screws with the pro­vided long­han­dled hex key. The LS 100 uses three tubes: two 6SN7 driver tubes and a sin­gle 5AR4/GZ34 recti er tube. The op­tional phono stage board re­quires two ad­di­tional tubes – a 12AU7 and a 12AX7. If you get

the LS 100 model with the phono stage, you’ll want to con gure the phono stage to have the cor­rect load­ing im­ped­ance (to match your turntable) while the cover is off. This is ac­com­plished by set­ting up two banks of board­mounted dip switches which pro­vide load­ing im­ped­ances of 50, 100, 500, 1000 or 47 kOhm, with the op­tion of 100 pf of ca­pac­i­tance. My Clea­r­au­dio Con­cept turntable has a load­ing im­ped­ance of 47 kOhms so I set the dip switches ac­cord­ingly. Fit­ting the tubes into the sock­ets is very sim­ple but set­ting the load­ing im­ped­ances may leave novice users scratch­ing their heads since it’s not ex­plained in the man­ual as well as it could be (a di­a­gram would be nice).

The KWA 100SE amp ($4,500) has the same brushed alu­minium en­clo­sure, with rounded edges and cor­ners. Its front panel is com­pletely free of but­tons, with only the blue back­lit ModWright logo sand­wiched by the ModWright In­stru­ments let­ter­ing on the top and KWA 100SE on the bot­tom. The power switch is tucked away, out of view, on the left side, on the un­der­side of the chas­sis. The SE des­ig­na­tion at the end of the model num­ber stands for Sig­na­ture Edition and de­mands $800 more, over the base model. The KWA 100SE fea­tures a solid stage de­sign but prom­ises to com­bine the ad­van­tages of both tube and solid state de­signs. The SE edition of this amp of­fers a lit­tle more power and less dis­tor­tion than the base model. Its power is rated at 120 watts per chan­nel (at 8 ohms, 0.07 % THD) or 210 watts per chan­nel (at 4 ohms, 0.07 % THD). The SE edition of­fers higher grade re­sis­tors and ModWright’s pro­pri­etary ca­pac­i­tors (also found in the preamp), as well as ve pairs of Mos­fet out­put de­vices per chan­nel, com­pared to the three pairs in the base model. To­tal ca­pac­i­tance is rated at 180,000 uf, com­pared to 90,000 uf of the base model. At the core of the KWA 100SE lies a sin­gle volt­age gain stage called the “Solid State Mu­sic Stage”, a cir­cuit de­signed by Alan Kim­mel, cre­ator of the vac­uum tube “Mu” stage. High­lights of this amp’s de­sign in­clude a high-low bias switch and true bal­anced oat­ing in­puts. Its rear panel ac­cepts both XLR bal­anced and RCA un­bal­anced in­puts. A mas­ter power switch, sil­ver multi-way speaker bind­ing posts and a power IEC port round out the rear panel.

Pow­er­ing on this ModWright In­stru­ments pair has to be done in the right or­der – the preamp rst and then the amp. Oth­er­wise, the pro­tec­tion cir­cuitry in the amp might be tripped up and in the worst case, you might dam­age your speak­ers. The preamp takes about 20 sec­onds to start up, while the amp takes closer to 55 sec­onds. I had the ModWright In­stru­ments pair hooked up to my trusty Fo­cal Elec­tra 1008 Be II speak­ers and used the Brys­ton BDP-1 Dig­i­tal Player / BDA-1 DAC and the Clea­r­au­dio Con­cept turntable as my sources.

Dur­ing the rst two months this duo spent at my house, I lis­tened to plenty of dif­fer­ent types of mu­sic and gave the com­po­nents am­ple time to burn-in. Un­for­tu­nately when I was about to sit down and be­gin my crit­i­cal lis­ten­ing for this re­view, an is­sue sur­faced with the LS 100 preamp. Sud­denly it be­gan

in­tro­duc­ing a no­tice­able noise into the sig­nal chain and also be­came ul­tra sen­si­tive to any kinds of vi­bra­tions – the small­est tap on the case got am­pli ed right to the speak­ers (even walk­ing in front of my sys­tem caused this to hap­pen). It turned out that one or more of the tubes had be­come mi­cro­phonic, some­thing that can hap­pen with tubes. How­ever ModWright quickly recti ed the prob­lem by send­ing me a new set. Af­ter go­ing through the burn-in process again, I was nally ready to give this pair a proper lis­ten.

I have to ad­mit that I was pretty ex­cited about the com­bi­na­tion of a tube preamp and a solid state amp work­ing to­gether to pro­duce sound – I gured that if they worked well to­gether I could po­ten­tially have the best of both worlds. It’s be­come some­what of a tradition now, that ev­ery time I test a new com­po­nent I go on a new al­bum shop­ping spree. Among the new artists, now loaded on my SSD drive and played by the Brys­ton dig­i­tal player, were Sonoio, Alabama Shakes, City and Colour, The Lu­m­i­neers and Alex Clare. As part of my tests I of course in­cluded nu­mer­ous al­bums that I’ve lis­tened to be­fore on many other com­po­nents.

I be­gan my lis­ten­ing ses­sion with Re­becca Pid­geon’s “Span­ish Har­lem” from the Best Audiophile Voices Col­lec­tion. I was im­me­di­ately cap­ti­vated by the re­al­ness of the sound pro­duced by this duo. Re­becca’s voice was silky smooth and echoed gen­tly in the orig­i­nally recorded en­vi­ron­ment. The strings of the dou­ble bass were well ar­tic­u­lated and pro­duced rich bass notes. Sim­i­larly pi­ano keys and the vi­o­lin played with rich over­tones. Ev­ery­thing about this pre­sen­ta­tion had a life­like qual­ity, as if I was lis­ten­ing to a live show. The highs had just the right amount of sparkle, while the bass line played tune­fully and never lacked in depth. The midrange of­fered great clar­ity and rhythm.

Tracks from AIR’s Moon Sa­fari disc pre­sented an ex­pan­sive sound­stage that I’ve come to ap­pre­ci­ate from this al­bum when played through ca­pa­ble au­dio equip­ment. The ModWright duo re­solved the nu­mer­ous, of­ten com­plex sonic lay­ers of this mu­sic with ease, while de­liv­er­ing all of the ne de­tails of each and ev­ery layer. The dy­nam­ics of the pre­sen­ta­tion never dis­ap­pointed.

Next I jumped to the Jagged Lit­tle Pill Acous­tic disc from Ala­nis Moris­sette. All of the tracks on this al­bum of­fered rich, full-bod­ied acous­tic gui­tar notes, with re­mark­able har­mon­ics that one would ex­pect from a real gui­tar. Dif­fer­ent gui­tars of­fered clearly dis­tinct sound char­ac­ter­is­tics. I could also eas­ily de­ter­mine the strum­ming pat­tern of each gui­tar on most tracks. Ala­nis’ quirky voice was re­pro­duced with all the ve­rac­ity of a live per­for­mance. The ModWright com­po­nents pre­sented me with a prop­erly laid out, three di­men­sional sound­stage where the vo­cals and ev­ery in­stru­ment had a pre­cise po­si­tion and a good amount of air around it. Tracks from City and Colour’s “Lit­tle Hell” once again re­con rmed all of my con­clu­sions about the imag­ing and sound­stag­ing.

Hav­ing a tube de­sign, the LS 100 does not of­fer as low of a noise oor as a non-tube preamp de­sign. If you’re close enough to the speak­ers you will hear a lit­tle bit of a con­stant noise. This how­ever is com­pletely expected and in my opin­ion does not take any­thing away from the lis­ten­ing ex­pe­ri­ence.

As men­tioned ear­lier, the LS 100 preamp pro­vided for this re­view in­cluded the op­tional on-board phono stage and this is what I turned my at­ten­tion to next. The LS 100 of­fers a gain of 70dB and is ca­pa­ble of han­dling both MC and MM turntable car­tridges even though it doesn’t have the typ­i­cal switch for this se­lec­tion. That’s be­cause it of­fers plenty of head­room for both car­tridge de­signs. Once again I lis­tened to a large va­ri­ety of record­ings, rang­ing from rock to clas­si­cal. Re­gard­less of the mu­si­cal se­lec­tion, I was con­sis­tently pre­sented with amaz­ing res­o­lu­tion and pre­cise imag­ing within a vast sound­stage. The LS 100 al­lowed my Clea­r­au­dio Con­cept turntable to de­liver del­i­cacy and smooth­ness from clas­si­cal record­ings and great dy­nam­ics from hard rock record­ings like I’ve never ex­pe­ri­enced be­fore from my turntable. Thanks to its tube de­sign, this phono stage added yet an­other level of re­al­ism and uid­ity to each song that I lis­tened to.

Dur­ing its stay on my au­dio rack, the ModWright In­stru­ments KWA 100SE amp and LS 100 tube preamp pro­vided me with many hours of en­joy­ment. What started as tap­ping my hands on my knees of­ten ended in air gui­tar or air con­duct­ing. There is no ques­tion that there is a great syn­ergy be­tween these com­po­nents – what I was lis­ten­ing to was truly a fan­tas­tic com­bi­na­tion of both tube and solid state de­signs. De­spite the is­sue that I ex­pe­ri­enced with the LS 100 preamp at the start, my over­all ex­pe­ri­ence with the ModWright duo was very pos­i­tive thanks to the ex­cel­lent sonic pre­sen­ta­tion achieved by them. I com­mu­ni­cated the pack­ag­ing is­sue to both the man­u­fac­turer and the Cana­dian dis­trib­u­tor and I’m cer­tain that both will ad­dress this ac­cord­ingly for fu­ture ship­ments. The LS 100 is a ex­i­ble pre-amp that of­fers plenty of in­puts, both bal­anced and un­bal­anced, and thanks to its tube stage is ca­pa­ble of breath­ing the tex­tures and re­al­ism that ex­ist in real voices and in­stru­ments. The KWA 100SE is an amp that of­fers the con­trol and dy­nam­ics that one would ex­pect from a high qual­ity amp, while of­fer­ing a great depth of de­tails. To­gether there is a sense of mu­si­cal magic be­tween these two com­po­nents, that’s for sure. Bravo ModWright In­stru­ments!

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