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Reviewer:
Srajan Ebaen
Financial Interests: click here
Source: Apple iMac 1TB running OSC 10.6.6 with AIFF files up to 24/192 on PureMusic 1.74a in hybrid memory play with pre-allocated RAM, Weiss DAC2, Burson Audio HA160D as DAC
Preamp/Integrated: Esoteric C-03 (transistor), Bent Audio Tap-X (AVC passive), ModWright DM 36.5 (tube)
Amplifier: ModWright KWA-100 SE
Speakers: ASI Tango R, Living Voice OBX-RW [on review]
Headphones: ALO Audio recabled Audez'e LCD-2, Sennheiser HD800, beyerdynamic T1 and AKG K-702; stock audio-technica W5000; stock Grado PS-1000; HifiMan HE5LE with optional silver wiring and grill mod; HifiMan HE-6
Headphone amps: Trafomatic Audio Head One; Woo Audio Model 5; Burson Audio HA-160; Schiit Lyr [on review]
Cables: Complete loom of ASI Liveline, Zu Event, Crystal Cable Ultra interconnects and power cords, Entreq Firewire 800 and USB cables, Black Cat Cable Veloce S/PDIF cable [on loan]
Stands: 2 x ASI HeartSong 3-tier, 2 x ASI HeartSong amp stand
Powerline conditioning: 1 x GigaWatt PF-2, 1 x Furutech RTP-6
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review Component Retail: $3.495


I wasn't counting but.
At the conclusion of my ModWright KWA100SE review, I'd contacted the maker to book the return shipping of the standard version. "I will arrange to have the KWA100 picked up. I would also like to send you a LS100 preamp to use with the KWA100SE. If you want to review it I would of course be grateful. If not I want you to keep it regardless because I feel it only appropriate given that you traded the KWA150 for the lesser cost KWA100SE and covered the associated shipping costs of returning the KWA150. I am confident that you will find the combination of LS100 and KWA100SE quite enjoyable. There are no strings attached. It is up to you if or when you choose to review it. I just want to do the right thing."


FedExing the heavy 150 back to Amboy/WA had indeed made a hole $700+ deep but given how amazingly well the 100SE amplifier worked out in my new digs, I'd been perfectly content with a trade which my accountant—had I one—would probably have chided me for. Happiness is a far more solid currency than those greasy greenbacks. Learning that the LS100 was housed in exactly the same enclosure as the matching amp and had a class A biased 300Ω headphone socket with 1.5-watt max output into 32Ω whilst being fed from the linestage's twin 6SN7s with 5AR4/GZ34 rectifier, I was doubly curious.


I'm an unrepentant headphone slut after all. My three favorite cans—ALO Audio recabled Audez'e LCD-2, Beyerdynamic T1 and Sennheiser HD800 in that sequence—happen to be 50Ω, 600Ω and 400Ω designs respectively. The 1-watt rating into 50Ω promised to be perfect for the orthos. It was rainy October by the lake when Dan's email arrived but felt like early Xmas with sparkly snow on nearby picturesque peaks.


Instead of output transformers behind the tube front end, this headphone circuit uses a discrete FET current buffer for impedance conversion. This avoids the cheaper and thus far more common op-amp solutions with their high feedback. Dan's 6.3mm headphone socket says no to NFB in invisible ink. The FET buffer is powered from the same 12V transformer windings as the tube heater circuit but the output voltage is of course separately regulated.


The preamp circuit is a single gain stage/buffer affair to invert phase (PureMusic's polarity control would account for that). Socketry is quite exploded. There are five standard inputs, one monitor loop, one HT bypass input and three paralleled pre-outs. While one i/o pair is on XLRs, the LS100 is no balanced circuit. That's reserved for the top model. Exploded too over the one-box predecessor are remote functions of power, bypassable balance control, volume control, mute, input and monitor select plus two remote triggers. There's also an upgrade slot with twin 20-pin ribbon cable headers for an optional DAC or phono stage. Frequency response "is flat from 20Hz to well beyond 100kHz". Instead of the earlier toggles, all control switches are sleeker push buttons. The inside chassis height of 5 inches allows for a greater range of rectifier rolling including 5U4GB, 5V4GB, 5U4G and 5V4G. My giant EML 5U4G obviously wouldn't fit.


"Our SWL 9.0 preamp was first released seven years ago and named after my son Spencer Wright who was 9.0lb. at birth. The first 9.0 quickly became the 9.0SE and eventually evolved to the 9.0SE Signature Edition. Like my son, the 9.0SE grew and developed into something greater over time. We found ways to improve it in small and greater ways. The most significant changes were the tube-rectified power supply and custom MWI capacitors. We then further improved upon the tube-rectified supply to include sophisticated dual-discrete transistor voltage regulation. The final price of the 9.0SE 'Sig. Ed.' was $3.000. The new LS100 replacing it costs $3.295. It takes up where the 9.0SE left off with more features and a larger fancier enclosure with upgrade options."
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