MikE
Color Me Gone
Moth s45 Arrives (ongoing listening impressions)
Moth s45: First SET - First Impressions
« on: February 24th, 2002, 2:07pm »
--------------------------------------------------------------------------------
February 22 11:35 a.m. Moth custom s45 (serial#53) delivered via AirborneX. The shipping crate is way cool with branded "Moth" emblems, and it required no tools to unpack!
X-Mass, two months removed: Another surprise; instead of the wrinkle powder coat finish, the new 16 gauge chassis was finished in a satin smooth gloss. Thinking I was going to miss the good looks of my VAC, the striking "Goth meets Captain Nemo" aesthetics of the Moth and the overall presentation were nothing but first-class and distanced my rememberances. The wait was worth it - on style points alone! The owner's manual is an enjoyable read, and hookup was quick-n-ez. Yet, my first sonic impressions were less than complimentary, puzzling actually. The damn center image (a very nice image at that) was hovering over the right Sonatina. Checking my connections, it dawned on me that in my haste I forgot to bias the Sovteks. Whipping out my handy-dandy volt metre, sure enough that one channel was turned way up! - oops. Biasing is a piece of cake with the external, rear top-plate pin jacks / bias knobs. 30 seconds later I was in the sweet spot enjoying a rock solid centre image.
The "stock" tube compliment I was listening to were the current-production Sovtek 2a3's, National NOS O-getter 6an4's and a NOS Chatham 5r4wga rectifier. Of the multiple combinations available to me, the stock quintet was by far the least impressive, and surprisingly the least stout in the power department (see update for later opinion).
Project / Amp Profile: Having contemplated "upgrading" from the EL34 triode-based 32wpc VAC to a directly-heated-triode 9-2wpc SET amp the last year, my main concern centered around the issue of power. Would the Moth, or most any 2a3/45 amp, have the balls to drive my 93db/flat 8ohm Silverline Sonatinas. Or a better question, to what degree and how would that presentation compare to the high standard of the tricked-out VAC. The performance, if not the personality, of the VAC was much improved with AC / acoustic treatment, silver cables, platform & footer agumentation and the pain-staking selection of vintage tubes. Of course, the Moth didn't take a back seat in the parts or tube department; in addition to the stock Electra-Print trannies, I selected (with Craig's approval) Exotica teflon coupling caps (2) Kiwame carbon film resistors (9) and CTC "Blowtorch" silver hookup wire; teflon insulated 99.99997 silver rods (equaling about 22awg for signal) and Wonder Wire (19awg) for ground. I must admit I chose the caps & resistors entirely on the research & recommendation of those with the experience I lacked on this subject. And based on their summation of the sonic signature (or lack of) of each part I made the best guesstimation, knowing that I could always switch them out later. One other deviation from the stock amp was the selection of a Borne 10k pot vs the stock 100k Alps. Craig felt the military-grade Borne's was slightly better. The chassis compartment would not allow the incorporation of the DACT ct2 attenuator w/o significant modification.
THE Power Issue: While not exactly pumping out the "chunkest" sound I've ever heard IMS, my primary concern, and the subject of much debate, was put to rest. The Moth+Sonatina combo swings, and very nicely. Even with my system fine-tuned to the VAC I was able to crank out smooth, non-compressed 93db peaks... WITH THE 2wpc 45 TUBE!!! And while my musical tastes do not include heavy orchestral, I eventually found myself selecting music as if the VAC were glowing in the dim light.
While I should have familiarized myself with the stock tube compliment, temptation got the better of me. Instead I delved straight into the mother-lode of NOS tubes, and jerked the Sovteks by their ugly head and dropped in the RCA bi-plates (1950s non-military, d-getter, gray plate version). Again I held my breath, as one of the RCAs were noisy in my buddies Cary 2a3 monos - IMS dead quiet. If anything, the Sovtek presented images from a more opaque background, while the RCAs fleshed-out a more organic sound as the entire presentation became less mechanical. Surprisingly there was no drop off in usable power or in the dimensionality of the ebb and flow.
Satisfied with the power tubes, I focused my attention on the rectifier: 1939 RCA 5r4gy in exchange for the Chatham - better still. Then I found bliss with the 1956 Amperex metal-base 5ar4. Similiar to the step up from the VAC>Moth or Sovtek>RCA 2a3; there was a "rightness" to the sound that swirled around the room, and once heard was impossible to ignore: More detailed, harmonically richer, with greater bass articulation and shifts in scale. The overall presentation representing an ease & naturalness that precisely echoed my replay priorities. Then almost as an after-thought I replaced the RCA bi-plates with National-Union mono-plate 45's (all 45s are single-plate) National O-getter 6an4>Sylvania D-getter 6an4, Amperex 5ar4>Sylvania jan-chs 5y3 (45s require either a 5y3/5r4) re-biased and let her rip. WoW! This tube kills, immediately I was struck by the coloration of the EL34 triode-based VAC, and the 2a3s I was familiar (however brief). It's like 3 veils had been removed. I was no longer sitting on the production side of the glass, but in the room with the musicians! With the 2a3, I'm listening to the tube, with the 45 I'm listening to the music. Once installed I completely forgot about evaluating the amp (or reminiscencing the VAC) instead I was focused on the music, paying particular attention to emotional nuance & micro-dynamics. There was just more snap, jump and aliveness to this tube, least with this one (1) pair of vintage National-Union 45's. The bass? Oh lordy, THIS 2wpc kicks ass!!!
Moth vs VAC driving Sonatinas: I'll be honest, I'm not sure if the quality of replay is better with the Moth. There are some trade-offs, the VAC surprisingly illuminates space better, and perhaps was more extended on top - IF memory serves. But overall the Moth is better, just imagine what it could sound like if she weren't shackled to a 93db speaker, or even with some fine-tuning to the present combo. So while the "newness" is still coloring my perspective, I'm definately enjoying the amp, my system, and MY MUSIC very much, and would absolutely make the same move again.
Summery: The architecture of the Moth with the big tubes right up front is very impressive perched on the 2" block of polished blk Chevelle granite. The s45 is the most transparent amp I've ever had the pleasure, and offers me another avenue to explore - SET - while maintaining the high standard I'm accustomed, and paves the way for the transition to horns / single-driver speakers should I choose to pursue.
Caveat: One last point I want to emphasis. This is my very first post on my first SET amp. This was after much research and a long-awaited delivery; my antiscipation / expectations were high. If I sound happy, I am - and relived too. But I'm far from any hard conclusions on the successful integration of the Moth IMS. That awaits further listening, and time, as my understanding is not complete but on-going. I would NOT recommend anyone rush out and order this - or similiar - amp hoping for the results I enjoy now. There are too many variables to consider, and re-consider if you hope to achieve lasting results, unless your idea of success is rotating components on a quarterly basis.
p.s. I'd like express my sincere appreciation to everyone who took the time to contribute to the success of this project - Thank You!
MikE
Moth s45: First SET - First Impressions
« on: February 24th, 2002, 2:07pm »
--------------------------------------------------------------------------------
February 22 11:35 a.m. Moth custom s45 (serial#53) delivered via AirborneX. The shipping crate is way cool with branded "Moth" emblems, and it required no tools to unpack!
X-Mass, two months removed: Another surprise; instead of the wrinkle powder coat finish, the new 16 gauge chassis was finished in a satin smooth gloss. Thinking I was going to miss the good looks of my VAC, the striking "Goth meets Captain Nemo" aesthetics of the Moth and the overall presentation were nothing but first-class and distanced my rememberances. The wait was worth it - on style points alone! The owner's manual is an enjoyable read, and hookup was quick-n-ez. Yet, my first sonic impressions were less than complimentary, puzzling actually. The damn center image (a very nice image at that) was hovering over the right Sonatina. Checking my connections, it dawned on me that in my haste I forgot to bias the Sovteks. Whipping out my handy-dandy volt metre, sure enough that one channel was turned way up! - oops. Biasing is a piece of cake with the external, rear top-plate pin jacks / bias knobs. 30 seconds later I was in the sweet spot enjoying a rock solid centre image.
The "stock" tube compliment I was listening to were the current-production Sovtek 2a3's, National NOS O-getter 6an4's and a NOS Chatham 5r4wga rectifier. Of the multiple combinations available to me, the stock quintet was by far the least impressive, and surprisingly the least stout in the power department (see update for later opinion).
Project / Amp Profile: Having contemplated "upgrading" from the EL34 triode-based 32wpc VAC to a directly-heated-triode 9-2wpc SET amp the last year, my main concern centered around the issue of power. Would the Moth, or most any 2a3/45 amp, have the balls to drive my 93db/flat 8ohm Silverline Sonatinas. Or a better question, to what degree and how would that presentation compare to the high standard of the tricked-out VAC. The performance, if not the personality, of the VAC was much improved with AC / acoustic treatment, silver cables, platform & footer agumentation and the pain-staking selection of vintage tubes. Of course, the Moth didn't take a back seat in the parts or tube department; in addition to the stock Electra-Print trannies, I selected (with Craig's approval) Exotica teflon coupling caps (2) Kiwame carbon film resistors (9) and CTC "Blowtorch" silver hookup wire; teflon insulated 99.99997 silver rods (equaling about 22awg for signal) and Wonder Wire (19awg) for ground. I must admit I chose the caps & resistors entirely on the research & recommendation of those with the experience I lacked on this subject. And based on their summation of the sonic signature (or lack of) of each part I made the best guesstimation, knowing that I could always switch them out later. One other deviation from the stock amp was the selection of a Borne 10k pot vs the stock 100k Alps. Craig felt the military-grade Borne's was slightly better. The chassis compartment would not allow the incorporation of the DACT ct2 attenuator w/o significant modification.
THE Power Issue: While not exactly pumping out the "chunkest" sound I've ever heard IMS, my primary concern, and the subject of much debate, was put to rest. The Moth+Sonatina combo swings, and very nicely. Even with my system fine-tuned to the VAC I was able to crank out smooth, non-compressed 93db peaks... WITH THE 2wpc 45 TUBE!!! And while my musical tastes do not include heavy orchestral, I eventually found myself selecting music as if the VAC were glowing in the dim light.
While I should have familiarized myself with the stock tube compliment, temptation got the better of me. Instead I delved straight into the mother-lode of NOS tubes, and jerked the Sovteks by their ugly head and dropped in the RCA bi-plates (1950s non-military, d-getter, gray plate version). Again I held my breath, as one of the RCAs were noisy in my buddies Cary 2a3 monos - IMS dead quiet. If anything, the Sovtek presented images from a more opaque background, while the RCAs fleshed-out a more organic sound as the entire presentation became less mechanical. Surprisingly there was no drop off in usable power or in the dimensionality of the ebb and flow.
Satisfied with the power tubes, I focused my attention on the rectifier: 1939 RCA 5r4gy in exchange for the Chatham - better still. Then I found bliss with the 1956 Amperex metal-base 5ar4. Similiar to the step up from the VAC>Moth or Sovtek>RCA 2a3; there was a "rightness" to the sound that swirled around the room, and once heard was impossible to ignore: More detailed, harmonically richer, with greater bass articulation and shifts in scale. The overall presentation representing an ease & naturalness that precisely echoed my replay priorities. Then almost as an after-thought I replaced the RCA bi-plates with National-Union mono-plate 45's (all 45s are single-plate) National O-getter 6an4>Sylvania D-getter 6an4, Amperex 5ar4>Sylvania jan-chs 5y3 (45s require either a 5y3/5r4) re-biased and let her rip. WoW! This tube kills, immediately I was struck by the coloration of the EL34 triode-based VAC, and the 2a3s I was familiar (however brief). It's like 3 veils had been removed. I was no longer sitting on the production side of the glass, but in the room with the musicians! With the 2a3, I'm listening to the tube, with the 45 I'm listening to the music. Once installed I completely forgot about evaluating the amp (or reminiscencing the VAC) instead I was focused on the music, paying particular attention to emotional nuance & micro-dynamics. There was just more snap, jump and aliveness to this tube, least with this one (1) pair of vintage National-Union 45's. The bass? Oh lordy, THIS 2wpc kicks ass!!!
Moth vs VAC driving Sonatinas: I'll be honest, I'm not sure if the quality of replay is better with the Moth. There are some trade-offs, the VAC surprisingly illuminates space better, and perhaps was more extended on top - IF memory serves. But overall the Moth is better, just imagine what it could sound like if she weren't shackled to a 93db speaker, or even with some fine-tuning to the present combo. So while the "newness" is still coloring my perspective, I'm definately enjoying the amp, my system, and MY MUSIC very much, and would absolutely make the same move again.
Summery: The architecture of the Moth with the big tubes right up front is very impressive perched on the 2" block of polished blk Chevelle granite. The s45 is the most transparent amp I've ever had the pleasure, and offers me another avenue to explore - SET - while maintaining the high standard I'm accustomed, and paves the way for the transition to horns / single-driver speakers should I choose to pursue.
Caveat: One last point I want to emphasis. This is my very first post on my first SET amp. This was after much research and a long-awaited delivery; my antiscipation / expectations were high. If I sound happy, I am - and relived too. But I'm far from any hard conclusions on the successful integration of the Moth IMS. That awaits further listening, and time, as my understanding is not complete but on-going. I would NOT recommend anyone rush out and order this - or similiar - amp hoping for the results I enjoy now. There are too many variables to consider, and re-consider if you hope to achieve lasting results, unless your idea of success is rotating components on a quarterly basis.
p.s. I'd like express my sincere appreciation to everyone who took the time to contribute to the success of this project - Thank You!
MikE
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