Just to amplify Bill's assessment of the Herron amps - they are WAY WAY underrated in the audiophile community. Terrific amps and highly synergistic with the preamps.
I think the disregard for the Herron amps is partly that few have actually heard them, and largely because when the M150s were first produced a review pair or two with incorrectly set bias that got away from Keith prematurely - there was a "meh" review in Stereophile and people didn't read subsequent reviews in other publications which praised the amps. The take was: terrific preamps. (BTW, I've never seen a review of the newer amps other than lavish praise at audio shows and would love for someone to point one out to me. To read reviews you'd think all Herron Audio makes are preamps and phono stages.)
My M150s sounded to me like Keith took the best attributes of ss amps and combined them with many of the virtues of tubed amps. The 150s themselves (and I would assume the M1s are similar to the 150s) don't have an obvious sonic signature per se - a GOOD thing in my estimation (being neutral ought not to be a fault!). But it can render the Herron amps a bit difficult to discuss without a simple handle to hang onto them.
When people would ask me what the amps sounded like I'd always respond that "they sound like music"...which wasn't an exaggeration but perhaps not terribly instructive to someone who hasn't heard them.
The 150s were harmonically accurate, grain free, very natural sounding amps that let you hear the "gestalt" of the music playing through them - they got out of the way. I didn't notice the amps, I was just loving the glorious music. (My M150s were paired with the Herron VTSP-1-166a)
However, so many people don't even know what non-amplified "natural" music even sounds like they have no reference for this and thus tend to think there must be something lacking in an amp praised as "neutral". And indeed, some listeners prefer a warmish, non-neutral sound...which is OK but not what Herron gear is about. The M-150s are also bi-polar amps, and many of that ilk can sound lean or cool. The M150s don't (and I assume neither do the M1s) but history was against them.
So what DO they sound like? I still can't precisely describe them but the M150s are one of the few ss state amps I've heard that have the "ease" and "flow" one finds in tubed amps, plus the harmonic accuracy that is so pleasing in tube gear. They display the richness of real instruments, if it's there in the recording, yet they are NOT euphonic, warmish or fuzzy, as many so called tube-like ss amps are. Neither are they lean or cool. They don't add - they don't subtract.
I've heard them with Alons (Circes and Vs) and Audio Physic Avanti IIIs and the bass was prodigious - not exaggerated, as alas some define "good" bass. These are current hungry speakers but not terribbly diffucult loads. (Keith once told me he did final voicings of the M150s on his Circes, which may account for much.)
I have a friend who bi-amped his Pro-Ac Response 3.8s, which are a bit tougher to drive than the above speakers, with 2 pairs of the 150Ms, ditching much more expensive (and highly praised) Clayton and Rowland amps. The Pro-Acs sound amazing with the Herrons and I would suggest that if your bass is a hair on the lean side you consider doing this. It may not be an issue with the M1s, and talking with Keith probably the best bet for any questions. If you aren't using a Herron preamp, then I would look not to the amps but to your pre. I simply can't imagine bass lacking with either the Herron pre VTPH2/VTPH-3a and M150 amp combinations.
Bottom line - the M150s are one of the great bargains in high end audio. Highly recommended! I wish I still owned them!!
(FYI, I'm not a violinist, but I've played keyboards and organ for years, sang in chamber, symphonic and church choirs - even played briefly in a rock band in college. I don't have golden ears but I do have a fairly good idea of what music in the real world sounds like...again, I understand some people aren't terribly interested in "realistic" sounding music reproduction, but for those of us that are, the Herron gear is a bargain.)
I think the disregard for the Herron amps is partly that few have actually heard them, and largely because when the M150s were first produced a review pair or two with incorrectly set bias that got away from Keith prematurely - there was a "meh" review in Stereophile and people didn't read subsequent reviews in other publications which praised the amps. The take was: terrific preamps. (BTW, I've never seen a review of the newer amps other than lavish praise at audio shows and would love for someone to point one out to me. To read reviews you'd think all Herron Audio makes are preamps and phono stages.)
My M150s sounded to me like Keith took the best attributes of ss amps and combined them with many of the virtues of tubed amps. The 150s themselves (and I would assume the M1s are similar to the 150s) don't have an obvious sonic signature per se - a GOOD thing in my estimation (being neutral ought not to be a fault!). But it can render the Herron amps a bit difficult to discuss without a simple handle to hang onto them.
When people would ask me what the amps sounded like I'd always respond that "they sound like music"...which wasn't an exaggeration but perhaps not terribly instructive to someone who hasn't heard them.
The 150s were harmonically accurate, grain free, very natural sounding amps that let you hear the "gestalt" of the music playing through them - they got out of the way. I didn't notice the amps, I was just loving the glorious music. (My M150s were paired with the Herron VTSP-1-166a)
However, so many people don't even know what non-amplified "natural" music even sounds like they have no reference for this and thus tend to think there must be something lacking in an amp praised as "neutral". And indeed, some listeners prefer a warmish, non-neutral sound...which is OK but not what Herron gear is about. The M-150s are also bi-polar amps, and many of that ilk can sound lean or cool. The M150s don't (and I assume neither do the M1s) but history was against them.
So what DO they sound like? I still can't precisely describe them but the M150s are one of the few ss state amps I've heard that have the "ease" and "flow" one finds in tubed amps, plus the harmonic accuracy that is so pleasing in tube gear. They display the richness of real instruments, if it's there in the recording, yet they are NOT euphonic, warmish or fuzzy, as many so called tube-like ss amps are. Neither are they lean or cool. They don't add - they don't subtract.
I've heard them with Alons (Circes and Vs) and Audio Physic Avanti IIIs and the bass was prodigious - not exaggerated, as alas some define "good" bass. These are current hungry speakers but not terribbly diffucult loads. (Keith once told me he did final voicings of the M150s on his Circes, which may account for much.)
I have a friend who bi-amped his Pro-Ac Response 3.8s, which are a bit tougher to drive than the above speakers, with 2 pairs of the 150Ms, ditching much more expensive (and highly praised) Clayton and Rowland amps. The Pro-Acs sound amazing with the Herrons and I would suggest that if your bass is a hair on the lean side you consider doing this. It may not be an issue with the M1s, and talking with Keith probably the best bet for any questions. If you aren't using a Herron preamp, then I would look not to the amps but to your pre. I simply can't imagine bass lacking with either the Herron pre VTPH2/VTPH-3a and M150 amp combinations.
Bottom line - the M150s are one of the great bargains in high end audio. Highly recommended! I wish I still owned them!!
(FYI, I'm not a violinist, but I've played keyboards and organ for years, sang in chamber, symphonic and church choirs - even played briefly in a rock band in college. I don't have golden ears but I do have a fairly good idea of what music in the real world sounds like...again, I understand some people aren't terribly interested in "realistic" sounding music reproduction, but for those of us that are, the Herron gear is a bargain.)