Review: Herron M1 Monaural Amplifier

Category: Amplifiers

Review: Herron M1 Monaural amplifier

System setup:
Speakers: Tyler Linbrook Signature System
Source: Sony ES-9000 DVP, upgraded to Level 6 VSE status
Amps: McCormack DNA-125, Herron M1 Monos, AES Sixpacs
Preamps: Dehavilland Ultraverve 2, (Hytron 6SN7, rest are Sylvania NOS) and Herron VTSP-1a/166 (stock Sovtek 6922 tubes)
Cables: All from Signal: Ultra 2 biwire speaker, Silver Resolution IC’s, Magic Power PC, Silver PC from wall into Ulimate Outlet 20a
Room size: 15x24, 10-foot ceilings, L-shaped that opens toward stage right, but room treatments keep it balanced-sounding
Music I enjoy: jazz, classical, vocals, indie rock, bluegrass: everything except crappy “classic” rock that all sounds the same. I also don’t like commercial country/pop.
What I like about my system: nothing in particular, just that it sounds real and enjoyable. I am a guy who likes to listen to music, and has no musical training whatsoever.

Review: The Herron M1’s have been in my system for about a week. Specs are 150w into 8 ohms, 275w into 4 ohms. They are dual monos, around 30lbs per unit. I am running them with both the Ultraverve 2 from Dehavilland and the VTSP-1a/166 from Herron.

Comparison: I have only heard these head to head with my McCormack DNA-125 Gold revision (done by SMC Audio). Comparisons were done mainly on my Ultraverve 2 from Dehavilland. At first, the differences seem minor. With additional listening, the differences become more palpable. The Herron has a somewhat cooler presentation, but no less “musical”. It has a tube-like presentation, with regards to soundstage and ease of listening, but is extremely detailed and dynamic. It seems to just let the music come through in an exact, easy to listen to way, without any sharp edges. The background is ultra-quiet with the Herron pre, not quite as quiet but a bit more euphonic with the Dehavilland. Compared with the McCormack, I found the Herron to be better in most every way. Low-end delivery was about the same on both amps, but everywhere else, the Herron seemed more realistic. Instrument decay sounded more accurate, the soundstage was larger, the vocals a little more realistic. Norah Jones, in particular, sounded better on the Herron amps (I have no idea what she sounds like in real life, but she came across as a bit chesty on the DNA-125, a bit brighter and life-like, yet more soothing on the Herron). The music just seemed more neutral and natural with the Herron, yet low-level details that were only hinted at on the McCormack were very easy to pick out on the Herron. On Air’s Kyoto, I was hearing strings and support insturments that were just background fodder on the McCormack, and the soundstage seemed to jump out of the speakers and surround me. On complex orchestral passages (the Brandenburg Concertos were an obvious one) the supporting instruments were easier to pick out and separate. They both seemed to have similar control on my speakers, with ample power to drive the 4-ohm load of the Tyler LSS.

With that said, the McCormack DNA-125 was very, very good. The Herron amps are 2x the retail price of a DNA-125 and Revision Gold upgrade, nothing to sneer at. If I could quantify performance, I would say that the McCormack was 97% of the performance of the Herron, and that I needed some time listening to really identify the differences. The DNA-125 is very musical and easy to listen to: even it if doesn’t have the huge soundstage or low-level detail of the M1, it is still a VERY good amplifier, as many people will attest to. I could happily live with the McCormack forever if it was all I could afford, but would rather have the Herron, as I feel it to be a superior piece. Nothing else I have heard in a showroom (Classe CA-M400 monos, Musical Fidelity KW-500) has me wanting more amp than the Herron. Perhaps if I had hard-to-drive speakers I would need more power, but for a moderately efficient speaker that presents a reasonable load (Herron doesn’t recommend a constant 2-ohm load with the M1) the Herron is awfully good.

I should note that I did most of the auditioning with the Dehavilland Ultraverve 2. The Herron preamp sounded much better on the M1 amps (no surprise there) and I wanted to give the amps a chance with a well-regarded preamp that wasn’t build with system synergy in mind. The Dehavilland may have added to the euphonic sound of the DNA-125, so it may or may not be the best choice. The Herron-Herron combo was superb, as one would expect. The Herron pre is every bit the Dehavilland’s equal, and which is a better unit is simply a matter of what type of presentation one is looking for. Extremely neutral yet musical: Herron; detailed yet a bit more euphonic and “fun”: the Dehavilland.

Associated gear
Tyler Acoustics Linbrook Sig System
Herron VTSP1a/166 preamp
Dehavilland Ultraverve 2 preamp
Sony DVP-9000es w/VSE Level 6 upgrades
All Signal Cable cabling

Similar products
AES Sixpacs
McCormack DNA-125 Gold
Hi there, I also commented on your other review.. Just a thought: given that the input impedance of the Herron is unusually high, why don't you try a high quality stepped attenuator instead of the preamp? If you like it you could save a lot of money..
Interesting and informative review. I currently own a pair of Herron M-150s, and have been pondering the move to M1's. Have you ever heard the older Herron designs? Just curious since it is hard for me to find a place to listen and evaluate in my area.
No, I haven't heard the older M-150, but supposedly isn't isn't a whole lot different than the new M1, but without the quick-start feature.

My friend, who ended up with these after my demo period of 3 weeks, says it is absolutely better than his Pass 350.5, in his system, powering his Wilsons. He was dubious after seeing how little the amps are on the outside, but the internals are very clean and they have a huge current capability. He said the Krell he used to have was much more impressive looking on the outside, but the transformer was puny in comparison and the amp seemed to be all show, no go, in comparison to the Herrons. I would have kept these had finances allowed it, but such is least I had a few sweet weeks with them!