[G8YU]

Here's my impressions on the M700 monoblocks that I got from Ivan. It's rather embarrassing that it has taken me so long to post this. In my defense, I had this nearly complete in the autumn; and the flash drive where it was saved suddenly died. Around Christmas I looked back at some notes and began writing this again the best I could from memory. My apologies to anyone who's been waiting for me to post this.

I'll begin at the unboxing of the black M700 amps. I guessed that class D amps would be light, and they are; but, they are solid and well constructed. They also have nice rubber feet and enough heft to stay flat and in place on the shelf with reasonably large, stiff wires plugged in the back. I like appearance of the design and the black, lightly textured finish. There is a red light that I think looks nice glowing from the case vents. I'm not too sure about that big glowing blue square for the power button. The amps are close to the floor and off center, so the glow doesn't bug me. I think it might have looked a little better to me if it had been a rounded corner square button/light which might match the faceplate design better.

I put the amps on separate shelves and had no trouble hooking them up. I even used the 12v triggers so that they turn on (or off) automatically when the Arcam A80 (used as a preamp) is turned on. I did have to change the speaker cable arrangement a little since each M700 would drive one speaker in traditional monoblock fashion. The Arcams had been hooked up for the A80 driving the tweeters and midrange and the P80 driving the woofers.

Reviews that I had read of the M700 said that they were very silent amps. Maybe we have noisy power then because I hear about the same amount of white noise hiss as the Arcams had. With no music playing I can't hear it from the listening position; but it's easy to hear at less than 2ft from a speaker.

As the A80 has a numbered volume control, I noticed that the volume control needed to be set quite a bit higher for the same apparent volume. We used to listen with the volume set in the 30-38 range. The M700 seemed to need the volume set above 40. This might have been expected since the M700 info lists a lower sensitivity value than the Arcam's amplifier sections. What wasn't expected was that we weren't turning up the volume as far as the amps got more hours of use on them. Maybe it was just our ears/brains adjusting all along. Something else that was strange was that in all the years we used the Arcams the sources had different volumes. The A80 has a menu to allow the adjustment of each source's volume so that you could get them to match; but we never bothered adjusting them. Now that the A80 was only functioning as a preamp/source selector driving the M700 pair, all the sources seem to match closely in volume.

The amps sounded mostly good at first and improved from there for probably more than a month. When we weren't listening to music, the amps were left on with a FM tuner playing through them at various low volume levels for a little over a week to hopefully quicken the break-in. I'm glad that I separated the amps on different shelves because they run warm. They don't get quite as warm as the Arcams did; but warm enough that it's obvious the vents in the amp case are necessary.

When we started to turn the amps off between listening sessions I noticed that the cases stay barely warm to the touch when turned off (standby), about 5 degrees above room temperature. This must help them reach optimal temperature quickly, as they seem to already sound their best within 10-15 minutes from turn on. The Arcams needed about 45 minutes of warm up to sound their best.

Once we started doing some serious listening with the M700 amps, the thing that stood out to me was the greater dynamic ease the music had. It was obvious that, even though the Arcams didn't sound like they were struggling at our usual modest volume levels, they had been flattening the dynamic contrasts. The M7si speakers still mostly had the sound signature I was accustomed to hearing; but with a bit better treble and bass extension and detail, and definitely better micro and macrodynamics. There was now, of course, plenty of power in reserve to increase the volume, while the Arcams couldn't get too loud without sounding flat and constricted (begging to be turned back down).

As I'd mentioned in a previous post, there was a specific desire to hear individual instruments separate in certain songs that seem to be covered up compared to the way we remember hearing the songs years ago. Dad was quite pleased when, for every song he played that seemed to have something missing before, he could now hear what he was looking for. For me, it was the improved microdynamics that was making individual instruments stand out better while they also seemed to have a bit more complex detail and texture. Add to that the more effortless macrodynamics, and I can say the M700's renewed the M7si for a more musically satisfying experience that was still to the style or type of sound (signature) that I like.

I don't know if it was some sort of upgrade-itis; or a case of “this is good, more must be better”. Dad began to wonder if we could find a pair of good condition used Mirage M5si or M3si speakers. I kept watch on the used market for a while and remembered that I had seen some used Thiel speakers at a local audio dealer a few months before. I checked on the Thiels and found that they still had them for sale. Years ago we had heard Thiel CS 2.? (I don't remember what exact model) driven by I don't remember what amplifier at that audio dealer. What I do remember is that Dad was so impressed that for a while he wanted to buy them, but could never manage to save up enough for them. I haven't heard many stereos; but I remember that those Thiels made the best sounding music reproduction I had ever heard. Even expensive stereo systems I've heard since then haven't made songs as present, alive and musical sounding.

Luckily, these used Thiels were barely going to fit in the budget. Since we could now get serious about the purchase I looked up information on them. They are the CS 3.6 model which have wattage requirements well within the limits of the M700 monoblocks; but they are rated at between 2-3 ohms for most of the audio band. The M700 info says that they aren't 2 ohm rated. I called PS Audio to ask if the CS 3.6 will work with the amps since it has such low impedance. They said it would work without a problem.

I called the dealer to find out if they would let us audition the CS 3.6 and they set up a morning for us to come over. When we arrived at the dealer they had left the speakers playing all night so everything should be warmed up and ready. We brought some familiar CDs with us to try out. The first song we played didn't sound that good. Basically anything we played seemed to lack bass and there was some sort of harshness and/or coarseness in an area of the midrange. It might seem odd to say that, otherwise, they sounded kind of good, like there was potential in there.

I looked the speakers over carefully, and couldn't find any damage. I hoped there was nothing wrong with the crossovers as those couldn't be inspected. They mostly looked like very gently used, well cared for speakers. The dealer was driving the speakers with Bel Canto e.One Ref600m monoblocks and had them connected with a very thick blue jacketed Cardas speaker cable.

Dad said he was hearing the same things I was as we discussed whether we should buy them. We remembered how great the other model of Thiels sounded years ago; and, perhaps unwisely, reasoned that these speakers just didn't like the associated equipment. This could be risky though because the Bel Canto Ref600m is a class D amp with a power rating close to the M700, although they use different class D modules.

This risky gamble weighed on us during the trip to the bank, while we loaded the speakers in the car, and on the rainy drive home. I unhooked and moved the M7si pair out of the way, and removed one pair of speaker cables since the CS 3.6 has only one pair of terminals.

Once all hooked up, it was time to try some music. I'll expand on this as you read on; but, to put it simply, the M700 monoblocks driving the CS 3.6 made really good sounding music. They sounded even better after I adjusted their room positions as best as space and slight rearranging would allow. The sound also seemed to still improve with time even though the amps should have already been broken in.

During these experiences I began pondering a few things. One was that I might have witnessed an unexpected system mismatch. The CS 3.6 must have had a problem with the cable or monoblocks at the audio dealer; because, at home, there was no trace of harshness and the bass was as mostly present as expected (more on that below). I also wondered whether a speaker would require break-in if it had been unused for a long time. I am reasonably sure that the dealer had the CS 3.6 for at least four months or longer; so who knows when they last had music played through them. If a long dormant speaker requires break-in, that might explain some of the reason they didn't sound too good at the dealer, and why they improved over time. The other possibility I considered was that amps not only need to break-in with use; but take time to adjust to a different speaker.

I won't be able to do a comparison with the CS 3.6 directly on the Arcam A80 and P80 used as amps because I doubt they could safely drive them; and I'm not going to find out. I had thought the CS 3.6 would require the volume to be set higher; but they actually don't need the volume set as high. They are also more revealing of the background hiss, but it still isn't noticeable from the listening position. With familiar songs there is ample clear detail that sounds naturally presented. Again, I think the sound improved over time gaining a bit of ease (or smoother continuity) and delicacy where it was appropriate in a song. Whether micro or macro, dynamics are impressive, and add more to music reproduction than I realized that I had been missing.

I don't know if it was my brain adjusting or the possible long break-in; but the bass seemed to improve for a while after I had repositioned the speakers. The speakers already had better bass in their initial positions than I heard at the audio dealer, but it seemed weaker in level and extension than I expected. I gradually moved the speakers, only a few inches overall, and seemed to get a bit better bass; but I still wasn't too happy with it. At first they seemed to have less extension and weight than the M7si had; but with time and the repositioning they finally surpassed the M7si. A few days after I had quit trying to reposition them and had inserted the three pins in the base of each speaker, I wasn't critically listening but heard bass that was deeper than I'd ever heard in that song. I returned to some familiar songs and, inexplicably, there was the quantity and quality of bass that I had been hoping for.

I wish the CS 3.6 had a soundstage style more like the M7si. I realize soundstage traits are not just affected by the speaker design; but by room placement and adjustment. If I had a separate listening room, I could probably reposition the speakers for even better sound. In my real life conditions though, the M7si presented a wide soundstage with depth that went from in between me and the speakers to behind them; and images that were a bit larger than they probably should be. I felt that suited the slightly warm, fun, enjoyable sound signature they had. The CS 3.6 presents more compact and precisely drawn images that are confined to a smaller area in the general space of the speakers.

Whatever I play on this stereo now is so detailed and musically satisfying that I get completely involved in the sounds of instruments, the interactions of sounds and musicians and what thing or feeling an artist is intending. With the M7si I was enjoying music; with the CS 3.6 I am becoming completely involved in experiencing the music. All this is thanks to the capabilities of the excellent M700 monoblocks.

The upgrade itch hasn't gone away yet. Now that it has been a year there is enough funds saved up to purchase the Stellar Gain Cell. It has just barely enough inputs for us, but no tape loop (which we rarely use anyway). It will add an internal DAC to the stereo (one fewer external source necessary) and I'm sure it will be as good or better a preamp than the A80.