Integrated Amplifiers

Simaudio Moon 700i Integrated Amplifier

ARTICLE INDEX

Introduction

As a Quebec, Canada based company that has spent the last 30 years manufacturing some pretty outstanding gear, Simaudio has (like some other Canadian companies) made its name via its products' performance levels rather than hype and huge marketing spending. The unit reviewed here, the Simaudio Moon 700i Integrated Amplifier maintains that standing. The 700i is the top integrated amplifier model in Simaudio's range and is part of the Moon Evolution series along with other well known components such as their W-7 amp, 750 DAC/Transport and Supernova CD player.

Specifications

  • Design: Solid State Integrated Amplifier, Dual-mono Balanced
  • Power: 175 Watts RMS into 8 Ohms, 350 Watts into 4 Ohms
  • MFR: 10 Hz - 100 kHz, ± 3 dB
  • THD+N: < 0.015%, 20Hz - 20kHz @ 1 watt
  • S/N: 105 dB (at Full Output)
  • Inputs: 1 Balanced XLR, 4 Unbalanced RCA, RCA Tape Loop
  • Input Impedance: 23.7 kOhms
  • Outputs: Two Sets of WBT 0763 Binding Posts, One Line Level Unbalanced RCA (50 Ohms) Out
  • Other Connections: Four 1/8" Jacks: Simlink In & Out for Connecting to Other Simaudio Products, 12 V trigger, IR in
  • Idle Power Consumption: 50W
  • Dimensions: 5.4" H x 18.8" W x 18.1" D
  • Weight: 60 Pounds
  • MSRP: $12,000 USA
  • Simaudio

Design and Set-up

The Moon Evolution series has a common aesthetic. The products are visually and structurally anchored on each corner by metal pillars that sits on inverted conical supports. They have finned heat sink side panels and a red dot-matrix style display. You can have any colour you want – as long as it is black or silver. This look continues on with the remote - a ¾ lb milled aluminium slab that doubles as a personal security device. Despite all that the front display is fairly subtle with 8 buttons flanking the fully dimmable display and a large volume control.

The volume control knob on the front of the unit actually drives an optical encoder which controls two multiplying DAC (MDAC) circuits vs. being mechanically connected and will spin freely for a second or two if you give it a good yank. The two MDACs are part of the M-eVol2 circuit which allows the 700i to keep it's dual mono design and balanced differential operation in place and the signal completely in the analogue domain. Channel balance (L-R) itself is adjustable via the remote in 1% increments from 0-100%

The volume control is remarkably granular, with 1.0db increments from 0 to 30 db and then 0.1db steps from 30db to 80db (the max) on the amplifier. It's a feature I didn't realize I was missing until I had to go back to the usual 0.5db stepping with other gear. It makes dialling in the level you want much easier and matching levels on the bench a breeze. Although you really have to pay attention when you hold down the volume key on the remote, for the first second the increment will be 0.1db then the 700i switches back to 1db increments. You can look away for a second or so and all of a sudden you are up 20db.

The separate amplification stages and use of MDAC in the volume control rather than a potentiometer allows the 700i to (very) tightly control the gain of the analogue input and enables a very quiet -130db of crosstalk @ 1kHz.

Each of the inputs can be individually set with a max volume level and individual input offset levels (+/- 10db) in 0.5db increments. Each input comes from the factory set to +6db. The inputs can also be set in a full bypass mode in the event a user wants to use another component to control the volume and bypass the 700i's volume control.

There is one set of balanced connectors (XLR) on the rear panel and 4 unbalanced (RCA) inputs with a in / out pair of RCAs for a tape/monitor and an additional set of RCA line level pre-outs. The WBT speaker terminals were quite nice and if you are a spade lug fan this design should be your choice - finger tight will give you a near permanent connection. Of course they also accommodate bare wire (up to 10 AWG) and banana plugs. There are four 1/8" jacks as well, two for SimLink (proprietary Simaudio equipment interconnection), an IR in and a 12V out trigger.

The 700i has 68,800µF of capacitance onboard and uses two separate 0.5kVa toroidal transformers with a claimed 3% regulation factor (vs. a more industry typical 10-15%) giving more consistent output voltage as current demands rise with higher volumes or more difficult to drive speakers. The preamp stage also gets it's own separate power supply and a dedicated, separate board within the chassis for signal isolation.

The 700i operates as a class A amplifier up to 5W of output. Of course like any class A it's pulling power all the time which explains part of the 700i's 50W power draw even in standby mode. The highest draw I observed during actual use was 215W over a one second interval.

The final piece of the puzzle is the "Lynx" architecture. While Simaudio doesn't claim to completely do away with the usual amplification feedback loop from the output stage back to the input (there is still some local feedback to keep THD low) they do claim to provide "no global feedback". This presumably will have benefits in a more natural and accurate sound while still maintaining some of the advantageous characteristics of the feedback loop such as a relatively high damping factor of 400 or more and low distortion. Not to give away the farm but as you will see on the bench I saw less than 0.008% @ 0.5W and less than 0.007% @ 1W into a 8 ohm load with a 1kHz test tone.


In Use

Setup and install went smoothly once you get used to balancing the feet cones on their supports. Do not leave the cone support pads out of your setup - if you are putting this unit on anything softer than the metal cones you'll be left with large indents after a very short time.

Simaudio Moon 700i integrated amplifier

The Who - Tommy DVDA

Solely based on the 700i's "Moon" product family I decided to give a homonymous fellow a shot for some listening. I actually hadn't listened to this one in a long while so I was struck by the inherent noise floor in the recording itself. Sometimes I appreciate a bit of stadium/studio noise or analogue hiss for the atmosphere it adds but in this case it had me scrounging around for cleaner recording to "enjoy the silence". That being said you could hear every string reverberation on the lead guitar during Pinball Wizard. The soundstage is as natural as this recording is likely to get given the nature of the recording ("lead guitar – thou shall appear in the left channel and left channel only) for this album but the vocals were centered and the soundstage depth was wonderful. Moon's (the drummer not the amp) intro ride cymbal shimmers in front of you on "Underture" and the transients from the snare and (endless?) toms were crisp. The mic positioning for this song must have been interesting because it feels like you were there drumming along with Keith.

As a side note, after spending some time with the 700i I had noticed a small hum centered around 5kHz had developed that I could not escape. It was only about 15dB above the ambient background but was noticeable both in standby and in use. After much troubleshooting and isolating of components and some discussion with Simaudio we swapped out the unit. The issue has not re-occurred with my second 700i nor were Simaudio able to re-create the issue back at their facility.

Simaudio Moon 700i integrated amplifier

Handel - Royal fireworks / Water Music SACD

During the first Allegro movement of the Suite in F Major the pounding harpsichords were quite detailed and almost "in your face" in terms of presence. The Hornpipe in the G Major Suite was it's usual celebratory self and the fact that this performance is made on period instruments comes through in the depth and timbre of the sound. This piece must have knocked the King's socks off the time it was first performed as the popular music of its day.

I listened to many other tracks during my testing and never found the amp drawing much attention to itself. No clipping no matter how loud I turned it up, no distortion, just music. The only times I noticed it doing it's thing was during high current demand music passages with sharp transitions as well as the overall clarity and resolution along with the noise floor via the balanced inputs. Having the dedicated clean power available makes a difference vs. my usual more HT oriented setup.


On The Bench

With a 1 kHz test tone in a 8ohm load via the balanced input at 2V (6dBV) the 700i shows a THD+N of less than 0.008%, at 2.8V (1 watt) THD was 0.007%. Via the unbalanced input into 8ohms the THD+N level is 0.03% and into 4 ohms it shows 0.07%. The noise floor of the balanced input is noticeably lower by about 10dBV across the board. Distortion is primarily odd and the 3rd harmonic being the largest at -75dBV in the balanced inputs. Unbalanced shows -70dBV into 8ohms and -60dBV into 4.

Even order harmonics are very low to almost nonexistent which is further highlighted when the amp is tested against a live speaker, even order harmonics almost disappear entirely while the 3rd harmonic remains -75dBV below the fundamental.

IMD is 0.006% via the balanced input and 0.02% via the unbalanced. 2nd order peak is very quiet at nearly 90dBV below the 7kHz fundamental.

With the 19kHz + 20 kHz test on the balanced input we see the 1kHz peak more than 90 dBV below the fundamental and only slightly lower for unbalanced.


Conclusions

I have to admit coming in that the market for integrated amps leaves me feeling a little uncertain. Brilliant in their simplicity, these products provide some advantages you can't get with separates (a optimized signal path from preamp to amp measured in inches instead of feet for example) but at the same time fits a certain niche where you may be looking at separates anyway or concerned about upgrades. By the time I was done I was wondering how I could justify setting up a dedicated 2 channel room, two speakers, a source and an integrated amp – only four boxes required!

The 700i is an impressive example of the genre. Enough power for the average user, some future proofing with the pre-outs and bypass feature plus one if not the best gain control schemes in the business. Great aesthetics that speak to it's quality and functional attributes vs. glare and gloss. Oh and gorgeous, clean sound that I will remember.