audio Viganoni - New Zealand

sachem pure v.2 hi-end preamplifier

Please click here to read the very first review of the original sachem pure, made by Ashley Kramer on Witchdoctor hi-fi magazine.
the new sachem pure v.2 - black and silver versions - you can choose between the two different sets of knobs
The text below has been partially copied from the Owner's manual included within every sachem pure v.2. Additionally, it contains notes that are useful for understanding the "philosophy" behind the pure, as well as becoming aware of technical and hi-fi related issues that you will never read about in magazines or hear in a hi-end shop.
The sachem pure v.2 is the new version of the original sachem pure, resulting from further research, new top components and a completely redesigned PCB. This version, unlike the previous one, houses the electronics in a single cabinet of clean and linear design, carved from bars of solid aluminium and machined to perfection. We still call it “pure” for the simple reason that we didn't find a better adjective to summarise the peculiarities of its design, layout, and sound. Firstly, the sachem pure v.2 (hereafter referred to as pure) has no inherent timbre or sound. It is neutral, meaning it does not introduce or blend its own "sound" into the musical program. For a hi-fi designer, achieving this neutrality should be both a priority and a challenging objective. However, it seems that many hi-end manufacturers fail to give this parameter the consideration it deserves. Convinced that one of the "secrets" to achieving this outstanding sonic reproduction is using the fewest possible components in the signal path, we have developed a minimalistic IC circuit. This design incorporates the most modern, high-performance, top-quality components in an ultra-clean layout. The logic and orderliness of the circuits eliminate the need for messy wiring, resulting in a completely wire-free preamp. Fully aware that voluminous preamps with messy wiring defy the principles of hi-fi electronics (regardless of exorbitant pricing, prestigious branding, or the glorious opinions of biased or incompetent reviewers), we have minimised the preamp sections to their most compact physical dimensions. Additionally, we have shortened and widened the signal tracks and ground path to reduce their electrical resistance. As a result, the specifications reveal that the pure establishes previously unheard-of benchmarks in preamp electrical measurements. Even though many audiophiles and hi-end "gurus" claim that electrical measurements are unimportant to sound quality, they are mistaken. Real hi-fi isn’t a matter of blind faith: it is grounded in physics, and those "numbers" are crucial unless you want a preamp that behaves like an additional musical instrument. And, as we've explained before, that would be the exact opposite of our goal! On the other hand, many preamps and amps with excellent "numbers" don't sound well. This doesn't mean that the esoteric crowd is correct, but rather that these machines probably have capacitors (and sonically, not the best ones) in the signal path. The capacitors have minimal impact on the "numbers", but they can adversely affect the overtones and high harmonics of the sound, especially the electrolytic ones. In my opinion, this is the primary reason why you might encounter a preamp (or amp) with impressive specifications but not "celestial" sound quality. So, you've probably already guessed my “phobia” of capacitors in the signal path because they are the electrical components that mostly affect and damage the sound. Therefore, pure's signal path is completely capacitor-free! I could be wrong, but, to my knowledge, the pure is the only preamp with this peculiarity, and this surely accounts for a large portion of its unique sweetness, unchanged overtones, lightning response, "granitic" bass and uncoloured sound. The pure is highly resistant to external interference. However, due to its incredible frequency response (flat from 0Hz to 4MHz), if you live in an area saturated by radio frequencies and/or magnetic fields (two situations very rare in NZ), there could be a chance that the pure will pick some of them up. In this case, we can try to stop them by adding a capacitor of tiny capacitance (47pF, in polystyrene) to the circuit of each channel. This addition will limit the frequency response to 160kHz (-3 dB). The PCB is designed to accommodate these possible “intruders”, and the installation process is simple, taking just a few minutes. Importantly, despite the addition, there will be no discernible sonic difference, as the selected capacitors have minimal capacitance and are of top sonic quality. The pure features an extremely low output impedance (8 Ω) and substantial gain, ensuring an ideal "marriage" with any main amplifier(s). The exceptionally low output impedance enables the use of long, shielded cables between the preamp and monoblocks without any loss in sound quality. This is especially useful if you place the monoblocks close to the speakers (something we always highly recommend), to minimise the length of the speaker cables. Another advantage of low output impedance is that the quality of the shielded cables connecting the preamp to the main amplifier(s) and/or a potential subwoofer becomes less critical, which is a welcome benefit to your wallet! Following our minimalistic “philosophy”, the output of the IC goes straight to the output sockets, without any resistors or capacitors on the signal path. Surely, this is sonically great, but it leaves the ICs unprotected against short circuits in the output sockets. So, if you need to connect or disconnect any devices to the output sockets (OUT 1 and OUT 2), you must turn the power off and wait for 20 seconds before acting. If anything happens to the ICs for not respecting this rule, the warranty becomes void, and you will have to pay for the cost of the replacement ICs. The power supply is a real beauty. It produces and delivers a wonderfully clean DC to feed the audio circuits. The purity of the DC is paramount for a “silky” reproduction of the high frequencies. This section features an oversized 15VA toroidal transformer, feeding twenty audio-grade, very low impedance and ESR capacitors through a 6A full-wave bridge rectifier. The block of capacitors features a total capacitance of 9.400μF and is paralleled by two high-speed WIMA polypropylene caps (MKP10 series). To wrap up the technical details, all resistors, except for the ones in the remote and delay circuits, feature “metal film” technology, boasting ±0.1% tolerance and a temperature coefficient of ±15ppm/°C. For those less steeped in electronics jargon, that temperature coefficient translates to a very low level of thermal noise. Another interesting feature of the pure is the USB power supply socket on the back panel. It features a very pure DC (5V - 500mA), suitable for powering a transmitter dongle, which, when connected to the TAPE OUT socket of the v.2, will deliver the musical signal to any piece of wireless audio equipment in other rooms.
sachem pure v.2 - back panel
It's now time to explain how the pure, unlike other preamps, can correct and optimise the bass range of the speakers. The quality of the bass range troubles (or rather, should torment) the vast majority of audiophiles, including those in the hi-end category. Indeed, “booming” bass is a "hallmark" of many expensive "dinosaur loudspeakers", especially when positioned close to a wall or in corners! It’s amusing to observe that the audiophiles (if and when they become aware of it) attempt to address the issue by investing in outrageously expensive, comical, and perhaps even "blessed" cables. However, the only truly effective way to resolve this "sonic vulgarity" is by feeding the speakers a rolled-off signal, and that’s where the pure makes the difference! In fact, the pure has a built-in electronic high-pass filter, which is essential to roll off and flatten the frequency response of the bass range in the speakers. This will also create a correct crossover point between a welcome subwoofer and the speakers, resulting in deep, clean, tight bass-infrabass ... free of “boom". Moreover, the dynamic range of the main speakers will increase, and the distortion will decrease because their woofers will no longer struggle (with pathetic results) to reproduce the very low frequencies your active sub is much better qualified to manage. Image and clarity in the mid-high range will also improve because of the lower distortion of the whole bass range. The same happens to the power amplifier/s and, if they are tube amps, this will be a real invaluable gift to them! However, if you don’t trust me and fall into the crowd that (very wrongly) considers adding a serious active sub to the system a drawback, leave out the sub (for now). If you’ve connected the power amp(s) to the pure's OUT1 socket, simply switch between flat and cut response (F and C on the back switch). You’ll likely be amazed at the transformation of your speakers when in the C position! Even if the default cut of the pure (130Hz - Bessel) is not correct for this job, it's already enough to let you understand the incredible potential of this facility! The booming disappears (or at least decreases), and the mid-high becomes clearer and cleaner. This way, you are losing the pathetic infra-bass that the floorstanders try to deliver, but the bass and all the rest of the audio band become ... another story! This happens because the roll-off lowers the “bulge” in the frequency response between 100 and 200Hz, which is in the “DNA” of the vast majority of these speakers (without limits of price) and the cause of booming. Anyway, for optimal results in this application, you should select a Bessel roll-off curve with the -3dB point between 130Hz and 250Hz, depending on the degree of "booming" in the speakers. If you're located nearby, we can handle this for you, and, with the help of the spectrum analyser, we can transform your system!
sachem pure v.2 - close view of the connections
Now a word on this selectable and very versatile built-in electronic, second-order (12dB/oct) filter, which can be set up with either Butterworth or Bessel roll-off curves. The cut-off -3dB point is continuously adjustable, and its range depends on the type of curve: for the Butterworth curve, the range is 65Hz <-> 300Hz and for the Bessel curve, it is 90Hz <-> 400Hz. Furthermore, each channel is independent and can be set up with different roll-off points and curves. This feature is essential to integrate a sub(s) into the system properly, or for correcting the problems generated by the speakers positioned asymmetrically, due to a room with a less-than-ideal layout (e.g. one speaker in a corner and the other in an open space, or just with a wall behind, etc.). In such cases, the left and right speakers will sound different from the mid-bass to the infrabass range. In this regard, please visit the school of hi-fi page and read the third article, which addresses this huge but normally neglected problem and provides a thorough solution. However, it’s amusing, if not outright sad, to note how audiophiles focus on negligible details while overlooking paramount problems such as "booming bass" or having the left and right speakers produce different sounds! Connections - The preamp output marked OUT1, depending on the position of the toggle switch on the back panel (F or C), respectively delivers a flat response or a rolled-off one; the output marked OUT2 is fixed and always delivers a flat, full-range response. So, if you have a subwoofer, connect the sub to the OUT2 and the main amp(s) to OUT1. If you need to use the rolled-off output (switching on C), please note that the pure leaves the factory with this filter set up for a -3dB crossover point at 130Hz and 12dB/oct Bessel curve. For example, if your speakers are not "booming" and your subwoofer is (hopefully) an Audio Pro, follow these simple steps: connect the sub to OUT2, the main amp(s) to OUT1, position the micro-switch on the back to C, set the sub's low-pass knob to 50Hz, and finally, adjust the sub's volume. That's it, and ... enjoy the sound! The pure features another interesting facility: the BYPASS option. This function is designed exclusively for owners of advanced home-theatre systems who also want the option to convert it into a hi-end stereo system. To illustrate, some users have a serious home-theater setup consisting of a 5.1 receiver, a hi-end stereo amplifier (or ideally two monoblocks) driven by the receiver’s PREAMP OUT for the front channels, two high-quality main speakers, top-tier sub(s), and center and rear speakers powered by the receiver’s built-in amplifiers. When they want to listen to stereo CDs, they select STEREO mode on the receiver. However, the preamp section in such receivers is typically not hi-end. In practice, the weak link is the preamp. It performs well and is more than acceptable for home-theatre applications, but falls short for hi-end stereo playback. Now, at last, they can solve this problem using a pure. You insert the pure between the receiver and the main amps, connecting the receiver’s output sockets (FRONT L and FRONT R) to the BYPASS socket of the pure and its OUT1 to the main amp(s); be sure to select F on the hi-pass micro-switch, because the position C doesn’t work in this configuration. So, if you want to listen to the 5.1, switch on the pure (compulsory) and select BYPASS: this way, the pure "doesn’t exist", and your home-theatre is exactly like before, but if you select any of the other three inputs, it’s now the turn of your receiver to drop out of existence, and you have a glorious stereo system! It looks very easy, and it is, but if you have a sub, it’s no longer quite so; in this case, many different configurations can be considered.1) If you have a sub (or subs) already connected to the receiver, keep it/them, and the perfect, comprehensive solution is to buy another sub to connect to the pure, as explained before. This way, you have two completely independent systems with completely independent subs, too; furthermore, you can perfectly tune each sub with the respective system.2) In the case that you have two sachem v.2 (or v.3) or any other main amp with an incorporated crossover, you roll off the frequency response in them and connect the sub in parallel to the inputs of the main amp(s). Now, connect the pure as in the previously mentioned system without the sub(s). This way, the systems have the sub(s) in common, but it’s not a problem at all. However, if you adopt this solution, please go to the “speaker set-up” menu of the receiver and set the front speakers to “LARGE”, the subwoofer to “NO”, and the CENTRE and SURROUND speakers to “SMALL”. To finish, position the pure's filter switch (on the back panel) to F. These are two of the most common situations, but, as I said before, there could be many others. Anyway, I cannot consider them all here, but don’t worry, there is always a solution: if anyone should have any particular problems in this regard, I prefer talking directly with them, so … just call me!
sachem pure v.2 - inside view
Now, let’s finally talk about what truly sets a pure apart from any other preamplifier: when you buy a pure, you’re actually getting not one, but two completely independent preamplifiers. You can switch between them in real time using the remote by pressing the button with a circular arrow, located just above the central mute button. To know which preamp is in use, it’s easy: when the second preamp is selected, a yellow LED on the front panel lights up and turns off when the main preamp is selected again. The main preamp features exceptional ICs, delivering top-tier performance, while the second preamp features ICs of a less prestigious pedigree. The most interesting and surprising (even for us) discovery has been that the difference in sound between the two preamps is incredibly minimal. This confirms my theory that capacitors in the signal path, rather than transistors or ICs, are the real factors influencing the sound. The pure stands as proof of it: with no capacitors in the signal path, what you hear is solely the "sound" of the IC itself, and, switching in real time, the differences are barely noticeable! Only playing very complex and highly dynamic tracks (using my recordings), it's possible to realise that the main preamp is slightly superior in clarity, with a more precise bass and a better third dimension. Anyway, to perceive these micro-differences, you need a real superior system or an electrostatic headphone set. I don't want to sound arrogant, but I think that many of you won’t perceive any difference at all. However, the possibility of switching between two preamps in real-time is useful for any future upgrade of your machine. It’s a fact that contemporary technology brings out on the market new astonishing electronic components every moment, so hi-fi machines become obsolete in quite a short time and this is the miserable end of the ordinary machines (no exceptions for the very expensive ones too), but the pure does not belong to this category and your preamp was thought out so that it will last a long, long time. Indeed, you can upgrade it at any time, spending peanuts! The "heart" of the two preamps is made up of the ICs. If a better one comes on the market, you can purchase two of them and have them replaced in the second preamp. Then, start switching in real-time between the main preamp and the upgraded second preamp. This will help you determine, beyond any doubt, whether there's any real difference and whether the game is worth the candle. Replacing the ICs is quite straightforward, but we strongly advise against doing it yourself! We’re more than happy to handle it for you, free of charge. We need to ensure that the new ICs are "stable" and don’t introduce any issues like self-oscillation. Anyway, at this point, you have probably realised that by buying a pure, you don’t buy “a preamp”, but an advanced machine, capable of continuous evolution! Speaking about the ICs, the ones used as standard in the main preamp are the result of a personal decision. In my view, they are currently the best option on the market. With my live recordings, they deliver an astonishingly natural sound: a perfectly dimensional rendering of the instruments, with precise performer localisation and a stable soundstage. The bass is tighter, faster, and deeper than anything I’ve heard before, and the high frequencies are silky, ethereal, and incredibly refined, preserving all the original high-order harmonics and overtones. It’s no coincidence that I also use them in the preamp-crossover-mixer of my recording system. Changing the subject, someone has surely noted that I haven’t equipped the pure with balanced inputs and outputs. To me, balanced connections in home audio are just another bait-and-switch scam for credulous audiophiles. I intentionally omitted them because, in a truly hi-end system (if free from any induced noise), I believe it’s better to avoid balanced lines unless the machine is fully balanced. But ... can you tell me how many machines with all the circuits completely balanced exist on the market? So, when faced with the choice between balanced and unbalanced sockets, and the machine is not completely balanced, my recommendation is to use the unbalanced ones, as they provide the "original and true" sound of the machine! Wondering why? Head over to the school of hi-fi page, where you will find a comprehensive article on this topic. After that, you will fully understand why I didn’t fit the pure out with balanced options. Anyway, I can anticipate that it's because I wanted to maintain the signal path totally “capacitors-free” and keep calling my “creature” pure.
sachem pure v.2 - front and top view
Looking after the pure is easy: avoid positioning the cabinet in direct sunlight (particularly if black) or a damp place. It’s also advisable to keep the pure at a distance from Wi-Fi transmitters or extenders to avoid any possible interference. We hope you now feel ready to use and care for your pure. So, press the power switch and … silence! No need to worry, the delay circuit is doing its job. Just wait nine more seconds, and you'll be rewarded with the pure’s "pure sound"! We are confident that you will notice and appreciate the improved performance of your system! However, it’s important to realise that the pure won’t work miracles. Rather, it will ruthlessly expose any weaknesses in your hi-fi chain. Likewise, its full potential may be overshadowed by any component in the system that lacks selectivity, speed, or clarity. Unfortunately, a bitter truth of the hi-fi world is that the final sound of a system is mostly shaped by its weakest component rather than by its finest. So, until all the components in your system match the calibre of your new preamplifier, the pursuit of sonic perfection will remain partly unfulfilled. Please feel free to contact us if you need any assistance or advice regarding the installation or use of our products, or if you have any questions! A note about the name: “sachem” (pronounced seɪtʃəm) refers to an elected paramount Chief of American Indian tribes in northeastern North America. The word originates from the Algonquian language of a tribe that lived near Lake Michigan. The Indians also used the epithet “sachem” as an honour for a senior warrior who had distinguished himself with particular merits. My heartfelt thanks to my dear friends Rino Cieri and Allen Gill, who is the designer of the remote control circuit. They are exceptionally talented technicians and have helped me solve significant problems on many occasions. Additionally, my gratitude goes to Kevin Munt, who machined the cabinets to perfection.

specifications (main preamplifier)

NOTE: the parameters in RED are paramount, but usually omitted in the specs of preamps. Nominal input sensitivity 200 mVInput impedance (referred to the IC) 5 x 10¹¹ ΩOutput impedance 8 ΩSlew rate (Rload = 1 kΩ, G = +1) 140 V/μsBandwidth @ 0dB DC ~ 4 MHzPhase deviation DC ~ 2 MHz 0ºTHD (Total Harmonic Distortion) at 1 kHz 0.00003 %Input voltage noise (referred to the IC) 12 nV/√HzSettling time to 0.1% (0V to 10V Step, Av = -1) 150 nsGain 12.55 dBHi-pass filter slope (Bessel or Butterworth) 12dB/oct @ xxx HzSignal-to-noise (inputs shorted) NO audible noiseCross-talk between adjacent inputs (second input shorted) NO audible cross-talk Cross-talk between L & R channel (second input shorted) NO audible cross-talk USB power supply socket 5V DC - 500mAOverall dimensions (W-D-H) 400 - 260 - 70 mm Shipping dimensions (W-D-H) 510 - 360 - 170 mmShipping weight 5.2 kg
sachem pure v.2 is on display at the following dealers:
Leonard Lucas - Auckland Signals - Auckland HiFi Auditions - Hamilton Tone Electrical - Paraparaumu (you'll find their contact details on the "partners" page) PLEASE NOTE: If you're outside the coverage area of our local dealers, feel free to contact us directly. We'll gladly provide an alternative solution so you can experience the sachem "difference".