Condenser Microphones + Audio Equipment for Recording Professionals

Sound On Sound - Dec 2006
Reviews-Microphones. CharterOak SA538 & SA538B
By Paul White

Can mics at this price really compete with the classics? Sound On
Sound puts them to the test...

US-based Charter Oak have been in the microphone manufacturing business since 2002, making them a relative newcomer to the field, but they seem very serious about what they're doing. Essentially, they source capsules, components and other parts internationally from companies in China, Eastern Europe and Sweden, but do all the assembly and testing is back in Enfield, Connecticut, in the US. The design differs from many superficially similar competitors in that very high-quality electronic components are used, especially the capacitors. Although this makes little difference to the paper specification, the subjective sound is improved and it will also have a positive effect on reliability.

OVERVIEW
The SA538 and 538B are both multi-pattern tube mics based around a pair of pressure-gradient, 1.07-inch capsules with six-micron, goldsputtered diaphragms (these are clearly different in each model, because the SA538 is edge-terminated while the SA538B is centre-terminated). This is a popular size and specification for Chinese capsules. If they are made elsewhere, I apologise for jumping to the wrong conclusion! Both mics look similar and have the same type of external power supply (PSU), which includes a nine-position pattern selector switch that goes from cardioid to figure-of-eight, via omni.

The PSU appears to be of Far Eastern design, and is a simple but robust folded-steel brick with IEC mains inlet, power switch and voltage selector switch. An included seven-pin, fabric-sheathed XLR cable connects the mic to the PSU, and from there a conventional balanced three-pin XLR accepts a standard mic cable (also included). Such differences as there are between the two mics manifest themselves in their technical performance — which I'll come to later — rather than in their physical presentation or feature set.

Both the SA538 and SA538B look like serious studio tools. They weigh around two pounds each, which means that you need a solid mic stand to keep them stable. An all-metal shockmount is included that seems very similar to the ones I've seen with certain Chinese microphones, but that doesn't detract from the fact that it is both robust and practical. This design incorporates a threaded, locking ring that locates onto the base of the mic so, once fitted to the shockmount, it is perfectly secure whether upright or inverted. Both mics, with their power supplies and all accessories, also come packed in aluminium camera cases fitted with combination locks.

CONSTRUCTION
Construction-wise, the microphones are conventional. But they are no less impressive for that, with a heavy machined basket support frame, a dual-layer mesh grille and a slide-on body cover finished in a vintage satin black reminiscent of some early European mics. An embossed silver Charter Oak logo marks the front of the mic, while a heavy, machined ring at the base of the mic holds the cover in The ECC83 dual triode tube, used in both place. Removal of the cover reveals neat construction, with plaited, PTFE-insulated cables connecting the capsule and main circuit board. The tube in both cases is a selected ECC83 dual triode, fitted to a ceramic base arranged so that the tube lies horizontally across the circuit board. None of the other components is visible, as they're all on the underside of the board. The board is shielded by an extension of the transformer housing, which in turn is joined to the basket assembly via four metal rods. There are no pad or roll-off switches on either model.

FREQUENCY RESPONSE
Individual frequency response plots are included, and these seem to be of the more honest 'warts and all' variety, rather than having heavily smoothed, and hence meaningless, curves. The response of the SA538 extends from 30Hz to 20kHz (-3dB points) and the cardioid curve is characterised by a flat mid-range, augmented by a fairly high-up presence hump in the 10kHz region. Off-axis, the midrange dips as expected, producing a very happy smile curve! In figure-of-eight mode, there's a dip at around 6kHz but otherwise the response is nominally flat, while the omni mode shows barely a hint of presence peak. In both cardioid and omni mode, the response curve gets a bit bumpy below 300Hz or so, but that isn't unusual. With a self noise of 22dB, A-weighted, this isn't a particularly quiet mic, even for a tube model but, by the same token, the level of background noise isn't high enough to be an issue when close-miking vocals or instruments. For comparison, it is roughly comparable with the noise spec of a good vintage tube mic.

The slightly more costly SA538B has a marginally better noise spec, at 20dB A-weighted, and its lower frequency limit is 5Hz lower at 25Hz, although the maximum SPL is 125dB, rather than the 128dB of the SA538. Both mics have a 12mV/Pa sensitivity at 1kHz and a nominal 200(omega) output impedance. Comparing frequency response plots shows that the SA538B has a little more height in the presence peak than the SA538, but otherwise the two microphones are broadly similar.

THE SOUND OF OAK
Before testing, I plugged in the mics and let them warm up for an hour, as recommended by the manufacturers. Though predominantly vocal mics, both models are equally at home on instruments such as acoustic guitar and percussion, with the SA538B having more presence. As I've found with pretty much all large-diaphragm mics, you have to work harder to find the best sweet spot for acoustic guitar than you do with small-diaphragm models, as these tend to be more forgiving for offaxis sounds, but you can get good results. In cardioid mode, the proximity effect is obviously present, but this isn't too pronounced under normal operating conditions and I got very acceptable results from a wide range of preamps, ranging from a cheap-as-chips Behringer desktop mixer to an SPL Gold Channel. Both models are on the bright side of neutral, though the SA538 has less of a presence peak, which makes it sound a little warmer and less edgy than the SA538B. I'm curious as to why Charter Oak found it necessary to create two such similar models, when a model somewhere in between the two could have been used with just a hint of EQ to cover the same territory. For my own vocals, I much preferred the SA538, as it gave more warmth and smoothed out the high end to some degree.

The character of both these mics definitely helps singers who need help with their upper-mid presence and projection (more so in the case of the SA538B), but who want to retain their low-end warmth without hearing that hyped-up, spongy low end that some modern tube mics dish out as a substitute for real warmth. Add a hint of compression and you can get a very refined, classic vocal sound from either of these mics without using much in the way of EQ or other processing. As expected, the omni mode isn't quite as open and natural sounding as from a small-diameter, single-diaphragm pressure capsule but it is still very usable and a nice option if you don't have a wide selection of mics in your locker. Similarly, the figure-of-eight pattern is valuable because of its excellent 90-degree rejection, which can really help separate sounds that are in close proximity. I used a number of tube and solid state mics for comparison, most admittedly a little less costly than the Charter Oak models, and in all cases the tube fixed horizontally across the circuit board. Charter Oak SA538 came across as both solid and present, cutting through a mix rather more assertively than most of the competition but without sounding edgy. The same is true of the SA538B, but I felt it had a less desirable balance of presence and warmth for my own applications, and could easily end up sounding too bright.

IN CONCLUSION
These are not the cheapest mics of their type around but, judged on their sound rather than their technical spec or the origin of the parts, they are probably worth the extra cost, as their sound compares favourably with high-end/classic mics costing a lot more, and they somehow help a vocal sit comfortably within a mix without getting buried or being too loud. In this regard, the use of higher quality electronic components certainly pays dividends. Just like the classics they are being pitched against, the noise figures are nothing special, but unless you're recording quieter sounds at a distance that shouldn't be a worry. Most of the time these models are likely to be used as close-up vocal mics, and in that role they are perfectly happy and even seem less prone to popping than the other models I tried for comparison — though you really should use a pop shield whenever recording close vocals.

There's a huge amount of competition in the low to mid-priced tube-mic market at the moment and you should also check out the other models in your price range, especially if the mic is mainly for one singer, as picking a mic with a character to complement a particular voice is something that can't be done by specifications alone. Other mics might be quieter, or capable of adding more character and leaving you with some change into the bargain, but these mics give you that little bit of extra class, and if you're looking for seriously good results in this price range you should definitely consider them.

ALTERNATIVES
There are a number of competitors in this category, and the differences are subjective. If you are considering the Charter Oak you might also want to look at mics like Rode's K2 or Classic, the Neumann TLM103, M-Audio's Sputnik, Sontronics' Helios, the Groove Tubes GT67, or the MXL V77S.

Pro Sound News - September 2005
By: Randy Pool

The CharterOak Acoustic Devices SA538 tube microphone makes a good first impression before it's even plugged in. The case and build quality are quite impressive, demonstrated by the sheer weight of the product. It has the look and feel of the some of the old classic European tube mics. With a stylish matte black colored body (machined brass) with an embossed silver CharterOak emblem, you won¹t get confused on which side is the front of the mic.

The capsule is a dual 1.07" 6 micron thick gold sputtered variety, behind an open type protective grill reminiscent of classic designs. The shock mount is also of solid contruction with two large elastic bands in a familiar Germanic style. The power supply, however, looks like the standard deal coming from the pacific rim countries these days, while the mic cable has a tight-weaved, fabric-covered outer shell that really adds a nice touch.

In listening tests it was obvious this mic has a good amount of top end‹the kind of high end that feels great on singers who need a little help in that department. With a male vocal, it was compared to some old favorite mics through a UA6176 channel strip. The SA538 had a little more high mids and highs, with a some-what subdued lower mid range. It also had less proximity effect than some mics, allowing a singer to work in close to the mic without it becoming muddy so quickly. There is this sweet spot in the high mids that, for certain vocalists, with the right compression, was found to really make the vocal sit great in the mix, without being overwhelming. There seems to be something unique about this mic¹s ability to handle good amounts of compression and still keep the clarity of the singer right where you want it.

On a female vocal, we achieved similar results, the mic sounding natural and clear. The mic¹s EQ curve really helps those singers that need a little extra high end clarity. I¹ve gotten really nice results with fairly bright mics paired with relatively dark mic pres like a vintage Neve, and the SA538 was suited to that combination.

We also experimented with acoustic guitar recording with the CharterOak, trying several guitars of top-notch session player Mark Bladwin. While the top end seemed to help the darker guitars, we quickly realized the result was generally too bright for this to be this mic¹s best application.

As always, you¹ll want to match microphone and preamp to the voice or instrument that you¹re recording. With its ample high end and detail, the CharterOak SA538 can add a valuable option to your mic collection.

-TOP

CharterOak Acoustic Devices have been quietly making quality tube mics for the past 3 years. Their first model is the SA538, a squat-looking condenser reminiscent of a short bodied U47. The outer shell is finished in a satin black and appointed with a silver silhouette of an oak tree. The mic is striking in person, and even after viewing high-resolution promotional photos nothing compares to holding this model in person. Speaking of holding it, be careful, it’s almost 2 pounds. The heft alone provides a hint of what a quality mic this is.

Internally, the SA538 is a dual diaphragm vacuum tube condenser microphone that uses dual 1.07” gold sputtered diaphragms. The electronics are of U.S. , Slovak Republic , Sweden , and Chinese origin, but the mic is hand assembled and tested at CharterOak’s headquarters in Enfield , CT. It is capable of nine pick up patterns ranging from omni to cardioid. The mic is delivered with first-class accessories, including a locking flight case, better than average power supply, and one of the best shock mounts I’ve ever used. The accompanying cables are coated in a soft webbing. The jacketing helps to avoid tangles, allowing the CharterOak cables to gently slide through potential spaghetti. Frequency response is reported to be 30Hz to 20kHz.

Sometimes you buy a mic for specific purpose, like an SM57 for the snare, or an EV RE-20 for broadcast. So, I set out to see what “special purpose” the SA538 might have. To make a long story short, I was having trouble finding where this mic could be a proverbial silver bullet. And that’s when it hit me: the SA538 is a mic that covers a lot of ground. So, I tested my hypothesis. I took a rock singer I know who sounds thin and harsh on our Korby C-12, but awesome on our Neumann U47 FET. Turns out the SA538 hung in there against the Neumann. Very usable. I took another singer who is the reverse, and usually only sounds good with the C-12. Voila! The CharterOak worked fine. But before I give the impression that this is just a utility mic, let me finish. We took country singer Ian Thomas, who sounds strong regardless of mic choice and had him sing into the SA538 and a BLUE Kiwi at the same time. In blind A/B tests, I could not pick the Kiwi vs. the SA538. In fact, I was wrong 50% of the time.

Another benefit of the SA538 is it gets along with many different mic preamps. From an API to John Hardy to a Mackie VLZ, the CharterOak gave a solid, detailed performance. Studios with smaller budgets should have no reservation using existing mic pres with the SA538.

If you’re a small studio that wants to buy a nice vocal tube mic, but can’t afford both a C-12-ish mic and a U47-ish mic, you simply have to audition the SA538. While it’s not a direct replacement for either - it’s a solid performer. Likewise, for location or mobile gigs, the SA538 would be a perfect centerpiece for your mic pack. No need to take a bright and a dark mic because the SA538 can manage nearly any vocalist type. It’s sturdy construction (the tube is protected by a rubber guard) make it suitable for the riggors of the road.

I only had two concerns with the mic. First, there is no ring mount for positioning the SA538 in tight applications. You’re stuck with the (great - but bulky) shock mount. Second, it seemed to take extra time to find a sweet spot when using it on instruments. In particular, engineers will need to be extra patient when placing it on acoustic guitars.

I believe CharterOak is charging too little for this mic given it’s build quality and sonic performance. My recommendation is to seek out a demo before more people catch on to this workhorse mic.

For more information: www.charteroakacoustics.com (List $1499, street ~ $1199 web) -gh

-TOP

----end SA538 Reviews-----

EQ Magazine - Mar 2006
NOT-SO-QUICK PICKS- CHARTEROAK SA538B TUBE MIC
By Joel Hamilton

So we got this cool mic here from CharterOak. Cool box. Even the cardboard part it was shipped in was printed with their cool-looking silhouette of a big old oak tree. I was in the middle of mixing a record on ROIR, called “Dub Trio.” Everyone in the room was like, “ooh . . . aaahhh!” about the box alone. Nice touch. I open the thing up, and we all said, “ooh, aah” because this is a great-looking package, and obviously well made from Jump Street. I mean the shock-mount is BEAUTIFUL. I don’t just mean, like, OK, or kind of OK: awesome. First class. It’s made to last, and is very functional. I weigh about 190, and I felt like if I hung from it (as I often do), it wouldn’t even bend. SOLID. The mic weighs a ton as well, so I guess it’s good that someone actually put some thought into how it would stay off the floor. . . .

So, OK: The mic looks really nice, and the shock-mount rocks . . . but is it any good as a recording device?
Hell yes.

This mic is a touch bright, but no more so than a C12 in good shape. I don’t normally like bright mics, but this one has the oomph in other places that really makes it kill.

And I tried this mic with a variety of common mic pres, uncommon mic pres, and downright obscure mic pres: always cool [though some better than others]. The mic pre REALLY seems to affect the sound of this thing, more so than with many other tube mics I own or operate daily. With the Neve 34120 mic pre in my sidecar (class A, discrete 70dB) the mic really sounded wide open, but not as gnarly in the top end as with a Sytek (surprise, right?), and the mic really came to life using a Manley VTL mono tube reference pre. Amazing with that combo.

But I had to record some piano for a very sparse, weird arrangement where the overall tone was really going to affect the presentation of some odd interval and note choices, and with the CharterOak in figure 8, on a big upright piano, a Sage electronics class A mic pre [the SE-PRE1], and a Pultec EQP1 I got one of the most amazingly detailed, forward, lifelike piano sounds I have ever recorded with any single microphone. Really. An upright, two feet from a wooden wall, with the mic between the soundboard and the wall, in figure 8: amazing. The Sage pre really is amazing, so I was really sure we would get it with that one. The bottom of the piano was resonant and solid, the mids were insanely detailed, and the hammer/highs were simply perfect. The overtone series represented by this odd piece of music came flying out of the speakers at my head! Awesome.

On drums as a mono ambient mic this thing was a little bright for my tastes, but it DID have some amazing detail when I rolled back some 16k on the Pultec. Then it really came to life, and just sounded HUGE through the Manley pre and the Neve 33609. ONE mic really was the whole kit. Super balanced from top to bottom when you roll the highs down a touch. . . . To tape this mic would be really good, so I printed some drums to the Studer 827 I have, and wow. Really liked that. The “right bright” on drums. I am glad I got the B, which is the “extended bass response” version. I can’t even imagine this mic without the OOMPH on the bottom. So great. Transparent, yet solid, with none of the wooly cartoon of tube mic BS people are trying to pass off on consumers these days. This thing is for real. Blow Marlboro smoke in it for 20 years if you want it to sound more “vintage” (or, as I found out yesterday, tailor the sound by working with the manufacturer). The website has all the tech specs. I skimmed over them and got bored and put the thing on a stand and got psyched again. . . .

After meeting the person responsible for this microphone at AES, and finding out that he is absolutely willing to tailor the sound of the microphone to YOUR tastes (!!!!), I really started to feel like this company and its products are absolutely something everyone needs to get hip to.

Anyway, the bottom line is this: In a condenser world gone crazy, this microphone is a welcome addition to any mic collection. I have a bunch of choices of tube mic, many classics, and CharterOak is going to have to drive down from CT and whoop me to get it back. I really, really like it. Thank you for making a really great microphone, and having a cool aesthetic. I LOVE that this is not simply a copy of anything: It is a great microphone that does not need to glom on to some bullshit historical validation to try and find a home.

Thank you, CharterOak! —Joel Hamilton

Sound & Recording (Japan) - February ’07 Edition
CHARTEROAK ACOUSTIC DEVICES - SA538B

Drawing attention to the attractiveness of high quality condenser microphones which were borne from fairly new microphone manufacturer.

CHARTEROAK ACOUSTIC DEVICES where is located in the State of Connecticut, U.S.A. is founded in 2002 by Mr. Michael Deming who is a music producer/recording engineer. Their products developed under the theme of “Creating the Classics of Tomorrow” have been first introduced and officially started marketing & selling here in Japan during the time of InterBEE ’06, and they have drawn a keen interest to the customers who visited the InterBEE stands with this microphones.

This time, we had an interview with Mr. Mizuo Miura, a recording engineer who has already used this CharterOak microphones for himself, and we would like to tell you about one part of its attractiveness through the episode of Miki Imai’s recording to which this microphones have contributed greatly.

The SA538B will never disturb other sounds, whereas the vocal is insisting with one stepping forward.

Among the CharterOak products which are officially sold in Japan, ranging from the SA538B which is a dual diaphragm type tube condenser microphone, their line includes the SA538 with the specifications of low noise/wide dynamic range applying a side termination type dual diaphragm, the S600 which is a front address type tube condenser microphone to be sold with matched pair and the E700 which is a solid state condenser microphone. They are 4 types of the microphones. Among them, except the E700, Mr. Mizuo Miura who works for Mixers Labs has actually used and tested 3 types of their microphones.

I(Mizuo Miura) borrowed 3 types of CharterOak microphones for about 1.5 months and I tested them from various angles. Among them, with regard to SA538B, Miki Imai liked it very much, and while I am borrowing these microphones, the SA538B is always kept for her.

To the vocalist, the microphone is very important equipment which is just like his or her musical instrument. There are lots of the vocalists who tell their frank opinions for its selection and have their favorite microphones.

I felt that Miki-san has her own philosophy to the expression about her song and also she has a clear image that her song had better be like this including her voice quality. And, with regard to the microphone, as her request of having her song record like this voice quality was made from the basic recording stage, then, I thought it had better be tested by various microphones, and with preparing for a series of the microphones which might meet her requirement, I was present at the vocal recording. I included the SA538B in the microphones, as I tested it several times for other sessions.

As the result, among various standard vintage microphones, she said that the SA538B is the most suitable for her requirement and taste.

Miki-san herself is deeply involved in the recording this time, while she is seeking for her style of singing, after her singing, she came back to the control room to check the quality of her voice and she tried to use this microphone this time and she did so repeatedly with using different microphones. Among these trials, the SA538B felt to be most suitable for her singing, when she used the SA538B. Including herself of course, Mr. Satoshi Takebe, a producer and myself, 3 of us have same opinions, and we have immediately decided to use the SA538B for the recording of her song.

What was the sound like for the SA538B which could satisfy with all of the vocalist, the producer and engineer ?

Although this is not a right expression, as a feeling that we listened to the sound, this microphone is not the one which will produce the flat sound. In the so called standard vintage microphones, there is an attractive sound quality somewhere, as it is said as “vintage”, there is a stable feeling, and in the whole sound field, there is a feeling that the voice and the musical instrument will come to a good and stabilized position.

To these microphones instead, when talking about the SA538B where there has an attractiveness, it is the microphone that the sound will come in front. Even if it is coming in front, it does not have a stuffy feeling, nor disturb the other sounds, but, it has the most attractiveness that the backward sound will be produced exactly. Especially, with the feeling that the vocal is coming out and pointing out with one stepping forward, the sound could be created more easily. Thinking of its microphone performance and Miki-san’s voice, there is the best combination for this recording.

I have heard that this SA538B has been used for another black male vocalist for his recording and the reaction was very good.

The engineer who recorded for this vocalist is a young engineer and as it has also a good combination with his voice, this engineer was told by this vocalist that if you purchase this microphone, it will surely become your very strong weapon without fail.

I used the SA538 for Gut Guitar and the S600 for Overtop of the Drum.

I was told that 2 microphones other than the SA538B was played an active part in Miki-san’s recordings as well.

The SA538 has been used to record the Gut Guitar for the album recording later. For the feeling of the sound, it is similar to that of the SA538B, but, the SA538 has a bit gentle feeling. However, as it has also the sound with standing, it is suitable for recording such musical instrument with gentle tone of sound as Gut Guitar to have it listened without being buried in the orchestra. With only standing it as it is, with almost no equalization, it has a feeling of producing a clear contour. I think it is good.

Regarding the S600, it has an impression with comparatively flatter than the other 2 microphones. This microphone was used for recording Yamamoto Hideo-san’s Drum as an Overtop with the same music. While standing another brand of the microphone as a backup which I always use, as the S600 is a matched pair and its performance is the same, I thought I would try to use it. Although it is just like jazz taste music with using the brush, in fact, for my impression of recording, I felt that the microphone which I have ever used would be better than it. This is probably due to the reason that I am accustomed to understanding its sound much better. However, when mixing, after comparing to listen to the two, the way of picking up the feeling of air is quite different.

Regarding the Overtop, not only cymbals, because of standing it to target the whole set in some sense, including the sound of the rim shot which is picked up there and overlapping of kick, the S600 is the microphone which could record the sound of feeling that the air can be “seen” much better. As the result, in mixing, I decided to adopt the sound recorded by the S600.

As stated in the above, although it is the experimental stage, thinking of the process that they have been used for actual recording and the result of using these microphones was after comparing with the standard microphones, we think that the CHARTEROAK microphones are very high quality. Furthermore, Miura-san pointed out that after using the microphones for a long time, it has a possibility that the sound will be changed.

Not only for the microphones, but also Miura-san is always thinking of checking a new product and if it is of good quality product, he would like to use it positively. For doing so, the new idea will be borne, he said.

In conclusion, he stated as follows:
The microphone ….. the sound which should come out forward is coming out forward exactly and what is happening and what is doing in the back, that can be seen precisely…. it seems to be difficult to find out this type of the microphone, but, for making the sound, it is a sort of an ideal issue to construct such sound. I think that these microphones would be most suitable for doing so.

CharterOak S600 - June 2007 [download PDF]
Large-diaphragm Tube Microphones - Hugh Robjohns

"With good looks and a unique sonic character, there's plenty to commend these mics."

HTML text version coming soon.

-TOP

Sound On Sound- May 2008 [download PDF]
On Test : CharterOak E700 Multi Pattern FET Microphone
By Paul White | May 2008

EQ Magazine - Nov 2006
CharterOak Acoustics E700 Multi Pattern Condenser Microphone
By Roy Stein, Tony Gross | November 2006

While microphone technology may not have moved on that much in the last ten years the available choice to users has been transformed by a much wider selection of brands. JON THORNTON looks at an imposing mic that seems to have defined a new position in the landscape.

IT’S BEEN SAID BEFORE, not least by me, but the world of microphone manufacturing is a long way from where it was even ten years ago. For sure, the big players are still there updating their product ranges, or in some cases still busily producing designs that have been around for several decades. But added to this have been an everincreasing number of new entrants. Broadly speaking, they can be split into two categories — those who go down the ‘boutique’ route with highly specified, hand-crafted and usually very expensive offerings, and those who seem largely intent on maximising the lower reaches of the price/performance curve. It’s probably also fair to say that the latter rely heavily on manufacture and assembly in China.

In this context then, it’s not surprising that I hadn’t heard of USA-based CharterOak Acoustics or its microphone range before the E700 turned up for review. Founded in 2002 by engineer Michael Deming, CharterOak has quietly developed a line of microphones that have attracted a significant following. To begin with, the product range was exclusively comprised of large diaphragm capacitor designs with valve-based electronics, but the E700 marks the first FETbased offering.

Featuring a dual 1.22-inch centre terminated diaphragm, the E700 features a switchable polar response (cardioid, omni and fig-8) and a twoposition pad (-10 and — 20dB). It’s a fairly squat looking microphone, with considerable girth and heft to it, and comes supplied in a hard case together with a basic shockmount. Finished in silver and black, it looks the part certainly, but I couldn’t help but get a sense of deja-vu — the smell of the packaging, the
construction of the microphone, even the supplied case seemed familiar and these things reminded me of brands of Chinese origin. A quick call to Michael Deming confirmed this — the majority of the components, including the diaphragms are indeed manufactured in China. The units are then pulled apart, checked, reassembled and tested in CharterOak’s facility in Enfield, Connecticut.

Michael was keen to point out to me that a great deal of time had been spent with their Chinese manufacturing subcontractors fine-tuning the construction of the diaphragms and selecting quality components for the electronic stage and transformers, which was encouraging — nevertheless the E700 is pitched at a price point that gives it some stiff competition from some pretty established brands (US street price $999). A quick poke around the internals reveals a tidy looking PCB with all discrete circuitry, and a hefty output transformer whose casing forms part of the structure of the microphone.

In use, the E700 sets up quickly, and despite its weight, the supplied shockmount holds it very securely. It sounds pretty quiet — equivalent noise is quoted at 17dBA — and it delivers a nice healthy output level. On a variety of close miked sources, the E700 sounded very impressive — in comparison to a 414-BULS used as a reference it more than held its own, and actually sounded remarkably similar on the cardioid setting. There’s plenty of detail, lots of low frequency extension, and it's ever so slightly ‘hard’ at the top end.

Moving on to drums, and positioned as an overhead above the kit on an omni setting, and the E700 again sounded similar. Good transient response meant that there was plenty of punch to the sound, and the slight lift in the microphone’s frequency response around 10kHz kept things sounding detailed as distances increased. Low frequency extension was good, but in comparison with the 414 sounded a little more rounded in this respect — not a bad thing as it helped curb some less than pleasant hard resonances. This trait was even more pronounced when the E700 was set up as a distant room microphone — preferable in
some ways to the 414.

The acid test with any microphone of this type, though, is vocals. Male vocals were the order of the day on the test session, and it’s clear that the E700 has been tuned pretty well to this task. As the 414 isn’t my favourite in this application, the E700 was compared to an Audio Technica 4050, which can deliver stonking results on most voices straight out
of the box.

The E700 sounded a little less mellow than the 4050, certainly bringing out a little more ‘spit’ in the voice, but used close up has terrific presence and depth — a definitely larger than life vocal sound that would suit broadcast and voice-over applications as well as music tracks. Although it never sounds overexaggerated, the E700’s performance didn’t seem to take EQ quite as well as the 4050 though — trying to dip the low-mids slightly and dial in some HF lift started to deliver results that sounded unnatural quite quickly.

This might just be a function of familiarity with the microphone though, and more time playing around with EQ bands might help. Interestingly, for its other (valve-based) models, CharterOak offers a customisation service, where by changing valve types and altering component values in the electronics the response of the microphones can be tweaked to the customer’s preference. Sadly, this isn’t on offer with the E700; as Michael Deming explained, there just isn’t enough scope in the FET-based amplifier design to accommodate the tweaks.

All of which leaves me trying to decide where the E700 belongs in the scenario I outlined at the start. Calling it a boutique microphone wouldn’t be strictly accurate. And putting it in the category of exploring those lower reaches of price and performance would be distinctly unfair — this is a quality piece of kit, backed up by a lifetime warranty for parts and labour. And it sounds good. It’s not as much of a ‘one-trick-pony’ as perhaps the AT4050 is, but it does have a definite sound to it. And if you like that sound, then it works beautifully. I think that CharterOak has actually defined a new position in the microphone landscape — quality design and Chinese manufacture, together with the attention to detail and the ear of an experienced engineer means that everybody stands to gain.

PROS
Good build quality; very nice ‘big’ vocal sound; nice rounded sound to LF; good detail and transient response.

CONS
Might be a little overstated for some applications and be a little hard to pull into shape with EQ.

EXTRAS
As Jon points out in the review, there are other mics in the CharterOak stable. There’s the SA538 side-address dual-diaphragm valve condenser, which employs a centre-terminated S-1 capsule, the SA538B side-address dual-diaphragm valve condenser, which employs a side-terminated S-2 capsule, and the S-3 capsule S600 front-address valve condenser, which is sold in sequentially numbered pairs.

-TOP

Prosound Magazine - Japan - April 2007
Reviews. CharterOak SA538, SA538B, E700 & S600

“CharterOak microphones reviews in PROSOUND April ’07 Edition”

CharterOak condenser microphones are manufactured in the factory located in
Connecticut, U.S.A. Only the parts with well selected and passing the very severe
quality criteria are assembled in the rigid body which is being machining from the brass.
And, furthermore, after 7 days aging for the tubes and testing in the studio
environment for more than 30 minutes, the microphones will be delivered to the
customers. In addition to this, such accessories as the flight case, the power supply, the
shock mount, the cables, etc. will be checked severely. By taking care of this
fundamental points in order to manufacture the products, the credibility will be
increased and the products will attract customers’ attention and the firm position of the
products will be established, which is a short cut to be successful for the products.

The products which I would now like to introduce you this time are 4 types of the
condenser microphones manufactured by CHARTEROAK ACOUSTIC DEVICES in
U.S.A. They are SA538, SA538B, S600 and E700.

First of all, from the external appearance of the microphones, the black shiny finish is a
feeling like having its very expensive products and the microphones have a feeling of
having its enough weight. Furthermore, except E700 which is solid state type, the
exclusive power supply will come with the microphones. About SA538 and SA538B, as
they equip the switch with 9 steps of which the directivity can be selected from
non-directivity to cardioid.

Let’s try to test them!

First, let’s start from SA538. This is a dual diaphragm tube type condenser
microphone(SA538B is the same.).

Checking it with vocal, it sounds like thinking of a vintage microphone and the
bandwidth ranging from mid-low sound to low sound is solid. Nevertheless, it is not
like a dull sound, but, it has apparently a feeling of existence against the sound source
in the back. Listening to only the vocal track carefully, it is understood well that the
room noise was not almost felt. Then, after recording while selecting the directivity
newly, with transferring gradually from non-directivity to cardioid(middle value), the
noise is becoming decreased and it is a feeling that I went to the country side where has
clean air, being away from the city. In doing like that, the high technique is necessary
in order to decrease only the noise, without spoiling a feeling of air. I feel that
CHARTEROAK ACOUSTIC DEVICES has very high technology research level.
SA538B is being the same, but, as this is a side termination type, the high frequency
sound is much extending with a feeling of hybrid.

Depending upon the vocalist is if it is a male or a female, it is fat or thin, utterance is
strong or not, what is the performance style of the back, etc., the choice will be changed.
In the studio, I would like to have both. In either way, the microphones can realize
sound image very well for which the vocalist is in the very front position of the stage,
and they are superb microphones, and they are also easy for mixing.

E700 is the low cost version for the above 2 microphones. This is a gold depositioned
myler diaphragm and pure class A solid state type microphone. The microphone equips
the switch which can be selected from 3 types of the directivity(cardioid/omni/figure 8)
and the attenuator of -10dB/-20dB(sensitivity switch).Though this microphone is in the
low priced range, the sound is fairly good and a feeling of clear air with less noise can be
realized well.

S600 is a front address type and the tube type, but, this microphone is different in
appearance from the above microphones. The top portion of the microphone is aimed at
the recording object and I think it is for the purpose of recording the musical
instruments. I recorded the Conga which is my favorite musical instrument. Although
it is a same feeling as sounding with a feeling of existence, this microphone is likely flat
in its frequency response. In its good aspect, it has a sound with non-peculiarity and
wide dynamic range.

For myself, in case of recording in stereo against the recording object(2 microphones),
especially to drams and percussion(also piano), not standing the microphone inside from
outside, reversely, I always request to stand it outside from inside. This means that I
consider it phase, but, with using this microphone, when I tried to make both settings
and to compare them, I realized that there are big difference in a feeling of existence
and a clearness of sound. In some sense, I am impressed with this microphone that it is
honest.

CONSTRUCTION

CONCLUSIONS