Can a solid‑state microphone really give you the sound of Sony’s classic valve C800G?
ZP Custom Microphones are an established vintage microphone repairer based in Belgium, and who are now a boutique manufacturer, too. Currently the company offer a single limited‑edition product, the ZP800G, and the microphone’s name provides a strong hint of its intention. This is a high‑quality vocal microphone designed to have a similar sound character to the much revered, but scarily expensive and exclusive, Sony C800G microphone.
Surprisingly, given its aims, most aspects of this new Belgian microphone are substantially different from Sony’s classic. For example, the Japanese original uses a triode‑connected 6AU6 pentode valve for its impedance converter, kept cool by a uniquely idiosyncratic cooling system extending to the rear of the mic body. In contrast, the ZP microphone features a completely conventional cylindrical body with solid‑state FET‑based circuitry.
One thing both mics do have in common, though, is the use of a customised 34mm, centre‑terminated, Neumann K67‑style dual‑diaphragm capsule made in China. However, whereas the Sony flagship microphone offers selectable omni and cardioid polar patterns, the ZP mic has a fixed cardioid‑only pattern.
The most significant difference of all between these two mics is that while the Sony C800G costs more than £10,500 in the UK, ZP Custom Microphones’ ZP800G microphone is available for less than a fifth of that!
Given such radical technical differences between these two mics it might seem surprising that company CEO and designer Gregory de Mee claims the “sonic footprint and audio quality… are identical”. While that was the primary goal, he also wanted the mic to be better suited to modern recording practices, meaning smaller, easier to rig, and more convenient to use — which was why he eschewed the delicate and slow‑to‑warm‑up valve and its associated heavy external power supply, and adopted robust and instantly functioning phantom‑powered FET circuitry.
The decision to provide only a cardioid polar pattern, when most vocal recordings with the C800G are probably made with the omni setting, might seem more perplexing, but de Mee’s reasoning is that project studio acoustics aren’t as good as those of professional studios and that a cardioid polar pickup is more forgiving in that context, as it excludes more ambient sound. Another way to reduce the ambient acoustic’s contribution is to place the mic closer to the source, and so de Mee has optimised the capsule and circuitry for a relatively close working distance of 100mm (four inches). That’s probably around half the distance that most vocalists in a professional studio would typically use the C800G. Obviously, working a cardioid pattern mic this closely invokes the proximity effect, but the ‘ZPK8A’ capsule is built to ZP Microphones’ own specs and the elements assembled and fine‑tuned in the company’s Belgian workshop to achieve the required tonal balance at that close distance.
One benefit of using a dual‑diaphragm capsule in cardioid mode is that it is inherently less noisy than it would be in its omni mode — the reason being that only one side of the capsule contributes electrically to the microphone’s output. Combining that aspect with high‑quality solid‑state electronics allows the ZP800G to claim a self‑noise figure of 12dB SPL (A‑weighted), whereas Sony specify the C800G in cardioid mode at 18dBSPL (and nearly 21dB SPL in omni mode).
The decision to provide only a cardioid polar pattern might seem more perplexing, but [designer] de Mee’s reasoning is that project studio acoustics aren’t as good as those of professional studios and that a cardioid polar pickup is more forgiving in that context, as it excludes more ambient sound.
The ZP800G Package
The ZP800G ships with a hard‑shell zippered case with internal padding. A net pocket in the lid behind a protective flap stores a hard plastic stand adapter and an ‘info card’ which is actually a flip‑out 4GB USB thumb drive. Sadly, though, none of my PCs were able to access it so I’ve no idea what information might have been supplied upon it. A little faux‑leather purse is provided to protect the microphone’s grille when not in use.
The stand mount screws onto a threaded section around the XLR connector at the base of the mic, but most users will probably prefer to use the substantial shockmount which is also supplied. Frustratingly, this is too large to store inside the mic’s case as it comprises a 120mm‑diameter stainless‑steel disc with attached stand adaptor. A stainless‑steel cylinder is suspended inside the disc on four cleverly laced elastic cord loops, and a threaded collar at the centre of the cylinder attaches to the base of the microphone. The design is similar to the plate shockmount supplied with some Oktava mics, and that’s not too surprising as ZP Microphones apparently worked closely with Oktava to develop the ZP800G’s body hardware and accessories.
The microphone body measures 192mm in length, 50mm in diameter, and weighs 405g. Finished in a polished black paint, the ZP logo is stencilled on the front just below the multilayer chromed wire‑mesh grille, while the 800G model name is at the rear near the base. Connection is via a standard XLR socket at the mic’s base, and 48V phantom power is required (the current consumption is not specified). Sensitivity is quoted as ‑33dB/Pa, and assuming ZP meant dB ref 1V/Pa that would be equivalent to a healthy 22mV/Pa — just 1dB lower than the Sony C800G. The maximum level the mic can tolerate is given as 130dB SPL, but no distortion threshold is provided. Nevertheless, it should accommodate even the loudest vocalist without complaint.
In Use
I was unable to disassemble the mic to evaluate its construction, but ZP Microphones proudly states it uses Wima resistors and Nichicon and Russian NOS ‘military‑grade’ capacitors, with hand‑wiring and “top‑notch quality control”. The mic certainly feels solid and well‑built, although the shockmount rattled on arrival as the stand attachment was loose. This was easily corrected with a screwdriver, but if it was my own mic I’d apply a thread‑locking compound to prevent it loosening again with use. Nevertheless, when installed in the shockmount the mic feels stable and secure, and it can be mounted upright or suspended from above equally safely. The mic is not too sensitive to plosive blasting, but I would always recommend using a good pop screen anyway — if for no other reason than to keep the expensive mic clean and dry!
Every part of the voice was present and correct — body, weight, clarity, crispness, breathy airiness, all ideally balanced from the outset.
The capsule is optimised for working with very close sources. The sound is quite lean when the vocalist is six inches or more away, but at three to four inches the ZP800G delivers a very nice, modern, mix‑ready vocal sound which has a slightly compressed midrange character with plenty of energy that delivers a full‑bodied quality. This is balanced against a distinct upper‑mid presence which has been shaped to give a nice clarity and clean diction without over‑emphasising the sibilance region. Above that is an open and airy top end that brings a silky smoothness to breaths, and the overall impression is of a larger‑than life voice with a well‑focused, almost 3D quality. Within mixes I found the vocals needed almost no further processing beyond some dynamic control. Every part of the voice was present and correct — body, weight, clarity, crispness, breathy airiness, all ideally balanced from the outset.
I’ve only used the Sony C800G a few times, but from memory I’d say ZP Microphones have captured its sonic essence pretty well here. Regardless of its notional accuracy, though, the ZP800 is a very appealing vocal mic in its own right and, despite its rather understated looks, it delivers such a flattering and complete sound that every vocalist will be impressed from the moment they don their headphones. And as we all know, happy talent delivers great performances!
From a technological point of view, there is little in this microphone that is out of the ordinary: it uses a replica capsule with pretty standard FET circuitry in a familiar tube‑shaped body. But as is always the case, it’s the little details that really make the difference. The specific machining precision of the capsule backplates, the hand‑assembly and careful tensioning of the diaphragms, the selection of the passive and active components... The complete product is so much more than the sum of its parts, and that’s why its high price can be justified. It is a very high‑quality vocal microphone with no caveats, limitations or provisos. And if viewed as a legitimate alternative to the legendary C800G — which I think it probably is — it is clearly an enormous bargain. Either way, it’s certainly a mic worth adding to the shortlist for an audition if your budget extends this far.
The Sony C800G
Sony introduced the C800G into the pro‑audio market as recently as 1992, and it was designed to be a no‑expense‑spared studio vocal microphone of uncompromising quality and accuracy — the very best microphone that Sony’s engineers could create.
It’s certainly one of the most distinctively recognisable vocal mics on the planet, thanks to its unique cooling fins sticking out at the back. These fins sit at the end of a box protruding from the rear of the mic’s cylindrical body, and that box envelops the microphone’s impedance‑converting valve which extends horizontally from the circuitry inside the microphone’s body. A Peltier thermo‑electric cooling system (see box) transfers heat from the valve to the finned heatsink, keeping the valve cool, extending its working life, and reducing low‑frequency noise and distortion. The cylindrical mic body is constructed from aluminium and zinc alloys in a design said to minimise mechanical vibration.
The circuitry is remarkably simple, featuring a 6AU6 pentode valve configured as a triode, running with an anode supply voltage of around 230VDC supply. However, as the tube draws about 1.4mA, the voltage drop across the anode feed resistor puts about 90V on the anode plate itself. A DC bias voltage of about 47V is derived for the capsule backplates, while the diaphragms are effectively at ground potential. The input signal to the valve’s control grid comes directly from the capsule’s front diaphragm in cardioid mode, while both diaphragms are wired together in parallel for the omni pattern. The valve output drives a relatively large 9:1 ratio output transformer to ensure a good bass response.
Sony employ a custom capsule built somewhere in the Far East, based on Neumann’s K67. The K67 was originally developed for the U67 microphone and was Neumann’s first dual‑diaphragm capsule to be built as two separate halves — a manufacturing technique which allows individual halves to be selected for perfect matching before being bolted together to form a composite dual‑diaphragm capsule. Sony’s version of this capsule is generally thought to have a slightly recessed midrange compared to a genuine Neumann K67, but with a similar high‑frequency peak in the 8‑14 kHz area and a warm, full‑bodied low end. However, the Neumann engineers incorporated ‘de‑emphasis’ filtering around the U67’s circuitry specifically to tame the K67 capsule’s natural HF resonance peak and to improve headroom, giving that characteristically smooth, mellow sound. The Sony C800G lacks any similar HF filtering, and that’s why the overall response has a lovely high‑frequency ‘sheen’ with a crisp, silky brightness and a clear upper midrange. (Some U67s have been deliberately modified to omit the de‑emphasis filtering to develop a brighter sound.) As always, it is the combination of characters at different parts of the spectrum, rather than any individual element, that give the C800G its legendary status as a magical vocal microphone, particularly for pop, rap and R&B productions, and especially with female vocalists.
The Peltier Cooling System
A Peltier device is essentially an electrically powered solid‑state heat pump comprising a thin wafer of semiconductor materials sandwiched between ceramic plates. Alternating adjacent pillars of p‑type and n‑type semiconductor stand between the ceramic plates, with each pillar connected electrically in series. When a DC current flows through the semiconductor pillars, the ‘Peltier effect’ causes heat to be transferred across the semiconductor from one ceramic plate to the other, making one side cooler and the other hotter — potentially by quite a lot!
In the Sony C800G microphone, the hot plate is thermally connected to a finned heatsink protruding from the rear of the mic so that its temperature remains close to the room’s ambient temperature. Consequently, the temperature of the cold plate is reduced well below ambient temperature, and that cools the valve. Sony’s Peltier device consumes around 5W of power, drawing around 1.2A of current from the dedicated power supply.
Alternatives
Ignoring the Sony C800G itself, the two obvious alternatives to the ZP800G are the Golden Age Premier GA‑800G and the Advanced Audio CM800T. Both of these mics follow the same core design of the Sony flagship, and both are valve mics, but the GAP GA‑800G is a very close clone, even retaining the Peltier cooling extension. So it looks very similar to the Sony original, but costs around a third as much, making it around $1000 more than the ZP product.
The Canadian Advanced Audio CM‑800T takes a rather simpler approach, repurposing parts from some of its other models and a different NOS military valve to come in at under $1000. The overall tonal character is very similar, though, and it has the added benefit of providing three polar patterns (omni, cardioid and fig‑8).
Pros
- Delivers a beautifully crafted, modern, crisp vocal sound.
- Well‑built and solid.
- Supplied with an effective shockmount.
- Cardioid response and close working help reduce ambient sound.
- Ready to go the moment it’s plugged in!
Cons
- The shockmount can’t be stored in the mic case.
- The looks don’t ‘wow’ like the sound does.
- Two grand is still a lot of money, even when it’s much less than 10 grand!
Summary
A conventional phantom‑powered studio vocal mic cleverly tuned and optimised to emulate the distinctive vocal sound of Sony’s flagship C800G.