AQVOX Makes the MIC 2 A/D a combination of a microphone preamplifier and 24bit/196kHz capable PCM analogue to digital converter, more info here, noticably it is primarily designed for the hi-fi market in mind and thus fairly keenly priced for such a device and it also means that it has an unusually full compliment of I/O, ranging from AES/EBU to cinch. Also note that the AQVOX USB 2 D/A actually contains a small microphone amplifier and USB A/D capability although the main purpose of the products is actually D/A conversion.
Beijing 797 Audio Makes a small range of mic amps, however since it does not feature any of them on their homepage (or rather the links have been dead for years) it is a bit difficult to access them, but the ones we have found on the market have been very keenly priced.
Demeter Makes the valve based HXM-1 and VTMP-2C stereo mic preamps, the main difference between the two is apparently tha the VTMP-2C is meant to emulate vintage pre's while the HMX-1 is cleaner.
Makes 3 high end valve based microphone amplifiers, they are all basically the same unit that is clamed by the manufacturer to emulate the sound of classic 60's valve pre's (you should read that as emulate vintage RCA's), the differences are that the VT-1 is a single channel unit while the VT-2 is a dual channel one. Those 2 however only offer 53db of gain and that is simply not enough for some vintage microphones so the company offers a 2 channel version called VT-12 that is slightly less flexible than the VT-2 but offers a whopping 70dB gain per channel which should be more than enough for even the most wimpy vintage ribbons. All the D. W. Fearn amps have transformer balanaced inputs and outputs.
Earthworks The company has the ZDT range of high end microphone preamps, these are all the same basic design but available in 1, 2 and 4 channel versions. Noticeably the unit is a balanced design, i.e. there is neither a transformer or an electronic converter at inputs and output but rather the signal is processed through the unit in balanced form.
Edcor The company has 2 keenly priced preamps in the form of the 2000 series of amps, the 2000D model is intended for use with dynamic microphones and the 2000E with back-electret types of microphones. They are slightly unusual in being a 2 channel designs that only have one output, balanced I/O and only gain as control, making it function as a 2 channel mixer if you are using both inputs. The company appears to be discontinuing the manufacture of the units and was blowing them out for less than 1/4 of the original price when this was written in July 2011.
Esoteric Audio Research - Yoshino (EAR) Makes the 2 channel EAR 824 high end mic preamp, very little info on the homepage, even the technical information given is skimpy. To which we can add that the unit comes with 48V phantom power as standard but can be had with 130V for use with DPA microphones, the gain is switchable from 16 to 60dB in 4dB steps, a switchable 10 dB attenuator for ribbon microphones and switchable 60dB input transformer can be added as oprions. It has transformer balanced outputs and a built in M/S decoder is available as an option as well, it is also one of the most expensive microphone pre-amplifiers out there if not the most expensive.
QES Labs Makes the PREQ-1 a mildly curious combination of a valve based microphone pre-amplifier with DI capabilities that has a resistor network/coil based passive equaliser making the unit reminiscent of a channel strip from a 50ís/early 60ís mixing desk, a pre-historic voice channel so to speak. Noticeably there are separate I/Oís for the EQ and the pre-amp making the unit quite flexible in a studio situation, the pre-amp has phantom power, switchable input filter and the ability to be driven by line level and musical instrument impedance type signals in addition to microphone level/impedance ones, but only has 55dB of gain, thus not usable with difficult microphones.
RTZ Professional Audio Makes the transformer coupled Model 9762 microphone preamp that is modelled on but not identical to the Class A mic pre on old Neve consoles, but somewhat more flexible having up to 75dB of gain which allows it to be used with even the most difficult of vintage microphones, and offers a DI mode as well. Got good reviews in the USA press when it was introduced a few years back. Switchable multi-voltage operation.
Tatic Audio This company makes a pre-amp called simply Mic/Line pre amp. It is a valve based 2 channel balanced unit derived from hi-fi technology and thus has a couple of unusual building techniques such as the use of silver wiring, gain is controlled by a switched rotary bank of resistors rather than a variable one and the power supply is valve rectified rather than usin a regulator. The only feature it sports really is a 48v panthom power but it is unusual in the sense that is can also handle line level inputs and thus can be used as a hi-fi preamplifier as well. More info here.
Valvotronics Makes the D-19 which the company actually describes as a DI-Box with a valve based gain stage and a built in microphone pre-amplifier, although since it is a fully fledged mic pre with all the trimmings like a pad and phantom power in many ways it is better to describe it as microphone pre-amplifier with an unusually flexible I/O, gain and impedance characteristics, mic preís are after all often used as DI boxes for bass and guitars in particular. It has a major UI design fault in that the gain knobs are far too close to each other. More info to be found here.
Wunder Audio Makes the PEQ2 a combination of a discrete transistor based & transformer coupled microphone preamp and a basic EQ intended to be used in a Neve 80 style racks, note that the unit does not offer phantom powering, more info on the Wunder Audio product page.
Beijing 797 Audio Makes at the least one model of a multichannel microphone pre-amp in addition to microphone preamp/power amplifier combo, however since it does not feature it on their homepage (or rather the links have been dead for years) it is a bit difficult to access them.
Earthworks The company makes the ZDT-1024 high end preamp, a 4 channel all balanced design, i.e. there is neither a transformer or an electronic converter at inputs and output but rather the signal is processed through the unit in balanced form.
Wunder Audio Makes the PAFOURplus, a 4 channel discrete transistor based & transformer coupled microphone preamp with DI capabilities and up to 60db gain per channel, note that the unit does not offer phantom powering, more info on the Wunder Audio product page.
Sonosax Has a range of microphone preams these are all high quality and ruggedised portable units with price tags to match, not unusual since since Sonosax is well known for the production of equipment for location recording. The most intiquing model is the highly specialised SX-BD1 but that is a preamp that integrates into a boom operators pole, more info here. The BD1 is probably only of interest to the film and TV industry but reprecents an a neat and ergonomic solution to a problem that I have not seen before. The M series of portable microphone and line preamplifiers are also intended for location work but are of a enough quality that they do show up in recording studios, although the flexible input and amplification ajustments that the units offers is something of an overkill for that application. The M series are available in a single channel version called the SX-M1 and a 2 channel version called logically enough the SX-M2, more info on the SX-M series here. Finally the company has a rack mount modular mic-preamp and distribution system called the M4, the individual modules appear similar to the other M series and the company makes 2 variants of the system in the form of the FD-M4 that is intended for recording applications and the PA-M4 which is intended for PA and sound reinforcement applications, more info here..
Sound Devices Makes high end mic preamps including a rather interesting model with a built in USB converter.
Stellavox Makes the MC2 digital microphone preamp, i.e. a combination of a preamp and a D/A converter. Currently uses a proprietary Stellavox digital interface but a forthcoming upgrade will utilise a 1394 connector.
Studer Makes the D19 MicValve, a valve based microphone amplifier with a built in A/D converter.
Universal Audio Makes microphone amplifiers "inspired" by classic American models.
The company introduced the Opre2 2 channel microphone pre-amplifier in 2002, it is for all intents and purposes a 1U, 2 channel version of the Curtis Technology Opre8 except that there is no mix bus but otherwise the specification per channel is the same as with the Opre8. Each channel has a transformer balanced input and electronically balanced output, features a 10 multi-coloured individual segment LED VU meter and backlit buttons for 48V phantom power, the 20dB pad and polarity reverse. Note that the company never published the specifications for any of their products so it is impossible judge its microphone compatibility. RRP in 2007 was 1495 USD.
The company introduced an 8 channel microphone pre-amplifier in 1998 called Opre8, it is housed in a 2U 19" rack unit and intended as much for live as for studio usage as is shown in the unusual mixing feature, but the unit has an additional stereo output and if that is used the mic channels function as a mixer, original intention was for it to be used as a drumkit sub-mixer. Each channel has a transformer balanced input and electronically balanced output, 48V phantom power, features a 10 multi-coloured individual segment LED VU meter and backlit buttons for, phantom power, the 20dB pad and polarity reverse. Note that the company never published the specifications for any of their products so it can be a difficult to judge its microphone compatibility. RRP in 2001 was 2495 USD, in 2007 3495 USD.