Sony C-800G
A tube condenser with a Peltier cooler bolted to it - the first microphone in the world to chill its own capsule.
Overview
The C-800G is a large-diaphragm tube condenser built around a hand-selected 6AU6A vacuum tube. Sony's documentation says plainly what the tube is for. The company describes the parameter selection on that tube as rigorous, and credits it with the microphone's high-frequency quality, exceptionally low noise, expanded dynamic range, and response to fast transients. Sony's own copy calls the sound warm, powerful, smooth, and quick. That reads like marketing until you get to the cooling system.
Vacuum tubes make heat, and heat degrades the performance of a condenser microphone. Sony's answer, documented in the C-800G manual, is a built-in semiconductor-based cooling system combining a Peltier device, a heat pipe, and a heat sink. The manual identifies this thermoelectric arrangement as the first of its kind in any microphone. The stated payoff is low noise and low distortion, and it's the most distinctive engineering fact about the design. Studio Sound (January 1997, p.13) picked up on this in period advertising coverage, crediting the "cool tube" heat dispersion with remarkably low noise and distortion. For once the ad copy and the engineering document tell the same story.
The capsule is a large-diaphragm condenser, and directivity is electronically selectable between unidirectional and omnidirectional. There is no mechanical pattern switching. The published figures are specific: frequency response from 20 Hz to 18,000 Hz, sensitivity of -28.0 dB/Pa in unidirectional mode and -31.0 dB/Pa in omni, and output impedance of 100 Ω ±20% balanced at 1 kHz. Signal-to-noise is better than 76 dB unidirectional and better than 73 dB omni (1 kHz at 1 Pa, IEC 651, A-weighted). Inherent noise is below 18 dBSPL unidirectional and below 21 dBSPL omni under the same weighting. Under 18 dBSPL A-weighted is genuinely quiet for a tube microphone, and it's the number the cooling system is there to protect.
Sony aimed it at critical vocal work in recording studios and film post-production houses. Mix (May 1996, p.69) noted that engineers at DMP Records frequently reached for the Sony C-800. It described the design as the product of five years of research, development, listening, and testing across both acoustic and electric music, with the caveat that specifications alone can only hint at the sound. The C-800G also turns up in studio gear lists from the era, including a New York room documented in EQ alongside a Neumann KM254 and a Soundelux U95.
It's a substantial piece: approximately 900 g (1 lb 16 oz) for the microphone itself, with the cradle suspension adding roughly 210 g (7 oz). The optional AC-MC800G power supply unit is a separate box at approximately 5.4 kg (11 lb 14 oz). This is not a microphone you tuck in a gig bag. The supplied kit includes a windscreen, cradle suspension, two stand screw adaptors (PF 1/2→NS 5/8 and PF 1/2→W 3/8), a microphone cable, carrying case, sticker, and two frequency response charts. The microphone output uses a JR16RK-7P connector, the power supply's mic input a JR16RK-7S, and the audio output an NC3MDL-8-1. These are proprietary multi-pin connections, and that matters a lot to anyone buying used.
The microphone will not run without its AC-MC800G supply. The supply is a heavy, dedicated, multi-pin unit that is not interchangeable with generic tube-mic power boxes. A C-800G offered without its matching supply is a project, not a purchase. Buyers should also confirm the cable is present. The manual lists it as a supplied accessory, and replacements are not something you find at a typical pro-audio counter. The same goes for the cradle suspension, which is part of the delivered package.
On value, Pro Sound (February 2018, p.33), reviewing the later C-100, framed the C-800G as a microphone priced north of $10,000. It used that figure as the benchmark against which the C-100's roughly $1,399 street price looked impressive. Treat that as a contemporary reference point rather than a fixed market quote. It does show this was never a budget tube mic. Buyers today should expect to pay accordingly and should budget for the power supply as part of the deal.
The C-800G is not a versatile utility microphone. Sony built it for one job, critical capture and especially voice, and hung an entire thermoelectric cooling apparatus off the tube to do that job with as little noise as possible. The 20 Hz to 18,000 Hz response is narrower at the top than some later designs, and the electronically switched two-pattern arrangement is deliberately limited. It is a specialist's tool with a proprietary power tether.
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