Gordon Instruments products are one of the few (many?) things I highly recommend to people. Why? Because I think they're the best mic. preamps made. Grant Carpenter is the owner/designer. He is very knowledgeable and a very nice guy. I own four sets of his preamps (so that makes 8 total). I must like them...
I've owned and used a fair number of preamps - vintage Neve (as in the Kelso), modern Neve (as in the Amek 9098), API, Grace, Millennia, Universal Audio, Focusrite Red, SSL Duality and others. While each has its appeal, the Gordon Instruments Model 5 is superior I believe. It is a very quiet preamp. When first hearing it I was startled by the lack of noise. The preamp just sounded "black" - dead quiet. It's low distortion was also ear-opening. The gain is switchable in 5 dB steps. There are times when I wish it could be 1 dB so as to more accurately match the gain between a stereo pair of microphones (rather than having to adjust the balance in the computer).
Going into the details of Grant's design is more than I want to take on in this space. He has however rethought how preamps should work and this has paid off tremendously. To my surprise no one has built preamps in this manner before (as far as I know). The concept is so simple in a certain sense that I wonder why not. You'll have to go to his website for all the details.
One of the things the preamp has is a very high input impedance. This greatly reduces the amount of current related losses and microphone load distortion. The signal path is balanced throughout, while the preamp's output constantly monitors the load and adjusts itself accordingly.
Of all the preamps I've heard, perhaps the SSL Duality is in the same sound class. I mean that in the sense both are extremely clean, clear preamps although I've not yet done a direct comparison. The AMEK/NEVE just sounds cloudy (lacking detail and clarity) in comparison while the Millennia reveals a pronounced midrange bump. The API remains itself - a preamp with a certain well-known sound color.
It is my experience mics sound their truest through the Gordon. Great mics sound great and poor mics sound poor. For instance some vintage mics which have been highly regarded just sound old, while a new mic had better be a good design or it will also be found out by the Gordon.
One of the nicest features is that the preamp and gain controls can be separated. A conventional mic cable is connected between the gain control box and the preamps. I find this very handy. On location I place the preamps right next to the mics but can control their gain in the makeshift "control room". With the preamps next to the mic I only need a short cable between mic and preamp. At the preamp, the signal is changed to line level. Putting the A/D converter next to the preamp, I can then run a digital signal a long distance to the recorder rather than having an analog mic signal travel 100 feet (while suffering cable-induced losses or exposure to electrical interference).
The construction quality is second to none, as are the component choices. The preamps by the way are transformerless and use relays when switching gain. Other features include phase reverse, phantom power switching (with 12 mA per channel)and mute.
I can't say enough good about these preamps. If anyone requires the truth for their recording, this is the product for finding it. These are modern classics which people will regard as highly as Neve, API, etc. are held now.
Because the website is not immediately obvious I am posting it here: gordonaudio.com As usual, IHNFOPSITP.