QES LABS SMP-2 tube stereo microphone preamplifier by Adkins
The unit is entirely hand-built in Italy, solid chassis, built to last.
2 retro-illuminated true VU Meters, each channel has the usual +48V, polarity, and -20dB pad controls.
A few electronic details deserve mention.
The various switches on the front panel do not switch but rather control precision relays which, in turn, switch the audio itself.
The audio path is therefore kept as pure and simple as possible.
The gain setting is stepped, and taken from the multi-tap secondary of a custom wound audio transformer, the benefit of this solution is that you get exactly the same sound in any position selected.
Just 3 switches and a gain setting knob, as simple as this, very easy to use.
It is a linear phase design, so it refuses the HPF filtering, audio path is pristine.
The PSU is in a separate chassis, an umbilical cable powers the main unit, in a 2U rackmount 19" chassis.
+48V and anode supply are SS fully regulated and filtered.
The unit has 3 custom wound transformers on the audio path, which is fully symmetrical (or balanced, if you prefer).
This has a tremendous impact on S/N ratio, which is extremely high even in the highest gain settings.
The transformers are an art of their own:
their high impedance prim, which power supplies the tubes, allow them to operate in their most linear region, and the push-pull design helps reducing distortion products.
With a stereo set of Schoeps CMC-6 with MK-4 cardioid condenser capsules.
This microphones have been designed to have extremely low distortion and abundance of details.
Quiet recordings: this preamp is dead quiet, it has an astounding S/N ratio, even in the highest gain settings, no noise audible (another rare feature in tube equipment).
Remarkably gain, and has a full bodied, solid sound that gives that slightly larger-than-life character that is the trademark of a really top-class preamp.
Even if it sounds pleasant and attractive, as I said, it still sounds transparent, totally accurate, clean and detailed in normal use, without that edgy crispness that can detract in some designs.
Recording classical and acoustic music, the preamp's low-end 'rightness' and solidity, paired with a correct, clear and open mids and highs, makes the difference.