Spatial Audio Raven Preamp

Part of the reason for the sonics (aside from the circuit) is the physical simplicity of the preamp. No circuit board is needed because there really isn’t that much to the audio signal path. Input selector -> balanced switched-resistor volume control -> balanced 6SN7 vacuum tube -> output transformer. That’s it.

There are no coupling caps, no multi-transistor current sources with Zener-diode references, no muting relays with time-delay logic, and no DC-balance servo circuits ... so there’s no need for circuit boards to contain all these secondary functions. Just very short point-to-point wiring.

The same is true of the Blackbird power amp, as well as the Raven. The audio path is surprisingly simple.

Indeed the signal path on both the preamp and amp is very simple.  That said, the power supplies supporting it are rather complex and they are kept well away from it.  Also, the preamp output transformer and amplifier interstage transformers took over a year of prototyping to get right.  So the circuits are "deceptively" simple, but there is a lot supporting them, and as Lynn stated, these circuits are kept well away from the signal path, both electrically and physically.

Also, if you spend time reading this thread and the very long 300b lovers thread, you will see that the "deceptively simple" circuits are also cleverly designed to eliminate distortion at its source as well.

I have word from Spatial that the next batch of 5 Ravens is in production, so those folks awaiting builds should have them pretty soon.  Then some of you can post your impressions here!  It will be good to know how people like the preamps in a variety of systems.

Heard from Spatial that my Raven should ship tomorrow.  I am very excited to hear this preamp in my system.  I will try to refrain from posting initial impressions until adequate burn-in (20+ hours).

@jc4659   Well, it's ok to post an initial impression:)  But then please follow up with the 20+ hour report.  You get most of it within 20-30 hours, but there are subtle improvements out to 100 or so as the big cathode bypass caps run in.  Most of it is there by 20-30 or so though...   Enjoy.  Hope it works well in your system.