Spatial Audio Raven Preamp

@williamdc

Glad you are enjoying your new Raven.  It does seem to tick all of your boxes!  We arrived there after much experimentation and listening.   I have always loved damper diodes, so I knew we were starting there.  The transformers took a few rounds to get exactly the performance we sought.  I had used the Khozmo attenuators for years, but I had to think hard about how to get them to do what we wanted.  It all came together.  You will find the bass improves over the first 100 hours as the very large cathode bypass film caps run in.  You get most of the sonics after 10-20 hours, but it subtly improves.  Enjoy!

Links to the aforementioned articles:

The Amity, Raven, and Karna Amplifiers

These articles date back to 2004 or earlier, and some of my opinions have changed since then. The availability of custom transformers opened a broader palette of tube selections, and Don’s work on precision power supplies offered a wider range of possibilities in the overall design.

I find it interesting that my objections to the sound of coupling caps is as strong now as it was back in 1997. Once you accustom to the sound of no coupling caps, adding them back in the signal chain is very noticeable. Much of what we expect of "tube sound" is nothing more than the sound of XYZ capacitors.

The Blackbird amps are indeed the next evolution of the Karna amps.  Same circuit, but updated power supplies and simpler tube choices.  All tubes are in current production with multiple manufacturers so there is plenty of choice.  The only exceptions are the voltage regulator tubes, but there are literally thousands of them out there to buy for under $10 per tube.  In the Raven, the damper diodes are no longer in production, but the same is true.  Many to buy and they last for years.

As for the coupling caps, yes I have heard most of the great ones.  I prefer a custom designed transformer.  To me, the transformer has basically no sound.  Not if they are custom designed for the circuit.  The caps all sound very different from each other, plus they take at least 20 hours to run in, with subtle changes for 100 hours.  The transformers sound the same from the first minute.  I was on the cap side of the ancient cap vs. transformer debate for years.  Then I got custom designed transformers.... Now I don't use coupling caps in any of my builds.....

@abd1

As far as I know, Spatial still plans on going to Portland in the fall sometime.  They are busy with the launch of the new smaller S6 speaker and the newer Q3 as well, plus they are ramping up the Raven builds.   I will post here, and of course on their board whenever there is a trip scheduled.  I know there are lots of folks in the PNW who would make the trip for a two day showing of all the gear...and Lynn and I would love to renew some friendships and meet new folks.

Yes, I plan to fly to Portland for the Spatial presentation and demo. This time I'll be sensible and fly Business Class, so I get decent legroom and seat width. And wear a mask at the airport.