Spatial Audio Raven Preamp

The Caladan a nice speaker and great value!  It is 93 dB and 4 ohm.  That means you can use most any amp you like of 10 watts or so.  I built a little pair of 45 monos and a pair of 6C4C (the Russian 6B4G) monos.  Both were push pull and clipped at about 6 W.  They easily drove my 95 dB 8 ohm open baffles to screaming levels.   So a properly designed low power tube amp would easily drive the Caladans for most folks.   The 300b monos are 24 watts and represent essentially unlimited power into that sort of speaker.  The 300b amps are spendy.  But there are plenty of good quality tube amps under $5000 that I think would be a sonic revelation compared to what you are listening to.  My 2 cents.   It might be a road worth exploring.  Especially if you have a friend with a decent tube amp who would bring it over...  XLR inputs would be best, but rca inputs are fine with the Raven.  Then you would know if a tube amp would sound more pleasing to you.

Hello Lynn and Don,

Thank you very much for your work on the Raven (and the Blackbirds). I wish am better with words.

I went down this path of upgrading my toys, initially from a laptop, Schiit Modi 2 DAC, Yamaha CA410 amp and a pair of bookshelf speakers to this present set up. The upgrades were very satisfying, with very good improvements initially. As I move up the chain, the improvement was subtle (law of diminishing returns) but there was sonic refinement with each upgrade. This hobby has no end to upgrades - just to let you know.

The Raven is truly a refinement. It sounded different and I like the sound. I would love the Raven to pair with the Blackbirds (I believe there would be synergy between the two) but I have to find the space to place it in the set up. And also to take turns at the Luxury Budget Committee and the approval from the chairwoman. Sigh. But yeah, it is a joy to listen to the Raven, set up and the Caladans.

Cheers

ghdprentice,

Thank you.

Don and I are pleased that Raven owners have an equal choice between RCA-input power amps and XLR-input power amps. The Raven treats both the same, so the sonic choice is on an equal footing.

Classic vacuum tube amps almost always have RCA inputs, with phase splitting handled internally. Similarly, low-powered SET amps have RCA inputs because they are single-ended throughout, from input to output.

Older transistor amps from the Sixties through the Nineties typically have RCA inputs, with phase splitting done in a differential first stage with either bipolar transistors or FETs. Contemporary transistor amps may offer both RCA and XLR inputs, but the highest performance option is typically the XLR input.

It’s all the same to the Raven preamp, since all signals pass through the output transformers, which have both RCA and XLR output taps, just like the 4, 8, and 16 ohm taps on a tube power amplifier.

P.S. I should mention in passing the Raven may be used as a signal conditioner, like other "tube interfaces" on the market. It removes both DC offsets and RFI interference from other components and environmental RFI. Transistor amps often have issues with RFI incursion, which might not be as obvious as hearing AM stations in the background, but as an increase in veiling and listening fatigue. What’s actually happening are the input transistors rectifying incoming signals in the MHz (AM, SW, FM) to GHz (WiFi, mobile phones, Bluetooth) range, which then splatters IM distortion across the audio band.

Get rid of the RFI interference, and the amp sounds cleaner and fatigue goes way down. That’s where the studio-quality input transformer of the Raven comes in; it is designed to reject RFI, and preamp tubes themselves are resistant to RFI. The result is that all that comes out of the Raven is clean audio, in the 15 Hz to 60 kHz frequency range, with nothing above or below that. The audio-only feed to the power amplifier reduces the burden on the input transistors (or opamps) of the transistor power amplifier.

Hello Lynn,

It is your (and Don's) detailed explanation of the technology used on the Raven and Blackbirds that helped me to decide on the Raven. I learned so much and had a better understanding about tubes, and transformers now.