[Daryl Zero]

Is anyone going to try the Raven preamp with Class D monoblocks? I'd love to hear a review.

[rfluongo]

It most likely is attenuating the input.  It depends on what sort of VC they use.  If it is a ladder then wide open is best.  If it is a shunt, then it doesn't matter much as there is only one resistor you are going through at any volume.  It certainly won't hurt anything no matter where you set it.  The Raven can drive 10K loads with ease.  The advantage of the Raven will be that you can use a balanced source (XLR) as well as rca.  So if you have a DAC that has XLR outs, use those.  Also, you can try any amp with xlr outs because the Raven supports those.  Our system is fully balanced from input of the Raven to the output of the Blackbirds.  It is a truly balanced tube circuit in each.

Thanks for the input, Don. My DAC does have XLR out so these will be used, as well as balanced out of the Raven whenever possible with future amps.

As far as variable gain and VC implementaion on the AMP-23R, Enleum does not provide much detail on their website. I was able to glean a few nuggets from reviews where the designer (Soo In Chae) gave input:

Stereo Times - ..."Soo In tells me that the volume knob, by the way, is apparently (digitally) capable of something like 1024 steps but is factory limited to about 40 times fewer steps as it is not strictly a potentiometer attenuating the amplifier’s fixed gain, but rather an extension of the amp’s ‘Ensence’ PCB module whose circuitry employs discrete transistors and, is a somewhat unique way of doing things in that it dictates the setting of playback volume by direct adjustment of the amplifier’s gain rather than by attenuation of a fixed maximum gain.”

HiFi Knights - …”at its core it’s a stereo power amp controlled via a user-selectable truly variable voltage gain. Each step on its knob-coupled resistor matrix generates one fixed voltage that determines amplification factor thus signal strength instead of maxing out and then trimming its level. This route makes AMP-23R the perfect candidate for standalone preamps. It also removes resistance and losses introduced by attenuators, maintains constant SNR at all voltage values and explains why under the Enleum’s knurl we see the word gain not volume. To simplify, if the usual integrated suspects rely on volume attenuation plus two or three optional gain settings to pull desirable SPL, Soo In’s latest has 1’024 of them to do the same without attenuation.”

[dls123]

Thanks for the input, Don. My DAC does have XLR out so these will be used, as well as balanced out of the Raven whenever possible with future amps.

As far as variable gain and VC implementaion on the AMP-23R, Enleum does not provide much detail on their website. I was able to glean a few nuggets from reviews where the designer (Soo In Chae) gave input:

Stereo Times - ..."Soo In tells me that the volume knob, by the way, is apparently (digitally) capable of something like 1024 steps but is factory limited to about 40 times fewer steps as it is not strictly a potentiometer attenuating the amplifier’s fixed gain, but rather an extension of the amp’s ‘Ensence’ PCB module whose circuitry employs discrete transistors and, is a somewhat unique way of doing things in that it dictates the setting of playback volume by direct adjustment of the amplifier’s gain rather than by attenuation of a fixed maximum gain.”

HiFi Knights - …”at its core it’s a stereo power amp controlled via a user-selectable truly variable voltage gain. Each step on its knob-coupled resistor matrix generates one fixed voltage that determines amplification factor thus signal strength instead of maxing out and then trimming its level. This route makes AMP-23R the perfect candidate for standalone preamps. It also removes resistance and losses introduced by attenuators, maintains constant SNR at all voltage values and explains why under the Enleum’s knurl we see the word gain not volume. To simplify, if the usual integrated suspects rely on volume attenuation plus two or three optional gain settings to pull desirable SPL, Soo In’s latest has 1’024 of them to do the same without attenuation.”

That's cool.  Then theoretically, you can select any gain setting you choose that works well with the Raven as you say.  Not sure how much improvement you will see by putting a Raven in front of that, but why not ....?   

[Spatial Audio]

Is anyone going to try the Raven preamp with Class D monoblocks? I'd love to hear a review.

We use a Class D amplifier from VTV (Purifi) in our lab (not monoblocks) and it sounds exceptionally transparent with the Raven. The Raven provides an organic / natural sound quality combined with the technical clarity and resolution of the VTV. Our experience is that the soundstage has more layers and complexity when run with the Raven versus having the source go direct to the VTV. Other tube preamps we have tested seem to strip out some of that detail and, in some cases, provide a "color" that may or may not be desirable depending on the speakers and the rest of the system.

[E Man]

@dls123,
I apologize if this has been asked before, I haven't seen the question. Will there be an image added to the Spatial website of the Cherry Wood version of the Raven Pre soon? Also, is there possibly a plan to make Plinths sized for the Raven and the Blackbirds?

[jac1920]

My Raven preamp with cherry base.

[rfluongo]

My Raven preamp with cherry base.

Thanks for posting. I have seen the wood samples in a few posts but never a completed unit. Looks great.

Hard to to tell from the pic, is it a low luster sheen or more glossy? I guess satin vs. semi-gloss?

[jac1920]

The finish seems closer to satin than gloss but I'm sure if you contact David at Spatial he can tell you exactly how it is finished.  I am very happy with mine and it looks really good on the Zoethecus rack.

[Spatial Audio]

@dls123,
I apologize if this has been asked before, I haven't seen the question. Will there be an image added to the Spatial website of the Cherry Wood version of the Raven Pre soon? Also, is there possibly a plan to make Plinths sized for the Raven and the Blackbirds?

We do have plinths sized for the Raven and Blackbird amplifiers. This is what that looks like with the cherry Raven. We can also use a darker stain to better match the sapele.

https://www.spatialaudiolab.com/plinths

[E Man]

Thanks for the replies, and the pictures. They are most helpful! I think I'm a fan of the dark finish on the wood!

[Cappy]

Is anyone going to try the Raven preamp with Class D monoblocks? I'd love to hear a review.

I received a Raven preamp 10 days ago and I've got >80 hours on it now.  Don suggests that much time for burn-in. 

I am really enjoying it.  I've been listening to music through it with two amplifiers so far, a pair of Hypex Nilai 500 class-D monoblocks, and a pair of DIY First Watt M2 class-A monos. 

With the Nilai monoblocks, it's a big bold clear sound with good rhythmic drive.  Bass is strong but nuanced.  It throws a wide and deep soundstage on my Pure Audio Project open baffles.  I can see where the Raven combined with Spatial Labs open baffles is going to work well with many amplifiers because of the complementary spatial qualities of the preamp and speakers.

Running fully balanced via XLR interconnects from my Holo May DAC through to the Nilai monos is pretty cool.  I've never had a balanced vacuum tube preamp before.  I've wanted one for a long time, but the Raven is the first one that appealed based on my pretty demanding wish list.

[Cappy]

The Raven volume remote is a heavy wand that feels comfortable in the hand and looks sleek.  The volume balance control feature is implemented intuitively and works well with the display user interface.  The display is easy to read from the listening position.  The mute button is well positioned on the remote for quick access.  Overall, it's a very nice preamp interface.

[Cappy]

[thestatman]

I used chatgpt to tell me what else is transformer coupled, balanced, 6sn7 based and no neg feedback.   It gave me:

Audio Research Reference 6 - Known for its use of 6SN7 tubes and transformer coupling, this preamp avoids global negative feedback and uses a fully balanced design.

Conrad-Johnson ART Series - Models like the ART II preamplifier use 6SN7 tubes and feature transformer coupling. They also employ a balanced design and do not use global negative feedback.

Vacuum Tube Logic (VTL) TL 7.5 Series III - While VTL preamps are known for using various tube types and often include transformer coupling, specific models like the TL 7.5 Series III align well with your criteria. The use of the 6SN7 tube and avoidance of global feedback are specific to certain versions.

Aesthetix Callisto Eclipse - This preamp is designed with 6SN7 tubes and utilizes transformer coupling. It also features a fully balanced design and avoids global negative feedback.

Would Lynn or Don like to comment if any of these truly meet the same design criteria as the Raven?   I suspect most of them don't.

[JackD]

Well the first two are wrong as the ARC uses 6H30 tubes and the CJ uses 6DJ8 family tubes. The Calypso uses a combination of 12AX7 and 6922.  So you need to find a better source of information.

[dls123]

Well the first two are wrong as the ARC uses 6H30 tubes and the CJ uses 6DJ8 family tubes. The Calypso uses a combination of 12AX7 and 6922.  So you need to find a better source of information.

What Jack said... plus the VTL says it uses a pair of 12AU7 followed by a solid state stage.  The 12AU7 is about the worst sounding of the 12A*7 types, and none of them can touch a bigger octal tube like the 6SN7 for sonics.  The small signal tubes have much higher levels of distortion than a 6SN7.  The Aesthetix lists for over $25,000, which is roughly 5X the price of the Raven.  I seriously doubt it sounds better:)   

The Raven is very good and very fairly priced given what it actually costs to build.  The power supply is fully regulated for both high voltage and filament supply, and could drive a small integrated tube amp quite easily so it is completely overbuilt for a preamp.  That is part of the effortless sound.  The Aesthetix has some sort of discrete resistor volume control setup.  They don't say whether it is ladder, series, or shunt.  The Khozmo we use is dual mono and shunt.  There is only a single naked foil resistor in the signal path of each channel at ANY volume setting.  It is like having a volume control without having to listen to a volume control. 

Anyway, I am sure more Raven owners will chime in here as more preamps are shipped.  The parts for the next run of 10 are on order.  So there will be many more in the world in a month or two.  Stay tuned.

[Cappy]

The way these AI Large Language Models work is by giving data points a weight, then using linear algebra to extrapolate a trend.  Extrapolation being the key concept.  Another possibly better term for this aspect of LLM operation might be "hallucination". 

Not only did ChatGPT hallucinate the tube types, it also hallucinated that all those preamps have transformer output.  In the real world, I see a lot of coupling caps when I look at the interior of those preamps. 

For example, from the Aesthetix marketing literature:

The Io Eclipse uses eight .22uF / 600v Stealth coupling capacitors made of exotic copper foil. These are used between the second and third gain stages, and the third gain stage and output stage. The Io and Callisto Eclipse output stages also use eight 4uF / 400v Stealth capacitors in a unique balanced configuration.

That's a lot of coupling caps (and a lot of gain stages too).

[dls123]

The way these AI Large Language Models work is by giving data points a weight, then using linear algebra to extrapolate a trend.  Extrapolation being the key concept.  Another possibly better term for this aspect of LLM operation might be "hallucination". 

Not only did ChatGPT hallucinate the tube types, it also hallucinated that all those preamps have transformer output.  In the real world, I see a lot of coupling caps when I look at the interior of those preamps. 

For example, from the Aesthetix marketing literature:

The Io Eclipse uses eight .22uF / 600v Stealth coupling capacitors made of exotic copper foil. These are used between the second and third gain stages, and the third gain stage and output stage. The Io and Callisto Eclipse output stages also use eight 4uF / 400v Stealth capacitors in a unique balanced configuration.

That's a lot of coupling caps (and a lot of gain stages too).

and... the Raven and matching Blackbird amps have NO coupling caps in the signal path. 

[thestatman]

ChatGPT led me up the garden path.   I can't find a single preamp that has the Raven characteristics.

[dls123]

ChatGPT led me up the garden path.   I can't find a single preamp that has the Raven characteristics.

That is because there isn't one:)