Spatial Audio Raven Preamp

Indeed on the speakers.  I own 95 dB speakers that are an easy 8 ohm load.  The giant 84 dB speaker that takes 200 watts to wake up really don't sound any better to my ear.  In general they sound worse.  Give me a 90+ dB well behaved speaker every time.  Then I can drive it with a 20 watt tube amp and be happy:)

As for tariffs, we shall see.  Now there are more negotiations going on.  One thing business hates is uncertainty.  Consumers hate it too.

Do the tariffs affect the used markets as well? I'm thinking yes but not sure.

@dz13    Yes. Think of it in terms of shortages. This will push the used market up as new prices go up as well. Its a manufactured inflation. 

We make our boards here in the US, but I expect materials to make those boards, plus parts that go on the boards (for example, tube sockets, resistors, semiconductors, capacitors) will likely go up even if they are made in the US.

That’s the logic of inflation. Buy Now, because it will cost more tomorrow. Once this gets baked into everyone’s consciousness, it affects pricing (and expectations) throughout the entire economy.

Deflation is the reverse, but is far more dangerous, since businesses hate to sell at a loss, so prices are "sticky" in the downward direction. Deflation of much more than 1% is associated with demand collapse and economic free-fall.

The ideal target for stability and maximum steady-state growth is about 1~3% inflation per annum. Shocks in either direction are very bad.

@atmasphere Thanks for your response but what I meant is if I buy something used from a member in Canada, are tariffs going to be assessed? 

The current de minimis threshold for goods entering the USA is $800.  So used things from Canada under that value will not see a tariff.  They may change that, but so far that has not changed.   It is also where the gear was made.  If the seller can prove the gear was made in USA and not Canada, then theoretically, there should be no tariff.  Now if you were to buy a preamp from me, when I was still making them, it is made in Canada and worth more than $800, so it would see a tariff.  Or a speaker from say Troy Joseph Crowe in Ontario.  Made in Canada.  

So the answer is it depends:)

Hello Folks,

I received my Raven a few weeks ago and I now have about 50 hours on it. I want to share my listening joy of the Raven. Caveat: I don't write very well and hence may not be able to describe with the right choice of words.

My setup is as follows:

Laptop and Yamaha CDS 700 player (transport only) into Schiit Yggdrasil Analog 2 DAC into Schiit Lokius EQ into Schiit Loki Max EQ into Raven preamp into Schiit Tyr Monoblocks. XLR interconnects throughout. Digital coax cable Belden 1694A. Schiit PYST Straight Wire USB AB cable. Speakers Clayton Shaw OB Caladans 93dB. Power cords Anticables Level 3. Interconnects Snake Oil Sound XLRs and SEs. Speaker wires Anticables Level 3.1.

The Caladans OB speakers have about 400 hours on it and placed 5 feet away from the back wall and about 20 inches from the side wall, slightly towed in. Listening spot is about 9 feet from the speakers.

The EQs are used to cut bass response and this tightens the bass (I like it). It is by-passed if not required. The equipment is plugged into 2 surge protectors (4 power cords on each surge protector).  No power conditioners or regenerators or other fancy expensive exotic power cords or interconnects or speaker wires (I would rather use the money to buy the Blackbirds Mono Blocks or other good equipment).

The Raven is fitted with Ray Tube Reserve 6SN7.

2) My other setup is using the Yamaha AS2100 integrated amplifier (used as a preamp, SE) into Schiit Tyr Mono Blocks. All else in the chain is the same.

3) There is no room treatment. Just gypsum drywall, a few pots of indoor plants and paintings. Living room measures 25ft (L), 13 ft (W), 8ft (H) It is L shaped. I don't hear any echo when we speak in the room. 

Both set ups (the Raven and Yamaha AS2100 integrated amplifier) are very good: there is clarity, accuracy, excellent vocals, and tight bass (can tell a bass guitar, double bass, kick drum). With about 50 hours on the Raven, this setup however sounded more natural, a lovely smoothness, more musically pleasing, clarity without the hard edge. It just sounds just right and real. For some recordings, I hear a different sound presentation that I think should be the correct sound of the instrument. The vocals are really really good, with the right texture (especially CDs with very good recordings). Both male and female vocals are exceptional eg Nat King Cole, Karen Carpenter. Jazz and classical recordings sounded superb.  The sound of the piano is so real (of course not like the sound of an actual piano in the room but close).

Opera female vocals in Mozart's composition - Le nozze di Figaro - Canzonetta sull'aria on the Raven is so good I cannot find the words to describe it. The Raven is able to control the high pitch without breaking and sounded just right. You cannot hear anything else in the background, just her vocals. It is so good that I replayed the same track a few times over and over and yet my ears felt so good. The Yamaha AS2100 is also able to do it but somehow the Raven is just so natural and sounded better. That's how good the Raven is.

This Raven set up is also able to handle superbly Sand's Airlock (Still Born Alive album 2001 Track 1 - noise genre). This is a very complex but opulent recording. Yes, it is all noise but beautiful noise that carries you away, over 6 minutes of it. Love it when the air valve is turned off towards the end of the recording. I think few set ups can handle this piece of recording well. It was really noise sounding before I got the Caladans and Raven.

I really cannot comprehend what soundstage, depth, separation, air, fast bass, music floating in the air, and many other terms that are described by other audiophiles in forums.

All I know is the sound of the Raven is just right.

Cheers

@phono2024 Congratulations on the new Raven preamp!  You have a very nice system. It's interesting that you "cannot comprehend what soundstage, depth, separation, air, fast bass, music floating in the air..."  I get all of those things to a greater or lesser extent and my Raven preamp is connected to a Pass Labs X350.5 amp which is a warmer sounding amp. It is rare for me to hear any music actually coming from the speakers (Verity Audio Parsifal Encore) as the sound source; the soundstage is open, deep, wide, holographic and as transparent and extended as the Pass amp will allow. I was curious what a more neutral amp like the Tyr mono blocks might sound like.  I have a feeling your system will open up with more hours on the preamp.  I also have Paul Speltz best XLR's and Triode Wire Lab speaker cables in my system.  Thanks for posting your impressions of the Raven preamp!

I would suggest you just try running your DAC straight into the Raven to compare. You may be surprised at what you hear. Just give it a try. 
 

Hi jc4659,

Thank you. It is a very nice set up. Yes, I cannot comprehend those terms, like layered. What makes the music layered? Fast bass, what is fast? Anyway, I don't analyze but only listen and enjoy the music. 

The Yamaha AS2100 integrated is already very good - clarity, accuracy and detailed. But the addition of the Tyrs made the music sounded better and livelier. For example, Chopin's Nocturne in C Minor, one can hear the immediate impact of the hammer hitting on the piano cords and decay with the Tyrs. Now with the Raven paired with the Tyrs, it is even better sounding. According to Jason Stoddard of Schiit, the Tyrs has a huge choke (old school) not capacitors to store power for transient needs and reduce ripple (technically I don't understand this) but the sound coming from the Tyrs tells me it is very good - power and control. According to a contributor in the Tyr forum, the Tyr's performance is at the dartZeel NHB 108 level. I have never heard the sound of the dartZeel but the price tells you something. US$53,000 2022. The Tyr is good enough for me.

One caveat on the Tyrs - some experience a hum. Mine had a very low hum and hiss when I first got it (ears 1 inch away from the tweeter and woofer drivers). I checked with Schiit and was told it is normal for an amplifier with this power. Anyway, after a few months, the hum was gone, with only a very very low hiss (white noise?), audible when I place my ear an inch away from the tweeter. Silent when I moved away. I guess it got burned in. For details and reviews on Tyr, check their website. Read the FAQs. Brings a smile on a not so good day.

Cheers

@phono2024

Congratulations on your new equipment. Thank you for your report. It is great to hear when someone is very happy with their new equipment and the music it produces.

Thanks for the review, phono2024! Always good to hear compatibility reports as well, much appreciated.

Although Don and I optimized the Raven and Blackbird to deliver their best performance with each other, we went to considerable trouble to make sure they add sonic value to other systems, too. For the Raven, this means optimal performance when matched with classical push-pull pentode amps and modern transistor amps.

Both RCA and XLR outputs offer equal sonic quality, since the only difference are the ratio of the output taps on the output transformer. The circuitry is exactly the same for both outputs, using a direct straight-through path from input to output. There are no "add-ons" like phase inverters to create the minus phase of the XLR output, no cathode followers, no dynamic loads, no current mirrors, no op-amps, nor DC servo circuits. The custom-design transformers solve all these problems at a stroke.

What you hear are point-to-point wires, triode vacuum tubes in a balanced Class A circuit, and studio-quality transformers. Nothing else. There are no coupling caps, no feedback, and no secondary signal paths in the circuit, just straight through from input to output.

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.

I have always preferred solid state amps over tubes because most of the time when I listened to tube amps (friends and at retailers), it sounded veiled, without the nice clarity of the top end. But the Raven changed my perception. Not only is the Raven very good on the top end but sounded real and a kind of lovely smoothness. Just right.

Hi phono2024,

Using the tube preamp with solid state power amp will enhance the sound quality. Having a good tube power amp would be even better. Unfortunately, lots of the tube power amps are not great at all. I think you should take an opportunity audition the Raven + Blackbird and see how you like it.

Johnny

Hi kmtang,

I will if there is an opportunity.

Another small note: conventional tube preamps can be dangerous for transistor amps unless they have an automatic muting relay with a timer circuit. A conventional tube preamp with cathode follower output typically has the output node (the cathode) somewhere between 150 to 200 volts, with a 1~3 uF capacitor keeping that DC potential out of the output of the preamp (a blocking cap). Unfortunately, as the preamp powers up or is turned off, large transients that are a significant fraction of that 150 volts can appear on the RCA output, which is why a muting relay (with timer delay) is required for safety.

This was harmless during the days of power amps using nothing but tubes, in the Fifties and early Sixties. The power amp would be warming up and unable to transmit the preamp transient to the speaker, and in addition, vacuum tubes are not harmed by high voltages ... they can accept hundreds of volts without risk of arc-over.

Transistor power amps are completely different. The input differential pair, either bipolar or FET, can be destroyed or degraded by pulses larger than 10~20 volts, as well as passing on speaker-breaking pulses since transistor amps turn on instantly. The damage to the input pair can happen even when the power amp is turned off, unless the power amp has input muting relays (the relays are usually on the output side).

The classic tube preamps of the Fifties and Sixties never had muting relays because they weren’t needed ... the tube power amps didn’t mind, and took a while for them to warm up and amplify. Muting relays appeared on high-end gear in the Seventies and later, because users were losing amps and speakers because of these transients. The catch with muting relays is they can introduce a new source of distortion from slow development of corrosion on the relay contacts.

Transformer coupling has the charm that it can never pass DC, under any circumstances, and unlike a capacitor, does not store energy. In addition, the circuit itself is balanced, and is only slightly out of balance as it warms up. Although we do not recommend it, you might only hear a minor "click" when the preamp is turned on with a "live" power amplifier. Doing this is dangerous for your system and we do not recommend it; always turn on preamps before power amps, and always turn off power amps first (and wait a little while) before turning off source components.

Being careless with a conventional tube preamp is quite different. The survival of your system depends on the reliable operation of the muting relay ... for example, if you have a power outage, or a power interruption, does the muting relay instantly activate? It must, if your transistor power amp is going to survive. A tube power amp would give a helluva bang (tough on your speakers) but it would survive just fine.

The output transformer sidesteps all that. No energy storage, and does not pass DC, ever. (There is no metallic connection between primary and secondary, only magnetic.) No requirement for a muting relay. No timing circuits that require a separate 5VDC supply. Worst case scenario, you might hear an annoying click, but no amps are harmed, or speakers destroyed.

Lynn,

Thank you for the advice - always turn on preamps before power amps, and always turn off power amps first (and wait a little while) before turning off source components.

The most dangerous of all are DC-coupled preamps and power amps. If the DC servo system in a preamp fails, the failure can propagate all the way to the loudspeaker. I saw this happen when I was visiting the home of a reviewer. It took out one channel of the preamp, one power amplifier, and one woofer in a $50,000 speaker ... all in less than a second. I saw a brief flash where the woofer was, the left channel went silent, then smoke wafted out of the power amp and woofer. That’s what DC coupling can do. No thanks.

@phono2024 Congrats on the Raven and I am happy to hear that it sounds great with the Tyr monos. I have the latest Schitt Wotan amp, and it is really good. A small powerful beast of an amp. I will rotate the Raven between 2 systems anchored by the Wotan and the CODA #16. Both amps allow for the easy integration of 2 preamps with a front toggle switch for RCA and XLR. Perfect for the Raven and another preamp.

You mentioned in your post that you also use your Yamaha integrated as a second preamp. You may want to check out the new Schitt Kara F for $799. I received it a few days ago and it is a very good preamp. 

Once taxes are done, I can start thinking about the Raven.

Hello yyzsantabarbara,

Thank you. Lots of good amplifiers out there to choose from. The Raven is perhaps one of my better decisions made to add on to my joy of listening to music.

Please share your experience with the Raven when you get it.

Cheers

Audio-gd Vacuum HE1 XLR Tube Preamplifier Review - HomeTheaterHifi.com         the best pre this reviewer ever reviewed.....and I can vouch for that.

@mbmi Glad you are enjoying your preamp. Not sure how it is relevant to this thread.

The most dangerous of all are DC-coupled preamps and power amps. If the DC servo system in a preamp fails, the failure can propagate all the way to the loudspeaker. I saw this happen when I was visiting the home of a reviewer.

@lynn_olson The highlighted statement above is false.

I don’t contest what you saw.

We’ve been making preamps with a direct-coupled output (which we patented) and its been one of the most reliable design aspects of the preamps over the last 35 years. If it were to fail, our preamps wouldn’t make a high Voltage anyway, even as it warms up. As a result this is something that we’ve never seen.

If a tube amplifier was used, DC at the input would not have caused damage.

If a solid state amplifier was used, it should have gone into protect mode as any competent solid state amp will have a proper protection circuit!

So IMO if this anecdote is true, the designers of both the amp and preamp didn’t know what they were doing. Equipment should always be fail safe!!

Was the preamp of this story a tube preamp?

The anecdote is true, not fictional. I was there and saw it happen.

Not surprisingly, the preamp and power amp were all solid-state and were stupendously expensive, in the $100,000 range. As we old-timers know, price does not guarantee quality in our business, unfortunately.

DC servo failure is not rare in the high-end solid-state world. It should be, but isn’t. When it happens, the results are very expensive, not to mention the cost of down time.

Looking back, my guess is poor solder technique somewhere in the preamp, or maybe a regulator in the plus or minus supply gave up, yanking the preamp output to 15V or more. Or a DC servo went nuts. Results were the same, a destroyed power amp and loudspeaker. The only unusual thing was a designer (me) seeing the failure in real time, in a domestic setting. You usually see this kind of drama on a test bench, not in the context of an ultra-deluxe system in a home.

Should it have been better designed? Of course! But how is the consumer to know? They assume [higher price = better product].

That’s the real difference between pro gear and audiophile equipment. The pro stuff is reliable, because it has to be.

That’s the real difference between pro gear and audiophile equipment. The pro stuff is reliable, because it has to be.

@lynn_olson If you're going to stay in business for the long haul producing high end audio products they have to be reliable too. I can't imagine how anyone thought that a solid state amp without the ability to protect itself from something like this was a good idea. At the very least if the amp smoked it should have blown a fuse...

Oh it blew a fuse all right. After the output section was completely destroyed, and a massive DC pulse killed the woofer. This was European oligarch-class audio gear from a well-known manufacturer.

The manufacturer is still around, twenty years later. The buyers are expected to suck it up and not complain, I guess.

The joke amongst designers of transistor gear is transistors do a great job protecting the fuses (because transistors fail in milliseconds, while fuses can take a half second or longer). Transistors fail much faster than any human response time, whether on a bench or across the listening room. And a good, solid DC pulse will destroy any woofer ... audiophile-grade woofers can only take 1 watt (or less) of DC on the voice coil. Professional 15" woofers with 4" voice coils can take a little more DC, but certainly not 200 watts.

Sheesh. If our stuff had been damaging speakers we'd not have been in business very long. Odd how a solid state manufacturer could get away with that!

Happens all the time in the small-production-run solid-state world. Oversights in manufacturing like no heat-conducting paste between transistors and heat sinks, for example. Or a wave solder machine not properly set up for EU-required leadfree solder, so the solder joints on a circuit board start going bad after a while.

There’s some pretty sketchy tube stuff too ... I remember seeing bulky, heavy electrolytic capacitors "attached" to the chassis with RTV silicone goo ... and no bolts, clamps, or other hardware! From a highly reviewed European manufacturer that is still in business twenty years later. Or a well-known American manufacturer that omitted, or forgot, the required 10~100 uF decoupling/stabilization capacitors for the multiple 3-pin voltage regulators, so they sang happily in the 10 MHz range. Easily visible on an RF spectrum analyzer, but not easily seen on a scope.

@lynn_olson 

Or a well-known American manufacturer that omitted, or forgot, the required 10~100 uF decoupling/stabilization capacitors for the multiple 3-pin voltage regulators, so they sang happily in the 10 MHz range.

I've seen preamps and amps where the parts were held in place with hot glue. All that had to happen was have it dropped in shipment and you have a shock or fire hazard. I've encountered oscillating regulators in some American built stuff so I know what you're talking about. Tends to make the 'regulated' circuit a bit noisy...

I have seen all sorts of things rebuilding old tube gear.  If it was original, then it was pretty well made and everything tied down.  If someone else had "restored it", all bets were off.   I won't name anyone, but there were a couple of well known vintage restoration places where I could not believe what I saw when I opened the hood.  50 cent caps with leads hanging in the air, etc....   The best story though, was an old Fender guitar amp I was fixing for a musician friend.   Someone had wired the hot side of AC to the chassis and neutral to the fuse!  The amp worked.... but if that guitarist has put his cold sweaty beer can down in just the right spot on top........

Hello jc4659,

I have replied to your message a few days ago. I hope you received it.

Thank you.