@phono2024 No hiss.
No hiss with past other units. (Macintosh 275, PrimaLuna, and Rogers High Fidelity) Way back a Fisher 400 did hiss, growl and bite.
Spatial Audio Raven Preamp
Spatial is supposed to be shipping the first "wave" from pre orders of this preamplifier in May, does anyone have one on order? Was hoping to hear about it from AXPONA but I guess they were not there. It's on my list for future possibilities. It seems to check all my boxes if I need a preamp.
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@phono2024 Perhaps you could share how other experiences had of 'Poking the Bee Hive' turned out for you. |
Hi, Theophile! I’ve written a lot of stuff over the last thirty years, both in print and many different Internet forums (going back to "rec.audio.high-end" in the days of the Arpanet). That’s when I was still at Tektronix in Beaverton, Oregon, and had access to lots of test equipment. One thing to note is the first capacitor in a classical CR or CLC supply is not actually a filter, and making this cap too large can create very large current pulses in the power supply, which then radiate out through the power cord and into adjacent equipment. Big transistor amps with more than 40,000 uF in the power supply are the worst offenders here. A bridge rectifier can "snubbed" to smooth out the worst of the current pulses, but the snubbing circuits must be tuned for the exact brand of power transformer. A mistuned snubber will actually make the ringing worse, so it’s not a one-size-all solution. As for pricing, Spatial is clearing a profit, but it’s not particularly large. Vacuum tube equipment is expensive to make compared to solid-state. Audio transformers are labor-intensive and the steels in the core are quite specialized and only made in small production runs. Vacuum tubes are not made by robots, but by experienced labor, in small production lots. Spatial uses hand-soldered point-to-point circuitry with exotic wire, instead of circuit boards, and switched-resistor volume controls are several times the price of conventional rotary controls. They are not made on a production line; one tech sits down and builds the whole thing, another checks his work, it goes on a burn-in rack, and gets thoroughly re-checked before final approval. By contrast, the most expensive part in solid-state gear is often the custom-machined front panel and case, followed by the power transformer. Transistors range from a few cents to a few dollars, and op-amps are rarely more than ten dollars each. Circuit boards are not that expensive if you buy them in lots of a hundred or more. So the actual working circuitry is surprisingly cheap, often less than 5% to 10% of the retail price. |
Lynn, Off topic. You once wrote in a blog page about rectification radio frequency noise being exacerbated by the tank circuit formed by the power supply. Or something to that effect. I'd love it if you could start a thread on the topic and give us your further thoughts. Apologies for interrupting the conversation. |
@fthompson251 Thanks for this information. I have a BAT VK-80 preamp on order, but it's been on backorder for 2 months now. Not sure I want to wait much longer and am looking at other options. |
@lynn_olson Obviously but I was asking people who recently ordered the preamp. Not looking for exact timelines. |
Actually, I am very curious which phono preamps are a good match with the Raven. As mentioned earlier, the Raven sounds equally good with RCA or XLR inputs, so it caters to all kinds of phono preamps ... solid-state, vacuum tube, or hybrid. Not going to touch the "which streamer is best" discussion ... there are other fora that go into that rabbit hole. |
Congradulation on your new preamp. I’m also 72. It sounds like you are getting amazingly good sound out of that OPPO. It is great that you have such a large vinyl collection. But thinking ahead, you might think about streaming. You can get the same sound quality and not be confined to vinyl as getting up and changing records is not going to get easier. I’ve got 2,000 pristine albums which I never listen to any more. I now spend my time exploring new music. Just something to think about. George |
Hello All, I received my Raven preamp early last week and have about 20 hours listening to the unit. My CD player is an Oppo 205. I am not into cd's only having 250 - 300 cds. My favorite media is LP's having about 4150 of all genres. Unfortunately my phono stage (Modwright PH 9.0 XT) is out for repair. So I have been listening to nothing but CD's. And all I can say is wow. I can't wait to get my phono stage back so i can listen to LP's again. The soundstage is wide and extremely clear. The instruments and voices are well separated and very musical, plus the sound stage is really deep. It is now very easy to listen to, no fatigue. The sound of cd's, for me anyway, is approaching LP quality. My whole system consist of the following: A VPI HW19 Mk IV with many modifications, tonearm is a Woody String Theory with a Soundsmith Zephyr MIMC cartridge, my DVD/CD Player is an OPPO 205, my phono stage is a Modwright PH 9.0 XT, my amps are V4 QuickSilver mono blocks. my speakers are Watt Puppy clones. So, I am 72 and believe this is my final system it ticks all my boxes. It is not too pricey, it is very detailed and still extremely musical. Now I can concentrate on collecting LP's specifically jazz and classical. I think i will get many hours of pleasure from my system in the future. I will post a review on how the LP's sound when I get my phono stage back. Richard |
No adjustments are necessary. The only requirement is the sections within the 6SN7 are internally matched, which is true for any good-quality tube. Each channel has its own 6SN7, and it is preferable the stereo pair are matched, although not essential. (This is a roundabout way of saying don’t just use random pairs of old tubes pulled out of a junk box. The ones we ship with the Raven are the best modern tubes available. Before you try old-stock, make sure they are tested and known to be good.) |
@jc4659 So glad the anticables worked out for you. Same setup I am running, with xlr from my Lampi Pacific 2 to the Raven and xlr to the Blackbirds from the Raven. I am going to get Paul to make me speaker cables eventually when I get around to it. It is always a bit of a stretch recommending cables because we all have our taste. There are lots of very good cables in the world and people recommend them to me regularly. I just tell folks what I am using that works for me. I heard Paul's cables when Spatial used them in our demo in Seattle and I was impressed, so I bought some. The Raven is very transparent and will certainly show you what your cables sound like. I don't think Paul's cables really sound like anything, which is the best praise I can give anything. They are just transparent without any trace of brightness in my system. Glad they worked out for you.
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@lynn_olson I’m a believer! The Speltz level 5.3 XLR Anticables are very reasonably priced in my opinion and seem to be a perfect match for the Raven. Talking with Paul Speltz about his cables and pickleball among other things was a pleasure. Many thanks to Don for pointing me in the right direction. |
I have owned the Raven preamp now for about 6-7 weeks feeding a Pass X350.5 solid state amp. Compared to my previous solid state preamp, a quite capable Ayre K-1xe, the Raven was better at everything but mostly in the areas of soundstage depth, image stability, 3-dimensionality, focus, clarity and tonal colors. However, I suspected that I wasn't getting everything the Raven was capable of due to my interconnect cables which are a good value for their price but after having owned the much better Nordost Tyr 2 in the past, had certain limitations. At the suggestion of Don Sachs I ordered up the top level 5.3 XLR anti cables from Paul Speltz and had them cryo'ed and burned in for 150 hours. They are used between my DAC and Raven, and from the Raven to the Pass amp. Speaker cables are from Triode Wire Labs. OMG! The gains in clarity, transparency, speed, dynamics and image focus are off the charts. Vocals are so clear that I can now understand certain words that I used to have to struggle to understand. My system now sounds leaps and bounds better than ever. Even the wife agrees but don't tell her I have my eye on the Spatial Blackbird amps. With a daughter getting married in the fall those will have to wait a while. |
Hi The Raven gain is about 13.9 dB (5X voltage gain). The RCA and XLR inputs have the same gain. The Khozmo volume control has a very nice log taper and you should have good adjustability in most systems. Not touchy.
I would run XLR from DAC to Raven if you can, but it is not required. It will generally sound better with most DACs. Also, if you ever change amplifiers you can run XLR out to an amp with balanced connections. The RCA output of the Raven will by definition have less gain. That said, there is plenty of gain to drive almost any amplifier. I believe Spatial has a return policy if it doesn't work in your system, but honestly, it will work well with most anything, single ended or balanced. |
Interesting thread. I recently demoed a budget preamp in my system and was surprised by how much more dynamic and alive it sounded compared to using the volume control from my dac. If there was any loss in resolution, I couldn’t hear it, and the improvements were dramatic, so I am now in the market. A couple of questions: 1) how much gain does the raven have, and is it the same balanced and single-minded? I don’t want to have so much gain that the volume control is touchy. 2) I’m currently using single engine connections from my dac to my amp. I’m going to need to buy a new set of interconnects. Any recommendations regarding whether I should stay single ended, run balance connections into the raven and single ended out, or sell my single interconnects and buy two balanced ones. I really like the iconoclast cables I have and they will add to the cost. Thanks. |
UK is now linked to Mainland Europe with a Trainline one service for high speed Pedestrian Transportation and another to replace the use of a Ferry Crossing for Vehicles. The idea of Plane to Paris is not the commonly used idea anymore, the Train is very popular. The Ferry suits those with additional time and on a tighter budget to transport a Vehicle. I was listening to a Tim de Paravicini designed 300b Power Amp' yesterday, was using E88CC Input Tubes and had undergone modifications to utilise Interstage Tranx's in the circuit. Very enjoyable it was too as an experience. The Pre Amp' was a DIY Built Pass design using a Khozmo VC. I made all who were at the audition aware of this Thread and the other, the Raven is further spoken off within the UK. |
Imagine high speed levitating electric trains down the insterstate medians..... They would be far more efficient than planes for the 500 mile or less journey. They have trains that go 199 mph in Japan. Imagine just 120 mph..... a few hours and you are across a couple of states and you can walk around, go down to the club car for a beer, etc... Contrasted with spending 2 hours in airports on either side of a 90 minute flight in a tuna can. Sure, for cross country flights the plane is better, but for the 300 - 500 mile journey... I would love a train. |
Oh, Amtrak is still around, just with fewer routes. The Denver/Portland route went away about fifteen years ago. However, as part of the Inflation Reduction Act, Amtrak is getting some routes restored, which I look forward to. As for airports, DIA is truly gigantic, with six enormous concourses, all radiating from a rattly and jerky central subway. United changed the gate THREE TIMES on the trip to Seattle, all on very short notice. By the time I got my seat on the 100% full 737, I must have walked two miles, with no place to sit and rest, just a nonstop slog the whole way. Although I felt sorry for myself, I felt more sorry for the exhausted single moms carrying infants. This is gross violation of the ADA act. There are old people (me), folks on crutches, and single moms force-marched to distant gates through an immense facility with nowhere to sit. I think it’s absurd the wealthiest country on Earth has only two modes of transportation, with the airlines steadily degrading service year after year, and the Interstate Highway System no better than it was in the Seventies. Of course, if you are uber-rich, you just take your limo to the private-jet-only airport and stroll out of the limo straight onto the private jet a few feet away. |
I got whacked with Covid after going to the Seattle show last year. Both the Seattle and Denver airports were overcrowded zoos, so I’m pretty sure that’s where I got it. Fortunately, Paxlovid knocked it out in about 36 hours. This time, I will NOT fly Economy Class, will ask the airline for a wheelchair to traverse the miles-long concourses at Denver, and will wear a 95% filter mask until the A/C on the plane comes on. For older folks like me, the airports are an exhausting trek without some kind of assistance. They are not ADA compliant unless you tell the airline a day in advance. Otherwise, you walk, with no place to sit and rest. It’s unfortunate there are only two transportation options between the Pacific Northwest and Denver: a very tedious drive through the wastelands of southern Wyoming, or a United flight on a 100% booked 737 Max. Well, yes, I could rent a private jet, but that’s $20,000 per trip. Don’t think the IRS would accept that as a tax deduction. The most pleasant trip was taking the Amtrak with a private cabin, but that disappeared ten or fifteen years ago. Sure was nice, though, eating in the dining car while watching the West roll by. |
@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. |
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..... |
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. |
@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! |
Lynn, Yeah, no negative feedback and single stage tube design should be added to my checklist. I recall first reading your articles on your nutshellhifi.com site -- "The Amity, Raven, and Aurora" and "The Karna Amplifer" close to 20 years ago. The schematics made a big impression on me back then - quite foreign but so inventive - a modern take on an old Western Electric brain trust concept. After finding this Raven thread recently, I then found the related Audiogon thread "300b lovers": https://forum.audiogon.com/discussions/300b-lovers?highlight=300b%2Blovers which I thought in some ways was as significant for tube amplifier design as your "Beyond The Ariel" discussion on diyaudio.com was for speaker design. Anyone interested in the Raven preamp or Blackbird monos and also interested in amp design might consider reading the 300b lovers thread carefully. After my own dilettante experience building low WAF tube preamps, owning various commercial tube, transistor, and passive preamps, and my search for an appropriate commercially produced tube preamp, then reading these two Audiogon threads, and recalling your Nutshellhifi writings, it really came together for me that I’d be able to own a pretty flexible natural sounding balanced preamp. |
Nice that the Raven ticks all the boxes! Seriously though, you’ve pinpointed (better than I could) what separates the Raven from a conventional Marantz 7C re-creation. The preamps from the Fifties and Sixties followed a pattern of 2-stage 12AX7’s for lots of gain, a 12AX7 or 12AU7 cathode follower to knock down the output impedance, and plenty of feedback around the whole thing. Look at an Audio Research SP-3A or SP-6 and you see the same circuit. This is what most audiophiles think is "tube sound" for the simple reason that hundreds of thousands of preamps and integrated amps were built just this way, so it’s a very familiar sound. But there are other ways to build a preamp, borrowing from studio electronics going back to the 1930’s. That’s the Raven, with no coupling caps, zero feedback, and a fully balanced circuit all the way through. More technically, when the Marantz (or similar) circuit is compared to the Raven, there are 1, 2, or 3 coupling caps in the signal path. "Tuning" the sound of a classical preamp is usually little more than a cap swap, leaving the circuit itself untouched. The classical preamp is single-ended, relying solely on feedback to get distortion down to acceptable levels. And the sonics of cathode followers remain controversial, depending on the nature of the cathode load (resistive, inductive, active current source, etc.). |
My (opinionated) tube preamp checklist: * Must take full advantage of balanced DACs * No Balanced to Single Ended input transformers * Must support XLR balanced out and RCA single-ended out for use with balanced amps or single-ended amps. * Balanced XLR out and single-ended RCA out must have equally good sound quality * Not capacitor coupled * Much prefer 6SN7s. Would consider 6SN7 family or DHTs. But balanced DHT preamp is large, heavy, pricey, with possible microphonics, etc. * No small signal tubes * Stepped attenuators with a good remote. No potentiometers. No TVCs or AVCS. (I do like autoformers combined with transistor buffers. I think resistor attenuation is a better match with vacuum tubes) * Must look good in living room. Prefer wood chassis. Conversation starter preferred. * Tubes proudly displayed, not hidden in chassis * Medium voltage gain * Damper diode or solid state rectification. Damper diodes preferred. (I bought a bunch of 6AX4 damper diodes in 2015 in anticipation) * State of the art power supply regulation * Must be good value for money More in next post... |
I received my Raven preamp a week ago. I've got about 80 hours on it now. It's great! I'm really digging the expanded tone colors, instrument textures, sense of space, and natural non-mechanical sound. My system is all digital using a Holo May DAC into the Raven. My main amplification is via a pair of DIY First Watt M2 monoblocks. I also own a pair of Hypex Nilai 500 monoblocks that I have been using with the Raven. I am running balanced from Holo May to preamp, and then out single-ended out to the M2 monos. With the Nilai monos the system is fully balanced. My speakers are Pure Audio Project Quintet15 open baffles. I'm finding that I'm listening more to whole albums, or parts of albums, instead of jumping around to different selected tracks and playlists of selected tracks. The music on the album sounds excellent, so I just keep going. This is how I used to listen to vinyl before I developed my unfortunately terminal record mold allergy. I found out about the Raven from this thread a few months ago. I've had a checklist of features, getting larger over the years, that I wanted to see in a commercial vacuum tube preamp. The Spatial Audio Lab Raven amazingly met my requirements. I immediately ordered one. More in my next post... |
@lynn_olsen This suggests that there is a grounded center tap of the output transformer. Normally a balanced line output (if it supports AES48) is floating (this practice is to prevent ground loops). Did you provide a switch to break the center tap's ground connection if the RCA is not used? I don't see it in rear panel photos. |
When I was playing around with Cornwall IV I pulled all the cheap $4 MKP caps out of the crossover and replaced them with vcap odam. I put path audio resistors in there as well. The main resistor directly in series with the midrange compression driver was a $1 sand resistor on a $5000 pair of speakers. I was not impressed. The sonic improvement was quite staggering. I then used a pair of decent quality Hsu subs run with their speaker level inputs with pigtail cables from each speaker. I simply ran a stereo pair of subs, one by each speaker. Much better.... Finally sold it all and got a custom pair of open baffle speakers made with a horn as the top end. Embarrased the Cornwalls and sub combo ..... Klipsch are lots of fun, but they are not the top of the heap when stock. They can be improved. Hence the millions of Klipsch modding threads in the world. |
A pair of subs don’t need to be exotic or anything, just fill in the gap below the horn cutoff. And two are definitely better than one. I prefer stereo bass, but the home theater folks use a mono input to drive 2, 3, or 4. I don’t care about sound effects on movie soundtracks (who cares), but do care about wideband sound. One thing about the Blackbirds is they will tolerate absurdly reactive loads, since they are push-pull Class A and do not use feedback. No protection circuits are needed. |
@curiousjim The answer is probably yes. We have run them with 86 dB 4 ohm speakers and it worked just fine. What kind of load is your speaker? Can you tell me the speaker so I can look up the spec? Unless it is some sort of terrible reactive load and you are trying to create rock concerts in a cathedral they would probably work just fine. |
@wsrrsw Good, sounds like you are on the right road. Subs are tricky. Good luck. I am sure you are getting some nice imaging and very real sounding instruments with great dynamics. Klipsch and bass... well...... that is not their strong point (but I didn’t say that out loud) |
@lynn_olson Bam! Thank you! One sub added. (Old one kept just in case) and will get another. Much better sound experience right away. The pre/system sounded aok with no discernible difference after putting cable into Pre’ Amp’s RCA output. Thought I could do as much but waited untill one of the birth fathers chimed in. Sub set around 50Hertz. Will mess wi/ setting up/down. Another round of thanks. |
