@atmasphere - If the input of the next component is balanced and not referenced to ground (e.g. transformer coupled), I don't understand why it is necessary to decouple the output in the source component from any ground reference to achieve the full benefits of balanced connections. Can you please help me understand. Thanks.
300b lovers
I have been an owner of Don Sachs gear since he began, and he modified all my HK Citation gear before he came out with his own creations. I bought a Willsenton 300b integrated amp and was smitten with the sound of it, inexpensive as it is. Don told me that he was designing a 300b amp with the legendary Lynn Olson and lo and behold, I got one of his early pair of pre-production mono-blocks recently, driving Spatial Audio M5 Triode Masters.
Now with a week on the amp, I am eager to say that these 300b amps are simply sensational, creating a sound that brings the musicians right into my listening room with a palpable presence. They create the most open vidid presentation to the music -- they are neither warm nor cool, just uncannily true to the source of the music. They replace his excellent Kootai KT88 which I was dubious about being bettered by anything, but these amps are just outstanding. Don is nearing production of a successor to his highly regard DS2 preamp, which also will have a unique circuitry to mate with his 300b monos via XLR connections. Don explained the sonic benefits of this design and it went over my head, but clearly these designs are well though out.. my ears confirm it.
I have been an audiophile for nearly 50 years having had a boatload of electronics during that time, but I personally have never heard such a realistic presentation to my music as I am hearing with these 300b monos in my system. 300b tubes lend themselves to realistic music reproduction as my Willsenton 300b integrated amps informed me, but Don's 300b amps are in a entirely different realm. Of course, 300b amps favor efficient speakers so carefully component matching is paramount.
Don is working out a business arrangement to have his electronics built by an American audio firm so they will soon be more widely available to the public. Don will be attending the Seattle Audio Show in June in the Spatial Audio room where the speakers will be driven by his 300b monos and his preamp, with digital conversion with the outstanding Lampizator Pacific tube DAC. I will be there to hear what I expect to be an outstanding sonic presentation.
To allay any questions about the cost of Don's 300b mono, I do not have an answer.
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@lewinskih01 You might want to study how balanced lines work. Properly done, balanced lines are the best cable drive available to audio. RFI and noise are rejected due to the low impedance aspect of balanced lines (in the old days the studio line inputs were 600 Ohms; these days its more like 1-2KOhms); weak signals induced in the cable are swamped by the low impedance. In addition the input that is being driven has a high Common Mode Rejection Ratio, which is to say that signals common to both the inverted and non-inverted inputs (such as noise and RFI) get rejection. In a true balanced line system ground is ignored to eliminate ground loops. If using tubes this is usually done using an an output transformer which can float with respect to ground. Its also possible to direct couple using a Circlotron output, for which Atma-Sphere has several patents. If you are supporting the balanced line standards (AES48 is one of the standards; the other is the low impedance aspect) these two methods are the only ways to do it. |
Great! Thank you for the answer. Would building such a device, passing said quality threshold, be super expensive? This device wouldn't need volume control nor the capability to handle multiple sources. Maybe the device increases gain by a given amount and then listening level gets adjusted down through software volume control. I agree it's an endless rabbit hole going down into the audibility of DACs vs upstream network settings vs software. And bleeding edge DACs bleed out their value soon after their peak in fame. Yet some more professional-oriented devices (such as Merging Horus/Hapi, Prism Titan, Lynx Hilo) are worth the same today as they were 7-8 years ago (nominal prices are higher due to inflation, price of Cu, etc) and still are the company's reference product. I like to stay among these, which of course are the ones capable of doing 8-ways. My gut feeling has been there is something else good preamps achieve, and your post helps put this into more specific words. I'm not aware of any commercially-available product that does this and I'm intrigued to explore and maybe DIY. The idea of introducing a tube-driven class A stage to achieve "better cable drive, partly signal conditioning, scraping off RFI and noise induced in the cables" is appealing. How would you recommend I learn about this? |
Love ’em or hate ’em, DACs have gone a long way in the last thirty years, and continue to evolve pretty quickly. The internals of the AKM and ESS converters run at 90 MHz, with stupendous processing power. It’s what makes 4K TV and digicams possible. That kind of speed makes up for many sins, and lets the noise-shaping algorithms operate much, much better than earliest days of SACD and single-bit MASH converters running at 2.8 MHz. In a lot of ways, it makes the endless upsampling discussions on the forums moot, since the internals are upsampling everything to 90 MHz anyway. Might as well let the chip do it, rather than play games in Roon. (Although converting PCM to high-rate DSD forces the chip to use different algorithms, which will definitely sound different.) It is a consciously retro decision to use antique Eighties-vintage Philips TDA1541A converters, or late-Nineties Burr-Brown PCM-63 or PCM-1704 converters. Those are true once-through flash converters, with no signal processing or noise-shaping involved. But the least significant bits are kind of marginal, since it took R2R to the limit of what can be done with laser trimming and ultra precise fabrication. Nowadays, speed and good algorithms are the answer. Which leaves the current-to-voltage converter as the last domain of audio tweakery. Op-amps are way, way better than the 1979-vintage 5532/5534 from Philips/Signetics, but you still find these antiques in consumer DACs. That’s probably where tuning happens in modern DACs, since there is little left elsewhere in the design. And if you want to "sweeten" things, do it in the power amp or speaker. Much easier to tweak. I think making records sound like ultra-quiet, ultra-precise digital, or making CDs smoothed-out and "analog", is taking away from the strengths of each medium. LPs sound like LPs, and PCM sounds like PCM. PCM to DSD256 is fair game, though, so why not? It’s what my Marantz SA-KI SACD player does to incoming PCM (it has S/PDIF and Toslink inputs), and an interesting "alternate view" of PCM sources. |
Lynn, I appreciate your candid views about the efficacy of DACs at varying price points. I was in the Spatial room when you heaped praise on the Mola Mola dac in the Songer/Whammerdyne room, a far less expensive DAC than the Lampi DAC in your room. I read an owner's report that a Topping DE90 SE DAC for $900 was, to his ears, pretty much the same as the sound of his DCS Bartok DAC that cost ~12X as much. My audio pal with nice gear has been is a rabid needle-dropper and he bought this same $900 Topping DAC and now honestly admits that his fealty to only analogue music is over as what he hears with this modestly-price DAC is pretty much the same as he hearing with his $15K analogue rig. DAC technology, top to bottom, is really fantastic these days. One of the happiest days of my audio life was getting a SOTA Sapphire vacuum TT in the mid 80's and another very happy day was the day I sold the TT to a local guy a few years ago, no shipping required. Once I got an Ayre QB-9 DAC in my system, it was game over for my TT rig. |
@lynn_olson You might want to play around with this applet: https://www.falstad.com/fourier/ Select 'sine' and the little dots below the waveform are movable and represent harmonics. It shows why euphonic colorations (which are only the 2nd and 3rd harmonics) can indeed add to (or subtract from) detail and 'dynamics' and alter your perception of depth and soundstage. If you only play with the 2nd and 3rd harmonics, and also work with their phase, you see some interesting results. For example if the phase of the 3rd is out of phase with the fundamental, the waveform actually gets taller. Harmonics define the sound of musical instruments. You can see from this little applet that distortion can bring out details of musical instruments or obscure them. |
Well, enough of the rant on DACs. Addressing the question in the post by lewinskyh01, what does a really good tube linestage bring to the table if the DAC can directly drive the power amps? A sense of ease, dynamic impact, and sometimes more vivid tone colors. How? Partly better cable drive, partly signal conditioning, scraping off RFI and noise induced in the cables. On paper, op-amps can do an amazing job driving a cable, in practice, not so much. If the preamp passes a quality threshold, yes, it can improve the signal compared to a direct connection to a DAC. Found that out the hard way with first Amity amp. |
Hi, Lewinskih01! You bring up two different approaches to system building. One is taking full advantage of modern multichannel DAC chips (8-channel is a common default size) and letting DSP do the heavy lifting. Taking it a bit further, tuning each amp for its own driver, rather than using a AV multichannel amp of marginal quality. It depends on subjective priorities. Does the speaker need DSP to reach its full potential, and is DAC coloration small change in the overall scheme of things? Can’t say I blame you. Speaker colorations are obvious and gross, and DSP is the most direct and powerful way to attack them. I have friends who own Altec Duplex 604’s and they don’t like it when I tell them the only way to straighten a 604 Duplex out is DSP ... no physically realizable crossover can fully correct it. Otherwise, you learn to live with the coloration, as Lowther owners do. DAC coloration ... hoo boy, let’s jump into that rabbit hole, shall we? I feel most audiophiles can barely hear DAC coloration for modern delta-sigma designs ... and measurements are essentially perfect, far exceeding the 44.1/16 Red Book PCM specification. If a modern AKM or ESS converter with a circuit board full of op-amps is perfect for you, you can save big money, and jump on the DSP train with confidence. Do not pass GO, collect your $200, and enter the wonderful world of DSP. Amps built to taste are entirely optional. Only a few people can hear differences between modern converters, and if you can’t, don't feel bad, you are part of the vast majority of audiophiles. Just buy a $700 Topping or S.M.S.L. and explore DSP. It’s what headphone jocks do these days. No shame in it. Differences between DACs are weird and extremely subtle, and frankly you have to train to yourself to hear them. I can’t honestly recommend audiophiles go down this rabbit hole. It’s extremely expensive to pursue and full of deliberately confusing technobabble from slick marketers. Maybe not as bad as cables, but still pretty bad. Trust nothing when it comes to DACs, no matter how famous the name, or how glowing the review, I was shocked and disgusted I could hear what sounded like "big" differences between my antique Monarchy DAC, with its Burr-Brown PCM-63K converters, and the latest confection from the Berkeley DAC (which any Topping will take to the cleaners these days). I also have the exaSound DACs which are ESS based. I find DAC chasing neither fun nor enjoyable. The best are insanely expensive, and they go obsolete really fast. I might love the $13,500 Mola Mola I heard in the Songer Audio room, but the Mola Mola won’t be worth as much three to five years from now. DACs should be thought of as consumables that depreciate the moment you buy them. Amps and speakers ... ah, now that is good value. Buy or build a good tube amp (and that certainly includes the $5000 Valhalla from Spatial) and it holds its value indefinitely. Similarly for speakers. The good ones cost more because the parts themselves cost more, and it takes serious design work to make them perform. |
I don't use tube rectifiers in power amps, but I do use them in preamps. In your amp, if you wish to keep the 5u4g, I would consider using it for the input and driver section and using good quality diodes to drive a separate power supply for the 300b. I use only regulated supplies, and I have my way of doing it that I don't wish to get into here. But, yes, it is a good idea to have separate supplies for the input/driver section and the power tube sections. What sort of supplies is up to you, but a DHT will echo your power supply AND your filament supply very clearly so make sure they are very good. Good luck! Don |
@lewinskih01 I have experimented for years with tube preamps. When I built the Raven preamp it was after I had sent the 300b monos down to Spatial Audio for the Seattle show. Then I built the matching preamp. They were able to run the mono amps directly from the tube output stage of the Lampizator Pacific DAC, and they had one with a volume control. I wanted to test it so I took used my Pacific DAC (no volume control) and implemented digital volume control in ROON. It worked fine and sounded good. I built the Raven preamp and inserted it in the system between the DAC and my 300b amps and the improvement was obvious. I have done this experiment before with other preamps and DACs and every time I have preferred the sound of my good custom tube preamps to a direct connection from a DAC to the amp. I have built passive preamps with the Khozmo volume controls. I always preferred the active tube preamp and it was never close. That is just my experience and others will undoubtedly have different opinions, but I have experimented off and on for years and always preferred a very high quality active tube preamp in the system. That said, I have never owned active crossovers, nor will I, nor have I ever bi or tri amped a system, nor will I. So my experience is not really applicable to your case. I prefer the simplest system with passive crossover and one amp per speaker. My 2 cents and of course your mileage may vary:) This is why I build high quality active tube preamps for people with fairly simple systems. Just my preference. |
I hope you don't mind me going a tangent, but delving into modern and old technologies and taking advantage of such knowledgeable folks sharing with an open mind I wanted to humbly ask what function does a preamp fulfill in the context of a single digital source (DAC) driving a good SET? Here's why I'm asking: time ago I got into DIY speakers and adopted software-based FIR crossovers and 4-way active stereo, driving amps directly from a multiway DAC. AMT tweeters are driven from a 45 Yamamoto SET (hopefully not considered "junk" here 😊, combo sounds great to me), mids by KT88, midbass and subs by class D. My system sounds better now than it did before with branded speakers with passive xo, but I do wonder if I'm missing something driving amps from a DAC...I did love my Lamm LL2 preamp but I decided to optimize for digital sound reproduction with multiway so a stereo preamp didn't fit anymore. In the context of not needing more than a digital source, the DAC producing enough gain such that using a digital volume control works well, and gain matching among amps being already solved, what would the advantage of using an interface between DAC and amps? Thank you in advance! |
IT coupling dates back to the 1920’s Atwater Kent and radios of that vintage. Like field coil loudspeakers, it is the oldest form of coupling of all. But transformers have always been labor-intensive and expensive (going right to the beginning of electronic amplification), so when coupling caps became practical in the late Twenties, ITs mostly went away, although Western Electric and high-end radio builders used them as late as the end of the Thirties. What pretty much ended them in all applications was the universal use of global loop feedback, with the landmark Williamson of 1948. You can wrap feedback around one set of coupling caps and an output transformer, but two transformers are out of the question. So IT coupling was moribund until zero-feedback amps saw a comeback in the early Nineties. In the mid-Twenties, the only signal source was AM radio. Electrical phono pickups were just coming on the market, and movie sound was brand-new and experimental. By the mid-Thirties, movie sound was universal, with a bandwidth topping out at 8 kHz. Electrical phonographs could reach 8 kHz, but users often used "scratch" filters to soften the sound of noisy shellac 78’s. AM radio reception could go higher, but people often used the narrowband setting to get rid of interfering whistles from adjacent stations. The only truly wideband source was the Armstrong "Yankee Network" of FM stations in the 42~50 MHz band, which was limited to a few stations in the Northeast. These were the only FM stations in the world, and could be received by the high-end radios of the day. It was only in the postwar years that wideband (30 Hz ~ 15 kHz) sources became widespread, with LP records in 1948, pre-recorded tapes in the mid-Fifties, FM broadcasting in the postwar 88~108 MHz band, and 70mm movies with magnetic soundtracks in surround sound. By then, all amplifiers were medium to high feedback designs, and used RC coupling throughout. Modern wideband transformers were in studio use from the early Fifties, and the triode designs of the early Nineties opened the market for more unusual products, such as interstage transformers. True, it’s a 1920’s technology, but they didn’t have modern bandwidths back then ... the recording technology was unforeseen and decades in the future. What we hear now, with our ultra-wide band, ultra-low distortion sources, is a brand new sound, running through new-tech devices. |
@antigrunge2 Yes, IT is known as an excellent way of coupling, but it is expensive for very good ITs, and also they take far more physical space than your typical coupling cap. So most vintage tube amps use RC coupling due to cost and size considerations. Bad ITs don't sound very good, they can oscillate, or have very poor frequency response. Done correctly with top shelf ITs and with a plan for the layout, then IT coupling walks all over RC coupling. Medium ground is LC coupling with a high quality anode choke and good capacitor. Also, there are circuits and tubes that are very difficult loads for ITs, so it is process of using the right method for the right circuit. It is not one size fits all.... But in the right spot, I prefer IT coupling.... |
@donsachs @lynn_olson It was great to meet you both at PAF and thanks to each of you for taking time to talk to me. That was the main reason I went there (and yes, Lynn, the lines at SeaTac were awful flying out). My given name is Jonathan and I know you were talking to a lot of different folks up there so you might not remember me. Don, you gave me information about a cable company and a semi-affordable DAC that wasn't as expensive as the top LampizatOr tiers. I posted most of my thoughts of the Blackbird (I suggested to David Whitt that you might come up with different names due to Raven Audio's avian naming for their tube amps) in the Spatial Audio Circle at Audiocircle but I was impressed with everything in both Spatial rooms and I spent significant time listening to both the Blackbird/Raven combo and Cloud's updated Valhalla amp with the X4 Ultras and both were impressive. I thought the Songer speakers were impressive as well although there are so many components in a room that, if you are unfamiliar with the speakers/amps/cables etc it is hard to attribute something you really like to one thing. Since this was my first audio show, I asked a guy in the Seattle HiFi/Modwright room how things work because it seems to me the speaker is like the lead singer in a band, getting most of the credit and the spotlight and not always deservedly. He told me that they try to get synergy and sell the equipment as a unit rather than just sell individual components and I thought that probably makes sense. I also saw certain kinds of music being played in most rooms, usually female vocals with sparse arrangements in order to show off the dynamics and quiet background. Some rooms had the music playing too loud to really make any opinions about anything other than "it's hurting my ears." One of the things I liked about the Spatial rooms is that they were willing to play any kind of music and not always modern/hi rez stuff and they played at what I would call reference volumes which Goldilocks would say was "just right." Anyhow, because of both of your willingness to share time and experience there and here, I really had a worthwhile time and learned a bunch. Thanks. |
Once you hear the difference an IT makes, you realize: "Aha! So that’s what RC coupling sounds like!" And then you start hearing that coloration everywhere in mainstream audio equipment, and can never forget what it sounds like. This is an experience no reviewer ever has, even if they have $250,000 systems. Because why would they? Everything has been handed to them on a platter. They don’t know what’s inside the pretty box... it could be elves doing magic tricks for all they know. What drives this exploration is curiosity. What will this sound like? Well, you don’t know until you try, and why take somebody else’s word for it? That’s no fun. Grounding in the physics of tube function helps, because you get a feel what the device "wants to do". Pilots have a saying, "the airplane wants to fly". If you’ve ever been at the controls of an airplane as it lifts off the runway, you feel it. The vibration stops, the wings lift, the ground falls away, and you keep moving forward, a creature of the air, not the ground. You are now in a different realm. Tubes are the same. They want to amplify. It’s what they’re made for. Our job is to get out of the way and let them do that, so we get into load-lines, the most linear region, what happens as the current dips downward, staying away from trouble spots, etc. I made a little post a few days ago on Facebook, quoting a meme from my Ukrainian friend, Misho Myronov. When asked what his amplifiers amplify, he replied: "Happiness! My amplifiers amplify happiness!" All of us who create tube amps get this. We do it because it makes us, and our friends who listen to them, happy. In the comments to Misho’s post, I added: "I was just talking to Karna, and said, an amplifier is like a dance partner for the speaker. If the partner is dull and disengaged, the speaker will be bored and not interested. If the dance partner is lively and fun, the speaker will light up and come alive." All of us who have solved a difficult technical problem, or just got a better amplifier, will hear the speaker really come alive and surprise us. That’s the happiness. |
Dear Don, |
@alexberger Fantastic! I love success stories! I came around to really good ITs on this project. LC coupling was next best, but once I got the custom wound Cinemag IT, designed specifically for the circuit it was no contest. Enjoy your amp. You have installed a top shelf IT and now you know why:) There is no going back to coupling caps..... |
Dear Lynn, |
When time served EE's who have leaned toward and made Valves a Circuitry, they have dedicated themselves to, there is a lot on offer under the hood, that should be very reasuring. As for reliability, my Amp's have been on the Oscilloscope for numerous Hours/Weeks prior to them being released to me. Never have the Amp's in all the time of ownership needed to be returned to the Designer/Builder EE due to any change in their performance from general usage. I do have a Balance Pot' that I have damaged during Transit coming home from a public attended event I exhibited at, they were incorporated to assist with correcting Psycho Acoustics. This will be checked out when the EE, has the Amp's for the circuit change, where a Balanced configuration is to be added. I am thinking these Pot's could now be removed?, as the Mono Pre-Amp's, which are my end game keepers, are each with a VC. |
There are only a few things one can do to keep someone from pirating a design. Point to point wiring and manufacture avoids circuit boards. When someone sends a PCB design for manufacturing, there have been cases when designs have been stolen. That said, there is little that can be done to eliminate someone tracing out the circuit. I used to restore vintage tube gear years ago and one major American manufacturer would actually use regulator and other chips whose labels had been erased so you couldn't tell what part they used. They guarded the schematics of course, so you simply could not repair their gear unless the problem was obvious. One just has to hope that owners are honest. I have never had a problem with the issue. I suppose should this design become wildly successful, someone may wish to steal it. The power supply is non-standard and would be a little more difficult to copy, but the possibility exists. So be it. |
@lynn_olson Another nice to read recollection of a History of Amp Design and the connections made over the years 'pardon the pun'. Some of the content once more Jogs my Memory. I recollect my 845 Power Amp designer/Builder, requesting that I keep him in the loop if any EE support is required during ownership. Again as a recollection, it was made known there was their own Hooks in the Circuit Design, that was beneficial to creating the perception the sound produced was transparent. I am now wondering if this was a similar description to your own, where creative thinking has been used to produce circuits with the potential to align the SET - P-P sonic where there is seemingly a mimic, rather than a contrast. I am due to spend time with the EE, in the not too distant future, My Balanced Pre-Amp will soon be complete. Which will then be passed onto the EE, who is to work on the 845 mono's, whare a Balanced Design is to be produced, with the Single Ended option retained. I have been a friend and loyal to this EE's Services for more than 30 Years, I think that has proved sufficient as a 'NDA' about his early works. As an aside, a few individuals have asked to see inside the Power Amp. One individual wanting to make a mark in the audio world, who I knew quite well, and have not at present not communicated with for quite some time, attempted on more that one occasion to be allowed to take the Power Amps Base off and see the Circuit. My not being supportive, at one time lead to my being threatened that I was on my own with any future EE concerns, if l did not accommodate the request. For other reasons relating to this individual, I am on my own 'Hey Ho'. I'm pleased I 'stuck to my guns' and honoured the Designer /Builders request , and I certainly am not on my own where EE support is needed. Lets hope owners of your New Amp design, do not find themselves meeting Pirates scheming to steal another's IP. |
Since I’m on a roll (and thankfully nearly out of the woods on Covid), let’s talk about PP coloration. It exists, it is real, and if you spend time with top-quality (not junk) SET amps, the absence of that coloration is wonderful and refreshing. Compared to Golden Age amps, everything is so clear, so open, so natural with wonderful tone colors. (Again, you never hear this with junk SET amps, which are murky and dark.) The magazine conventional wisdom would tell you that clarity and beauty is "euphonic coloration". That’s complete horse****. Euphonic colorations can’t add detail, resolution, more depth, and more in-the-room presence ... colorations can twiddle with subjective tonal balance, and usually adds mush, murk, or grain. They don’t remove it. Build your own amps and you find this out right away (I can see Don nodding his head). The magazines have had this wrong for forty years. Back to PP coloration. The mainstream "alternative" view is that it is inherent to to all PP, so just build SET and forget about it. Entirely aside from power considerations, SET has its own universe of colorations unique to SET, and they can be quite severe. What I call "junk" SETs sound like old antique equipment. So designing a really good SET isn’t quite as simple as it appears at first glance. At the top of the performance spectrum, it gets fiendishly difficult, with costs and complexity reaching into the stratosphere, and all charm and simplicity lost. I’m in the small minority that feels the colorations of PP are very real and not imaginary, but can be solved. The Golden Age amps of the Fifties and Sixties, and the modern copies from the big name vendors, all have remarkably similar circuits, boiling down to three types (Williamson, Mullard, and Dynaco, with a handful of variants). These were adopted because they were well understood, responded well to feedback, and were cost effective at the time. Even Marantz and McIntosh were part of the watts-per-dollar race, which only ended when the Crown DC300 and Phase Linear 700 came on the market, putting all tube amps in the shade. From then on, if you wanted Big Watts, you got a transistor amp. Still true today. But Golden Age is not the only way to build a tube amp. There were other, pre-war circuits, before the Williamson wiped out everything in 1948. The pre-war "floating paraphase" phase inverter ... not as perfectly balanced as later circuits, but more powerful. Transformer coupling, which passively inverts phase, but demands ultra-performance transformers, and also rules out global feedback. And other methods. The prewar era had a lot of interesting byways and interesting circuits, which all disappeared by the 1950’s. And they do sound different, and get away from the 1950’s monoculture which dominates tube audio. The tubes don’t care; they cheerfully work in any circuit, provided you pay attention to operating point, loading, and stability (part of any amp design). At any rate, when you stop using Golden Age circuits, the "PP sound" changes. It’s no longer a thick blanket that lays on the sound. It might be a brand-new coloration, or might go away. That’s where the fun starts. |
Matt Kamna, the designer of the Whammerdyne, is an old Tektronix guy I’ve known since the late Eighties. We were at the second meeting of the Oregon Triode Society, and were both so impressed by what we heard at the meeting we set aside a project on a transistor amp .... for the simple reason it is much easier to get good sound than with transistors. Tubes are simple to work with and sound great, right out of the box. Back in 1996, when I lived in Portland, Matt physically built the first Amity amp, although it was 100% my design from the ground up, and my first amplifier project. At the time, Matt went down the path of gigantic and extremely rare Western Electric power tubes in the transmitter class, I moved to Washington State, and then to Colorado. Matt approached me a few years back and wanted me to write the user manual for the Whammerdyne 2A3 amp. He had definitely moved in a new direction. Matt’s an old friend and I didn’t mind some spare change, so yes, I agreed. The Whammerdyne 2A3 has some interesting user setup settings, and I had fun coming up with various names for the internal features of the Whammerdyne. Yes, I know what’s inside, in order to write the fairly complex user manual. (NDA’s were signed, etc.) Internally, the Whammerdyne 2A3 couldn’t be more different than the Amity, Karna, Raven, and Blackbird (which are all closely related). Matt’s design is almost the anti-Blackbird, but what can I say, it works really well. I know from personal experience these things don’t design themselves. They look simple, but I can tell you, they are tricky to get right. It was delightful to hear the latest Whammerdyne at the 2023 PAF. It physically looks more or less like the original, but sounds much more refined and elegant. It’s clear they’ve been working on it, and good for them for doing it. And it works really well with the Songer Audio speaker, another Portland company. It’s interesting the SET folks are all-in on the single-ended concept, and have been since the early days of Sound Practices magazine. I certainly fell in love with direct-heated tubes, but felt from the beginning that the colorations of push-pull amps (compared to SETs) could be solved with a little creative thinking, and a return to the well of Western Electric research. I credit Vacuum Tube Valley and John Atwood for pointing me in the right direction. |
Lynn, I hope you bounce back soon from Covid. I got Covid in the remote state of South Dakota last year so go figure. Your meds will surely alleviate the symptoms. Pindac, I heard the Jubilees in a local dealer's room and they are truly sublime, really stunning, fit for a way big room. I visited with the owner of Whammerdyne Audio who had his 2A3 SET amp driving the stellar Songer speakers. As far as I can tell, the Whammerdyne designer has a different amp design philosophy than Don and Lynn, who favor a P-P design. Both Don and Lynn loved the sound of the Whammerdyne/Songer room at the Seattle show so that might say that there a lot of paths to get tube amps performing in an excellent fashion. I would have liked to hear those exemplary Songer speakers with Don and Lynn's 300b monos. Yes I would and I bet Don and Lynn would too. I had a couple of flea watt tube amps including an excellent 8wpc Dennis Had amp that just ran out of gas even with my easy-to-drive Spatial Audio speakers. Don and Lynn's 300b monos have ~27 wpc, which can drive a boatload of speakers. Their mono's drive both my Spatials and Cube Audio speakers with alacrity, no question, no limitations. And with dead silence between songs, more so than some of my excellent SS amps. |
I’ve been a little quiet since I got whacked by Covid on my return to Colorado. Got an intense sore throat on Tuesday, tested positive on Wednesday, and started Paxlovid that afternoon. Doing better today ... actually, mostly better, and my mind is finally clear again. The metallic taste Paxlovid is famous for hasn’t been too bad, and it is fast-acting. (I tick three of the boxes for "high risk", so Kaiser Permanente of Colorado prescribed it right away.) Strongly suspect the Denver or Seattle airports as the culprits. Total zoo in both places. If I go next year, I will ask for airline assistance getting to and from the gates. Two things that did work well were TSA Pre-check and Express Bag Check-In. Don continues to evolve the Blackbird. Full-size chassis, some excellent parts choices, and bringing elements of the much-loved Raven to the Blackbird. The people on the Spatial Audio pre-order list are going to like them ... a lot. |
I got a little side tracked with this thread, I'm back into the 300b theme . I did not share, that on Sunday 25-06, I was able to attend a demo' of a 'new to me' system, which has Klipsch Jubilees as the resident speaker. The resident system in use was quite special. Following the Lunch recess, a friends P-P 300b Power Amp' was put to use. The 300b is a late 90's model of which Tim De Paravicini has an input to the design. This Amp is now overhauled and a few circuit tweaks are carried out. The system owners reaction to this Amp' was immediate, the Cheshire Cat Grin lasted for many tracks. All attendees were thoroughly impressed by the way this Amp' interfaced in this system and it really shone out for its attractive traits. That is not the whole story, the systems pre-amp was swapped out for a Bread Board mounted, part completed pre-amp build. This addition of the New Pre-Amp had a substantial impact in conjunction with the 300b. My take is that the design of the 300b in this Thread, has another 25ish Years (50 Years Combined) of experiences of Two Amp Designers, put to use, to help create this latest design. I would get great pleasure from receiving a demo' of these mono's, to see where there are sonic traits that stand out as being more of a attraction and very much wanted to be kept. |
Robert, We are among the fortunate to have Don's gear and I certainly share your opinion of the the room. We both got to meet Don in person for the first time and he is a great guy, for sure. Same with Lynn Olson. Now with a month of run in with the new 300b monos in my system with my Cube Audio Jazzon speakers, every day of listening brings new joys to my ears. |
FWIW, I drove up from Portland and met three friends to attend the show. There were three or four rooms that stood out, although our short lists were not identical. However, all four of us picked the Spatial Audio/Don Sachs room as our favorite. End game for all of us. I’ll leave descriptive words to others, but it was simply wonderful. It was crowded in there, but I had no problem getting in twice and listening to a couple songs each time. Great to meet Don in person after owning his pre and amp for several years. |
I now have a VC, which comprises of two matched Stepped Att' VC's for the mono block Pre-Amp' Design . These are produced by a friend of mine specially for my Pre-Amp's Design only. The usual ones produced are for my friends Buffer Pre' Design, I was requiring ones that are with a different measurement at 50K. The Pre' Builder has expressed his satisfaction with them, and has heard them compared to a very similar Pre-Amp' design that has the other VC I referred to. |
Yes. That is what keeps any manufacturer in high end audio in business :)
@lynn_olson FWIW dept.: We've been using a direct-coupled output for our fully balanced tube preamps since their inception in 1989. To that end we've used a servo to sense and correct DC at the output. Here's the FWIW bit: a servo is (or should be) very reliable. We've not had a failure since their inception. |
I am all in, 'in this thread', it has catapulted me back in time, to when I was involved in discussion with a EE, who was helping me achieve something quite unique as a Valve Power Amp'. A very enjoyable period and wonderful to be reminisced. The Bruised Ego is certainly not pointed at any regular contributor to this thread. It is specifically for @me! me! me! carter, who felt the need to declare two designers as ringleaders and many/all Thread contributors as accomplices to a 'Sting'. What a Bungalow this individual has shown themselves to be.
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Our egos are not too bruised. We have a pretty thick skin. No matter what you do, there will be a certain number of people who are unhappy. It cannot be helped. This thread has been a wonderful discussion of amp topologies, with all points of view respected and debated. Even a little philosophy and the nature of perception tossed in. As was stated early on, these are prototypes that were shown in Seattle. Most people seemed to have a favorable impression, and there are already tweaks afoot before the final versions start to be manufactured later this year. We had great fun in Seattle meeting many other audiophools:) We tried to accommodate most people and play tracks and volume levels they wished to hear. Things got crazy on Saturday in our and many other rooms. It was quite the turnout. Again, we tried to accommodate everyone. Friday and Sunday were much calmer. If one person felt mistreated so be it. We can only do the best we can, I have enjoyed the project with Lynn for over a year now, and we are close to making them available for sale. Like any audio product, some folks will really like them, and some folks not so much. This is always the expectation. The Pacific Audio Fest was a perfect example of how many different ways there are to build a stereo at different price points and levels of performance. Some things are well worth the asking price, and others are not. Let the customer decide. |
Who is this @edisoncarter, whom feels they were overlooked when visiting a Room, that was on all accounts buzzing with excitable interest and inquiries. Most who arrive at such an atmospheric place, would humbly inquire about when music was to resume, maybe even ask, if I return a little later could I hear a track of choice. I don't know how the @edisoncarter made their approach, I was not their. The follow up communicating of their interpretation of their experience has been presented in my observation with a Forked Tongue, this is pretty much self evident by the content of the last comments made from @edisoncarter "You want my unbiased view on this thread? Never seen one so dedicated to shilling allowed to go on and on. Free advertising. Must be nice." If this is the case as a casual observer of this Thread and then becoming influenced enough to contribute through making posts, is suggesting I have been complicit in Shilling a Product presented by a few individuals I have never met, or never communicated with until this very Thread. Have the individuals behind the product got their correspondence absolutely honed to the point where they are able to compel others to do their bidding, either of the above are all BS, and not reality. You want my unbiased view, "well done to 'Cutting the Head of the Snake'. Fortunately it is only one's Pride hurt, @edisoncarter has engineered their 'What about me Moment'. It does look like the Reputation of those that put in the real Sweat, Blood and Tears remains intact, credit where it is due. Hopefully my 5 x referencing @edisoncarter in one Post has been a Band Aid for the Bruised Ego incurred. I'm feeling like this following experience, might be a description that is accused of being a Shill, for a Certain Brand of Stepped Attenuator, so I will tread carefully. A Certain Brand of Stepped Attenuator, referenced on the 25-06 @ 6.13 am, is a device I am quite familiar with. I have been demo'd it as a Upgrade VC in a few Pre-Amp's over the past 5 Years. Most recently a Pre-Amp' I get to sit in front of regularly had undergone exchanges of a few VC's over course of a Year, and the Pre Owner thought they had made a Good Choice with a DACT, which most who had heard it in use was in agreement. Not too long ago the itch was scratched and out with DACT an in with said VC. The difference the Part made was Night and Day, the new an impressive insight into the recordings was immediately perceived and as the session went on there was too many attractors detected and spoken about, to even consider the DACT might be worth a revisit. I am not poo pooing the DACT, I have heard them as a Mono Device used a Balance Control on a 300b Monoblock Power Amp and they have been superb, when used as a VC on this set up. I also own a Brand New unused Stereo DACT The said VC, has just shone out as belonging in this Particular Pre Amp's Circuit.
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Wow. I’m just seeing this thread, and I just want to take just a moment to thank everyone for spending time with us over the weekend, and for sharing these lovely comments. We loved doing the show. @lynn_olson @donsachs Meeting you and the immense praise you’ve offered for the driver and loudspeakers... it really is indescribable. I won’t even bother attempting it here. I’m so grateful to you both. And, your room with Team Spatial was absolutely astonishing. Incredibly clean sound, unbelievably deep and wide soundstage, razor sharp imaging... Between the two of us, it's hard to say which I felt was subjectively better. |
The takeaway from your observations (quoted below) is that no system is universal, and we all latch on to different elements of the sonic illusion. Well done! ... Thom
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I wish I had heard the Dutch & Dutch 8C’s. The exact opposite approach of our room, but 100% valid: internally tri-amped with DSP for the side-firing drivers to create a near-perfect cardioid radiation pattern. Digital-in is limited to 48/24 PCM (higher-rez content is accepted but internally downsampled), and the triple internal amps are Class D with 400W each. I was reading Amir’s ASR show report (third section) and the Dutch & Dutch exhibitor was measuring 15 Hz during setup. This might be anathema for some readers, but I like the massive engineering effort that must have gone into this bookshelf speaker. DSP to shape the polar response with side-firing drivers is not trivial, and from the reviews, they actually tamed the hotel rooms that were driving the rest of us nuts. Of course, with DSP tailored for each driver, the speaker would be flat as a pancake, not a bad thing. For analog fans, the prospect of converting every precious LP on-the-fly to plain old 48/24 PCM is appalling, and for high-end DAC fans, the standard-issue ESS or AKM converters hidden inside the Dutch & Dutch are probably not acceptable. So you pick the approach that you like. Surprisingly, Amir, of all people, liked both Spatial rooms. Did not expect that. The real invective on ASR was reserved for the absurd cables in the ballrooms ... to be honest, have to agree there. The Anticables we were using worked just fine, and were unobtrusive, as a cable should be. |
My personal award show notes from PAF, including the room with the amp in this thread: *Most intensely rich yet detailed tubey midrange: LTA prototype DAC, LTA Pre, LTA Ultralinear+ monoblocks, and Daedalus Argos V3 speakers *Most delicate and intricately revealing top end with too much mid-bass: VAC components and Von Schweikert Ultra 7 speakers *Second place for best top end and also clear midrange but garbled bass: Songer + Whammerdyne *Most gossamer presentation: Don Sachs' Raven/Blackbird + Spatial Audio Lab X series speakers *Largest sounding very small, yet full range speakers: Gershman *Most humongously oversized images and stage and most impressive driver tech: Aavik/Ansus and Borreson M6 *Most resonant enclosures: Black Ocean Audio *Most disappointing tonality: Joseph Audio Pearl Graphene speakers *Biggest surprise: Vanatoo's little office stereo sized powered speakers *Friendliest exhibitor reps: Tie between Furutech and ASC *Most advantaged by vibration control: Millercarbon *Most classic solid state sounding room: Infigo Audio *Most inoffensive yet not all that unique sounding room: Bella Sound |
The Raven is particularly well-suited to driving transistor amps because: 1) The transformers prohibit the transmission of DC pulses to RCA and XLR outputs, under all conditions, including total failure. 2) Unlike solid-state preamps, there are no DC servos to fail. There are no coupling caps on the output to store turn-on pulses, unlike cathode-follower designs. No muting relays are needed, or used, so the signal path is direct from transformer secondary to output. 3) All internal circuitry is fully balanced. The faint click when the VR tubes light up is only due to small residual imbalance (no more than 2%) in the 6SN7’s. Balanced operation alone reduces noise by 30 to 35 dB, then the VR tubes another 20 dB, and then 130 dB from the regulated power supply. 4) In addition to internal balanced operation, phase splitting at the input and output is entirely passive, not using discrete transistors, op-amp inverters, or split-load tube inverters. The custom transformers are precision balanced through 30 kHz, ensuring accurate phase balance for the power amplifier, whether it is solid-state or vacuum tube. 5) The input connections are floating, breaking any potential ground loops from the DAC or phono preamp. The transformers only respond to differences between signal pairs, with 80 dB or better common-mode noise rejection. The transformers also reject radio-frequency interference (RFI), passing only audio-band signals. |
Lynn makes note of hearing Purifi Class D amps at the show in a favorable way. I did hear Atma-Sphere's new GaN mono amps driving the the Tekton Moabs and I thought they sounded excellent. I could easily see a synergy between the Raven and Ralph's mono amps and I personally would require a tube preamp with any amp I might choose to use. That Ralph has made such a move to Class D technology after decades of being a tube designer/manufacturer ought to make the audio community sit up and take notice. What I heard of his $5500 amps was very impressive. Of course, let your ears be the judge. I am luxuriating with Don's DS2 preamp and his new 300b monos driving my now run-in Cube Audio Jazzon speakers. I am enjoying the sound in my room to a degree that I have never experienced before. From morning to night...
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"However ... the way the Raven is configured now, it can only drive one output at a time, either XLR or RCA. Well, technically it can drive both at once ... no harm is done to the circuit or any parts ... but the load is then unbalanced, with more cable capacitance on one side than the other. So the amp with the balanced inputs will receive a signal that doesn’t quite match at high frequencies."
I wonder if this is an issue since the XLR’s are just driving the bass, however this happens with in the internal crossover in the speaker. I spoke with Don on the phone today, getting clarification from Legacy how this works with RCA and XLR together in bi-amp. |
Coming back to Earth, I heard the Purifi Class D amplifier at the show. Quite good, and free of the usual transistor Class AB metallic coloration. The Raven preamp would make an excellent match for the Purify, since it is very transparent, has plenty of drive current, and is also an ultra-quality ground and RFI isolator. It might seem like an odd pairing, but for somebody that needs cool-running Class D power, the combo would probably work really well. However ... the way the Raven is configured now, it can only drive one output at a time, either XLR or RCA. Well, technically it can drive both at once ... no harm is done to the circuit or any parts ... but the load is then unbalanced, with more cable capacitance on one side than the other. So the amp with the balanced inputs will receive a signal that doesn’t quite match at high frequencies. This is probably true of other preamps with XLR and RCA outputs ... unless the literature comes out and says it has independent and isolated output sections for each set of outputs, you should assume the RCA is simply connected to one side of the XLR output. If that is so, then the added capacitance of the RCA cabling, plus the input capacitance of the RCA power amp, will unbalance the XLR output. I should also mention when a transistor power amp is turned off, the input section of that amp is not isolated from the cabling, and the turned-off input transistors can create a nonlinear load for the preamp. Once it’s on again, feedback and power is restored, and the amp operates as specified. But when it’s off, best not to have another amp connected in parallel. This is an important difference between tube power amps and transistor power amps. The input grid of a turned-off tube amp just sits there with a few pF of capacitance from the tube socket. Nothing else happens. It would take hundreds of volts to arc-over the tube, or break something in the input section. By contrast, the base or gate of the bipolar or JFET transistor has a nonlinear input capacitance that remains when the power is off, and there is serious risk of damage if a 20 volt transient comes by ... this is a real hazard with conventional cap-coupled tube preamps and their associated turn-on thump. (The Raven is transformer-coupled and cannot pass DC transients, but there’s a small click when the VR tubes snap on, but small enough that even the most delicate Lowthers would not be harmed.) |
I am glad I followed this, am in search of a new line-stage and the Raven looks like a good prospect. I have simple needs with only one RCA and 1 XLR input and same with outputs. I will pair it with my VAC Renaissance 70/70Signature amp and XLR into my Legacy Audio Focus XD’s. Saw the Raven design on a You tube show Video. |
I heard, and liked very much the Songer fieldcoil speakers I heard at Capital Audiofest. I believe the dipole driver speaker and the more conventional box speaker were the same price, even though it appears that you get much more with the dipole version (two-way instead of a single driver). Both sounded quite good to me. It would be interesting to hear them more or less contemporaneously with my other show favorite--Charney Audio full range systems (higher efficiency than the Songers so even more low-powered SET friendly). |