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New here. I've had a Carver system for years, but I'm going to need some help from the seasoned vets to keep it going! Sonic Holography HR-752 (amplification bypassed) TFM-25 MFP amplifier TDR 2400 Cassette deck TLM-3600 10 disc CD player Polk Audio RTA 11t tower speakers

Thanks again for the warm welcome, Everyone. Here are more details and pictures. The TLM-3600 is out of rotation due to malfunction. Sonic Holography Receiver HR-752 MFP Amplifier TFM-25 TDR-2400 Dual Cassette Deck TLM-3600 10 Disc CD Player Tascam CD-RW900 Mk II Yamaha YP-701 TT (Ortofon 15XE MK II) Polk Audio RTA 11t Tower Speakers

Customers keep asking and we hear you. The concept is a C9 type stand alone component with black steel chassis and machined aluminum faceplate styled like the V12- RAM 285, with radiused corners and round selector buttons. So far popular request have been to include selector switches to add or defeat an onboard Gundry filter and tube buffer to the SH unit. It would have 3 options that could be used individually or all at once. What are your thoughts? Do you want to see tubes poking out the black top with some copper cages? Also a pair of vu meters was suggest as an option. They would serve no real purpose other than cosmetics. Thoughts. The target price is $499.

Welcome! You can get schematics and service data at the top of any page by clicking on the 'Manuals and Specsheets' tab. As to recording, I've done a fair amount of location recording over the years (almost all acoustical) and the closest I've come to reproducing the Sonic Holography effect has been with the Neumann KU 100 Dummy Head. If you aren't familiar with the KU 100, it essentially produces a binaural recording taking into account the natural spacing of our ears and the accompanying time delay. And while the effect is good with quality speakers, it's great with headphones where room reflection artifacts aren't present. I think the KU 100 is somewhere around $10,000 right now, so kind of tough to justify to simply play around with it The genius of what Bob Carver figured out with SH was how to deal with the left/right delay and room artifacts in a normal room with normal speakers. The only real requirement is to make sure the listening position is at a nodal point so the cancellation effect is at maximum. I know many have recorded Sonic Holography encoded content and got good results. I'm not sure how one might use DSP to do similar, but I suppose a contemporary engineer who's familiar with that tech may have some ideas. And there are some good threads here on restoring/upgrading the C9 and some members with some real expertise with that unit. Try a search and you should find plenty of info.

his is a page from the booklet in the new Dolby ATMOS mix of Larks' Tongues in Aspic, a 1973 album by King Crimson. I haven't listened to it yet, but the description at the bottom sounds like it was mixed with sonic holography in mind, doesn't it? I'll listen tomorrow and let you know how it sounds. I can't wait!

More coming in the next few days.

First being a consumer of audio products myself before being a dealer and later a partner with Bob, I've seen it all. I had no idea how deep seated the snakes were in audio. Honestly, you couldn't make it up. This is not a rant. It's just advice to consider when spending your money and seeking the best for you. Most often, people of means to buy these limited production products, did not gain their wealth by spending foolishly and value is still appreciated. Having owned an aerospace manufacturing company for decades and accustomed to one of the most regulated industries on earth, audio is truly a wild west of conflicting information and deception for a consumer to attempt to navigate in order to spend their money wisely. IMHO this is really sad and consumers deserve better. It's destructive to the niche market for these products for both companies and consumers, IMHO. This post is not meant to discourage people from entering the hobby, but more as a guild to hopefully save consumers the frustration and expense that comes with being educated by industry snakes and lab rats. If a company won't let you audition their audio product without restocking fees, I suggest you walk away. Don't fall into the BS of listening for chocolate in a wire or the premise that a designer chasing specs like SINAD provides a higher quality listening experience. There is no free lunch in audio design. Some of the best measuring products come and go like the wind. More often than not, companies get great reviews in the pay to play world of food flavor adjectives, hear by number and sci-fi physics, only to fail in the actual market when compared directly to others making music. You have likely noticed the brand of the month in audio publications. Every month there is a new brand that is a game changer with either an improved number or richer chocolate, to prevent the consumer from finding contentment and to keep buying more, chasing an illusion of improved audio based in words and charts of very limited value to the customer in making their decision. What are the snakes? Snakes are products with no basis in science. The list is long. Companies actually invent products and create a market for problems that don't actually exist. This is really sad. Physicist and real engineers, like those from regulated industries in which snake oil is called aerospace fraud, with lives a stake, are laughing at the snakes in the industry, I can assure you. This is damaging to a great industry made up of mostly passionate people busting their butts to deliver a more pleasing experience and overall value for the customers they are loyal to. Snakes do not care about the customer, they want the customers money and do as little as possible to provide actual value to the customer. If the company is telling you what you will hear, and not offering a trial offer without needing a restocking fee from you. Think about it before spending your hard earned cash. Talk is cheap. Make them earn your money without risk to you. Sonic results talk. Tell the BS to walk. What are lab rats? Lab rats are at the other end of the spectrum. These are those claiming to have truth and standing in judgment based on simplistic numbers as a representation of customer value. The lab rats steer customers based on absurd claims and ranking of products, claiming that a number like SINAD further below audibility equals a better value for the customer. Numbers don't lie right? Recommending or discouraging customer purchases with this entirely erroneous perspective, is possibly more damaging to the hobby than the snakes. The value to the consumer is less than worthless. So what can a consumer do to get beyond the extremist at both ends of this spectrum disorder? Hear for yourself. Don't believe any salesman selling science fiction physics or a guy playing a BS game of SINAD of 120 will sound better than 100, and taking a poll based on followers who read his numbers.. Don't follow, lead. If the SINAD game was audio reality, they would show up at audio shows and put everyone else to shame. Here again, if a lab rat is trying to tell you what you will hear based on a numbers game, don't believe them until you hear for yourself. They are no more credible than the snakes, just a different angle on their game of leveraging misunderstanding. In no way am I saying believe me, if fact I'm saying don't believe me. What I am saying, is hear audio for yourself. Audio and hearing are inseparable. Fundamentally, you can not read about it with enough relevance to make a good decision. If you can't hear a product without a restocking fee, the company already knows they have trouble competing in the cold hard realty of the customers system in their home driving a wide variety of loudspeakers. We call it The Carver Amplifier Challenge. Step right up snakes and lab rats. We have a trap set for both of you that offers the customer 100% satisfaction by helping consumers sort through this maze of misinformation. Regardless of the brand they choose to purchase, a happy customer will result from the value offered by one outstanding designer or another. The customer and industry will be better off. Honestly, lets save the consumers the endless confusion and let them hear audio products for themselves at home, without taking money from them if they choose another brand. $799 or $24,999, don't charge them 10-15% to experience your product at home making music compared to ours. This industry has been in contraction for more than 30 years. Putting the customer first, may slow the contraction of the hobby from within caused by both the extremist snakes and lab rat deception. Make companies waive their restocking fee in writing so you can hear the truth for yourself without losing money. I've been working with the owner (Bob Carver himself) just over 2 years now. We do not play games with the customers money. A good competition driving loudspeakers in the customers home is fair enough. This educates the customers by experience, being of far more value than the confusion being sold by both the snakes and the lab rats. Jim Clark Director of Operations Bob Carver LLC.. CEO BC Audio LLC.. 4563 Hydraulic Rd Rockford, IL, 61109 jim@bobcarvercorp.com

Her observations with output transformers and measurements vs sound, is similar to Bob's teachings. This relates to the 275 design running the smaller output transformers at higher voltage potential. They don't measure as well into a test bench resistor, but they sure make beautiful music with speakers. The anomaly she speaks of in bench testing with the smaller, worse testing, better sounding transformer, does not show up in loudspeaker testing per application. Bob views the output transformers as the interface between the tubes and speakers, when determining what sounds best as the 1st priority of the design. These are topics related to how the lightweight 19lb 275 sounds so good in spite of criticism from some who are not amplifier designers. Great designers always prioritize audio sonic performance above all else. Designing to measure well is relatively easy. Going down rabbit holes chasing analyzer numbers and assembling a ranking of audio performance based on SINAD, as if offering a better audio experience or sonic value for the customer, is either ignorance or deception by one measurement reviewer that comes to mind. "Arrogance is a sign of ignorance", so there you go.. "Designing an amplifier to sound the best and designing to measure the best, are not necessarily the same goal." Bob Carver. Thank you to EveAnna Manely for sharing the experience and maintaining focus on what sounds best, as the 1st priority for her company.

Welcome, @SBrekken, so glad you found us. @4krow is the resident expert on C-9 sonic holography generators, and DIY questions. And, if you are not a DIY'er, I do believe that Nelion Audio also does C-9's for full refresh. Check out: https://nelionaudio.com/index.php?/services.html/carver/carverpreamps/carver-c-9-restore-r6/

Hi everyone, Here is a link to a new processor that seems very similar to sonic holography. In fact, it seems to me that this is using almost the same verbiage Bob used when describing SH. How is this not infringing on Bob's tech? https://www.audiosciencereview.com/forum/index.php?threads/bacch4mac-short-review-first-impressions.39494/

Here are some reasons why we sell our products with a "Carver Amplifier Challenge 30 day in-system, in-home guarantee, without restocking fees." 1) Happy customers, every time - Our goal is 100% happy customers. There is no reason to have unhappy customers. When running Jim Clark Stereo we started this policy. We want the customer to enjoy their experience for the good of our company and the industry as a whole. If the customer has or can find a more enjoyable product than the Bob Carver in their home, they should buy it. Either way, the customer wins and their money is well spent. Of course we know the odds of someone returning a Bob Carver after living with it for 30 days, are extremely low. The product and the enjoyment becomes personal and people will not give them up. 2) Marketing - Bob Carver LLC/BC Audio LLC today is a small operation made up of only 4 people. Bob and Peggy, Jim and Lerma. We are a start-up just barely 2 years old. Letting the customers enjoy our product, directly compared to others is very effective and strongly in our favor. Our new RAM 285 is undefeated in customers system. Restocking fees are not needed because we don't have returns. If returns were common, we would have to charge a restocking fee like most others. 3) The legacy - There have been several attempts (at least 4) at building Bob Carver tube amps by others over the last decade or so. The last casualty was Glass Audio leaving the legacy for dead after closing late in 2021, leaving orders unfilled and customers unsupported, followed by press critical of the 275 that had been produced at 3 locations by that time. Bob Carver and my venture together is largely in defense of Bob's legacy. None of us are getting any younger and I convinced Bob to "take the gloves off" and leverage his ability to build a special legacy line, not considering weight or parts cost savings as he tends to do in the interest of affordability. We didn't waste money on the RAM 285 but in the areas that make it sound the best, we didn't spare expense. 4) Honesty - The Carver Amp Challenge is the most honest way to sell audio products we know of. We don't have expensive shiny ads running in the pay to play realm. We don't give away products in exchange for good reviews. We don't modify our most musical designs to reduce measured numbers further below audibility at the expense of other important sonic qualities. We don't play silly games as though another decimal point further below audibility results in a better customer experience (it does not). We do not sell products with no basis in science, promising varieties of chocolate flavors that defy the laws of physics. Bob is a physicist and I can tell you there is no magic in audio, just good science. You can hear good science, we guarantee it with every purchase. Jim Clark Director of Operations Bob Carver LLC. CEO BC Audio LLC. jim@bobcarvercorp.com 815 985 3557

Sting, Brand New Day, the whole amn dalbum. Track eight, Tomorrow We'll See, checks a lot of boxes for me; great bass line, great with sonic holography, and the echo/reverb on this track makes me think of Joe Bonamassa, Dust Bowl.

Reading about Bob’s initial introduction of his Sonic Holography system is what cemented his name in my mind. Add to that the Carver Amp Challenges and I was further intrigued. One day, a friend replaced his unimpressive receiver with a pair of PL components. I was quite impressed! Eventually, I finally bought my c-1 and m1.0t. The hook was set. Oh, and I stumbled upon this article this morning. Nelson Pass goes a long way into explaining feedback and it’s effects on the signal, measurable distortions and sound quality. Pretty interesting read over coffee…. https://www.passlabs.com/technical_article/audio-distortion-and-feedback/

@Ar9Jim A simple, quick-to-market sonic holography component would have my vote. One function: updated sonic holography. In this case, less is more. None of us are getting any younger, and it seems to me having something to market quickly would make a lot of sense all around. I echo what @jvandyke_texassaid about the circuit itself: it shoulld to be different, or upgraded. Otherwise, it would essentially be a new C-9. And if it includes the Gundry circuit, it would definitely need to be switchable. It's been my experience when switching my Gundry circuit in and out that Gundry can negatively affect the sound of some recordings in terms of their holographic dispersion. Thank you for this excellent news and informative update.

https://www.stereophile.com/content/parasound-halo-jc-2-line-preamplifier-measurements Above are the measurements of the Parasound JC2 (John Curl) by John Atkinson at Stereophile magazine. John has been testing audio gear for 40-50 years and ranks the APx555 measurements of the JC2 as excellent. Below is the same Parasound JC2 review by ASR. The product does not measure state of the art and can not be recommended. The same type of reviews can be found regarding Carver, Curl, Pass, King and other pioneers. https://www.audiosciencereview.com/forum/index.php?threads/parasound-jc2-preamplifier-review.14779/ Both reviews are using the AP555 for their opposite conclusions. ASR does a good service on calling BS on snake oil or salesman quantifying specs before my time at Bob Carver. I applaud ASR in many respects. Like Bob says "there are companies selling products today with no basis in science." ASRs work is good in this regard. The only issue I have is the premise that designers of audio equipment should priorities their attention on improving specs further beyond audibility, that often come with sacrifices in an audible aspect of the design. The premise that prioritizing measurements in a design, will provide the most musical sonic value for the customer is just wrong IMHO.. It's an easy premise to do away with, when people actually hear audio by the great designers, instead of reading about it. You can buy great testing products highly recommended as state of the art measurements by ASR for not a lot of money. If you want state of the art sound quality, that is a different goal and it cost much more to build. My concern is for customer value and the state of the industry. Those selling "products with no basis in science" as Bob says, on one side, and on the other side, measurement sites inferring that better numbers equate to better sound quality, without end, as if the designers first priority should be to qualify as 'state of the art' on a chart, over ultimate sound quality goals. The best designers are smarter than to go off on tangents, chasing numbers beyond their sonic priorities. Who is serving the customers best interest here? The companies selling products with no basis in science, or those designing products to test 'state of the art' as a sales tool priority above the real goal of ultimate sound quality? We certainly have no issues with measurements. They are indispensable objective tools we use every day in quality control. Each RAM 285 has an inspection report included in the box. Some asked if I have an issue with ASR. Not at all, for the most part they are good at calling BS on snake oil, and that is healthy for the hobby, IMHO.. The only issue I have is the premise that the designers who design for best measurements, are superior to the world famous, world class, American designers who prioritize audio reproduction in their definition of state of the art. In the 2 reviews of the same product linked above, I'll put my bet on John Atkinson.

Hi Chris, Excellent post. Thanks! I could not agree more about the use of non-inductive resistors as a useful tool for objective standard measurements. We perform resistive load QA test of every amp that goes out the door at Bob Carver and a serialized report is included with the unit for the customer. They are great tools of the designer and quality control, but not ultimate design goals as some sites would imply in their ranking of state of the art. Here's something from earlier on FB.. Your thoughts are appreciated. I'll ask Bob about the op amp choice. There's an interesting disconnect from reality in audio today. The science of audio designers is reproducing the best sound in audio possible, after higher education and decades of study and experimentation in most cases. Men like Carver, Curl, Pass, Hafler, King, Rowland and other real scientist, decide what parameters are most important to the sonic objectives they are working to achieve. This is the real audio science. Analyzers and test equipment are the objective tools of the designer. These same often highly educated men have focused intently for decades to design the most musical products. These men are world famous for their work, for good reason. Several sites exist today for the purpose of measuring audio products. Some even use the word 'science' in their titles, while others recognize the limitations of their measurements to describe sound quality and admittedly refrain from the science title. There is a disconnect between real audio science, that has provided wonderful music for generations, by truly advancing the state of the art in audio (and becoming world famous for doing so), even when compared to other designers found world wide. Compare this to the science of measuring audio equipment with higher resolution and better numbers as the goal of the science on some sites. The scientist listed above have long been using analyzers as tools of their trade. I've read discouraging reviews for products designed by all of these men, largely due to the fact that they know enough to not go down rabbit holes chasing measurements over their priority of improving sound quality for their customers. The best audio designers on earth use analyzers as objective tools but not as their primary design goals. To imply that the best audio designers on earth (Americans seem to be the target, all of them) are not state of the art, based on a lowest measurement like SINAD is absurd. Analyzers are great slaves but I wouldn't expect the best designers on earth to make them their master. The real audio science of sound quality will take priority with these world class designers, over pursuing the best measurement rabbit holes, that beyond a point, offer no sonic value to the customer. Customer value is why we have a trial offer. The customer always wins.

It's a subjective question. You may be happy with solid state Carver gear because it has a tube amp like transfer function by design. Being happy with it, you have no reason to buy a tube amp. Has Bob improved sonic performance in the last 25 or 30 years? Of course he has, but the solid state will still measure better than a tube amp, so objectively there is no reason to buy a tube amp. You have to compare Bobs tube amps for yourself to determine the sonic value to you. That's why we have the Carver Amp Challenge. We don't expect anyone to take our word for it. We don't deal in snake oil at one extreme in the hobby or chasing the best numbers at the expense of sound quality priorities, to satisfy the best measurements sounds best believers. If best measurements are the goal, solid state is the way to go. People have to experience audio. Then the choice is clear. It just happens to land in our favor 98% of the time. I'll ask Bob what he thinks, but this reflects our mission statement. Great question.

Alternative to tubes sticking out the top with a cage, would be to put a window on the faceplate, a la Sunfire VTCC. My thinking is that this unit has to be "sexy" to reignite the fervor that the original C-9 had - it was the highest volume, and highest profit Carver Corp product ever sold. I don't think that it will get off the ground at all, if it is just a reincarnation of the original. If identical to the original, it will compete with $100 used C-9's on ebay..., Not a good strategy. People who try a tube buffer rave about them..., And, Bob Carver Corp already announced a "Tube-based" Sonic holography device..., so having a tube buffer is somewhat of an easy-to-implement (using knock-off Music Fidelity units from Asia) so pundits won't poo-poo the unit, when launched. Meters are sexy, and while add no sonic value, are extremely inexpensive to implement a la the "carpenter builds an amp" thread last week. No one can deny the "love them factor" that meters have on the 500t 😉 I just think that compared to all the black-box-style enclosure components in people's rigs, these days (endpoints, DACs, etc.) Having meters on the face of this unit are like a sunroof in a car. They become a "gotta' have it" item, when given the choice - and therefore will likely drive sales volume. I have not found a "combo unit" that implements these three things..., (SH, Gundry, Tube Buffer) in an elegant way - and this unit could replace a lot of clutter in a lot of people's systems. And, of course, this has to get to market FAST..., can't be a 2+ year thing like the 285 or the V12... Make it simple, make it sexy, and ship it fast... 😉

Thanks Jim....complete update posted to the Carver Preamplifer and Sonic Holography page today. Keep the updates coming!

track 1 Introduction track 2 Loudspeaker phasing track 3 Absolute phase track 4 Frequency response 1KHz, 15KHz, 10KHz, 5KHz, 100Hz, 50Hz track 5 Frequency response 1KHz, 24Hz, 16Hz track 6 Log sweep track 7 Electrical Balance track 8 Autocorrelator adjustment track 9 Peak unlimiter adjustment track 10 Time delay and echo density track 11 Introduction to tracks 12, 13 and 14 track 12 Noise bursts track 13 Music track 14 Holographically encoded music track 15 Stereo pink noise

It would be hard not to have it as a sonic improvement, especially after considering the 285. Bob Carver has always been known for improving sound. I believe that Our Bobfather would lead us to the promised land once again. As 4krow has said the Carver promise will have your ears be the judge.

Nice to hear! Sonic Holography is such a groundbreaking and legacy technology of Bob Carver that it seems like it should be in the product line (and maybe built-in to the RPM V12?) And while on the topic of some of Bob Carver's amazing IP, I think the Peak Unlimiter is another tech that would be worthwhile to consider including. Even though most recordings today are direct digital, a lot of it is still pretty aggressively compressed for broadcast or simply in anticipation of miserable playback environments. Plus, true audiophiles (who are likely purchasers of the new Carver products) are playing lots of legacy media which would benefit from this tech. I'm restoring a C-4000 right now and I'm more and more impressed with the PU in this unit. It's subtle but I like the effect. I haven't heard the Gundry filter in operation so can't really speak to it. But I have no problems at all with the original SH frequency response. Personally, I'm a solid-state fan and don't care about tubes or meters although I know many people like them for various reasons. But I can see the marketing benefit to have all current products visually coordinated.

It has been a while is there any forthcoming news about the new Sonic Hologram Generator?

Hi Everyone, New guy here! I probably got a bit of info here 2 years ago when I wanted to repair my C1. Instead of just repairing I found out about the BillD mod and went ahead got it and I love it! However... I've always lusted after a C4000 and my luck came in yesterday! I now have a version 2 unit. After cleaning the pots she mostly works. I can hear the AutoCorr work as does the LF cal. Not sure about the peak unlimiter. Barely flashes at max even with loud passages. Delay and rear amps work fine. I'll have to set up my speakers a little different to properly try the Sonic Holography. But this all lead me to joining this site! Now that I know what the BillD did for my C1 I'm looking for similar upgrade for the C4000 MkII Many thanks for letting me join! Tekerman

The RAM 285 is a great testing amp for comparison with tube amps. It meets it's specs and sounds wonderful. The folks at ASR are playing a numbers belief game that what measures best, should technically sound the best. This incentivizes a numbers race well past audibility, over sound quality and a host of other priorities considered in creating a musically enjoyable design with real customer value for it's intended application. Naturally, an ASR review would not recommend a RAM 285 because solid state devices can measure far better than vacuum tubes by orders of magnitude. Solid State is much lower cost to build and will measure better than vacuum tube amplifiers, unless greater complexity than is necessary for audio is added to the tube amp design, increasing the build cost even higher needlessly. Some will always purchase audio products considering the best measurements as the true measure of sonic value, and that's great. There's certainly nothing wrong with that viewpoint. A tube amp at 1Khz with .2 %THD+N vs a solid state at .00002% and the choice seems perfectly clear and made really easy for some. These measurements are really simple to comprehend and to judge products by. It's scientific. It's good. These consumers would never purchase a tube amp of any brand and they shouldn't without hearing them first. This is a solid state type customer, not a tube amp customer, by nature. At the opposite end of the spectrum from ASR, you have people describing the subjective qualities of listening to multi-thousand dollar power cords. What is the customer supposed to believe in this day and age, with the hobby so polarized into these 2 camps? This is why we have the Carver Amp Challenge. Our customers do not need to rely on subjective reviews or best measurement reviews at either of the extremes in the hobby. Hearing our products in their system compared to others, answers all their questions and sends many much more expensive solid state and tube designs back for refunds.