Ar9Jim

Carver Amp Challenge rules! Let the customer hear and feel what is the best value. You can't read about it. Eye's and ears don't work that way.😁 Hopeful more manufactures will feel the need to let the customers hear their designs with a trial period. We win.

No sarcasm noticed my friend. Just good conversation. Thank you! I don't doubt Stereophile or ASRs equipment. That's the interesting part. I'm not so sure John Atkinson is snake oil. I'm not ready to discredit either guy. I'm just saying audio involves ears and to suggest the customer should make their purchases based on a narrow range of measured parameters is also misleading. Not the measurements themselves.

Question: What types of patch cords are commonly used for amplifier testing? Are they high end audio cables? Answer from Jim: At Bob Carver's lab in Snohomish and in Rockford the most common test cables are made by Pomona. The stackable banana plugs are very handy for piggy backing loads and test instruments. They make several BNC adaptors as well. On most test benches you will find Pomona. High end audio cables are generally absent from test benches. These stackable bananas are very handy when measuring loudspeaker / amplifier interactions like Bob does in development. https://www.pomonaelectronics.com/products/patch-cords/banana-plug https://www.digikey.com/en/products/detail/pomona-electronics/B-36-02/737939?utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=PMax Shopping_Product_Medium ROAS Categories&utm_term=&utm_content=&utm_id=go_cmp-20223376311_adg-_ad-__dev-c_ext-_prd-737939_sig-CjwKCAiAmsurBhBvEiwA6e-WPLPgfpiCd0_9DncUvRJlZPRmJob0HopBWPGvtguafGdVycBROOIFBxoCWeQQAvD_BwE&gad_source=4&gclid=CjwKCAiAmsurBhBvEiwA6e-WPLPgfpiCd0_9DncUvRJlZPRmJob0HopBWPGvtguafGdVycBROOIFBxoCWeQQAvD_BwE

I'll ask later today, AJ..

Member 625 619 posts Posted 20 hours ago "It's almost like they were testing two different pieces of equipment lol" Exactly!!!! My droning about measurements has nothing to do with measurements. We use measurements every day.. Computer simulations used in RAM 285 manufacturing engineering are all math based. We embrace tech and objective measurements as the indispensable tools that they are. The conflict in the measurements and product recommendations are polar opposite between Stereophile and ASR while using the same model analyzer. In this case, one of these sites has an issue measuring audio equipment, regardless of the device resolution. What about the customer reading conflicting reviews while trying to spend their money as wisely as they can for long term entertainment, and trying to not be disappointed in the end? Without customers the hobby is dead. Where is the customer focus is this madness between products with no basis in science, and the premise that forever improving measurements should be the goal of audio designers, as if the science is that simple. Not even the same model of analyzer can agree on the same product while discounting John Curls work on one side. All I have to say is, you need to listen to audio. It's audio. Your ears play a small part and have to be present, you can't read about audio or measurements with any clarity at all. The Carver Amp Challenge is the only way we know to serve the customers best interest.. Read the 2 reviews linked earlier for the same product. From the customers point of view who are they supposed to believe? In the end the customer has to hear the product to be sure of their purchase.

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.

The new board design is 90% complete, the chassis design and prototype are 90% complete. With the holidays upon us and many vendors on holiday. We hope for February shipments. Thanks.

Hi Bob, After the SH.. Hopeful for this Summer.

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.

Thanks to those who participated. Jeffs, that is great. Most people with vintage Carver gear love it as do I. I would never try to twist your post to fit the pole. I was just asking a question that had nothing to do with how much vintage Carver gear you own. It's wonderful that you have experience and share with others hear on TCS.. The question was entirely hypothetical, about gear that doesn't even exist. I'm not sure how that could be offensive. It's not binding, it was just asking a simple question about peoples opinion of what they would like to see in the future. You came to the defense of the Topping so I assumed you leaned that way, so I asked again with a question to clarify. Is that twisting words, dude? Honestly? Now if I get defensive here on TCS, even so far as ASR is concerned than I'm a problem here and negative. Thank you for the social media example. I consider it a parting gift. So with that the last posted question has concluded.

Thanks for the opinions. It's a great day to turn off social media. I'm easy to find by phone or email. Enjoy the Music!

Good point. Not all Topping amps. So your vote is for new gear that is cheap that test great? I understand that most people are here for the vintage gear info and the economics of it. Very few at TCS have ever bought new products. I like most the people. There has never been a financial motivation here.

I'm leaving the social media game as I find it toxic as hell over all. It's exhausting and I'm done. If it takes social media games to grow, then we will stay small and continue to have fun doing what we do, not giving a damn about the extremist polarized views in social media. Leaving social media entirely and doing what we do best and ignoring the rest is my choice. It's making me become toxic. Our priority is not trying to make tube amps sound like solid state, chasing the priority of SINAD set by a software designer or anyone else with an oversized ego manipulating his sheep with 'truth.' Bob made solid state sound like tube amps. We have no desire to make tube amps sound like a Topping for god sake.. There's a full page of Toppings for sale on US Audio Mart right now.. Why is such a highly rated unit for sale in droves for nearly half retail? Very highly rated on ASR. How can the customer be parting ways with such a highly ranked product? They are taking losses on ASR's great performers? How could this be? https://www.usaudiomart.com/search.php?keywords=topping We can bend to the social media BS if that's what it takes to grow.. It's easier and profitable. What's your opinion? (A) We can build Bob Carver designs that sound fucking awesome that are expensive to design and manufacture and remain a small niche company with products too expensive for most. (B) Submit to the social media BS? What does submitting to the social media BS look like? It's real easy to submit to the BS.. We are contacted by several Chinees companies that email us every week, offering Topping like products that measure great for about $200. To hell with how they sound, companies are here to make money right, and none of this audio quality matters right? Give the market what it wants or die right? For the cost of developing the new products, we could have purchased many thousand units for stock, that measure just as well as topping, and put the Carver name on them for a wholesale cost of $100 - $200 each.. Talk about easy. Low cost gear that test great as the main priority is not hard. This is exactly the same trap the Carver Corp board fell into, wanting to rebrand products that test well instead of building original Carver designs. The designers priorities were replaced by corporate marketing priorities against Bobs will and what happened? Who cares how it sounds, it test great and we will make nice clean profit. Is that serving the customers best interest? If that's the goal, we are working way too hard and have spent way too much money on development. Just stupid I guess. Maybe that is what people want today? Make it cheap and tell me it sounds the best, because it measures better than tube amplifiers.. OK fine. That makes our job infinitely easier and we will make lots of money on low cost ready made solid state designs. We can buy these cheap. So that's the question. Buy readily available cheap imports that test great and have Bob Carver silk screened on them, or build the more expensive original Bob Carver designs focused on sound quality? I'm just curious what you think before I close this computer and stop droning. Your opinions are appreciated. Management please don't remove this question for fear of upsetting ASR. I won't do it again. Enjoy the music.

This makes a good question for Bob. Why did feeding a passive preamp with line level (2v) source, seem less dynamic than adding a preamp with gain outputting less than 2v output during use.. 2 volts would be plenty of voltage to clip the amplifier. Was it more voltage potential or headroom that made the improvement? Impedance match issue? I read about passives with buffers being better, so the impedance doesn't change with volume pot position.

Passive and preamp are often used together.. If it's passive, is it a preamp? That's the conflicted word, imho.. It's like passive active. Seems a bit conflicted. I've only used the Mod Squad with a 2 v DAC and CD player feeding the passive. Preamp with gain was better in that set-up.

After that the straightest path is a "passive preamp" It's a conflicted word but often the description. Steve McCormick ? IIRC . Made some really nice passives under Mod Squad brand. There is a purity about them but they are a bit lifeless. The construction of the Mod Squad I tried was excellent. That's a straight wire without gain.

I'll be the 1st to admit that the specs on the 275 were poorly quantified. The marketing at the time not getting this right was tragic, imho.. I had heard an opinion from someone I respect, that has been in the industry since digital audio began. This man is smart almost beyond belief. I can't tell you companies this man has designed for but you know them all. I heard a comment about one of the measurement sites being a fixer for Chinese audio companies. Lots of interesting reading on the topic to be found online. This was the 1st click on the list. I don't know if it's true but people can look deeper and decide for themselves. Measurement sites discrediting measurement sites. https://www.superbestaudiofriends.org/index.php?threads/audio-science-review-review.9827/

Thanks for the questions.

It seems like a simple question. In this video one of the measurement sites reveals the marketing games that are played in the "best measurement equals best audio performance" deception in the hobby. Now these 'noble' sites are becoming more common and have started discrediting each other. This video says "take them with a grain of salt." These sites will eventually discredit each other, while attempting to discredit others themselves for views.. "Designing an amplifier to measure the best and designing an amplifier to sound the best are not necessarily the same goal." Bob Carver

UPDATE.

Question: J. Clark - There is a big difference in bench test numbers between the RAM 285 and Crimson 275. The 285 weighs 56lbs and the 275 weighs 19lbs. Can you explain the different approaches and design goals please. A) Bob - Sure. With the 275 I spent many months listening and applying many decades of research and what I've learned about making an amp sound best. I wanted the Crimson 275 to sound great while being light, powerful and affordable. The roll-off you noticed is by design it starts at about 60Hz actually. This kept the weight and cost down, so more people could afford it. Frequency response needs to be flat, but power response does not. The spectral power distribution of music is not flat and there is not as much power requirement at either end of the spectrum. At the high end no tweeter in the world could take 75 watts at 20KHz. I designed the Crimson 275 to sound the best at the best value and let the bench test numbers land where they may. J. Clark - That makes sense. If we turn off the amp but leave a sub running that's crossover around 50Hz, most times it's not actually doing much. Bob - Exactly. The majority of full range speakers won't go that low and people use subwoofers. J. Clark - The specs were written like boilerplate solid state specs and caused a commotion as we have talked about before, but it's good to get it on the record. Bob - Yeah, I tried to retire and just walked away for a couple years. I didn't pay much attention and you have had a tough job to deal with because of it. J. Clark - No doubt. I promise you sales or marketing will never write specs on my watch. What a mess. Bob - The RAM 285 is designed to a higher price point. At this price point and selling direct things get exciting. I've designed everything I have learned at the bench and decades of study into what sounds good into the RAM 285 without concern for weight or cost. The 285 in a legacy product. I really can't imagine how anyone could design a better sounding amplifier than the RAM 285, I really can't. J. Clark - I can't either Bob. At any price. I'll bet we never lose Carver Amp Challenge. The 285 is really special.

A new week ahead. Ask your question before 11-24 for the 11-26 reply from Bob. Enjoy!

A) Bob - The Crimson 275 is designed to be light, powerful and affordable. Work(W)=1/2Capacitance(C)Voltage(V)2. Remember the voltage is squared. To increase power 9x requires a voltage increase of 1/3. With this high voltage design, I chose my EM0946 output transformer designed more than a decade ago. They provide the amplifier / speaker interface qualities I prefer at the best value. The 275 makes a lot of power. Does any other tube amp make that much power at 19lbs.? Q) On the bench in Rockford the 275s make 75-80 watts at 1KHz into 8 ohm resistors. Frequency response test at full power showed some roll-off and some anomalies below about 50 Hz.. We changed the power spec to 75w @1KHz like tube amps are typically specified as you instructed when we started the new company. The full power to 20Hz spec was corrected. A) Very good. Designers should write specs, never marketing or salesmen. When running loudspeakers and measuring, those anomalies don't show up. The frequency response is flat. The power response curve closely matches the spectral power distribution of music. It's one of my best designs.

Bob, Q) Why do tube amps have much smaller power supply caps than typical solid state? A) Bob - Well, they are smaller in capacitance but not energy storage. Its about energy storage. Remember .Work(W)=1/2Capacitance(C)Voltage(V)2. Tube amplifiers have very high voltage and the high voltage capacitors store a lot of energy.