Inside Bob Carver's Lab with Director of Operations, Jim Clark

[4krow 5,118]

I really thought that I had something cool when I found a PS Audio preamp from the beginning of time. I forget the model, and even tried to work past the kind of circuit board that Jim posted about. To sum up it ended up in the trash, and I put a different circuit in instead. It turned out 'ok' but nothing that I would brag about. Even worse, it had survived a fire, but probably not as well as it looked. The rubber feet were melted. That ought to tell a story right there.

 After that I mostly stick to kits/designs that I know to trust.

Edited October 28, 2023 by 4krow
clarification

[Ar9Jim 6,164]

Getting the ducks in a row.

 

Edited October 29, 2023 by Ar9Jim

[jjptkd 1,253]

On 10/26/2023 at 3:06 AM, Ar9Jim said:

Today is a great day. RAM 285s are arriving and looking great. Initial test are great.

 

So who is building these amps?

[Ar9Jim 6,164]

Good question.

 

In the case of RAM 285. Designed, tested and serviced in USA. Assembled in China from globally sourced parts.

 

The best source we could find for automated assembly that could meet the required ISO certifications, with the best delivery and price is a company called ABP.. Our criteria is quality, delivery and price, in that order. ABP has great technology and huge capacity in both SMT and Thru-hole assembly.

 

  We have north American sources coming on-line as well, to prevent disruptions from politics, natural disasters, etc.. Interestingly, the north American sources also use boards from China or Taiwan. There are some items that can't be found anywhere else.  ABP is doing great. We are very happy with them as a supplier. The quality is top notch.

 

Originally, we planned to do the final integration of the boards to the chassis here in Rockford, but ABP had a lower cost to do that operation than we quoted doing it in Rockford, so they won the job.  The assembly is excellent and the finish is flawless. 

 

The component parts are sourced from Mouser regardless of assembly location and we receive Certificates of Conformance traceable to the manufactures to assure counterfeit parts do not enter our supply chain. Mouser provides the required documentation for ISO/AS quality system compliance. 

 

Our 285 transformers are purchased in matched sets from Hammond in Canada.

Black Magic 25,275, 350s transformers are made by 2 sources in California. 

 

With fully digitized product designs and process engineering, we can respond quicky to world changes not being locked to one supplier like in times before the information age. 

 

From a process engineering view, we must have options and flexibility to prevent 'single point sources of failure' in the supply chain. Note during COVID, how state of the art companies were able to move their production as needed and minimize disruptions to their supply chain by moving 'data' between sources, where ever they were found. This minimized the impact on their customers. World Class.

 

The Black Magic 25s and 275s are assembled in California.

The Black Magic 350s are assembled in California

The Sonic Hologram Generator is being assembled in Rockford

The Phono Preamp is being assembled in Rockford

The RAM 285 is being assembled in Shenzhen

The RPM V12 is being assembled in Shenzhen

All from globally sourced parts.

 

Final quality control inspections, measurements and documentation of all products and warranty registration is in Rockford.

 

Even the Rockford plant has to provide the best quality, delivery and price and compete, by offering the greatest value added processes for our customers. Quality, delivery and price, in that order..

 

Here is a video about ABP.. Good people. Excellent quality. They make more than 30k boards per month. Our boards are custom multi-layer per specs.

 

 

 

 

 

 

Edited October 30, 2023 by Ar9Jim

[Ar9Jim 6,164]

Jim,

Why are ISO certifications and registrations of suppliers and vendors required by Bob Carver Company?

 

It's all about customer value, quality and preventing counterfeit or substandard components from entering our supply chain. I'll explain.

 

Today, component parts and processes are provided at a wide range of locations around the world. Transformers from Canada and USA, potentiometers from Japan, automated board assembly and integration in China, manufacturing engineering in Germany, final inspection and test in USA. This is a broad base to monitor for small companies that make niche products.

 

Gone are the days of having people living abroad just to monitor quality to assure the suppliers were not cutting corners and using counterfeit untraceable parts in your assemblies. Bob has been to Japan for these reasons, back before the information age. At that time, Japan offered excellent quality and value, but you still needed boots on the ground for quality control. 

 

Enter ISO. International Standards Organization.

At the former aerospace manufacturing company I founded in 1996, we witnessed a change to ISO or higher yet AS certifications being required to continue doing business in aerospace. All companies working in aircraft, military and space were required to have AS quality management systems in place with full traceability back to the source. It's accurate to say the traceability begins when the materials come from the ground.

 

Our company was audited by ISO/AS auditors every 6 mo. for 2-3 days at a time. They pull paperwork on random jobs and follow the traceability though your certified vendor list. You can only use vendors that also meet these requirements. If you have a "finding" during an audit, it could result in you losing certification and disabling your company. It's life and death in aerospace and more serious than a heart attack. This is how it's done, imho.. Bob Carver knows these requirements from interacting with his engineer and physicist friends at Boeing in WA.. Boeing has the same AS certified quality management system. It's uniform and world wide. It works.

 

ISO is very good. We know the quality management system in place at the vendors very well. While we don't need AS certification for amplifiers, ISO gives us the quality assurance required to keep the quality of Bob Carver amplifiers truly World Class..

 

 

 

 

 

 

Edited October 30, 2023 by Ar9Jim

[ChrisTFM35 598]

How is the phono preamp coming along?

[Ar9Jim 6,164]

35 minutes ago, ChrisTFM35 said:

How is the phono preamp coming along?

Good. Chassis and faceplate tooling is ready. Hoping to make good progress on the boards in November. 

[BobTFM35 1,662]

3 hours ago, Ar9Jim said:

Good. Chassis and faceplate tooling is ready. Hoping to make good progress on the boards in November. 

 

Is an artistic rendering available that you can share on the phono preamp?

[Ar9Jim 6,164]

1 hour ago, BobTFM35 said:

 

Is an artistic rendering available that you can share on the phono preamp?

Hi Bob,

Just prints at the moment. Haven't made 3D solid models yet.

[BobTFM35 1,662]

Looking forward for their introduction.

[Ar9Jim 6,164]

Topic:

THD+N in Bob Carver tube amp designs.

 

There are many conflicts between Bob Carvers design philosophy and the mainstream audio "beliefs". Some are of the belief that the lower the number the better the sound will be. Some believe that a lower number equates to an improvement in musical performance and the association of sound quality improving with ever lower numbers.

 

Many of you have been in this hobby for decades and have experienced many products. The product that had the best numbers is not likely what you are using today, am I right?

 

This may be interesting to the 'listen to the numbers' types.

 

This is from a recent conversation with Bob Carver about the numbers on the production RAM285, some will find it enlightening.

 

J.Clark - Bob I just emailed graphs from the 1st production RAM 285. Please call.

 

Bob - I see the voicing in the graphs (details deleted) , that is great. I'm glad to see they didn't try to improve it and screw it up.

 

J.Clark - Well our team is from aerospace and you never make changes to a design without authorization. It won't happen.

 

Bob -  THD+N of .2-.3% that's great too. If it were any better than that, I would know they tried to improve my design and likely messed it up.

 

J.Clark - That's very interesting Bob. It's all your design.

 

Bob - Jim, you have no idea how uncommon it is, to not have a manufacturer change my design, trying to improve it, meaning well, but messing it up.. These are really great results. They will sound wonderful.

 

J.Clark - They are all your designs Bob. We would never make a change to the design without your approval.

 

Bob - This is great. Lets roll..

 

I hope sharing these conversations helps you understand Bob physics based view of these topics. Bob doesn't follow, he leads.

Notice if the team would have improved the numbers, Bob would have known we tampered with his design, not happy we improved it, but upset that we improved it measurement wise, and messed it up. Big difference in viewpoints.

 

Powerful - Musical - Accurate. 

 

 

Edited October 31, 2023 by Ar9Jim

[3M_Audio 934]

40 minutes ago, Ar9Jim said:

Many of you have been in this hobby for decades and have experienced many products. The product that had the best numbers is not likely what you are using today, am I right?

 

 

It's nice to hear those insights and feedback from Bob.

In my experience - especially with quality amps - I find that after a certain point, further improvements in specs is not discernable - at least by me. I expect the THD, S/N ratio, etc. to be good in any quality amp. What seems to separate the exceptional from the good is the engineering that goes into providing real dynamic headroom. 

[Ar9Jim 6,164]

Topic- Power conditioners with Bob Carver power amplifiers.

 

J. Clark - Bob, you have always recommended plugging power cords directly to the power outlet with your designs, with no filtering or devices in between. Today, it's said that the grid is dirtier and now these devices are needed to clean up AC and reduce distortion in the AC waveform. Customers ask about the need for these products often.. Have things changed ?  What is the proper response?

 

Bob Carver - It's still the same. Plug directly to the wall or good power strip. 

 

J. Clark - You have said "those devices can not help, but may hurt." Some of the measurement sites have found what you said to be true. Not helping and sometimes hurting performance.

 

Bob Carver - Yes that's correct. You see, any device inserted between the amp and the wall outlet will have associated losses of it's own, regardless. 

 

J. Clark - How about noise on the line? 

 

Bob Carver - That's all taken care of by the amplifiers power supply.

 

J. Clark - Some say that the devices lower impedance of the AC to improve the dynamics. How about that?

 

Bob Carver - The power supply capacitors are there to lower impedance.

 

J. Clark - How about a lower distortion AC waveform?

 

Bob Carver - Any knowledgeable power supply designer, designs a supply that provides perfect DC power to the amplifier from the wall outlet AC power.  There is no need for a conditioner because the amplifiers already have one. 

 

J. Clark - Thanks for clearing that up. Direct to the wall for Bob Carver amplifiers.

 

Ask your amp designer for their advice. Maybe some poor designs would benefit, but AC conditioners are not advised with a Bob Carver amplifier.

 

 

Edited November 1, 2023 by Ar9Jim

[radtraveller 221]

For me the question is not about “cleaning” AC power, it is protecting amplifiers, especially the silver seven 900, from the vagaries of rural 240v, single phase power so I don’t have them damaged.

[Ar9Jim 6,164]

17 hours ago, radtraveller said:

For me the question is not about “cleaning” AC power, it is protecting amplifiers, especially the silver seven 900, from the vagaries of rural 240v, single phase power so I don’t have them damaged.

I'll mention your concern to Bob and lets see what he says. I'll be back.

[Ar9Jim 6,164]

Listening before going to shipping. It's a tough part of this job but someone has to do it. Heavy amplifiers stay right on the work lift through their process, even listening test.

 

[ChrisTFM35 598]

What music are you using for testing?

[Yamacarver 664]

It's calling for heavy metal LOL

 

[Kurt 1,429]

If you're getting too busy and need help, I would like to apply for the position of 'quality control checker' on the amps :).  

[Ar9Jim 6,164]

4 hours ago, ChrisTFM35 said:

What music are you using for testing?

Studio recording. Tom Jung producer. IIRC it was recorded live to a two channel digital recorder. Talks about it in the info.. Earlier digital and it was great on this label. 

Edited November 2, 2023 by Ar9Jim

[Ar9Jim 6,164]

Here is some information regarding the various quality levels and standards in electronics manufacturing. Audio is absolutely not an exception. These standards are precisely why the RAM 285 PCBs are assembled at high end suppliers that are comfortable working to the Class 3 standards of medical and aerospace. As a supplier for GE Aviation, the blue ESD coats like the man in the video is wearing were required. Wires connected the jacket to ground while working at a bench to keep you discharged. 

Only Class 2 level electronics are required for audio, but using ISO approved vendors that work to Class 3, adds value for our customers.

 

 

Edited November 4, 2023 by Ar9Jim

[Ar9Jim 6,164]

Small portion of the RAM 285 2 sided, multi layer, main board.

These 800v film caps were custom made for this voltage.

These 1% low noise Dale resistors contribute to the SNR of 100-102. The SNR might be even better. The RAM285 is checking at the limits of this analyzer, reading the same as connecting a 1m cable alone. 

 

With the inputs shorted, you have to almost touch your ear to the dome tweeter to hear anything at all. Reference Amplifier.

https://www.vishay.com/docs/31018/cmfind.pdf

 

 

 

Edited November 4, 2023 by Ar9Jim

[Ar9Jim 6,164]

On 11/1/2023 at 10:47 AM, radtraveller said:

For me the question is not about “cleaning” AC power, it is protecting amplifiers, especially the silver seven 900, from the vagaries of rural 240v, single phase power so I don’t have them damaged.

Had a meeting with Bob today and went through the questions list. 

 

Question- Bob, The topic of power conditioners came up and I mentioned all Bob Carver amps should be plugged directly to the wall. One customer mentioned his concern for having unstable rural power that can blink and act odd. He is asking if protection is needed to protect Carver amps especially his SS900s.

 

Bob - Not at all. The power supplies can handle all of that. Plug them directly to the wall and enjoy!

Edited November 4, 2023 by Ar9Jim

[3M_Audio 934]

19 hours ago, Ar9Jim said:

Had a meeting with Bob today and went through the questions list. 

 

Question- Bob, The topic of power conditioners came up and I mentioned all Bob Carver amps should be plugged directly to the wall. One customer mentioned his concern for having unstable rural power that can blink and act odd. He is asking if protection is needed to protect Carver amps especially his SS900s.

 

Bob - Not at all. The power supplies can handle all of that. Plug them directly to the wall and enjoy!

 

Reminds me of the 80s super-amps that had massive capacitance in the power supplies. I asked one of the engineers at the radio station I was working at about brownouts and he laughed, pulled the power cord from one of the big amps we used, and it kept playing for about 30 seconds, lol.

 

There's nothing like a good power supply designed by someone who knows what they are doing.

[Ar9Jim 6,164]

RAM 285 preorders are being delivered to customers and will be 100% filled next week 11-17-23

 

We are working hard to get the RAM 285s on the shelves for fast, world class delivery before the end of Nov.. Order now.

Edited November 8, 2023 by Ar9Jim