Event – A Visit to Krell

Event – A Visit to Krell
Steve Ekblad
1 January 2001

I had the pleasure of visiting the KRELL factory along with 5 salespeople from United Audio Centers in the Chicago, IL area. KRELL asked these top salespeople to attend a special on-site factory tour along with an intensive theory, product, and technology seminar over two days. This involves a considerable investment by KRELL and North American Sales Manager, Bill McKiegan informed that they are doing these seminars with monthly regularity. This investment in education is developing expertise in their dealer’s sales staff in all areas of KRELL products and technologies.

Our visit had three distinct goals: One, to establish the core information we need to become very literate on all of the many KRELL products and technologies. Two, to be fully aware of the sonic advantages of their product offerings. Three, to gain intimate knowledge of the quality of construction of KRELL products by touring the factory and carefully observing the actual build of individual products. All three objectives were accomplished plus one additional personal one–I couldn’t wait to hear a Master Reference Amplifier based system!!

Our session began with some information surrounding the company and its remarkable mission to simply create the best possible gear. KRELL’s name is based on a fictional character from the movie “The Forbidden Planet” where the KRELL were the most powerful beings in the universe. Certainly KRELL holds this title in audio! We discussed many details that make KRELL the company and product it is today.

The next step was a bite to eat with Rondi D’Agostino and the KRELL management team. We enjoyed meeting the legendary team that makes KRELL what it is today. Dan D’Agostino was traveling in ASIA with some new products and visiting distributors and dealers and could not join us at the time. While eating lunch we discussed new manufacturing systems moving into place at KRELL that will allow even higher production capability and more critical care to be included with each KRELL product.

After our discussion, we began our visit to the innermost areas of the factory–the assembly areas! Our first stop was the cell where the KPS 25sc was manufactured and burned-in. The KPS 25sc begins it’s life as subassemblies made up of metal parts, circuit boards, power supply parts, and all of the trimmings that make up electronics. The folks at KRELL use some outside suppliers for work that makes logical sense to have done outside the plant. Circuit boards are stuffed and wave soldered outside the facility. The first point of assembly is careful inspection of these circuit boards and if any solder connection is not up to KRELL’s stringent par, they re-solder the connection at this point. Additional parts are added to the boards that are soldered manually to avoid the heat of wave soldering or because their physical size or shape. Then the sub assemblies are added step by step to the rugged chassis. The CD transport is added and the final chassis assembly is completed. The next stop within the cell is circuit trimming. A trained technician adjusts the circuit for exact specifications using an Audio Precision analyzer [BTY–I lost count of these during my visit after the 20’s]. The final stop within this cell was the automated torture test to assure that the unit is meeting all of the demands of the KRELL standards to eventually be cosmetically finished and shipped to a very happy customer!

The next stop was to the area where the Master Reference Amplifier [MRA] and the Master Reference Subwoofer [MRS] are manufactured. It is safe to say that in this cell, the finest amplifier and subwoofer possible are manufactured and shipped to the most devoted and heavily invested listeners in the world. Imagine having no limits to a design, then add the every whim and design dreams of a team of 10 engineers with the demanding imagination of Dan and you begin to get an idea of what these things are made of. As we went through the components that make up these two products we marveled at the amazing attention to detail that goes into a fanatical product like a KRELL. What is most interesting is that a piece of what goes into the MRA and the MRS is in every KRELL product. As we walked past the burn-in area for KRELL woofers, we saw a pack of 15″ monsters being tormented with a low frequency tone. These drivers undergo an extensive burn-in outside of the box they will eventually occupy to assure that once they are added to the MRS- they will play with KRELL performance for many years to come. After they are absolutely certain the drivers are up to the KRELL specs, they are removed from burn-in and added two at a time to MRS cabinets. Their exact position while in motion is governed by KRELL’s proprietary Active Motion Control circuit for constant correction to keep the woofer precisely aligned with the signal while producing its beefy output. Keep in mind that the design goal of this subwoofer is to be able to a solid 120 dB at 20 cps. This is an amazing physical output into a room let alone considering the pressures that must be inside this box. Inside the cabinet is a very sophisticated digitally controlled passive crossover system. This crossover has many flexible user controls. The net result is the end-user can perfectly match the subwoofer to a speaker system for seamless integration. They can change filter types [Bessel, Linkwitz, and Butterworth] on the fly as well as phase, level and slopes [6dB/oct–48dB/oct adjustable]. Add a huge 2600 watt amplifier, house it all in a 1″ thick solid billet aluminum chassis and you will find what a KRELL MRS is all about. The MRA chassis was amazing. We looked at the output transistor array and wondered if we could even physically pickup the driver board! National sales manager, Bill McKiegan, proved it was possible, but it wasn’t something he wanted to carry for a long period of time! Two MRA amplifiers were nearing completion while we walked by. These beasts were each perched atop a heavily reinforced cart that was labeled with a 1000 lb load maximum warning. It seemed very appropriate looking at these brute force monster amplifiers. Each time the impedance load on these monsters is halved, they respond with double the power. This doesn’t stop until the limits of resistance are reached and a short is all that is left. Try 16,000 watts of current based power on your fractional impedance speaker load and see what massive muscle can do with grace and maximum resolution added! How can you get this amount of current? Each amplifier requires 40 ampere 220 connections for ideal power. The shipping containers for these looked like giant custom wood boxes that might house a commercial air handling unit or the like. We moved onto another cell where workers were assembling the brand new KAV1500 amplifier. This 5 x 300 amplifier was jam packed with Krell heat sinks and power. The twin toroidal transformers are bolted into place using 4 massive stove bolts. This gives you an idea of the rest of the construction–heavy-duty. This will certainly be a popular amplifier solution for home theaters.

The next stop was the engraving room. In this room, numerous computer controlled engraving machines are staged to create the famous KRELL faceplates. The average lifespan of a cutter used here is 10 faceplates before sharpening. The typical life would be more than a hundred. The reason for the shorter life is the hardened surface of the KRELL panels. KRELL expends a considerable effort to make certain that their products will stand the test of time. Nothing at KRELL is easy except enjoying the fine performance of their products.

Also located in this area is the pair of PEM application machines. PEMs are a mechanical fastener that under pressure provide a mechanical connection that is stronger than a weld but allow screws to be inserted and locked. This method is used to apply devices to circuit boards. It is beyond the physical construction of other board I have ever seen, but commonplace at KRELL.

The next stop on our tour was the cell area where many of the KRELL products were being assembled. With the cell method of construction, KRELL can assure high quality production standards while minimizing any production flaws. KRELL amps of many sizes and configurations were in progress. It was a dizzying sea of tight tolerance hand picked parts, glass epoxy boards, giant toroidal power transformers, massive heat sinks, and thick chassis parts [dizzying for a rabid audiophile that is–grin]. Each cell area is assigned a particular product from start to finish. The Full Power Balanced 350Mc is a good example of what we saw in these groups. From circuit board level hand soldering to hand torque fastened parts, each cell is responsible for the entire build-up of the final product. The last step in each line is a visit to an Audio Precision analyzer to fine tune the product to KRELL specs. Then it is off to the KRELL burn-in room for a long torture test to make certain it will live up to the KRELL name. The burn-in room itself generates a terrific amount of heat. It is exhausted by a large fan to the outside during the summer, while during the cooler weather, another fan drives the heat generated into the factory area for auxiliary heating.

We were allowed some time to interview some of the talented workers in the cells. We were also able to witness the final quality testing of a KRELL amp. Giant banks of load resistors are used to create a test path that allows full power testing down to a 1/2 ohm load. The Audio Precision analyzer bore out the results of their labor, vanishing distortion and massive class A power.

After our tour, we headed back to our classroom for some product demonstrations. We started by listening to the wonderful KAV 250a amplifier driven using unbalanced connections. It sounded great until we switched to the balanced connection and we were reminded just how important a low noise signal transfer is! The sound stage, depth, and dynamics were impressive. Next we listened to a Full Powered Balanced 200c amplifier with a single pair of high quality caps switched in on the input to protect the amplifier from DC leaking tube preamplifiers that some audiophiles like to use. After conditioning ourselves to the sound [which was great] we switched to the same amplifier but with the caps removed and listened to the DC Servo Direct Coupled technology in full force. It was jaw dropping to hear what a single pair of high quality caps robbed from the music. After regaining our composure, we listened to a Full Power Balanced 300c connected using the balanced inputs. Then we switched to the proprietary CAST connection [CAST is an acronym for Current Audio Signal Transfer where all signals are treated and amplified in the current mode instead of a traditional voltage mode]. The results were staggering. We were so amazed we had to ask our hosts if the only change was CAST connections from CD to preamplifier and to the amplifier. As it turns out, quite by accident the CAST connection was only changed between the preamplifier and the amp. We listened again as they added the CAST connection between all of the devices and we heard still another improvement. Last, we heard the difference between a Full Power Balanced 300c and a pair of mono chassis Full Power Balanced 350c amplifiers. Again we noted remarkable improvements. All of us were now in agony–we had to own CAST equipped mono chassis systems! The difference was simply remarkable!

After this experience, we needed to prepare for our next stop, a visit to the D’Agostino home where the entire sales, financial and human resources team had joined Rondi in preparing a KRELL feast. We enjoyed a remarkable meal while listening to their amazing system. Dan and Rondi have a pair of MRA amplifiers driving a pair of prototype speaker arrays flanked by a pair of prototype subwoofer arrays powered by an MRS equivalent amplifier. How can I describe the experience? In a word–KRELL-like! After hours of enjoying each other’s company and an amazing system, we reluctantly returned to our hotel.

The following day we returned to the factory for more information. We spent more time learning about the amazing KRELL products. We experienced the power of KRELL driving a full theater system. How can I ever go to a theater again? The quality of reproduction will be sorely missed.

As the end of our trip loomed near, we realized just what a special company KRELL is. If I had to describe KRELL in a new words, I would have to use every superlative in one giant run-on sentence. They are simply amazing!

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