By: Steve Nazarian
The audio electronics company I worked for in the 1990s was called Crest Audio. I was hired to write the user manuals and promotional literature for a new series of mixing consoles called the “Century Series.”
This new line of consoles was a shift down market from the rarefied air that the company’s Gamble EX series occupied. As colorful and exciting as mixing consoles are, the company’s bread-and-butter was power amplifiers. Having been an innovator since the 1970s, the Crest had a reputation for building amplifiers of both the highest power and quality.
In 1987, Crest introduced the Professional Series 8001 amplifier. At the time it delivered the most power in the smallest package and it did it while sounding… well, awesome.
The 8001 became the Toyota Camry of professional amplifiers.
For more than six years, Crest sold as many 8001s as they could make in their northern New Jersey factory. However, the competition was nipping at its heels, and the modern concert was demanding more and more power. So, in 1992, Crest began developing the successor to the 8001, the 9001.
The 8001 was capable of 1,400 watts of music power.
The planned 9001 would deliver more than 3,000 watts.
Before I get on with the story I need to tell you a little about how power amplifiers are built. They are made up of the following parts:
- A chassis that holds it all together
- A power supply that provides all the different voltages the unit requires
- An input section that receives signals and allows for volume settings
- A preamplifier that prepares the signal for amplification
- Output modules that multiply the signal from the preamplifier to make things really loud
- Protection circuitry that monitors all stages of the amplifier, and makes adjustments to keep it from destroying itself
- A fan to keep the whole thing cool
Since the 8001 was both a critical and financial success, the plan was to take everything from that design and just make it bigger. In addition to being regarded as a great sounding amplifier, the 8001 was highly reliable. You know your product is a success when everyone in the industry refers to it as a “workhorse.”
A pair of Crest Audio 9001 Output Modules.
The initial design and engineering of the 9001 took several months. Then came the construction and testing of the prototypes. Everything went smoothly and exactly as planned. The result was a 110 lb, 3,300 watt, screamer of an amplifier and we couldn’t wait to sell them. Now, once an amplifier goes into production, manufacturing involves the following steps:
- All circuit boards are populated with their components
- Circuit boards are run through a soldering machine
- Each individual section is assembled separately (preamp, output, power supply, etc.) and tested to make sure it meets or exceeds all specifications
- All sections are assembled into a chassis making a whole amplifier, which is then run through dozens of tests and measurements
- The completed unit is put through a “burn-in” process, which is basically the electronics equivalent of taking that brand new Camry and driving it at 120 mph… for twenty four hours straight.
- Once the burn-in is done, the amplifier undergoes the same tests that were performed before the burn-in. The pre/post test results are compared and only after passing is the amplifier allowed to be packed and shipped
This process had served the company for years and it produced such reliable product that the standard Crest Audio warranty was five years… the best in the industry.
A brief aside – the burn-in room was something to see. On a busy night there might be more than a hundred amplifiers connected up to signal and dummy loads (silent resistors that mimic speakers) with their lights flashing and fans blasting. The amplifiers give off a great deal of heat, so the burn-in room could get as hot and dry as a 120-degree desert. Rumor had it that some of the third-shift guys would re-heat their lunches in there. So the 9001 went through the development, engineering, prototyping and testing process. With all the details sorted out, 9001 production got the green-light. The 9001 had been announced in October and started shipping just in time for the summer tour season the following year. They sounded so good, and were so desired that they would ship just as fast as we could make them.
The tour sound companies ordered their 9001s, installed them into their rigs, tested them and then headed out on the road.
Most summer concert tours kick off in indoor venues like large theaters and arenas. Once things start to warm up however, tours usually shift to outdoor venues, or what the concert professional would refer to as “a shed.”
CMAC, PNC Arts Center, Jones Beach & Red Rocks – Sheds are a great place to see a show!
There are famous sheds all over the country. Here in upstate New York we have CMAC. Over in Saratoga they have SPAC. New Jersey has PNC Arts Center, DC has Wolftrap, Jones Beach has one, and of course the big-dog of all outdoor venues, Red Rocks in Colorado.
It was only when the 9001s started going outside that the trouble began.
We started getting calls that the amplifiers were “breathing fire,” right before completely failing. When the first few failed units came back tor inspection, it looked like a bomb had gone off inside. Every time the story was the same. The tour sound company would get to the shed, they would set up, perform a sound check at full volume in the afternoon and everything was fine. As the audience took their seats, they would play recorded music through the system and everything was still fine. As the sun was setting, the opening act would come on stage, and not too long after there would be a popping sound and one or more of the 9001s would spit fire out of the front vents and then fail. Sales Director Greg McVeigh and I had the pleasure of meeting up with the sound company for the Spin Doctors one day at the Jones Beach Amphitheater. The night before the tour had been in Philadelphia, and right in the middle of the opening act, five of their ten 9001s had flamed out, leaving them with very little bass in their system. They were pissed. We delivered replacements (plus two spares) but since we didn’t know why it was happening, confidence was low. As time went by the problem got worse. The number of failures in the field was alarming, and the overnight shipping of 110 lb replacements to customers was getting very expensive. What’s worse, the replacements were failing too.
I could go on for pages about what we went through to figure out the problem, but the bottom line was this… we had never tested the 9001s in the environment in which they were ultimately failing.
There is this thing called the Dew Point. The Dew Point is the temperature at which humidity in the air turns back to liquid water and deposits itself on surfaces as dew. As the sun was going down over these outdoor concert venues, the temperature approached the dew point. This meant that the air moving through the 9001 fans (at 140 cubic feet per minute) was very, very wet. This had never been a problem for the 8001, but when we took the same design, moved twice as much power through the same circuit design, and then bathed it in moist air, we ended up creating ideal conditions for electricity to “arc” through the air.
Electricity arcing through the air is more commonly know as… lightning.
You see we tested the amplifiers in the only way we knew how; in a hot dry room and they were fine. Once we added a dose of humidity to the equation we were able to duplicate the problem… BOOM, fire-breathing amplifier.
The guts of a 9001 showing the original design.
Once we understood what was happening the solution was a small design change. The part of the circuit board where the arcing was taking place was upgraded with something called a laminated buss bar… problem solved.
The guts of a 9001 with the fix applied. Look for the orange bars that resist lightning.
I know this story has been a bit more technical that my usual offerings, but the lesson is universal. Most things are scalable to a point, and then you need to re-think the whole thing. Look at something as common as a bridge. From crossing a small culvert all the way up to the Golden Gate, as the distance to be spanned grows, the design changes. Each approach is scalable to a point and then you have to start over. Think about the organizations and groups in your life. Do you have some that used to work well together, but don’t anymore? Have they grown? Chances are the model that once worked as been pushed beyond its scalability.
“More of the same” works to a point, and then it doesn’t.
So, when you think nothing has changed, but the 9001s in your life are breathing fire and failing, take the time to look at the big picture. You will find the problem… and once you do you’ll know what to do to keep the music playing.
Copyright © 2014 – Stephen S. Nazarian – All rights reserved. (Not Everything Is Scalable)
You can read the original presentation of this story and many more at stevenazarian.com
Originally posted 2014-08-20 13:18:46.