Time, Temperature and Making Yourself Feel Good 

I recently received an email from a reader who tried to take me to task for not using 105°C capacitors. I tried to explain to him that for most applications it is completely unnecessary to use such parts and here's why.

It is a widely accepted fact that the rated life span (in hours) of electrolytic capacitors will double with each 10° drop in temperature. For this example I will use the Elna LAO Series of capacitors.

On the LAO data sheet, Elna states that this series of capacitor has an endurance rating of 1000 hours at 85° C. If you calculate the increase in hours by the drop in temperature, the chart will look like this:

85° C (185° F) = 1000 hours

75° C (167° F) = 2000 hours

65° C (149° F) = 4000 hours

55° C (131° F) = 8000 hours

45° C (113° F) = 16,000 hours

35° C (95° F) = 32,000 hours

25° C (77° F) = 64,000 hours

If you figure an average internal temperature of an amplifier of receiver is 30° C (86° F) the capacitor would have a calculated endurance of 48,000 hours. If you operated the amplifier 24 hours a day, 7 days a week the expected life of the component would be 5.47 years.

Most of use do not operate our equipment any where near this amount of time each day. My own use is typically just 3-4 hours each day and perhaps 5-6 hours each day on weekends. With an average use of 2000 hours per year, the capacitors should last at least 24 years.

Odds are that something else will fail long before my new Elna capacitors do. Anyone can use 105°C capacitors if they want to make themselves feel like they are treating their equipment to something special, but in reality for most applications it's completely unnecessary.      



Open Source 

There's a movement in the world of which is called Open Source Hardware and I think it's one of the most important ideas in the world of technology to happen in a long time..

Here's part of the definition from Wikipedia: “ Open source hardware(OSHW) consists of physical artifacts of technology designed and offered in the same manner as free and open source software (FOSS). Open source hardware is part of the open source culture movement and applies a like concept to a variety of components. The term usually means that information about the hardware is easily discerned. Hardware design (i.e. mechanical drawings, schematics , bill of materials , PCB layout data, HDL source code and integrated circuit layout data), in addition to the software that drives the hardware, are all released with the FOSS approach.”

The idea of sharing information and ideas and allowing others to add, change or modify the ideas is revolutionary. The sharing of ideas leads to innovation and solves problems which then can help others. OSHW is a community building idea which brings people together and enhances everyone who participates in it.

When I started this site it was just my way to share a hobby which I enjoy very much. Because of this site I have met many other people who also enjoy the hobby of audio and electronics. These like minded people have exposed me to new ideas and ways of thinking which include OSHW.

While I'm not designing new products, I am working hard at conserving the audio products from the past. Some long time visitors of this site may have noticed an increase in the number of manuals, data sheets and other technical information that I have posted for free download. This is my version of OSHW.

I will continue to share everything I know and everything I learn about audio electronics. I hope that this will enable others to conserve their audio equipment for the next generation.


Sometimes you just want a switch

The power switch on my Marantz Model 30 is flakey and it’s likely that it was the cause of the failed bridge rectifier.  There is definite slop in the mechanism and you can hear electrical noise when the contacts slide on and closed.

I went into research mode for a proper replacement switch and I can up with a very close match from E-Switch.  Their P227 Power Pushbutton Switches are a very close match up for the original mounting position on the model.  The original mounting screws have a spacing of 15mm center to center and the switch mounts its own bracket inside the chassis.

I worked through the Switch Configurator on the E-Switch web site and determined the correct switch would be model P277WW2B15B.  A quick search on-line turned up no results for this model and my usual sources like Mouser and Digi-Key only stocked a few 18mm versions.

I fired off an email to E-Switch requesting a few samples of this switch.  Most of the time a manufacturer is more than happy to supply a few samples to an electronics business as a gesture of good will and the hope of more business in the future.

A few days later I received a reply from a fellow named Kip who politely informed me that I should seek the switch from one of their stocking distributors. Kip even provided a list of the distributors and the models they stock.  Unfortunately none of the switches that were stocked were the model I needed.

I shot off a second email to good old Kip letting him know than none of his stocking distributors had the switch I needed and would I be able to buy it directly from E-Swicth.

His reply was:

This is a part number that has never been produced before, and in order for us to be able to produce it from our factory, we would need a minimum order of 4,000 pieces. That is why we are unable to sample you with the part number you requested. Your only option at this point is to select an alternative option from one of our distributors.”

I can’t understand why any manufacturer would list a component on their website if they have never produced even a single unit.  I guess Kip didn’t think another option was for me to look to another manufacturer for a part that has actually been manufactured and is available for purchase, After all I wanted was a switch.


What a Time We Live In

We live in a great time for the audio and electronic hobbyist.

If you have an interest in audio equipment beyond listening to music on your vintage gear, you really can’t escape the connection that exists between audio and electronics. Eventually your vintage equipment will need some type of work and weather you take it to your local repair shop or you work on it yourself, electronics will come into the picture.

We live in the age of the internet and the amount of information, knowledge and the availability of parts are unprecedented. This became clear for me a few months ago when a customer called and he need a little tube set repaired. The last time I was asked to work on a unit like his was probably 12 years ago. Back then searching for tubes and tube components was a like look for a needle in a hay stack. There was really only one local shop that had some NOS tubes and carried NTE caps. If I had asked for some Sprague Orange-Drop capacitors they probably would have laughed at me.

This time searching for the parts I needed was so easy. A quick Google search allowed me to choose a single site which had everything I needed. A week later the parts arrived and the repair was under way. So easy.

What a time we live in. With a few clicks on Digi-Key or Mouser you can order everything you need to repair you amp. If you have questions, an internet search will give you almost unlimited access to the information you need. If you questions are specific or exotic, you can join a forum and ask others for their input and ideas.

Free software will allow you to design your own custom circuit boards and with minimal effort you can get them manufactured in China or New Zealand and have them in just a few weeks. Need a custom case for your project? Join your local Hacker Space and have access to a laser cutter and a Maker Bot machine.

The access to high quality used test equipment is amazing. There is an almost unlimited supply of once top of the line bench equipment that now sells for one-tenth the original price. Specialized test gear is so available that every hobbyist can have the equipment they need. If your concerned about buying used equipment, no problem. You can buy a Rigol Digital Storage Oscilloscope for under $400.00 and probe to your hearts content.

The average beginner hobbyist can put together a complete first time work / test bench for right around $500.00. If you use it to repair just 2 units, you will have save enough money to cover the costs of the equipment and your home free from that point on.

What a time we live in.



Pure Audio

Recently I followed a discussion started by someone that I would call a Pure Audio enthusiast and even if they are a small group, they have very strong feelings about their audio beliefs. Of course the discussion started out about the topic of the effects that capacitors have on the sound of audio equipment and then moved on to other areas of audio equipment modifications.

At first I was very resistant to the group that felt they could hear a difference between the different brands of capacitors. By endlessly swapping different brands and grades of capacitors into various circuits they felt that they could hear small incremental changes and improvements in the final sound. Of course the person who was conducting this experiment was using an ultra expensive turntable and high end speakers, which he stated were necessary to have to actually hear the changes. What I read into the comments he made regarding the peripheral equipment was that if you are listening to ordinary speakers and using an ordinary turntable you will probably not be able to hear the improvements, because you equipment is not good enough.

A lot of his results seemed to be more magic than science and frankly I thought more of his writing quality and style than I did of his technical ability. As his tests progressed and his evaluations became more specific and detailed. His comments flowed using images to create a mood and adjectives that could easily have been describing a fine wine rather than a sound. More and more of the followers of the experiment began to voice their support or objections to his methods and results. As with many heated discussions there was a certain amount of finger pointing and yelling between the different sides.

As I followed along, I began to see what the tester was actually trying to achieve. He was making his own best personal effort at creating a truly custom piece of audio gear that met his personal requirements for sound quality. This is a noble task that everyone should take on within some aspect in their life at sometime.

When I made this realization, my opinion of his experiment changed. I began to see the value in his attempt for his own personal satisfaction. Where my opinion did not change was in his stead fast position that his work should become the standard that all others should base their improvements on. I do not believe in a one-size-fits-all approach.

During the discussion he gained several stead fast supporters that rallied together, giving him encouragement and support to his ideas, methods and conclusions. These supporters railed against the disbelievers and their doubts and questions. At one point this band of supporters began to turn on each other over their differences in how far these modifications should be taken and the conclusions of the results.

There were several times that the leaders honesty and integrity were called into question. It seems that he was also conducting this discussion in several other venues at the same time and interjecting comments and ideas from those sources. For some reason many felt betrayed by this and called him out about it. Oddly enough the leader was angered and annoyed by being called out, he threatened to pack up his belongings and ideas and go home. He couldn't understand how he could be treated so badly when all he was trying to do was enlighten, educate and lead all of us to his audio nirvana.

There are true believers within every group. The searchers for Pure Audio aren't really any different than those in any other group. They believe that they have the answers and everyone should listen to them and use their insight to improve their lives. The belief in special audio capacitors, ultra pure copper wiring, directional lacquer insulated speaker wire, fuses with diodes, ultra expensive interconnection cables, heavy gauge power cords, dedicated power circuits, power conditioners and bypass capacitors upon bypass capacitors are just part of the list of fixes for those looking for Pure Audio.

So many people believed in these items and who could blame them for wanting to believe after spending their hard earned dollars on such things. What it comes down to is that subjective observations are impossible to prove. While some of these items may have an effect on the sound of an audio system, without objective technical proof the results will remain opinions and not facts.

I am doubtful that most of the magical items have much effect of the final sound of any audio system. Especially if it's necessary to have ultra high end peripheral's to be able to hear the difference. This just sounds like elitist snobbery to me. Most of us, myself included enjoy our audio hobby just for what it is, a hobby. Something that we spend our free time on for our own personal enjoyment and pleasure.

Everyone is entitled to their opinions, the believers in Pure Audio shouldn't try force us to follow them down their path audio enlightenment. Let us find our own way to our own state of Pure Audio.