anatech said:
I don't miss these parts, 2SC5171/2SA1930 are much better 🙂
BTW, 2SA968/2SC2238 were made by the same Toshiba in the same PCT process.
JPV said:
Us oldens remember the Friden Flexowriter, could read paper tape at 1000ch/sec !!
Lots of other stuff from them crowning the Teletype terminal market.
ASR, KSR - Nurse! The Screens!
Hi syn08,
For new designs, sure. These are great. I do have some 2SC4793 / 2SA1837 on hand, but they are only good for 1 ampere. I guess I'll have to buy some of these ones as well. I have used them before, but there was a while when they were out of stock.
-Chris
My problem is that for repair purposes, these are over molded. I need something with a metallic collector tab. Otherwise, the repair looks sloppy with a tabbed ring and a lead soldered to the collector. That and it's just generally less fun having to mess with the parts before you can install them.
For new designs, sure. These are great. I do have some 2SC4793 / 2SA1837 on hand, but they are only good for 1 ampere. I guess I'll have to buy some of these ones as well. I have used them before, but there was a while when they were out of stock.
-Chris
Friden was famous in the 40's through the 60's as a MECHANICAL CALCULATOR builder. Every REAL engineer had access to a Friden for calculations beyond a slide rule. I was an expert on the machine.
Edmond Stuart said:
You're still missing the point. When you have multiple pairs in a high power amplifier and are trying to maintain a very small Iq voltage drop across low value emitter resistors it takes rather little temperature variation between devices to cut-off Iq in many pairs (uniformity of heat distribution across the heatsink and Vbe multiplier placement become critical factors) - and that does have a detrimental effect on distortion. Have built it, have measured it.
Hi John,
The audio business is no way to support yourself these days. Industrial electronics or communications. Either one is far less work for way better pay. Every skilled individual I know in audio is undervalued, big time.
-Chris
I agree with you there!
The audio business is no way to support yourself these days. Industrial electronics or communications. Either one is far less work for way better pay. Every skilled individual I know in audio is undervalued, big time.
-Chris
Many occupations are not 'profitable' even with years of training and preparation, BUT if you love it, then it is worth it.
Of course, many engineers have family obligations, which leads to compromise of what you want to work on, and whether fooling around with audio design is worth taking a chance on. I was advised 45 years ago to get into aerospace, and build military weapons. I chose a different path, but it has not been safe or profitable, although many around me have gotten very rich. I think that it takes marketing hype (something that I get continually accused of) to really be successful with money. Mark Levinson, Noel Lee, and many others started with me, but they controlled the money, and I only did the designs. It always comes down to 'What have you done for me lately?' while they get fancy cars to match their new image.
However, with all their wealth, I feel that I have actually learned my craft, and that many people are pleased with the products produced with it.
Of course, many engineers have family obligations, which leads to compromise of what you want to work on, and whether fooling around with audio design is worth taking a chance on. I was advised 45 years ago to get into aerospace, and build military weapons. I chose a different path, but it has not been safe or profitable, although many around me have gotten very rich. I think that it takes marketing hype (something that I get continually accused of) to really be successful with money. Mark Levinson, Noel Lee, and many others started with me, but they controlled the money, and I only did the designs. It always comes down to 'What have you done for me lately?' while they get fancy cars to match their new image.
However, with all their wealth, I feel that I have actually learned my craft, and that many people are pleased with the products produced with it.
G.Kleinschmidt said:
I don't think I'm missing the point. For an optimal crossover Vre has to be small (26mV), no matter the value of RE (provided that RE' << RE) and of course the placement of the Vbe multiplier is critical. Besides, it will never do its job perfectly, due thermal delay, thermal mismatch etc.
But tell me how large the maximum temperature difference might be along the heat sink? 10 degrees? 20 degrees?
The JC-1 went through a few iterations as a prototype, in order to fix various problems. The first prototype found a residual hum due to too much resistance in the power ground.
Then we had some problems with thermal runaway due to the low Re and marginal beta matching. We fixed the heatsink for more even dispersion of heat between devices and the rest is a production level product.
Then we had some problems with thermal runaway due to the low Re and marginal beta matching. We fixed the heatsink for more even dispersion of heat between devices and the rest is a production level product.
Hi John,
Case in point. I love working in audio, I love learning and experimenting. None of this has ever paid me well, although it did help considerably in gaining warranty contracts and trust in engineering departments. However, no matter how well I did, performing audio service honestly is not a well paying endeavor. In fact, most audio manufactures and distributors are working so close "to the bone" that there really is no money there to speak of. What little is there stays in the accounting department and the sales department. Service is regarded often as a cost that must be reduced and controlled, rather than an opportunity to enhance sales and improve engineering (due to accurate failure analysis). Not that it matters anymore with one and two year product model life.
A neglected service program does up the costs of doing business in the form of higher replacement parts usage, increased shipping costs and unit replacement situations. Customer dissatisfaction is another "intangible" that the accounting types like to use to prove that service is a negative. Well, of course it is when done incorrectly!
So, after many years in the business, a change in vocation showed me the following. You have to know far less about what you are doing in industrial electronics. Your activities are focused in a much smaller area. The work load is far lower as well and the renumeration is much, much higher. In fact, I have been on vacation ever since leaving the professional audio service industry with much more disposable cash and much more free time. Keeping up with technology is incredibly easier and more training opportunities exist (since audio companies ceased holding service seminars). You also get far more professional respect in industry. This while not working as hard and thinking less.
You wonder where the good technicians are going? That's the reason for it. Even an instrumentation technician gets more job satisfaction than what I would call a top flight audio technician.
As in everything, there are those who can make very good money in audio. Not much different than being a lawyer or anyone else who works for themselves. But an audio technician is considered by many to be a replaceable commodity, one pretty much the same as others. Not a recipe for being able to advance in the profession and make a living that reflects the knowledge and skill you need to have.
The three best technicians I ever had all went to the industrial sector, and I am still on good terms with all of them. They were the ones who did convince me I was wasting my life and that audio service is more of a hobby than a career. The best advice I could give you John, is that they are correct. I am just sorry you were not convinced much earlier in time.
Remember one sad truth. In business, you are only paid as much as you are thought to be irreplaceable. Good audio designers and technicians are badly undervalued on average. You are evidence of that, and so am I.
-Chris
I'll agree with you, mostly.
Case in point. I love working in audio, I love learning and experimenting. None of this has ever paid me well, although it did help considerably in gaining warranty contracts and trust in engineering departments. However, no matter how well I did, performing audio service honestly is not a well paying endeavor. In fact, most audio manufactures and distributors are working so close "to the bone" that there really is no money there to speak of. What little is there stays in the accounting department and the sales department. Service is regarded often as a cost that must be reduced and controlled, rather than an opportunity to enhance sales and improve engineering (due to accurate failure analysis). Not that it matters anymore with one and two year product model life.
A neglected service program does up the costs of doing business in the form of higher replacement parts usage, increased shipping costs and unit replacement situations. Customer dissatisfaction is another "intangible" that the accounting types like to use to prove that service is a negative. Well, of course it is when done incorrectly!
So, after many years in the business, a change in vocation showed me the following. You have to know far less about what you are doing in industrial electronics. Your activities are focused in a much smaller area. The work load is far lower as well and the renumeration is much, much higher. In fact, I have been on vacation ever since leaving the professional audio service industry with much more disposable cash and much more free time. Keeping up with technology is incredibly easier and more training opportunities exist (since audio companies ceased holding service seminars). You also get far more professional respect in industry. This while not working as hard and thinking less.
You wonder where the good technicians are going? That's the reason for it. Even an instrumentation technician gets more job satisfaction than what I would call a top flight audio technician.
As in everything, there are those who can make very good money in audio. Not much different than being a lawyer or anyone else who works for themselves. But an audio technician is considered by many to be a replaceable commodity, one pretty much the same as others. Not a recipe for being able to advance in the profession and make a living that reflects the knowledge and skill you need to have.
The three best technicians I ever had all went to the industrial sector, and I am still on good terms with all of them. They were the ones who did convince me I was wasting my life and that audio service is more of a hobby than a career. The best advice I could give you John, is that they are correct. I am just sorry you were not convinced much earlier in time.
Remember one sad truth. In business, you are only paid as much as you are thought to be irreplaceable. Good audio designers and technicians are badly undervalued on average. You are evidence of that, and so am I.
-Chris
Anatech, I do not regret going into audio design. It was my chosen profession 45 years ago, and it is still. Oh sure, I have made industrial designs for teletypes, instrumentation and video tape recorders, and laser electronics for medical applications, but my heart is ALWAYS in audio, and I still read everything I can find, to do it better. It is a single-minded avocation, especially in my later years. I do regret having a series of setbacks. I have closed down three operating concerns, besides my own personal consulting, due to financial losses, and then I had a firestorm that destroyed my parts inventory. Did I give up? No, I just started working as a consultant for a few firms, and have been paid fairly well, over the years, by them, for the amount of effort that I needed to put forth, but I have been in semi-retirement since 1991, and never made enough to put aside large sums of money for my old age. I regret this now, but that is my major regret.
The only repairs that I do, are my own custom designs. Right now, I have a mike preamp channel that I made for Dave Wilson 19 years ago, that is driving me nuts. It sort of works, and if cold, can work perfectly. I have checked every important active device, and went through the layout with a magnifier, but to no avail. I might fire up my micro-video camera and a color television and see if I can see even more, today. I really don't like to troubleshoot, but I am the only person who can with these designs. We don't even have a schematic to work with.
The only repairs that I do, are my own custom designs. Right now, I have a mike preamp channel that I made for Dave Wilson 19 years ago, that is driving me nuts. It sort of works, and if cold, can work perfectly. I have checked every important active device, and went through the layout with a magnifier, but to no avail. I might fire up my micro-video camera and a color television and see if I can see even more, today. I really don't like to troubleshoot, but I am the only person who can with these designs. We don't even have a schematic to work with.
Hi John,
I don't regret starting in audio service, and didn't suggest that you shouldn't have. It's just that you have to feed your family, and have time to spend with them.
Now that I am in forced retirement, I have a different viewpoint afforded me by the fact that I can't work anymore. These days, I can dive into my love of audio. It is an all consuming love of subject and technology that my wife doesn't understand (at all!).
My only point is that with the equivalent knowledge and effort in the industrial sector, you would have been paid far more. You would also probably have been more secure against the dealings of other people or companies.
I completely understand your view on this. Heck - I share it, but the reality of having to pay money to raise a family overrode my passion.
BTW, I love troubleshooting. I believe I'm reasonable good at it. However, you should always document your circuit. If you haven't, recreate this information from memory and your current observations. This make troubleshooting much easier to do.
-Chris
Edit:
Not an attack, just a mental space adjustment. 😉
I don't regret starting in audio service, and didn't suggest that you shouldn't have. It's just that you have to feed your family, and have time to spend with them.
Now that I am in forced retirement, I have a different viewpoint afforded me by the fact that I can't work anymore. These days, I can dive into my love of audio. It is an all consuming love of subject and technology that my wife doesn't understand (at all!).
My only point is that with the equivalent knowledge and effort in the industrial sector, you would have been paid far more. You would also probably have been more secure against the dealings of other people or companies.
I completely understand your view on this. Heck - I share it, but the reality of having to pay money to raise a family overrode my passion.
BTW, I love troubleshooting. I believe I'm reasonable good at it. However, you should always document your circuit. If you haven't, recreate this information from memory and your current observations. This make troubleshooting much easier to do.
-Chris
Edit:
Not true. Anything that can be built can be understood and repaired by someone else. That is the first thing a service person has to understand, and we are all capable of learning.
Not an attack, just a mental space adjustment. 😉
Anatech, there is no mystery here, it is JUST that I lost the circuit schematics in the '91 firestorm and would rather not remake them. Also, I have all the matched parts, that almost nobody has to fix the unit. This is a one time repair, as there are only 8 total units ever made, so it isn't like I can court future business.
Also, I found that office politics was just as significant in video, lasers, etc as in audio. I just don't do it very well. I prefer a 'closet' and to be left alone, except for my techs.
Also, I found that office politics was just as significant in video, lasers, etc as in audio. I just don't do it very well. I prefer a 'closet' and to be left alone, except for my techs.
Hi John,
I'll agree though. I just simply want to do my job and go home once it's properly done. Makes me an easy target for some types of people, but I can sometimes handle the situation.
-Chris
You are reading too much into my comments John. Besides, you could probably just draw out something close from memory. It might save you troubleshooting time. I say this as friendly advice as someone who does enjoy troubleshooting.
That is an entirely different issue. That is even if those parts are actually required.
And that has exactly zero to do with my comment. I said that someone else could figure out what you did and repair it. What I did not address is whether this was financially worthwhile. For you, it is a question of customer support. Just pointing out the difference between what I said and your comment in answer to that. There is no disagreement here really. Just a mental position that you are taking.
In every walk of life, where there are offices or organizations, there are people who wish to manipulate others around them. Often this is not in the best interests of the business. This, John, is a constant in this world.
I'll agree though. I just simply want to do my job and go home once it's properly done. Makes me an easy target for some types of people, but I can sometimes handle the situation.
-Chris
Edmond Stuart said:
Hasn't that been said already?
Edmond Stuart said:
Depends on the heatsink of course.
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