What the heck where they thinking in 1970's?? A 10MFD 450V Cap???

[ElectronTubesRule]

Ok so as if the Cap on the front side of the board was not bad enough I removed the board and found a (2) 10mfd 450V paper Beaver brand paper cap on the back side.......

Get this they are 20mm in diameter by exactly 30mm in length and when I measured how much larger they could be then that and not interfere with other parts I got roughly 32.5mm yes my machinist rule has 1/2mm increments. I about screamed......It would not be bad had they left some room for error in sizing or latter designs etc.......Unfortunetly in aluminum caps today they tend to make them longer and thinner not fat and short.


I do not not even want to try and figure out what some of those diodes are since they failed to label them all the way around the label side is facing the board......Never seen such stupidity in my life but then again this is 41 years latter so I am sure this was prob. good for it's day.

I can only imagine how spoiled we are today with the huge capacitance we can get in some really small packages and high voltages. If finally settled on on 22uF 450V 105 C caps that are only 1mm longer and are 4 mm smaller in diameter with more the double the capacitance. I could have put some 10uF ones in their but I figured 10uF x 2 is not a lot of filtering and not much head room for an amp that can for short bursts do 400watt'sand does 200watts continuous in (am) mode.

I can not even imagine how bad things must have been 41 years ago in terms of capacitors and other parts. I can not even fathom saying to myself " I think 20uF is more then filtering capacity for a 3 tube amp."!!!LOL If I could have come up with 8mm more room I could have put a 100uF 450V cap in each side of the circuit for 10X more capacitance. That really says a lot about foil etching and modern electrolytes when you can almost get 10X the filtering capacity in a package almost the same size and the 10uF package!!! It truly is amazing. People always want to think about transistor packaging and such as it relates to CPU's and such but I think the ever improving tech for capacitors is really amazing in itself and we take it for granted. I know I sure do until today. I am sure you guys that have been working on old stuff a long time find this amazing too but are used to it.

Imagine what an engineer from 41 years ago would say if he say a 450uF 450V cap that is about just a little bigger then a shot glass?!

 

[W5LZ]

Oh, ain't it awful!!
And you're right, you can't imagine what it was like. But you're pretty good about 'poo-poo'ing old technology. So why start with a piece of crappy junk like that, build a better one with newer components!
- 'Doc

Also keep in mind that crappy junky thing worked...

 

[wavrider]

Electronics and electronic parts have progressed and improved in the last few decades.

That old piece of equipment did what it was designed to do back in it's day, and with a proper rebuild it will work again.

No need to talk down about yesterday's technology, it is what it is.

 

[Captain Kilowatt]

Electronics and electronic parts have progressed and improved in the last few decades.

That old piece of equipment did what it was designed to do back in it's day, and with a proper rebuild it will work again.

No need to talk down about yesterday's technology, it is what it is.

Agreed. Just imagine. They actually got things to work and work well using that kind of technology. I guess it wasn't so bad after all.

 

[mackmobile43]

waste not want not.

 

[Beetle]

The generation that produced the item you're upset about is the same generation that put men on the moon. I don't see the new generation knowing what the moon IS! (Sorry ... school volunteer here...)

 

[Mudfoot]

Old stuff works!

 

[Captain Kilowatt]

Old stuff works!

If it didn't there would be nothing to build on to improve to make new stuff.

 

[ElectronTubesRule]

I am not poo-poo'ing old tech. If I was I wouldnot be building a tube amp now would I???? Capt. Kilowatt talked me out of doing a mobile tube amp for the time being. So I am not a Tech. snob.

As for going to the moon prove it? You can no more prove it then I can disprove it. Kind of odd that Russia,Japan, and everyone else including us have failed to go back their after all these year's!!! No I am not saying we did or did not go to the moon only that it is odd we have not been back don't you think?!?!

As for that your generation is also the Generation that buried PCB's in the Ground in plain metal 55gallon drums that rot and leak all over the place. The same generation that to put a solid energy program in place for the future. The same Generation that almost took the world into Nuclear War on more then one occasions. The same generation that created Love Canal disaster and polluted the Oceans of the world with oil,plastic, trash, nuclear waste from Bikini Atoll Hydrogen Bomb Testing. Michigan Lakes where so polluted that one of them spontaneously caught fire due to all the chemicals in it. I could go on but you get the point your Generation is far from perfect more then enough stupidity to spread the blame around. In fact the world will still be dealing with the toxic nature of your Generation for at least another 100 years if not longer. So lets not get into a peeing contest about what Generation did what!I will freely concede that from 1940 to about 1980 more advances where made in all area's of science then probably any other time in terms of new idea's and such. Today it is really more about taking what has already been invented and making it more cost effective and smaller Moores Law is definitely true!

If I hated old tech I would just build using simple and cheap transistors of the old school bipolar type like the MRF 421 and 2SC2879 I could have already had one of those built. Fewer parts, cheaper parts, light weight, lower cost power supply inthe form of a switching power supply etc...... Instead I am useing tubes, HV transformer's and no IC's at all just discrete componets. So that takes most of the steam out of your " I hate old tech argument!".

I was not making fun of the tech. I was more pointing out how spoiled we are today because we have it so good from the standpoint of diodes, capacitors and resistors. I was more saying "Wow it must of been hard to design things with such limitations in the tech at the time in terms of price point, size and durability!".

I think it is foolish though to no end to buy 40-60 year old caps made out of paper and wax to build a modern device or to repair an old device. First no guaranty that your gigantic .047uF 630V cigar sized Sprage Atom Cap is even any good and you will pay a premium for it. Their are much better caps with better ESR rating , better leakage ratings, smaller size, that are cheaper and sound as good if not better. So why not take advantage of modern diodes, capacitors and non-carbon resistors and make a device better in every way then it was when it rolled off the assembly line. Why pay a premium for old waxed paper caps that might not be any good and might not be "reform-able"???

I love old machines mechanicals from the 1800's up to about 1980's after that things get very light weight and just are not durable. So things like lathes, power hammer's, steam engines, large dynamo's, and other industrial machines are fantastic the older they get they are so over built they last forever.....Old tubes, old transformer's, are fantastic when in like new shape no one makes a linear today with a 76lbs. transformer anymore! Instead you get a 20-35lbs. transformer and a voltage doubler board. Why? Well lets see no one wants to pay for all that extra copper, no one wants to pay the extra shipping cost, everyone wants more profit and repeat sales. If you build it too well it will last too long with no repairs and no profits from part's! On top of that many companies today want their money up front not on the back side. So unlike car's where Dealerships have Salesmen to sell cars most of the Dealerships profits are on the back side on the repair side of the business. The salesmen are just their to drive the back side of the business where the real money is made. If you look at modern electronic devices it is normally an insanely cheap transistor, diode or cap that takes out the device. Does not matter if it is a Plasma TV or a Computer's Mother Board or a huge monster sized Linear. If the warranty is up most people do not attempt to repair their Plasma TV and most Electronic Shops will tell you to toss it and buy another one. So all those companies in China making LCD or Plasma TV are not looking to make money on the back side and they do not want the electronics to last too long. So trust me I see not only a change in technology, manufacturing but also a change in design and marketing philosophy. So just because I can appreciate modern discrete component capacities and packaging does not mean i think all that is new glitters and is golden!!!

Keep in mind I am only 38 years old so I did not mean to offend anyone that was not my goal or intent and I am sorry if that is how my post was taken! I have a lot of repsect for all the stuff that has transpired during my first 38 years of life and the men and woman that made it happen!

 

[Mudfoot]

Relax, it's just the internet.