Ok I am looking for a 450V Electrolytic Cap with not less the 30uF capacitance to replace some 30++++ year old Cornell Dublier paper caps in a rectifier board that are blistering even though they are still amazingly testing out as good. Only a matter of time before they give way. My problem is the caps with the smaller dimensions for diam and length are listing at a higher rated capacitance @ same voltage. Just wanted to make sure this was not out of the norm? I have been gone for a long time from consumer level electronics and there are names I do not recall ever seeing before and the ones I remember are not in business or they have dropped a lot of their old line to focus on industrial only type stuff.Voltage
First specs are as follows: Brand, ELUM
450 V
Capacitance 100 uF
Quantity 2 pcs
Tolerance ±20%
Temperature -40℃ ~+105℃
Diameter * Height 18 X 36 MM
The second set of spec.'s: Brand, Rubycon
Capacitance = 47uf
Voltage =450V
Tolerance = 20%
Temperature = 105ºc
Diameter = 22 mm
Height = 40 mm
So the second listing is physically larger in diameter and length but 1/2 the capacitance???
These are both axial types for the record. I only need 2 of them for the circuit but it struck me as odd that one brands would be physically smaller but have well over 2X the capacitance @ same voltage ???? I am used to a little variation from brand to brand but not smaller and over 2X more capacitance. That just seemed like too much of a good thing to be true? So my alarm bells where ringing. So far I have been happy with a Webster brand Cap to replace my 500V Cornell Dublier ones. Only time will tell if they last as long and work as well but they tested out as rated so not more you can hope for then that! Oh but it took a month with their free shipping to get to me..... Hard to go wrong though @ $5 with free shipping for a 500V 100uF cap that I can not find in stock any place in Michigan with in 3 hours one way from my door!
I did try joining easy to come by 450V and 63V caps but the space this bad boy has to fit is so tight that it just was not a good fit. I even tried relocating the caps and running shielded cables to the old spot. They simply did not leave any space on the underside of the RF deck unused and air flow would have been non-existent and seeing how these are directly off the center tap going into the rest of the circuits and the rectifier I thought heat might be an issue. So that is why I ordered 500V 100uF caps. Unfortunately my 100uF 450V Teflon Caps are Monster's size wise and would not fit where I needed it to fit. Seeing how this is a sweep tube amp I really did not want to have any long runs of cabling even shielded. I was unsure how much RF is leaking in this unit. This unit really does not have any long wire runs on the RF Deck Side and I figured that was on purpose. I have seen really bad things happen on radio's when people had long wire runs picking up RF and dumping it back into the circuit some place it was not wanted. So I just decided I would order the right part for the job size wise. So now I could put the parts back where they belong. Amazing how little space their is to work with in a unit that takes up as much space on your desk or under it as 1 1/2 show box's. Most of that is air space though not actual real-state you can use! I felt like I was trying to put 10lbs. of sugar in a 5lbs. sugar bag.....It was like playing with a Rubic Cube!!LOL No matter what I did I could not package the larger parts in a way that maintained the appearance of OEM parts lay out. I would have had to basically redo everything to fit the larger caps in this unit my common sense over rode my desire to be frugal after a few hours of drawing and redrawing the layouts and visualizing the parts in space........It only took 3 days and about 3 hours each day of trying before I final gave up and went on the internet to get the right size packaged parts!!!LOL
That is huge leap for me to give up that quickly! I am losing some steam in my old age....I think as I seem my time on this earth getting shorter each day I think I can better spend my time on things then trying to fit parts that are too big into a space that is too small!LOL
First specs are as follows: Brand, ELUM
450 V
Capacitance 100 uF
Quantity 2 pcs
Tolerance ±20%
Temperature -40℃ ~+105℃
Diameter * Height 18 X 36 MM
The second set of spec.'s: Brand, Rubycon
Capacitance = 47uf
Voltage =450V
Tolerance = 20%
Temperature = 105ºc
Diameter = 22 mm
Height = 40 mm
So the second listing is physically larger in diameter and length but 1/2 the capacitance???
These are both axial types for the record. I only need 2 of them for the circuit but it struck me as odd that one brands would be physically smaller but have well over 2X the capacitance @ same voltage ???? I am used to a little variation from brand to brand but not smaller and over 2X more capacitance. That just seemed like too much of a good thing to be true? So my alarm bells where ringing. So far I have been happy with a Webster brand Cap to replace my 500V Cornell Dublier ones. Only time will tell if they last as long and work as well but they tested out as rated so not more you can hope for then that! Oh but it took a month with their free shipping to get to me..... Hard to go wrong though @ $5 with free shipping for a 500V 100uF cap that I can not find in stock any place in Michigan with in 3 hours one way from my door!
I did try joining easy to come by 450V and 63V caps but the space this bad boy has to fit is so tight that it just was not a good fit. I even tried relocating the caps and running shielded cables to the old spot. They simply did not leave any space on the underside of the RF deck unused and air flow would have been non-existent and seeing how these are directly off the center tap going into the rest of the circuits and the rectifier I thought heat might be an issue. So that is why I ordered 500V 100uF caps. Unfortunately my 100uF 450V Teflon Caps are Monster's size wise and would not fit where I needed it to fit. Seeing how this is a sweep tube amp I really did not want to have any long runs of cabling even shielded. I was unsure how much RF is leaking in this unit. This unit really does not have any long wire runs on the RF Deck Side and I figured that was on purpose. I have seen really bad things happen on radio's when people had long wire runs picking up RF and dumping it back into the circuit some place it was not wanted. So I just decided I would order the right part for the job size wise. So now I could put the parts back where they belong. Amazing how little space their is to work with in a unit that takes up as much space on your desk or under it as 1 1/2 show box's. Most of that is air space though not actual real-state you can use! I felt like I was trying to put 10lbs. of sugar in a 5lbs. sugar bag.....It was like playing with a Rubic Cube!!LOL No matter what I did I could not package the larger parts in a way that maintained the appearance of OEM parts lay out. I would have had to basically redo everything to fit the larger caps in this unit my common sense over rode my desire to be frugal after a few hours of drawing and redrawing the layouts and visualizing the parts in space........It only took 3 days and about 3 hours each day of trying before I final gave up and went on the internet to get the right size packaged parts!!!LOL
That is huge leap for me to give up that quickly! I am losing some steam in my old age....I think as I seem my time on this earth getting shorter each day I think I can better spend my time on things then trying to fit parts that are too big into a space that is too small!LOL
