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Post subject: Electrolytic Capacitors for a 69 SFSR
Posted: Tue Sep 27, 2011 5:53 am
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Professional Musician
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Has anyone used MIEC or heard of this brand of capacitor before they have the 20 uF 600 v
and 80 uf 450 v I am looking to recap and these seem easy to get I am not looking to sell my amp so I do not care if they are the boutique type I just want to play and have it sound like it is suppose to


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Tue Sep 27, 2011 8:14 am
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I'd used either Sprague ATOMS or F&T. These are tested, reliable caps. You don't need boutique filter caps (IMHO). Now, if you REALLY want stone, cold LONG life realiability--motor runs are the way to go. But they are HUMONGOUS! But, you'll never blow one out. A short through the PS will prolly WELD the chassis parts before blowing out one of these.

http://www.capacitorindustries.com/capa ... fault.html


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Tue Sep 27, 2011 8:16 am
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BMW2002Ti wrote:
But they are HUMONGOUS!


Understatement of the year!

I doubt that these would fit inside the doghouse.

:lol:

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Tue Sep 27, 2011 10:23 am
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The issue I am having is the sprauge caps that are 2 uf at 600 volts are way to big I see most folks are putting in 500 v will that work. If that is not the way to go can someone direct me to who is selling F&T and will they fit in the dog house


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Tue Sep 27, 2011 2:11 pm
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You should be able to find everything you need here......

http://www.tubesandmore.com/

Follow the links on the homepage to "electrolytic caps".

HTH

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 7:45 am
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Thanks I have been to that site and others, maybe it's me, but I do not see any 20 uF over 500 v. I do see that most people use 500 v sprauge's some blogs say what ever you do do not use 500 v is this not correct


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 7:53 am
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OK, for the FIRST filter stage the overall voltage should be above 500VDC. That's why you place two 100mfd/350VDC in series with distributing resistors. The final filtering of this stage then becomes 50 mfd, but rated at 700VDC (caps in series = half the mfd and double the VDC rating). Fender OEM are two 70mfd/350VDC = 35mfd/700VDC in series.

These two caps supply the heavy horsepower of your amp (the PT and power tubes). The remaining caps (usually 20mfd) filter the screen grids/gain stage/input/PI and EFX. In other words the much lower mA required screen grids or the smaller 9-pin miniature tubes (12AX7 & 12AT7) sitting under their hoods. Current and HV is not as critical as the power stage. So you can get away with 500VDC rated caps in this section. See schemo:

http://www.webphix.com/schematic%20heav ... _schem.pdf


Last edited by BMW2002Ti on Wed Sep 28, 2011 9:09 am, edited 1 time in total.

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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 8:31 am
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BMW2002Ti wrote:
OK, for the FIRST filter stage the overall voltage should be above 500VDC. That's why you place two 100mfd/350VDC in series with distributing resistors. The final filtering of this stage then becomes 50 mfd, but rated at 700VDC (caps in series = half the mfd and double the VDC rating). Fender OEM are two 70mfd/350VDC = 35mfd/700VDC in series.

These two caps supply the heavy horsepower of your amp (the PT and power tubes). The remaining caps (usually 20mfd) filter the gain stage/input/PI and EFX. In other words the smaller 9-pin miniature tubes sitting under their hoods. Current and HV is not as critical as the power stage. So you can get away with 500VDC rated caps in this section. See schemo:

http://www.webphix.com/schematic%20heav ... _schem.pdf


+1

Basic Kirchhoff's Law.

Great dissertation, Steve!

8)

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 9:31 am
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Thank you, I got it. I do know about the two 80 uf in series I just was not sure if the 20 uF 500 volt would be OK but Now I now I can get away with the 500 volts To all of you THANK YOU VERY MUCH I do know what to order now .


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 10:14 am
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Cool! You can play some pool while waiting of the caps to arrive.


Image


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 10:29 am
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A OK for pool


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 11:31 am
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She can "rack my balls" any day!

:mrgreen:

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 12:23 pm
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Tubes and more has them for $17 20x600v


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 12:28 pm
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Yes but the sprauge 20uF 600 Volts seem to be a little long for the dog house cover


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Post subject: Re: Electrolytic Capacitors for a 69 SFSR
Posted: Wed Sep 28, 2011 12:38 pm
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Mud, You can run either Sprague or F&T 500 VDC rated caps in the last three positions, under the hood. The choke (TR2) just past the standby effectively isolates the surge running to the HV of the PT. I've used the 500VDC rated caps, in these three positions for a long time. No problems. Just get good quality ones.

http://www.webphix.com/schematic%20heav ... _schem.pdf


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