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Post subject: circuit different from schematic
Posted: Wed Oct 17, 2018 4:59 pm
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I would like to know what the function of the capacitors C41, C42, C43, C44 and C45 that physically are in the circuit of my Fender Twin Reverb 65 reissue 2008 or 2009 but are not in the scheme provided by Fender, in the circuit they seem to be near the bridge rectifier.

https://imgur.com/a/DnC4PWL


Last edited by fatube on Tue Oct 23, 2018 3:07 pm, edited 1 time in total.

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Post subject: Re: circuit different from schematic
Posted: Sun Oct 21, 2018 2:34 am
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Nothing on schematic , highest cap number is C40

We can't see your picture.


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Post subject: Re: circuit different from schematic
Posted: Sun Oct 21, 2018 8:06 am
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There are disk caps across the rectifier to quiet the switching noise of the rectifier diodes. There are two different methods that Fender uses.
C40 is an 8200pf 1kv disc cap across the secondary winding of the pt.
Old silverface models use .002 1kv disk caps across each diode.
I'm not sure why yours doesn't show up on the schematic, but those high ref numbers point to a recent factory addition.
Filter caps aren't very good at absorbing these fast switching transient noises. It also filters high frequency noise coming from the ac mains.


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Post subject: Re: circuit different from schematic
Posted: Sun Oct 21, 2018 1:01 pm
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You mean C41 Tim
I make a mistake to only see C40 :oops: Fatube did not see C41 too :lol:

Now where are C42, 43,44,45 ?


Last edited by stratele52 on Mon Oct 22, 2018 12:57 pm, edited 1 time in total.

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Post subject: Re: circuit different from schematic
Posted: Mon Oct 22, 2018 9:23 am
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TimsAudio wrote:
Old silverface models use .002 1kv disk caps across each diode


I remember Rivera era Twins had these (2000 pico-farad, 1kv ceramic discs), across the diodes.


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Post subject: Re: circuit different from schematic
Posted: Tue Oct 23, 2018 3:03 pm
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stratele52 wrote:
You mean C41 Tim
I make a mistake to only see C40 :oops: Fatube did not see C41 too :lol:

Now where are C42, 43,44,45 ?


in the picture (link below)

https://imgur.com/a/DnC4PWL


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Post subject: Re: circuit different from schematic
Posted: Tue Oct 23, 2018 3:06 pm
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fatube wrote:
stratele52 wrote:
You mean C41 Tim
I make a mistake to only see C40 :oops: Fatube did not see C41 too :lol:

Now where are C42, 43,44,45 ?


in the picture (link below)



https://imgur.com/a/DnC4PWL


I mean on schematic , I read OP see them on the amp, not in schematic


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