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Capacitors

D

DavidDesens

Guest
I'm in the process of replacing some electrolytic capacitors in an old Fisher tube amp. I just wanted to make sure that it is ok to substitute higher values. In other words, if I need to replace a multi section can cap that is rated 60MFD-450VDC and 40MFD-450VDC, is it ok to replace this cap with a 100uf-500VDC and 100uf-500VDC?
 
Probably

It depends on the rectifiers used. For example, with the 5AR4 tube rectifier, I know that it's specifications state that the maximum filter cap will be 50 or 60 uf. This is because the inrush current on a larger cap could damage the tube.
If you're using a tube rectifier, what I might try is to use a single 100 in place of the 60 and put two 100's in series for the 40, essentially making a 50 uf capacitor. Connect them plus to minus.

If you've changed the rectifiers to silicon then there should be no problem.

It's always okay to go higher in voltage though.
 
Re: Probably

I would be a bit concerned about power sequencing. Perhaps the caps are different values to sequence the power. More than likely not - but it is possible.

Unles you are a tube purist, there is little reason to stay with a tube rectifier. A couple of 1N4007's are almost a universal replacement.
 
> I'm in the process of replacing some electrolytic capacitors
> in an old Fisher tube amp. I just wanted to make sure that
> it is ok to substitute higher values. In other words, if I
> need to replace a multi section can cap that is rated
> 60MFD-450VDC and 40MFD-450VDC, is it ok to replace this cap
> with a 100uf-500VDC and 100uf-500VDC?
>

what model ?

E
 
> > I'm in the process of replacing some electrolytic
> capacitors
> > in an old Fisher tube amp. I just wanted to make sure that
>
> > it is ok to substitute higher values. In other words, if I
>
> > need to replace a multi section can cap that is rated
> > 60MFD-450VDC and 40MFD-450VDC, is it ok to replace this
> cap
> > with a 100uf-500VDC and 100uf-500VDC?
> >
>
> what model ?
>
> E

X-101
>
 
Re: Probably

> It depends on the rectifiers used. For example, with the
> 5AR4 tube rectifier, I know that it's specifications state
> that the maximum filter cap will be 50 or 60 uf. This is
> because the inrush current on a larger cap could damage the
> tube.
> If you're using a tube rectifier, what I might try is to use
> a single 100 in place of the 60 and put two 100's in series
> for the 40, essentially making a 50 uf capacitor. Connect
> them plus to minus.
>
> If you've changed the rectifiers to silicon then there
> should be no problem.
>
> It's always okay to go higher in voltage though.

5AR4/GZ34 are labeled near the socket but the actual tube in the socket is a F31B9B. Any more advice is greatly appreciated.
>
 
> > > I'm in the process of replacing some electrolytic
> > capacitors
> > > in an old Fisher tube amp. I just wanted to make sure
> that
> >
> > > it is ok to substitute higher values. In other words, if
> I
> >
> > > need to replace a multi section can cap that is rated
> > > 60MFD-450VDC and 40MFD-450VDC, is it ok to replace this
> > cap
> > > with a 100uf-500VDC and 100uf-500VDC?
> > >
> >
> > what model ?
> >
> > E
>
> X-101

d*mn

never had any experience with that one

sorry



> >
>
 
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