Capacitor question VL503

[sweatyk]

I have a few 450V and a 500v caps in this amp that will need to be replaced. The weird thing is that for C64 in the schematic it calls for a 47uf@500V. What actually came in the amp was a 60uf@500v. And what a technician I know replaced one in another VL503 with a 100uf@500V. Not knowing how far you can increase the capacitance I'm not sure what to order for a replacement. Can't find a 60uf but 68uf is no problem. Any advise you can offer before I order caps? I'm attaching the schematic for reference.



VL-503 Schematics 1.pdf

[The Dude]

That 60UF was probably the closest thing the last tech had in stock and nothing wrong with that- close enough for a filter. If you are going to order parts, you might as well get the original part. It's a standard value and will be cheaper and more readily available.

[sweatyk]

That 60UF was probably the closest thing the last tech had in stock and nothing wrong with that- close enough for a filter. If you are going to order parts, you might as well get the original part. It's a standard value and will be cheaper and more readily available.

Thanks for the advise. On a side note when it comes to capacitors, is there a rule of thumb on how high you can raise the capacitance? Is it based on the tolerance rating?

[The Dude]

That would be circuit dependent.

[Enzo]

With a tube rectifier, there is a limit to how large the first filter cap can be, the reservoir cap. With solid state rectifiers, it doesn;t matter. These are just guitar amps, not NASA laboratory gear, so most parts are not critical. Where it starts to matter is in the signal path, when cap value has some affect on frequency response.

[sweatyk]

So in my particular case if i couldn't get a 47uf in the physical size needed because of limited space, what would be a recommended limit to stay within.

[52 Bill]

So in my particular case if i couldn't get a 47uf in the physical size needed because of limited space, what would be a recommended limit to stay within.

I don't understand your question here. If the space is limited and you can't find a 47uF cap that fits, a higher value cap will probably be larger rather than smaller.

I can't find C64 on the schematic that you posted. I can only assume that it is at the screen grid node of the power output amp.