advice please (smoothin caps)

I'm more of a guitar tech than an amp man so if someone could help me out and let me know if its possible to replace smoothing caps with a slightly lower voltage than those factory fitted. My friend needs his H/H bass machine(250w@4ohms) fixing and I'm finding it difficult to obtain 4700uF @ 70 v.d.c. caps. I can get the farrads o.k. at 63v or go much higher on the farrds on a higher voltage. As its so much more expensive to get the higher rating I'd like to get the cheaper lower voltage, however I dont know how that would affect the ripple(raspberry?). Go on, help a lowly fetling guitar tech out all you experts. Thanks in advance, Peg.

Posted by Peg (chorltonguitars@ntlworld.com) on 11/06/2004, at 14:26 GMT

Capacitor voltages

If the original capacitors were rated 7OV DC it is OK to replace them with ones rated 67V. The 3V difference is too small to matter in this case. Be sure to connect them the correct way round - reversed electrolytic capacitors can explode!

Posted by John Hewes on 11/06/2004, at 15:35 GMT

Thanks John

Thanks John, I'm taking it that means that 63v caps(7v under) is to much. Sorry if I'm being a bit slow but I can gat these really easily & cheaply. If you do have time to clarify that I'd really apreciate it. thanks again. By the way I have actually fitted an electro cap in reverse before(years ago when I was a kid). White stuff everywhere, great noise though. Thanks for the reminder.

Posted by Peg (chorltonguitars@ntlworld.com) on 11/06/2004, at 16:57 GMT

63V is OK

63V capacitors are OK. Sorry about that, silly mistake by me, I muddled the 3 and 7! The 7V difference (10%) is not large enough to be a problem.

Posted by John Hewes on 14/06/2004, at 13:47 GMT

Good news.

Thanks alot for that John. This will make someone very happy in his pocket.

Posted by Peg. on 14/06/2004, at 16:34 GMT