Marshall Power Cap Value Question

[cryptozoo]

In continuation of my "inner-workings-of-an-amp-ignorance series," I have another question for those who are up to the task.

I've got an old '74 Marshall Super Lead 100 watter with a local electronics guy right now to get it back up to fighting form. He works on a lot of my amps, but doesn't particularly know a lot about guitar amps. I just give him a schematic and off he goes.

Anyways, he wrote me yesterday and said that two of the power caps are shot, and the value we need is 200uF / 350v. I looked around on the net last night and have had no luck finding an exact value match for these caps.

Are there caps from Mouser or Metroamp that I could get away with using in place of this value? If so, will it drastically alter the tone from what its intended to be?

[Trout]

In continuation of my "inner-workings-of-an-amp-ignorance series," I have another question for those who are up to the task.

I've got an old '74 Marshall Super Lead 100 watter with a local electronics guy right now to get it back up to fighting form. He works on a lot of my amps, but doesn't particularly know a lot about guitar amps. I just give him a schematic and off he goes.

Anyways, he wrote me yesterday and said that two of the power caps are shot, and the value we need is 200uF / 350v. I looked around on the net last night and have had no luck finding an exact value match for these caps.

Are there caps from Mouser or Metroamp that I could get away with using in place of this value? If so, will it drastically alter the tone from what its intended to be?


I am far from a Marshall expert, but I did restore a 1973 super lead 100W recently, I do not recall ever seeing a 200UF 350V power supply cap in it.
There were 6 power supply caps in mine and they were all dual section can style caps. You might want to give him a call and see what he is doing for sure.
The Can caps are easy to get.

[John Phillips]

The value for the first four caps (two pairs) is 100uF. If it has 200s they may be old replacements... although I think I remember seeing one with them that might have been original a long time ago.

The old amps usually used actual 100uF 350V caps, but you can use modern 50uF+50uF 450V or 500V caps instead, with the two halves paralleled. These are the same type you need for the remaining two caps, and you should replace all six at once, not mess about changing just the failed ones... the others won't be far behind.

[cryptozoo]

Cool, thanks for the info again, guys. I'll pass it along to him and see what we can come up with.