marshall post '84 JCM800 question...Filtering

[skoora]

Ok, so I know on the 2203 in '85 they started using less Cans in the Power section, but did they actually reduce filtering or bump up the values in the remaining cans to be the same filtering as before?

 

[skoora]

techie bump

 

[Greazygeo]

Its been a long while, I think the values were the same but 3 cans in place of 6.

 

[Wizard of Ozz]

1/2 of the pre-1984 models... just minus 3 of the 50 uF cans.

 

[skoora]

1/2 of the pre-1984 models... just minus 3 of the 50 uF cans.

Did they re-wire the remaining three to increase their combined filtering? I forget if series or parallel would achieve this.

 

[JakeAC5253]

1/2 of the pre-1984 models... just minus 3 of the 50 uF cans.

Did they re-wire the remaining three to increase their combined filtering? I forget if series or parallel would achieve this.

Parallel caps have additive capacitance.

 

[Anonymous]

Same filtering, they just used higher voltage caps to make up the same values. A cost cutting mod only. I've seen a lot of the later JCM's with bulging caps. Not good!


The later JCM's used 500VDC cans, but the older used two 350VDC or 400VDC cans in series which can take 700-800 VDC. Much less chance of overheating them or getting damaged because of voltage spikes.

 

[skoora]

Same filtering, they just used higher voltage caps to make up the same values. A cost cutting mod only. I've seen a lot of the later JCM's with bulging caps. Not good!


The later JCM's used 500VDC cans, but the older used two 350VDC or 400VDC cans in series which can take 700-800 VDC. Much less chance of overheating them or getting damaged because of voltage spikes.

Right on, good info.

 

[MrDan666]

Horizontal input models have 100uF mains filtering and 100uF screens, whereas the vertical input models have 50uF mains and 50uF screens. Also the PI doesn't have it's own dedicated filtering on the horizontal models, while it did on the vertical models.