My New Early Model PL400 w/ 4 Fin Heat Sink

[laatsch55]

In the standard cap configuration you have a plus and a minus grounded to the chassis....

 

[VSAT88]

Like Lee said. I went part for part and checked it twice and ordered all nichion muse caps for the main board. Perhaps I did not need muse caps in every position but why not if they are easy enough to find. When I first put my MFC's in I checked that continuity thing with my meter and was baffled as to why I read a dead short from the caps to the chassis. I knew after checking, re checking, photographs, documentation and thru the guys here that it was right so I just went on with the show. I did not want to ask why and how this was and be embarrassed any more than I already was. I thought I knew a little bit about electronics and now I have found that I know less than I thought .

 

[laatsch55]

Punch. You cannot have the negative terminal of each cap grounded. One minus and one plus is supposed tobegrounded as the caps are seriesed notparalleled

 

[punchback]

Punch. You cannot have the negative terminal of each cap grounded. One minus and one plus is supposed tobegrounded as the caps are seriesed notparalleled

After looking at the schematic I realized I couldn't use the stud mount caps. If I would have used them the negative rail cap would have been shorted. Not good... I've requested a RMA from Mouser hopefully they allow me to return them. I've identified a 16KuF 100V Kemet that I'll be ordering.

 

[laatsch55]

In the original configuration, the negative rail cap is also to ground, through the positive post. And the positive rail cap is also to ground through the negative terminal...

 

[laatsch55]

.......IOW..

one of those caps would have worked...

 

[jbeckva]

Eyup.. might give ya a ground loop tho. One conx goood.

 

[laatsch55]

Amen...

 

[punchback]

Since I'm going to be placing another Mouser order I figured I'd get replacements for the few electrolytics that are on the, I guess, PL400C board. Based on the actual board each channel has (1) 10 uF/50V, (2) 40uF/15V, and (1) 100uF/10V. I already have a replacement for the 100uF/10V as specified by laatsch55 (470uF/50V).
Alan

You cannot buy a 40uF cap in the Nichicon UFG or UKZ series. Given the choice of 33uF or 47uF, which would be most appropriate?

Alan

 

[VSAT88]

Far as I know going up a uF or so is cool Long as one does not go lower in voltage.

 

[Gepetto]

After looking at the schematic I realized I couldn't use the stud mount caps. If I would have used them the negative rail cap would have been shorted. Not good... I've requested a RMA from Mouser hopefully they allow me to return them. I've identified a 16KuF 100V Kemet that I'll be ordering.

Be warned these Kemets are 2" diameter and will likely run into physical interference inside your amp.

 

[punchback]

The caps that are currently installed are 2"D x 4.2"L Sprague 5900uF 75V. They are up tight against the fuse holders. Other than that there's no clearance issues.

 

[VSAT88]

Nothing some fat washers behind the faceplate cant fix right ?

 

[laatsch55]

Did that myself a few times . Put some 22k/ 100 volters in a 400..

 

[punchback]

I love Mouser's search function. I ended up with the Kemets by searching for a ~2"D x 4"L 100V screw terminal cap. Earlier I was focusing on a 15KuF along with the other details. I've found that you just put a minimal amount of search details and sneak up on the result.

 

[WOPL Sniffer]

This is very entertaining for sure.

 

[WOPL Sniffer]

I love a good plan

 

[punchback]

WOPL Sniffer... Thank you for the support . I know how you feel about putting money into the 400. Everything was going OK until that damn stud mount oversight.

 

[WOPL Sniffer]

These guys here have upgraded a thousand 400's here in these pages. Did you not see what they used for caps?

 

[punchback]

This amp currently has 2"D by 4"L caps installed, as stated before. I really didn't go looking for a cap to use. Based on the date code of 7152 Im sure that's the the cap that's in there from the factory. Why not do what the factory did? I did see the white oak audio solution but I'm not a fan of that look.

I did see that going to a 15K uF or so seemed to be what was typically done. So a 15KuF or so cap that was 2" x 4" seemed to make sense. I'll have the Kemets tomorrow so we'll see if there's any space issues.