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Sherwood S-5500 Restorations

Noticed wireing is solid as opposed to braided. Any issue in using braided or should I use solid? Advantages and disadvantages of each? I typically think that braided is good for flexibility and in higher frequencies where skin effect might be an issue. Solid for DC. Thoughts?
 
Solid stays put better and can be easier to deal with looping through terminals. If stranded is all you have, that will work though. None of what you're moving around is anything but DC or 60hz ac heater so skin effect isn't an issue either. If you have any old lamp ballast wire, that works pretty good for this. Its slightly heavier gauge than original but not so bad that its an issue. Its also high voltage and high temperature insulation, which is more useful.
 
rolleiman said:
. . . remove the cans and re-stuff or install on the bottom? What caps did you end up going with?
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daveyh said:
Just sprang for a new multicap can since it was easier from CE.
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A replacement can is certainly easier but the cost is much higher and the quality is lower than using individual caps mounted below deck. In this particular amp, there is plenty of space to work with too. I just leave the original can in place for looks, disconnected of course. I've never tried to restuff cans.

Here's some comments I made about this in a post last year - different cap values since it related to a different amp but the general comparison is still valid:

I'd suggest using caps rated at 105 degrees for 10,000 hours. Can caps are generally rated at only 85 degrees and sometimes less.

Replacing the cans is also a much more expensive option.

A CE can with four 20uf sections, sells for $36.70 plus shipping at Antique. Its heat rating is only 55 degrees, no hour rating listed and tolerance as much as +50%. Shipping costs for small orders can get expensive.

The cost of four individual Nichicons (22uf 450v) is $1.13 each for a total of $4.52. They are rated at 105 degrees for 10,000 hours and have a 20% tolerance. And, if ordered from Digi-Key, there's the free shipping option. Here's how you can get free shipping:

http://www.audiokarma.org/forums/in...hipping-on-parts-orders.739513/#post-10018562

So the CE can will likely cost about 10 times the price when shipping is factored in.

You can get custom made cans from someplace like Hayseed that use caps with the better specs but they are even more expensive than the CE cans. But, if limited space prevents you from using individual caps, the Hayseed caps are the way to go since the specs are better.
 
- About to order capacitors that I need. decided to put under chassis. Taking some time since schematic does not match what is actually in amp.
- I am having issues finding a source for a non-polar plug to use with flat two wire SPT1 cord, 18 gauge. Would be ice to be able to just purchase cord attached to a plug. Any idea where I can source a plug?
 
rolleiman said:
- About to order capacitors that I need. decided to put under chassis. Taking some time since schematic does not match what is actually in amp.
- I am having issues finding a source for a non-polar plug to use with flat two wire SPT1 cord, 18 gauge. Would be ice to be able to just purchase cord attached to a plug. Any idea where I can source a plug?
Click to expand...
Why not put a polarized plug in?
 
Hardware stores usually have common non-polarized plugs but I don't know a source for a cord with a molded non-polar plug. They are much easier to find with polarized plugs. Honestly a polarized cord is not a bad idea and it won't hurt anything. Run the hot side to the fuse and switch, neutral to the transformer.
 
rolleiman said:
- I am having issues finding a source for a non-polar plug to use with flat two wire SPT1 cord, 18 gauge. Would be ice to be able to just purchase cord attached to a plug. Any idea where I can source a plug?
Click to expand...

A polarized plug is a good idea as mentioned above. If you want a molded on plug, just buy an appropriate extension cord and cut off the socket end.
John
 
When I rebuilt my 5500 I had to replace all of the filament wiring for the output tubes, had the same issue as yours. Green corrosion and missing insulation, seller said it worked fine. Just lucky I guess.
Now that it is done it is one of my favorite amps.

Greg
 
gadget73 said:
Hardware stores usually have common non-polarized plugs but I don't know a source for a cord with a molded non-polar plug. They are much easier to find with polarized plugs. Honestly a polarized cord is not a bad idea and it won't hurt anything. Run the hot side to the fuse and switch, neutral to the transformer.
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Thanks. Not essential that I have molded plug and perhaps not much gained in being able to reverse the plug. Is the hot side the wide or narrow blade of the plug? I would like to keep with flat 18 gauge wire to use standard grommet a member provided me with so I do not have to alter the chassis.
 
GregBilodeau said:
When I rebuilt my 5500 I had to replace all of the filament wiring for the output tubes, had the same issue as yours. Green corrosion and missing insulation, seller said it worked fine. Just lucky I guess.
Now that it is done it is one of my favorite amps.

Greg
Click to expand...
Glad you are enjoying the unit. It was a pain replacing the wire. I only have 18 gauge stranded. Wish I could find 18 gauge 600volt solid wire in 5 or 6 different colors in small quantities. Do not need much but places I checked required purchasing minimum of 25 feet or more of each color.
What other mods did you make? Is yours an S-5500 II model?
 
I'm interested in your project as I recently got one of these too. It will be a while before I'm ready to work on it but I'm still going to enjoy watching.
John
 
the reason you can reduce noise by flipping the plug is you are connecting the chassis to the neutral side rather than the hot. There is a resistor or a cap, forget which, going from one side of the power line to chassis. If you use a polarized cord and ensure that cap or resistor is always on the neutral side, it will be quiet.
 
rolleiman said:
Glad you are enjoying the unit. It was a pain replacing the wire. I only have 18 gauge stranded. Wish I could find 18 gauge 600volt solid wire in 5 or 6 different colors in small quantities. Do not need much but places I checked required purchasing minimum of 25 feet or more of each color.
What other mods did you make? Is yours an S-5500 II model?
Click to expand...

Mine is the S5500 and I made no mods. I re-stuffed the cans, replaced all paper caps and most of the resistors. I like them as original to design as possible.

Gregb
 
Hi team,
Ordered some caps and wire today hopefully back at the amp this weekend.
Thoughts on replacing the 0.068 dog bone coupling caps that are in the signal path going to the output stage. Should the be replaced with polypropylene?
 
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rolleiman said:
Thoughts on replacing the 0.068 dog bone coupling caps that are in the signal path going to the output stage. Should the be replaced with polypropylene?
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Originals are mylar, which is a polyester film. Honestly they are probably just fine. I've not had a bad cap of this type. I ran a set through a dishwasher just to see what would happen. On the bottom rack they lose the print but thats about it.
 
gadget73 said:
Originals are mylar, which is a polyester film. Honestly they are probably just fine. I've not had a bad cap of this type. I ran a set through a dishwasher just to see what would happen. On the bottom rack they lose the print but thats about it.
Click to expand...
It looks like one or two Mylar coupling capacitors are outside of the tolerance so will probably replace all 4 with polypropylene since I have to replace. Digikey has a few .068uF, 600+ Volt polypropylene caps.Nichicon, Kermit, Panasonic and CDE orange drop. Quit a price difference. I will buy extras and match 4. Any brand I should avoid? Any preference?
 
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