Illinois makes some nice yellow caps for short cash...
Eico HF-81 Help?
- Thread starter wncwalker
- Start date
Dmannnnn
Up Late
I used the Russian K40y PIO caps in mine. Once you factor in shipping I think I paid around $1.60 a piece (I usually buy em by the dozen). Most of the larger overseas sellers will have them to your door in a week. Sprague orange drops or xicon films would also be fine.
Here is a picture of the installation. You will want to heatshrink them as they have metal bodies.
Here is a picture of the installation. You will want to heatshrink them as they have metal bodies.
wncwalker
New Member
I have 9 disk shaped caps labeled "sprague .02 @ 20% Z5R. There are 4 axials (PIO I think) labeled "Pyramid imp .1uf 400V 10%". Two axial caps that are wax covered labeled ".25uf 200V" and 2 axial caps connected to the output tubes that say "Cosmic Elecrtolitic 50uf 25v japan" and tons of carbon comp resistors which I guess I can assume have drifted.
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Looking at his pic, he replaced all of the ceramic caps in his amp.
Looks like he used silver mica to replace the small ones and the Russian
caps for the larger ones. He probable could have reused the ceramics
but decided to upgrade.
Dmannnnn
Up Late
The two wax caps are in the phono preamp. Those should be replaced.
The pyramids may or may not be good. Like I said, if you don't have a way to test them for leakage, you should probably just replace them.
The two 50uf electrolytics are part of the bias network for the power tubes. Replace them. No need for anything fancy, plain electrolytics are fine.
I guess the ceramic disk caps don't usually go bad. You can leave them in and listen to the amp with them. See how it sounds. You can always replace them with something else later.
There are also a couple of small electrolytics on the phono preamp tubes. You might want to replace those as well.
Don't forget that new can cap on top.
It can get pretty tedious desoldering resistors and checking everything. Just take your time. Sometimes when the carbon resistors get to much heat from soldering they can drift and not come back down. I'd take out all the caps first then start checking the resistors. They usually recommend changing them if they are 10% or more out of spec. I tore everything out and started from scratch, so I didn't check all of mine.
I can't tell if you did or not, but you should use a ring terminal on that new ground wire. Crimp it then solder it. Use some steel wool on the chassis where it will attach to the transformer bolt. This will ensure a good connection.
I'm sure we'll hear back from you before then, but once you get all the new parts in, do a resistance check first, then when it gets powered up, do a voltage check. I can scan the manual for this if you don't have one.
Here is a link to the Eico Schematic and one for the Sam's schematic.
The pyramids may or may not be good. Like I said, if you don't have a way to test them for leakage, you should probably just replace them.
The two 50uf electrolytics are part of the bias network for the power tubes. Replace them. No need for anything fancy, plain electrolytics are fine.
I guess the ceramic disk caps don't usually go bad. You can leave them in and listen to the amp with them. See how it sounds. You can always replace them with something else later.
There are also a couple of small electrolytics on the phono preamp tubes. You might want to replace those as well.
Don't forget that new can cap on top.
It can get pretty tedious desoldering resistors and checking everything. Just take your time. Sometimes when the carbon resistors get to much heat from soldering they can drift and not come back down. I'd take out all the caps first then start checking the resistors. They usually recommend changing them if they are 10% or more out of spec. I tore everything out and started from scratch, so I didn't check all of mine.
I can't tell if you did or not, but you should use a ring terminal on that new ground wire. Crimp it then solder it. Use some steel wool on the chassis where it will attach to the transformer bolt. This will ensure a good connection.
I'm sure we'll hear back from you before then, but once you get all the new parts in, do a resistance check first, then when it gets powered up, do a voltage check. I can scan the manual for this if you don't have one.
Here is a link to the Eico Schematic and one for the Sam's schematic.
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wncwalker
New Member
Thank you, especially for putting your suggestions in terms I can understand.
Am I being stupid listening to it at low volume? One amp is at least 50% quieter than the other now which I didn't notice before. I swapped the output tubes from one side to the other with no effect and it happens on phono and line in.
Am I being stupid listening to it at low volume? One amp is at least 50% quieter than the other now which I didn't notice before. I swapped the output tubes from one side to the other with no effect and it happens on phono and line in.
You might try swapping tubes on the other stages as well.
If it still acts the same then you would need to start focusing
on the passive components.
wncwalker
New Member
Is there any reason why I should order a multi-section capacitor and not just the three individual caps? There is room on the chassis and I may be able to save some on shipping since not too many places have a multi-section cap like I need as well as the other capacitors I need to have shipped. Thank you!
