So I just got my Heyboer PS transformer in the mail today, and as I started working on my Eico preparing to remove the stock transformer. My hand slipped and i ended up breaking a lead off a .03 MFD 600V molded capacitor. My question (as a beginner that I am) is, would the molded capacitor be necessary? The reason I ask is because I've looked at other restored/rebuilt HF-81s and noticed that some of them don't have it installed, so is the molded capacitor required for the HF-81 to work?
Eico HF-81 Transformer Help
- Thread starter Eafnb
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- eico hf-81 tube amp
The capacitor is there for a reason.if your amp is a stock hf 81 then it should be there. The other amps you were looking at could of been modified with different pc boards etc.. In which it might no longer be needed.
I see, so in your opinion, should I buy a replacement nos molded capacitor, or go for a coupling or polypropylene capacitor?
No need for a nos cap as it'd probally be leaky But you need to replace it anyways so any newer cap should suffice. I take it your trying to get the amp working as you said you bought a new power transformer.
What is the exact state of the amp? Did you buy it and the power transformer was shot or did it go south when you were using it. More knowlagebale people here on ak can help guide you on getting it back into shape but we need more information.
What is the exact state of the amp? Did you buy it and the power transformer was shot or did it go south when you were using it. More knowlagebale people here on ak can help guide you on getting it back into shape but we need more information.
I was about to ask where it was located as wellIs this the disc capacitor connected from the line to the chassis? Pics would be cool!
It was connected to the power transformer center tap (I believe) to ground. This is what the capacitor looks like.Is this the disc capacitor connected from the line to the chassis? Pics would be cool!
It's more of an upgrade to be honest. I'd rather change the transformer now than later and not having to worry about it. I'll still keep the stock transformer in case something goes wrong. The amp was rebuilt, but the way it was shipped was poor. When I got it in the mail, the fuse holder broke and the area where the fuse holder would be was bent. I changed out the fuse holder for one I found recently, but you could see the bend that was caused from poor shipping.
Apologies for the delayed response by the way.
primosounds
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There is no cap from the PT center tap to ground but there is a .03 uf cap from the AC line input to ground. This is the so called "death cap" which should be changed to a modern X1/Y2 or is x2/y1??? safety cap. The cap helps to reduce the noise in the AC line but fails in the open position so that no AC will be on the chassis which of course would be a shock hazard.
Oh, so all i need is a .03uf 600v x1/y2 or x2/y1 safety cap? Does it matter which one I pick?
primosounds
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It doesn't matter which one you choose. They are all pretty much the same , ceramic disc cap. Their use might be required by codes.
What do you mean by codes?
So if I were to not install the death cap, should I at least install a 3 prong power plug to ground the circuit?
Safety regulations today require ground leakage current to be less than 0.7 mA. That's the current passing through YOU if you touch the amp chassis and a water pipe, for example. For this reason, line-to-chassis capacitor should be .015 uF or less (use a .01 if you can't find .015), and it must have the 'Y' rating. (I don't use any 'Y' cap when I install a 3-wire cord).
It seems like it's simpler (and safer) to just install a 3-wire cord rather than just installing a safety/death cap.
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primosounds
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Electrical codes that manufacturers have to abide with. Anything electrical sold in the USA needs certain safety requirements or it will be in violation of the law.
This is what I used ( no affiliation) in my HF-81, scroll down the center column to the Y2 safety cap 0.033 uF 250v...bummer tho there's a $20 minimum order but you get the idea.
https://www.justradios.com/cart.html
https://www.justradios.com/cart.html
Good to know, thanks!
Gotcha, but why 250v instead of 600v like the original cap?
primosounds
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that is 250VAC.
