[terrylett]

Hello gurus. I recently picked up a Hippo on ebay for $10.50 probably because the case was in multiple pieces. I had a spare case in fine condition so I jumped on the sale. I recapped and decided to put new resistors in as well. After I cleaned everything up and powered it on it works fine. It gets multiple stations, the tuner cap moves freely and the volume control is not scratchy at all.

The only issue I have is that there is a slight 60 cycle hum after the tubes heat up. The hum doesn't get louder when the volume is increased but it is a little irritating. You can hear it in the background when you are on a station too.

I thought maybe I had some leakage in a tube (concentrating first on the 50L6) but I swapped out 13 50L6s, over 20 35Z5s and about 8-10 of the 7C6s, 7B7s, 7C7s and 7A8s. I would have trouble accepting that I have a tube issue.

All the replaced cap values are what is in the schematic and parts list except a couple of .05 mf were replaced with .047. I think also a couple of replaced caps were 400V instead of the original 200V caps. The electrolytics are brand new 20mf and my solder points are clean and shiny (I made sure my connections were good - especially to B-).

What I am wondering now is if it would be worth replacing any cap or caps with a lower value as I read in the past that that can reduce or eliminate hum.

Any suggestions?

Also would it be a hum reduction to install a Y2 safety cap? I guess on the neutral line.

Thanks in advance.