diytube.com

Well, I must say, it sounds excellent when turned all the way up and connected to my Mac with a 1/8" to RCA.
Incredible, really.

I have something going on though, there is a pretty audible buzz in between everything but the lowest and the highest range of the gain knob.
Identical in both channels, so it is not a left right deal.

I used 12 volt AC for the heaters, Tom never has any problem with that.

I went through with and pushed on connections, moved groups of wires (with a plastic probe that I have), I was not able to make a single difference in the sound?

I don't have any deoxit, but I am using an old spare 100k pot, I guess it could be that, but I dunno. I have never had a Darling hum, ever.

Let me know what you think. I am stoked to get this finished, the sound quality on full gain is really good.

Ya, it is a 60hz hum, I have something going on with shielding or placement.
Still confused as to why it is quiet at the top of the gain. I listened to some 60 an 120 hum sound in the interwebs. lol

Do you have a center tap on the filament grounded?. (virtual or actual)

That was it! Thanks so much. Grounded the center tap, not a whisper out of this thing.......