Tube Ampp Almarro low level hum

It sounds like it could be some transformer hum since it goes away when you touch the amp on occasion. Not guaranteed to be the answer, but you might try tightening down the transformer bolts and or putting a dense heavy object on top of the transformers. You don't need any magic pebbles or crap like that, just a brick would do(doesn't have to be "magic" either), though not very pretty to look at. Place felt or rubber pads between the heavy object and transformer to keep from scratching it (beware that rubber may melt if those trannies get hot - use felt in that case). Use whatever you might have on hand and see if it improves and if it works you can look for something that floats your boat to put on there. Mapleshade makes brass "HeavyWeights" that they charge a bit for or you can go to a scrap yard and find some scrap brass or?

Good luck!

Jax2 - good thinking. If it is a transformer, is it humming because it is aging? Malfunctioning? Or is that just how transformers are? Can I address the source of the problem or just deal with the symptom? Thanks for your comment.

sometimes transformer hum can (as Jax2 said) just be the result of loose mounting bolts, sometimes not. Sometimes its just how that particular tranny is. Toroidal trannys are often less susceptible. One other cause sometimes is DC offset, IIRC.