[Wolframme]

Hi all. Long time lurker, especially in the Little Dot tube rolling thread. I've been running into a nasty and persistent issue with my Little Dot MKIV SE for a decent bit now, and its frustrating. Its a majorly annoying hum that is very loud in the left channel, but still partially in the right channel.

The hum appears once turning the amp on and gets louder as it heats up.

It doesn't matter if a source is plugged in, it will hum being one of the sole electronic devices running in a room.

The hum gets worse as I turn the volume knob down. Turing it all the way up, the hum is still present but almost eliminated.

What's interesting is that this is almost persistent across different tube families since I've been rolling different tubes - but it gets worse, or better depending on the tube family. But almost across all of them at this point this issue rears its ugly head when the MKIV heats up for a bit, if not immediately.

Hoping that with all my troubleshooting I've done that this can help anyone more experienced than I am come to a solution. It's just disheartening since I really enjoy using this amp.

 

[Wolframme]

I'll go ahead and update my post after finding other things out:

I'd like to point out my mistake not mentioning my gain setting - it was on 10, highest possible.

Second, changing gain settings to the complete opposite, lowest possible, did eliminate hum from MOST tubes I used - those of which I completely expected to be free of hum were, since I used a Little Dot MKII before the MKIV SE with several tubes exhibiting no issues before this amp.

I've read from other threads saying that its possible with higher gain settings in amps that hum could be present, especially with higher impedance headphones (mine being Sennheiser 6xx). But others mention a product like this should have absolutely no hum present regardless of gain setting.

I guess the piece of advice I'm looking for now is if this tube amp is definitely humming by itself, no source, almost exclusively the sole electric device in the room, should I just bother with returning it? Or could this just come down to an expected issue using my Sennheiser 6xx's with it's highest gain setting?