[iammikeDOTorg]

Just noticed this today. Even with my source disconnected, I'm getting a VERY faint ringing/high pitched whistle out of my Little Dot MKIII.

I'm hearing it in all my headphones so it's unrelated to them.

Source is USB->USB DAC->MKIII.

Drivers are Russian 0TK7s and powers are Russian 6H6P-Is. Have a handful of spare tubes I can pop in... just tell me where to start...

Edit: Swapped in my Mullard 6065 drivers and the noise seems to be gone. What's this mean? OTK7s are done for? I've never end-of-life'd a tube... I don't know what to be looking for.

TIA!

 

[Trapper32]

Sounds like they might be microphonic...you could try tube dampners. Do you have any wireless transmitters nearby?? They can pick up interference from routers etc..

 

[iammikeDOTorg]

Ah... Microphonic = picking up small vibrations from the environment and amplifying them? I could TOTALLY see that being the cause. Also, tons of wireless stuff around them.