[monsterbill]

My Almarro A205A amp just started emitted a loud feedback sounding noise from both channels.  It makes the same noise whether I'm playing through headphones or speakers, and it's coming from both channels.  Swapping the tubes made no difference, nor does changing the source.  It only makes the sound when warmed up.  Deafening, even when the volume is turned all the way down. 

What could it be?  Transformer? Anyone know where I could take it for a repair in the SF Bay Area?

Thanks!

[JohnR]

When you say it only does it when warmed up, how long is that after turning it on?

[monsterbill]

A few minutes.  It sounds just like when you hold a microphone too close to a speaker.

[wilsynet]

L&M Electronics in Daly City has been in business a long time and has broad experience with both tube and solid state gear.

[JohnR]

It sounds like some sort of feedback. I recently repaired an amp that did something similar and it was due to dried-up power supply caps. I gather this is a fairly recent amp so that seems unlikely but still, I'd suspect the power supply. It could also be something like a bad earth connection - given that it does the same in both channels, again the power supply seems like the first place to look.