Aguilar DB359 Question

Hi,

When you flip the standby switch to on, give it a nudge or light pull to the right on the way up. Sometimes the standby switch gets dirty and needs to have contact cleaner applied, but try this first to see if the switch is at fault. Worked like a charm on mine, and I was having exactly the same problem.

If this works, you need to either clean or replace the switch.

 

There is a pico fuse inside the unit, that can go bad and will eventually need to be replaced. This fuse is inside the unit and needs to be soldered. Check the glow on each tube. If a tube is going bad, the glow will be different. Also, check the biasing on the tubes. It may need to be rebiased. I don't remember the settings, but call Aguilar and they will help you

 

Hey Guys,

In the older units there is an internal pico fuse. If a power tube is not working properly, the fuse may short and a new fuse will need to be installed. However, the fuse itself doesn't go bad, and will be fine unless it's called upon to protect the circuit. It's basically a back-up protection system. If it does pop, no sound will come out of the amp until the fuse is replaced. In the later DB 359's we designed a "smart card", which could be reset.

IME, it's pretty hard to tell from the glow of a tube much about how they are working-unless there is an obvious hot spot.
I vote for having a tech test the tubes. You could easily have a tube that needs to be replaced. Checking the bias is a great idea to do in any case. Jot us a note at [email protected] for instructions.

Hope this helps.

Happy New Year!

Dave B.

 

I had a very similar issue with mine a few weeks ago - sounded like almost the exact same problem. I took it into the shop and all it was was a ground connection that had gone bad and needed to be replaced/re-connected (only charge was the bench fee). You might want to check that out prior to spending the $$ on new tubes.

 

Your preamp tubes could be going. Take off the top lid and tap on each one. In particular, check the 12AU7. (It has a cover on it, so take that off first.) I've had the scratchy problem too, but replacing preamp tubes fixed it right up.