2:90 Crap

[sinfish]

Hi Guys,

I have a 2:90 amp that is making noise just when it starts and is cold crackling and popping. Also the 1/2 drive light stays on for about a minute and I cannot turn it off. My question: Is the 1/2 drive on thing part of it's design? Is it telling me the tubes are not warm yet? Or is what I suspect true and there is some sort of short in the 1/2 drive?

Also is it common to have some hum when both Bass and modern switches are active?

I just had this retubed and an LED replaced. I noticed the 1/2 drive thing after the LED started working again.

Thanks

 

[TOOLGUY]

My 2:90 does not do that (the 1/2 drive led thing and all of my leds work). I power up in standby mode and have not heard any pops or cracks. I am having a problem with the "a" channel droppout out though.

 

[desertdweller]

Nah it shouldn't be doing that, there's a problem in there somewhere.

As for hum, my 2:90 has a faint hum when Deep is engaged, but as I roll the volume pots up it goes away at about 80-90% power where it's totally dead silent. At 50-60% power, where I usually play the amp, it has a slight hum (and I do mean very slight), but nothing that would come across in a recording or when playing. Just normal tube amp hum.

 

[mr_fender]

The intermittent crackling usually means something is getting a poor connection in the signal path. It could be a dirty pot, jack, or tube socket. It could also be a loose pin contact in one of the tube sockets. It could also be a cold or bad solder joint somewhere. These kind of things can be very frustrating to track down.