DSL20HR White noise problem

[BakedBeans]

Client brought me a DSL20HR head that exhibits a weird issue. After allowing the amp to warm up, I flip the standby switch to the full power position and there is a VERY loud white noise immediately, but it fades away in about 3-4 seconds. This noise happens even with the output volumes on zero. Switching from standby to low power, this doesn't happen. After the noise fades away, the amp seems to function fine. If I boot up from cold to full power with using the standby, I hear a few slight crackle/pops that quickly fade without the white noise hash. Amp appears to be virgin, having never been worked on. All original radial capacitors. Any ideas? Is this a known issue with these amps? I have not yet check key point voltages yet.

 

[thesunship]

May be the same issue here

Rushing water noise as the amp comes on from standby

When I turn my amp on and let it heat up on standby then flip it on, there is a pause then a rushing water noise for about 3-5 seconds then it fades. The amp is a little noisey but not horrible once that goes away. It fades to some background hiss. Before I start poking through things I figured...

www.marshallforum.com

 

[fitz]

Client brought me a DSL20HR head that exhibits a weird issue. After allowing the amp to warm up, I flip the standby switch to the full power position and there is a VERY loud white noise immediately, but it fades away in about 3-4 seconds. This noise happens even with the output volumes on zero. Switching from standby to low power, this doesn't happen. After the noise fades away, the amp seems to function fine. If I boot up from cold to full power with using the standby, I hear a few slight crackle/pops that quickly fade without the white noise hash. Amp appears to be virgin, having never been worked on. All original radial capacitors. Any ideas? Is this a known issue with these amps? I have not yet check key point voltages yet.

Lots of noise issues have been reported with the DSL20.
Mine was dead quiet when I first got it, but started to develop the "hiss" after a few years.
I didn't have the coming off standby noise that faded - just a constant background noise that was getting louder.
The problem went away when I sold it.

 

[BakedBeans]

Lots of noise issues have been reported with the DSL20.
Mine was dead quiet when I first got it, but started to develop the "hiss" after a few years.
I didn't have the coming off standby noise that faded - just a constant background noise that was getting louder.
The problem went away when I sold it.

"...when I sold it." Pretty funny!