Falcon Deluxe mod 500 G.R. All Transistor buzzing noise

[kaio-ken]

Hello everyone,

I recently came across an old amp, the Falcon Deluxe mod 500 G.R. All Transistor. When I turn up the volume, there's a strong buzzing noise. Other than that, I can still play through the amp. I know these are limited details, but perhaps someone has an idea of what might be causing this.
My video shows the problem.
https://youtu.be/mFx7VJUvYu0?feature=shared



Upon powering on, I hear a humming sound. It's approximately 50 Hz. The power grid is at 230V and 50Hz (there might be a correlation, but I'm not certain).


Unfortunately, in my area, there's no one who repairs transistor amps, only tube amps

Thanks for your help.

Cheers

Kaio-Ken

[GuitarBilly]

Honestly, this doesn't sound out of line for an older amp. Some buzz/hiss is normal when the amp is turned up to loud volumes. Your pots are scratchy so I'd start by cleaning all the pots and jacks with contact cleaner. That could be enough to lower the hiss. The next thing to look at would be the grounding. A lot of the older amps didn't have a properly ground power cable and changing it to modern, properly grounded cable does reduce the buzz. Does you power cable has 2 or 3 prongs?

Other than that, I don't think your amp is defective. Try to do a thorough cleaning first. Here in the US we use DeOxit but you might have something different where you're at. The important thing is to use proper contact cleaner and not lubricants like WD-40 etc...

For the pots, you can spray down the shaft and give it several twists until the scratchy noise disappears. For the jacks, spray the cleaner on a plug and go in/out of the jack several times fast. You can have the amp while you do this. It's actually a good idea so you can hear the difference. There is no need to pull the amp off the chassis either.

[kaio-ken]

thank you! I'll try it out

[kaio-ken]

Someone suggested trying quieter preamp transistors (BC149 or BC109) according to the schematic. (I found the schematic online.)
What do you think?

[GuitarBilly]

Maybe down the line. You should rule out the simple stuff first with some basic maintenance.

Look at cleaning, grounding, wiring. That stuff needs to be ruled out first.

For example, if your windows were foggy, what would you try first? Cleaning it or replacing the glass?

With troubleshooting, you start simple and go outwards.