I have a D150 that I bought in late 1970s.
I had amp refurbished in 1981 by Remcron (in Canada) and upgraded to D150A with IOC added and the gain pots moved to front with new faceplate.
I haven't used this amp for about 6 years. It is boxed and stored. I was considering setting it up again as small system in the den.
I have noticed that shortly after amp is powered off, there is a low frequency thump heard on both channels.
Is this normal? Is there a fix for it?
My main system includes a pair of DC300A-II, each running bridged mono mode.
D150 power off thump
1 reply to this topic
Posted 16 August 2005 - 12:27 PM
It could be the plus and minus 10 volt power supplies are bleeding off non-symmetrically. Using an Oscilloscope it will need to be determined which supply is bleeding off the fastest. Starting with a 2.2 electrolytic capacitor add capacitance across to the faster side until you can get that side bleeding off as close as possible to the other.