stevem Messages: 4735 Registered: June 2004 Location: NY
Senior Member
These amps want a 4 ohm speaker load to produce there full 125watts of clean output,
Is your 18" speaker the original?
In terms of volume and clean punch the amp May need to have its two main power supply filters replaced, especially if the amp has sat for long periods without being powered up.
When the mod is done to add a grounded power cable all that needs to done is to cut the death cap lead off at the switch and bolt down the ground wire from the new power cable to the chassis.
This assumes that the hot and neutral of the new cable are hooked up right, as in white to white and black to black
Why you got the shock would lead me to think that one of the two amps is not grounded right, or the outlet one of them was plugged into was not grounded .
stevem Messages: 4735 Registered: June 2004 Location: NY
Senior Member
In 72 due to complaints from guitar player a circuit change was put in place on the 250 and 150 amps to provide more gain.
This worked great for the guitar player, but I find that for bass I like the pre 72 non mod better , there more dynamic range for bass use and as such less chance of driving the amp into clipping
If you have one of these amps it's all of 5 bucks worth of parts to put it back to it original production form.
Another thing that helps when you have a active bass with hot output is to run the volume on the bass down to 3/4s or less and turn the amp up more.