CHAMP ELECTRONICS -" THE VINTAGE VALVE
SERVICING A CARLSBRO CS60 REVERB Mk I PA AMPLIFIER
Though I keep saying it, I have never yet found one Carlsbro amp that doesn't do what it is supposed to...and more! This is the second series Mk1's of this style
of PA Head. It featured four inputs but with a communal tone circuit. Also notice the lack of a treble control.....just a presence! The tone-stack is actually incorporated across two sections of an ECC83 (12AX7) and is done in a kind-of active fashion using feedback within the circuit across the two tube sections. [Please see the previous article of a rare 40 watt first series version of this amp but with a GZ34 instead of solid-state rectification].
This actual amp had already had a fair bit of previous work carried out, and most of it had been done fine.
A bias pot had been added to the fixed bias supply.
Spot the little light-blue 2.2uf cap roughly in the middle of the photo........replaced but the wrong way around!! Also the Vero-board with the hand-wired solid-state components for the reverb send & return. This board is powered from the main HT supply through a 25k, 10 watt wire-wound resistor.
You can see that little cap a bit better in this
photo. I did replace it, and put it in the correct way around too. I also changed a few other bits.
Not the original back panel, but hell......who cares......yet another nice Carlsbro amp!